Azure Identity & Access Managemen

Introduction

As we know Microsoft Azure Cloud platform works seamlessly with Azure Active Directory (AAD).

The following products are three of many cloud-based Microsoft products.

As demonstrated below each of them has its own RBAC. But only AAD manages the identities and the Azure Subscription & Azure DevOps and also the other products which can use ADD use the AAD’s identities.

We see that the users/identities are managed via AAD and products which can connect to ADD can profit from centralized identity management. AAD supports the single common digital identity. It means a user/identity must not have a separate identity to work with different services or products.

Note
To keep this post simple I considered a user as an identity.

Identity is actually more than a user. It can be an identity of a user, or an identity of a service.

Identity protection in AAD

When having a single identity which is a great idea for identity management especially when you are talking about it at an enterprise scale, the security and protection of the identity are getting more important. An identity breach can cause unexpected and unimaginable consequences. Such as provisioning expensive resources on subscription, deleting a Repo, or a Project in DevOps.

For such breaches/compromises, there are different solutions. The easiest and quickest one is activating Multi-Factor Authentication (MFA) for the whole AAD. It means all the users that are managed with ADD must sign in with MFA.

How to activate MFA? watch the answer in this video.

Note
I recommend having a comprehensive concept for activating MFA in huge projects or at an enterprise scale.

It doesn’t matter which cloud provider you are using never forget identity security and protection.

After activating MFA in this way the user has to log in to all the services, which are connected to this AAD, with MFA. MFA means using not only the username and password method but also a second authentication factor to identify who the user is.

Clouds : Shared responsibility model

In doesn’t make difference which cloud vendor you have chosen as the platform. All of them follow the shared responsibility model.

What does it mean?

It means the cloud provider has the security responsibility of the cloud and cloud customer has the security responsibility in the cloud.

AzureAWSGCPIBM
Shared responsibility modelShared responsibility modelShared responsibility modelShared responsibility model
[Source]

What is customer responsible for?

  • Configure the access to the resources e.g. servers
  • Responsible for operating system hardening of the servers
  • Ensure the disk volume has been encrypted
  • Determine the identity and access permissions of specific resources
  • ooo

Who should take care of security?

In companies where they up and run services/application on the cloud, the responsible teams have to have enough knowledge about the security on the cloud.

Developers
and Enterprise architect
Ensure cloud services they use are designed and deployed with security.
DevOps
and SRE Teams
Ensure security introduced into the infrastructure build pipeline and the environments remain secure post-production.
InfoSec TeamSecure systems

In which step of the project the security have to be applied?

Develop containerized microservices in VS

Let’s have fun with developing a sample together

Related topics

Containerize project

It’s really simple to containerize your projects specially when you have api project.

Change controller route in containerized microservices project


You owe your dreams your courage.

Koleka Putuma


Onboarding : Azure API Performance and secure backend

Topices

  • Key concepts
    • API Management Components
  • Improve performance by API Management caching
  • Configure caching policy in API Management
  • Caching possibilities
  • Authentication possibilities
  • Expose multiple Azure Function apps as a consistent
  • Azure Front Door

Related topices

Key concepts

  • Azure API Management
  • API
  • API definition
  • API Gateway (APIM component)
    • Accepts API calls and routes them to the backend.
    • Verifies API keys, JWT tokens, certificates, and other credentials.
    • Enforces usage quotas and rate limits.
    • Transforms your API on the fly without code modifications.
    • Caches backend responses where set up.
    • Logs call metadata for analytics purposes.
  • Cache
  • Policies
  • Redis cache
  • Front Door
API Management Components
API gateway

The API gateway is the endpoint that:

  • Accepts API calls and routes them to the backend.
  • Verifies API keys, JWT tokens, certificates, and other credentials.
  • Enforces usage quotas and rate limits.
  • Transforms your API on the fly without code modifications.
  • Caches backend responses where set up.
  • Logs call metadata for analytics purposes.
Azure portal

The Azure portal is the administrative interface where you set up your API program. You can also use it to:

  • Define or import API schema.
  • Package APIs into products.
  • Set up policies such as quotas or transformations on the APIs.
  • Get insights from analytics.
  • Manage users.
Developer portal

The Developer portal serves as the main web presence for developers. From here they can:

  • Read API documentation.
  • Try out an API via the interactive console.
  • Create an account and subscribe to get API keys.
  • Access analytics on their own usage.

Source: https://docs.microsoft.com/en-us/learn/modules/control-authentication-with-apim/1a-understand-apim

Improve performance by API Management caching

Scenario: Suppose you are a developer for a board game company. A product line produced by your company has recently become popular. The volume of requests from your retail partners to your inventory API is growing quickly: much faster than the rate that your inventory actually changes. You’d like your API to respond to requests rapidly without incurring load on your API. You use Azure API Management to host your API. You’re considering using an API Management policy to cache compiled responses to requests. 

  • Api management for changing the behaviore of the api without changing the code
    • policy for set limit
    • for changing response format
    • check mandetory headers
    • authenticared caller / enforce security requirements
    • certificate verification
    • has XML format
    • policies section
      • inbount
      • backend
      • outbount
      • on-error
    • policy scopes
      • global
      • api
      • operation
      • product
  • it exposes apis of a company for the api customers
  • it is used for api inventory
<policies>
    <inbound>
        <base />
 # it means first the policy of the higher level is applied
        <check-header name="Authorization" failed-check-httpcode="401" failed-check-error-message="Not authorized" ignore-case="false">
        </check-header>
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
        <base />
        <json-to-xml apply="always" consider-accept-header="false" parse-date="false" />
    </outbound>
    <on-error>
        <base />
    </on-error>
</policies>
  • policies for
    • restricting access e.g. Check Http Header, Limit call rate by subscription, Limit call rate by key, Restrict caller Ips, Policies for Authentication, Cross domain policies, Transformation policies
  • Cross domain policies
    • Cross domain requests are considered a security threat and denied by browsers and APIs
    • Cross-Origin Resource Sharing (CORS), use the CORS policy
    • Some AJAX code, which runs on the browser, uses JSON with padding to make cross-domain calls securely. Use the JSONP policy to permit clients to use this technique
  • Caching policies
    • better performance for caching the compiled responses
  • Advanced policies
    • apply a policy only when the response passes a specific test, use the Control flow policy
    • Use the Forward request policy to forward a request to a backend server
    • To control what happens when an action fails, use the Retry policy
    • The Send one-way request policy can send a request to a URL without waiting for a response
    • If you want to store a value for use in a later calculation or test, use the Set variable policy to persist a value in a named variable

Source : https://docs.microsoft.com/en-us/learn/modules/improve-api-performance-with-apim-caching-policy/1-introduction

Configure caching policy in API Management

  • using a cache of compiled responses
<policies>
    <inbound>
        <base />
        <cache-lookup vary-by-developer="false" vary-by-developer-groups="false" downstream-caching-type="none" must-revalidate="true" caching-type="internal" />
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
        <cache-store duration="60" />
        <base />
    </outbound>
    </on-error>
        <base />
    </on-error>
</policies>
  • store individual values in the cache, instead of a complete response
  • with an identifying key
  • Retrieve the value from the cache by using the cache-lookup-value policy
  • want to remove a value before it expires, use the cache-remove-value policy
<policies>
    <inbound>
        <cache-lookup-value key="12345"
            default-value="$0.00"
            variable-name="boardPrice"
            caching-type="internal" />
        <base />
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
        <cache-store-value key="12345"
            value="$3.60"
            duration="3600"
            caching-type="internal" />
        <base />
    </outbound>
    </on-error>
        <base />
    </on-error>
</policies>
  • we can use vary-by tags/attributes in cache-lookup-value policy.
    • vary-by-query-parameter (tag): if all users have to see same price/result for a specific product, then we have to set vary-by-query-parameter to partnumber. APIM groups the requests based on partnumber.
    • vary-by-developer (attribute): becase vary-by-developer=”false”, APIM understands that different subscriptions key doesn’t alter the response. if this attribute is true, APIM serves a response from the cache only if it was originally requested with the same subscription key.
    • If a header can make a significant difference to a response, use the <vary-by-header> tag
<policies>
    <inbound>
        <base />
        <cache-lookup vary-by-developer="false" vary-by-developer-groups="false" downstream-caching-type="none" must-revalidate="true" caching-type="internal">
            <vary-by-query-parameter>partnumber</vary-by-query-parameter>
        </cache-lookup>
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
        <cache-store duration="60" />
        <base />
    </outbound>
    </on-error>
        <base />
    </on-error>
</policies>

Source: https://docs.microsoft.com/en-us/learn/modules/improve-api-performance-with-apim-caching-policy/4-configure-a-caching-policy

Caching possibilities

  • Internal Cache -> API Management
  • External Cache -> Azure Cache for Redis service

Why using external cache

  • you want to avoid the cache being cleared when the API Management service is updated.
  • you want to have greater control over the cache configuration than the internal cache allows
  • You want to cache more data than can be store in the internal cache.
  • if you use apim with consumption pricing tier, then you have to use external cache. because this pricing tier follows the serverless designprincipal and we should use it with serverless web apis, and it has no internal cache.

Example:

# Create a Redis cache

Source

Authentication possibilities

  • OAuth 2.0
  • API keys / subscriptions (query string / header parameter)
    • The default header name is Ocp-Apim-Subscription-Key, and the default query string is subscription-key.
  • client certificate

Scenario: Suppose you work for a meteorological company, which has an API that customers use to access weather data for forecasts and research. There is proprietary information in this data, and you would like to ensure that only paying customers have access. You want to use Azure API Management to properly secure this API from unauthorized use.

Scenario: Businesses are extending their operations as a digital platform by creating new channels, finding new customers, and driving deeper engagement with existing ones. APIM provides the core competencies to ensure a successful API program through developer engagement, business insights, analytics, security, and protection. You can use APIM to take any backend and launch a full-fledged API program based on it.

Use Subscription key to secure access to an API

  • Azure api management service helps to expose the apis
  • developers musr subscrib the api / product (these are two different scope)
    • used to secure the api / product with a subscription key / API key
    • preventing denial of service attacks (DoS) by using throttling
    • or using advanced security policies like JSON Web Token (JWT) validation
  • Enabling independent software vendor (ISV) partner ecosystems by offering fast partner onboarding through the developer portal
  • we can define who can access api through the api gateway (only customers who have subscribed to your service can access the API and use your forecast data, by issuing subscription keys)
# how you can pass a key in the request header using curl
curl --header "Ocp-Apim-Subscription-Key: <key string>" https://<apim gateway>.azure-api.net/api/path

# example curl command that passes a key in the URL as a query string
curl https://<apim gateway>.azure-api.net/api/path?subscription-key=<key string>

# If the key is not passed in the header, or as a query string in the URL, you'll get a 401 Access Denied response from the API gateway.

# call without subscription key
curl -X GET https://[Name Of Gateway].azure-api.net/api/Weather/53/-1
# output
{ "statusCode": 401, "message": "Access denied due to missing subscription key. Make sure to include subscription key when making requests to an API." }

# call with subscription key as header
curl -X GET https://[Name Of Gateway].azure-api.net/api/Weather/53/-1 \
  -H 'Ocp-Apim-Subscription-Key: [Subscription Key]'

# output : {"mainOutlook":{"temperature":32,"humidity":34},"wind":{"speed":11,"direction":239.0},"date":"2019-05-16T00:00:00+00:00","latitude":53.0,"longitude":-1.0}

Use client certificates to secure access to an API

  • used to provide TLS mutual authentication between the client and the API gateway
  • allow only requests with certificates containing a specific thumbprint (through inbound policies)
  • TLS client authentication, the API Management gateway can inspect the certificate contained within the client request for the following properties
PropertyReason
Certificate Authority (CA)Only allow certificates signed by a particular CA
ThumbprintAllow certificates containing a specified thumbprint
SubjectOnly allow certificates with a specified subject
Expiration DateOnly allow certificates that have not expired
  • two common ways to verify a certificate
    • Check who issued the certificate. If the issuer was a certificate authority that you trust, you can use the certificate. You can configure the trusted certificate authorities in the Azure portal to automate this process.
    • If the certificate is issued by the partner, verify that it came from them. For example, if they deliver the certificate in person, you can be sure of its authenticity. These are known as self-signed certificates.
  • apim consumption tier
    • this tier is for serverless APIs e.g. azure functions
    • in this tier for using client certificate must explicitly enable it APIM Instance > custom domains > Request Client Certificate: Yes
    • this step is not necessary in other tiers

check thumbnail of a client certificate in policies

# Every client certificate includes a thumbprint, which is a hash, calculated from other certificate properties

<choose>
    <when condition="@(context.Request.Certificate == null || context.Request.Certificate.Thumbprint != "desired-thumbprint")" >
        <return-response>
            <set-status code="403" reason="Invalid client certificate" />
        </return-response>
    </when>
</choose>

Check the thumbprint against certificates uploaded to API Management

n the previous example, only one thumbprint would work so only one certificate would be validated. Usually, each customer or partner company would pass a different certificate with a different thumbprint. To support this scenario, obtain the certificates from your partners and use the Client certificates page in the Azure portal to upload them to the API Management resource. Then add this code to your policy:

<choose>
    <when condition="@(context.Request.Certificate == null || !context.Request.Certificate.Verify()  || !context.Deployment.Certificates.Any(c => c.Value.Thumbprint == context.Request.Certificate.Thumbprint))" >
        <return-response>
            <set-status code="403" reason="Invalid client certificate" />
        </return-response>
    </when>
</choose>

Check the issuer and subject of a client certificate

<choose>
    <when condition="@(context.Request.Certificate == null || context.Request.Certificate.Issuer != "trusted-issuer" || context.Request.Certificate.SubjectName.Name != "expected-subject-name")" >
        <return-response>
            <set-status code="403" reason="Invalid client certificate" />
        </return-response>
    </when>
</choose>
Create Self-Signed Certificate [Source] and use in APIM
# create a private key and certificate
pwd='Pa$$w0rd'
pfxFilePath='selfsigncert.pfx'
openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout privateKey.key -out selfsigncert.crt -subj /CN=localhost

# convert the certificate to PEM format
openssl pkcs12 -export -out $pfxFilePath -inkey privateKey.key -in selfsigncert.crt -password pass:$pwd
openssl pkcs12 -in selfsigncert.pfx -out selfsigncert.pem -nodes

# When you are prompted for a password, type Pa$$w0rd and then press Enter.

# Get the thumbprint for the certificate
Fingerprint="$(openssl x509 -in selfsigncert.pem -noout -fingerprint)"
Fingerprint="${Fingerprint//:}"
echo ${Fingerprint#*=}

# output is hexadecimal string without any accompanying text and no colons
  1. create the self-signed certificate
  2. apim > custom domains > Request client certificates: yes
  3. configure the inbound policy on any scope as follows
<inbound>
    <choose>
        <when condition="@(context.Request.Certificate == null || context.Request.Certificate.Thumbprint != "desired-thumbprint")" >
            <return-response>
                <set-status code="403" reason="Invalid client certificate" />
            </return-response>
        </when>
    </choose>
    <base />
</inbound>

4. call an operation

curl -X GET https://[api-gateway-name].azure-api.net/api/Weather/53/-1 \
  -H 'Ocp-Apim-Subscription-Key: [Subscription Key]'

# output : return a 403 Client certificate error, and no data will be returned.

then test this

curl -X GET https://[gateway-name].azure-api.net/api/Weather/53/-1 \
  -H 'Ocp-Apim-Subscription-Key: [subscription-key]' \
  --cert-type pem \
  --cert selfsigncert.pem

# output: {"mainOutlook":{"temperature":32,"humidity":34},"wind":{"speed":11,"direction":239.0},"date":"2019-05-16T00:00:00+00:00","latitude":53.0,"longitude":-1.0}

Source

Expose multiple Azure Function apps as a consistent API by using APIM

Combine multiple Azure Functions apps into a unified interface by importing them into a single Azure API Management instance.

Scenario: Suppose you work for an online store with a successful and busy web site. Your developers have written the business logic for the site as microservices in the form of Azure Functions. Now, you want to enable partners to interact with your online store from their own code by creating a web API that they can call over HTTP. You want to find an easy way to assemble your functions into a single API.

In your online store, you have implemented each part of the application as a microservice – one for the product details, one for order details, and so on. A separate team manages each microservice and each team uses continuous development and delivery to update and deploy their code on a regular basis. You want to find a way to assemble these microservices into a single product and then manage that product centrally.

  • use Azure Functions and Azure API Management to build complete APIs with a microservices architecture
  • Microservices has become a popular approach to the architecture of distributed applications
  • we can develop distributed systems with serverless architecture e.g. azure function
  • servreless architecture uses stateless computing resources
  • azure function
    • enables serverless architecture
    • we can use NuGet or Node Package Manager (NPM) for development
    • authenticate users with OAuth
    • you can select a template for how you want to trigger your code
clone the functions project,
git clone https://github.com/MicrosoftDocs/mslearn-apim-and-functions.git ~/OnlineStoreFuncs

cd ~/OnlineStoreFuncs
bash setup.sh


after the azure functions are created then we can add them to apim

Source : https://docs.microsoft.com/en-us/learn/modules/build-serverless-api-with-functions-api-management/

Azure Front Door

  • secure entry point for delivering global performant hyperscale apps
  • for application acceleration at microsoft’s edge
  • ooo

Source: https://www.e-apostolidis.gr/microsoft/azure/deliver-your-app-at-global-scale-with-security-resiliency-with-azure-front-doo/


Let the light of your talent lighten your road to success.

Parisa Moosavinezhad


Onboarding : Azure Management Features

Topics

  • Key concepts
  • Azure scopes
  • Policies
  • Role-based access control (RBAC)

Key concepts

  • Azure AD Group
  • Policy
  • Role-based access control

Azure scopes

Azure provides four level of management

  • Level 1 : Management Groups
    • Level 2: Subscriptions
      • Level 3: Resource Groups
        • Level 4 : Resources

Note: lower level inherts setting from the higher level.

Apply the critical settings at higher levels and project specific requirements at lower level.

Policies

The policies are like guard rails. They keep the usage of azure resources in a specific frame and help to accomplish the requirements.

Examples:

  • Allow locations for resources.
  • Allow locations for specific resources.

Role-based access control (RBAC)

The user who manages the role-based access control needs the following roles

  • Microsoft.Authorization/RoleAssignments/* (this role is assigned through Owner or User Access Administrator Role)


You owe your dreams your courage.

Koleka Putuma


Onboarding : Azure Compute

Topics

  • Keywords
  • Manage VM
  • Availability Set
  • Scale Set
  • Snapshot
  • Image
  • Deploy VM from VHD
    • Generalize a server
  • Azure Batch
  • Automate business processes

Related topics

Keywords

  • Virtual Machine (VM)
  • CLI
  • VM
  • Availability Set
  • Scale Set
  • Snapshot (from disk)
  • Image (from vm)
  • Azure Batch: Azure Batch is an Azure service that enables you to run large-scale parallel and high-performance computing (HPC) applications efficiently in the cloud.
  • High-performance computing (HPC)
  • MPI: Message Passing Interface
  • Workflow: Business processes modeled in software are often called workflows.
  • Design-first approach: include user interfaces in which you can draw out the workflow
  • Azure compute: is an on-demand computing service for running cloud-based applications
    • Virtual machines
    • Containers
    • Azure App Service
    • Serverless computing

Source

Manage VM

VM management roles (RBAC)
  • Virtual Machine Contributor
  • Network Contributor
  • Storage Account Contributor

Note: The roles have to be assigned to an Azure AD Group instead of a user

To have a proper management on VMs, different management opptions have to be used

Available VM commands
az vm [subcommands]
Sub-commandDescription
createCreate a new virtual machine
deallocateDeallocate a virtual machine
deleteDelete a virtual machine
listList the created virtual machines in your subscription
open-portOpen a specific network port for inbound traffic
restartRestart a virtual machine
showGet the details for a virtual machine
startStart a stopped virtual machine
stopStop a running virtual machine
updateUpdate a property of a virtual machine
# Create a Linux virtual machine
az vm create \
  --resource-group [sandbox resource group name] \
  --location westus \
  --name SampleVM \
  --image UbuntuLTS \
  --admin-username azureuser \
  --generate-ssh-keys \
  --verbose # Azure CLI tool waits while the VM is being created.
    # Or
  --no-wait # option to tell the Azure CLI tool to return immediately and have Azure continue creating the VM in the background.
  
# output
{
  "fqdns": "",
  "id": "/subscriptions/<subscription-id>/resourceGroups/Learn-2568d0d0-efe3-4d04-a08f-df7f009f822a/providers/Microsoft.Compute/virtualMachines/SampleVM",
  "location": "westus",
  "macAddress": "00-0D-3A-58-F8-45",
  "powerState": "VM running",
  "privateIpAddress": "10.0.0.4",
  "publicIpAddress": "40.83.165.85",
  "resourceGroup": "2568d0d0-efe3-4d04-a08f-df7f009f822a",
  "zones": ""
}

  # generate-ssh-keys flag: This parameter is used for Linux distributions and creates 
  # a pair of security keys so we can use the ssh tool to access the virtual machine remotely. 
  # The two files are placed into the .ssh folder on your machine and in the VM. If you already 
  # have an SSH key named id_rsa in the target folder, then it will be used rather than having a new key generated.

# Connecting to the VM with SSH
ssh azureuser@<public-ip-address>

# for exit
logout

# Listing images
az vm image list --output table

# Getting all images
az vm image list --sku WordPress --output table --all # t is helpful to filter the list with the --publisher, --sku or –-offer options.

# Location-specific images
az vm image list --location eastus --output table


Pre-defined VM sizes

Azure defines a set of pre-defined VM sizes for Linux and Windows to choose from based on the expected usage.

TypeSizesDescription
General purposeDsv3, Dv3, DSv2, Dv2, DS, D, Av2, A0-7Balanced CPU-to-memory. Ideal for dev/test and small to medium applications and data solutions.
Compute optimizedFs, FHigh CPU-to-memory. Good for medium-traffic applications, network appliances, and batch processes.
Memory optimizedEsv3, Ev3, M, GS, G, DSv2, DS, Dv2, DHigh memory-to-core. Great for relational databases, medium to large caches, and in-memory analytics.
Storage optimizedLsHigh disk throughput and IO. Ideal for big data, SQL, and NoSQL databases.
GPU optimizedNV, NCSpecialized VMs targeted for heavy graphic rendering and video editing.
High performanceH, A8-11Our most powerful CPU VMs with optional high-throughput network interfaces (RDMA).
# get a list of the available sizes
az vm list-sizes --location eastus --output table

# output
MaxDataDiskCount    MemoryInMb  Name                      NumberOfCores    OsDiskSizeInMb    ResourceDiskSizeInMb
------------------  ------------  ----------------------  ---------------  ----------------  ----------------------
                 2          2048  Standard_B1ms                         1           1047552                    4096
                 2          1024  Standard_B1s                          1           1047552                    2048
                 4          8192  Standard_B2ms                         2           1047552                   16384
                 4          4096  Standard_B2s                          2           1047552                    8192
                 8         16384  Standard_B4ms                         4           1047552                   32768
                16         32768  Standard_B8ms                         8           1047552                   65536
                 4          3584  Standard_DS1_v2 (default)             1           1047552                    7168
                 8          7168  Standard_DS2_v2                       2           1047552                   14336
                16         14336  Standard_DS3_v2                       4           1047552                   28672
                32         28672  Standard_DS4_v2                       8           1047552                   57344
                64         57344  Standard_DS5_v2                      16           1047552                  114688
        ....
                64       3891200  Standard_M128-32ms                  128           1047552                 4096000
                64       3891200  Standard_M128-64ms                  128           1047552                 4096000
                64       3891200  Standard_M128ms                     128           1047552                 4096000
                64       2048000  Standard_M128s                      128           1047552                 4096000
                64       1024000  Standard_M64                         64           1047552                 8192000
                64       1792000  Standard_M64m                        64           1047552                 8192000
                64       2048000  Standard_M128                       128           1047552                16384000
                64       3891200  Standard_M128m                      128           1047552                16384000

# Specify a size during VM creation
az vm create \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 \
    --name SampleVM2 \
    --image UbuntuLTS \
    --admin-username azureuser \
    --generate-ssh-keys \
    --verbose \
    --size "Standard_DS5_v2"

# Get available VM Size
# Before a resize is requested, we must check to see if the desired size is available in the cluster our VM is part of.
az vm list-vm-resize-options \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 \
    --name SampleVM \
    --output table

# Resize an existing VM 
az vm resize \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 \
    --name SampleVM \
    --size Standard_D2s_v3

This will return a list of all the possible size configurations available in the resource group. If the size we want isn’t available in our cluster, but is available in the region, we can deallocate the VM. This command will stop the running VM and remove it from the current cluster without losing any resources. Then we can resize it, which will re-create the VM in a new cluster where the size configuration is available.

# List VMs
az vm list

# Output types
az vm list --output table|json|jsonc|tsv

# Getting the IP address
az vm list-ip-addresses -n SampleVM -o table
# output
VirtualMachine    PublicIPAddresses    PrivateIPAddresses
----------------  -------------------  --------------------
SampleVM          168.61.54.62         10.0.0.4

# Getting VM details
az vm show --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 --name SampleVM
# we could change to a table format, but that omits almost all of the interesting data. Instead, we can turn to a built-in query language for JSON called JMESPath.
# https://jmespath.org/


# Adding filters to queries with JMESPath
{
  "people": [
    {
      "name": "Fred",
      "age": 28
    },
    {
      "name": "Barney",
      "age": 25
    },
    {
      "name": "Wilma",
      "age": 27
    }
  ]
}

# poeple is an array
people[1]
# output
{
    "name": "Barney",
    "age": 25
}


people[?age > '25'] 
# output
[
  {
    "name": "Fred",
    "age": 28
  },
  {
    "name": "Wilma",
    "age": 27
  }
]

people[?age > '25'].[name]
# output
[
  [
    "Fred"
  ],
  [
    "Wilma"
  ]
]

# Filtering our Azure CLI queries
az vm show \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 \
    --name SampleVM \
    --query "osProfile.adminUsername"

az vm show \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 \
    --name SampleVM \
    --query hardwareProfile.vmSize

az vm show \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 \
    --name SampleVM \
    --query "networkProfile.networkInterfaces[].id"

az vm show \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 \
    --name SampleVM \
    --query "networkProfile.networkInterfaces[].id" -o tsv

# Stopping a VM
az vm stop \
    --name SampleVM \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844

# We can verify it has stopped by attempting to ping the public IP address, using ssh, or through the vm get-instance-view command.
az vm get-instance-view \
    --name SampleVM \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 \
    --query "instanceView.statuses[?starts_with(code, 'PowerState/')].displayStatus" -o tsv

# Starting a VM    
az vm start \
    --name SampleVM \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844

# Restarting a VM
az vm start \
    --name SampleVM \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844
    --no-wait 

# Install NGINX web server
# 1.
z vm list-ip-addresses --name SampleVM --output table

# 2.
ssh azureuser@<PublicIPAddress>

# 3.
sudo apt-get -y update && sudo apt-get -y install nginx

# 4.
exit

# Retrieve our default page
# Either
curl -m 10 <PublicIPAddress>
# Or
# in browser try the public ip address

# This command will fail because the Linux virtual machine doesn't expose
# port 80 (http) through the network security group that secures the network 
# connectivity to the virtual machine. We can change this with the Azure CLI command vm open-port.

# open oprt
az vm open-port \
    --port 80 \
    --resource-group learn-5d4bcefe-17c2-4db6-aba8-3f25d2c54844 \
    --name SampleVM

# output of curl command
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
    width: 35em;
    margin: 0 auto;
    font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

Source: https://docs.microsoft.com/en-us/learn/modules/manage-virtual-machines-with-azure-cli/

Availability Set

  • An availability set is a logical grouping of two or more VMs
  • keep your application available during planned or unplanned maintenance.
  • planned maintenance event is when the underlying Azure fabric that hosts VMs is updated by Microsoft.
    • to patch security vulnerabilities,
    • improve performance,
    • and add or update features
  • When the VM is part of an availability set, the Azure fabric updates are sequenced so not all of the associated VMs are rebooted at the same time.
  • VMs are put into different update domains.
  • Update domains indicate groups of VMs and underlying physical hardware that can be rebooted at the same time.
  • Update domains are a logical part of each data center and are implemented with software and logic.
  • Unplanned maintenance events involve a hardware failure in the data center,
    • such as a server power outage
    • or disk failure
  • VMs that are part of an availability set automatically switch to a working physical server so the VM continues to run.
  • The group of virtual machines that share common hardware are in the same fault domain.
  • A fault domain is essentially a rack of servers.
  • It provides the physical separation of your workload across different power, cooling, and network hardware that support the physical servers in the data center server racks. 
  • With an availability set, you get:
    • Up to three fault domains that each have a server rack with dedicated power and network resources
    • Five logical update domains which then can be increased to a maximum of 20
Diagram showing availability sets update and fault domains that are duplicated across servers.
Your VMs are then sequentially placed across the fault and update domains. The following diagram shows an example where you have six VMs in two availability sets distributed across the two fault domains and five update domains.

Source

Scale Set

Scenario: Imagine that you work for a domestic shipping company. Your customers use one of the company’s websites to manage and check the status of their shipments. This website is deployed to virtual machines and hosted on-premises. You’ve noticed that increased usage on the site is straining the virtual machines’ resources. However, you can’t adjust to load fluctuations without manually intervening and creating or deallocating virtual machines.

  • Scale set is for scalable applications ( automatically adjust to changes in load while minimizing costs with virtual machine scale sets)
  • adjust your virtual machine resources to match demands
  • keep the virtual machine configuration consistent to ensure application stabilit
  • VMs in this type of scale set all have the same configuration and run the same applications
  • for scenarios that include compute workloads, big-data workloads, and container workloads
  • to deploy and manage many load-balanced, identical VMs
  • it scales up and down automatically
  • it can even resize the vm
  • A scale set uses a load balancer to distribute requests across the VM instances
  • It uses a health probe to determine the availability of each instance (The health probe pings the instance)
  • keep in mind that you’re limited to running 1,000 VMs on a single scale set
  • support both Linux and Windows VMs
  • are designed for cost-effectiveness
  • scaling options
    • horizontal: adding or removing several VMs, by using rules, The rules are based on metrics.
    • vertical: adding resources such as memory, CPU power, or disk space to VMs,  increasing the size of the VMs in the scale set, by using rules.
  • How to scale
    • Scheduled scaling: You can proactively schedule the scale set to deploy one or N number of additional instances to accommodate a spike in traffic and then scale back down when the spike ends.
    • Autoscaling: If the workload is variable and can’t always be scheduled, you can use metric-based threshold scaling. Autoscaling horizontally scales out based on node usage. It then scales back in when the resources return to a baseline.
  • Reducing costs by using low-priority
    • allows you to use Azure compute resources at cost savings of up to 80 percent.
    • A low-priority scale set provisions VMs through this underused compute capability.
    • these VMs, keep in mind that they’re temporary. Availability depends on size, region, time of day, and so on. These VMs have no SLA.
    • When Azure needs the computing power again, you’ll receive a notification about the VM that will be removed from your scale set
    • you can use Azure Scheduled Events to react to the notification within the VM. 
  • low-priority scale set, you specify two kinds of removal
    • Delete: The entire VM is removed, including all of the underlying disks.
    • Deallocate: The VM is stopped. The processing and memory resources are deallocated. Disks are left intact and data is kept. You’re charged for the disk space while the VM isn’t running.
  • if the workload increases in complexity rather than in volume, and this complexity demands more of your resources, you might prefer to scale vertically.
# create custom data to config scale set
code cloud-init.yaml

# custom data 
#cloud-config
package_upgrade: true
packages:
  - nginx
write_files:
  - owner: www-data:www-data
  - path: /var/www/html/index.html
    content: |
        Hello world from Virtual Machine Scale Set !
runcmd:
  - service nginx restart

# create resource group
az group create \
  --location westus \
  --name scalesetrg

# create scale set
az vmss create \
  --resource-group scalesetrg \
  --name webServerScaleSet \
  --image UbuntuLTS \
  --upgrade-policy-mode automatic \
  --custom-data cloud-init.yaml \
  --admin-username azureuser \
  --generate-ssh-keys

# More about scaling : https://docs.microsoft.com/en-us/learn/modules/build-app-with-scale-sets/4-configure-virtual-machine-scale-set

By default, the new virtual machine scale set has two instances and a load balancer.

The custom-data flag specifies that the VM configuration should use the settings in the cloud-init.yaml file after the VM has been created. You can use a cloud-init file to install additional packages, configure security, and write to files when the machine is first installed.

Configure vm scale set

# add a health probe to the load balancer
az network lb probe create \
  --lb-name webServerScaleSetLB \
  --resource-group scalesetrg \
  --name webServerHealth \
  --port 80 \
  --protocol Http \
  --path /

The health probe pings the root of the website through port 80. If the website doesn't respond, the server is considered unavailable. The load balancer won't route traffic to the server.

# configure the load balancer to route HTTP traffic to the instances in the scale set
az network lb rule create \
  --resource-group scalesetrg \
  --name webServerLoadBalancerRuleWeb \
  --lb-name webServerScaleSetLB \
  --probe-name webServerHealth \
  --backend-pool-name webServerScaleSetLBBEPool \
  --backend-port 80 \
  --frontend-ip-name loadBalancerFrontEnd \
  --frontend-port 80 \
  --protocol tcp

# change the number of instances in a virtual machine scale set
az vmss scale \
    --name MyVMScaleSet \
    --resource-group MyResourceGroup \
    --new-capacity 6



  • a mechanism that updates your application consistently, across all instances in the scale set
    • Azure custom script extension downloads and runs a script on an Azure VM. It can automate the same tasks on all the VMs in a scale set.
    • create a configuration file that defines the files to get and the commands to run. This file is in JSON format.
    • to know more about custom script refer to Onboarding : Azure Infrastructure deployment.
# custom script configuration that downloads an application from a repository in GitHub and installs it on a host instance by running a script named custom_application_v1.sh
# yourConfigV1.json 
{
  "fileUris": ["https://raw.githubusercontent.com/yourrepo/master/custom_application_v1.sh"],
  "commandToExecute": "./custom_application_v1.sh"
}


# To deploy this configuration on the scale set, you use a custom script extension
az vmss extension set \
  --publisher Microsoft.Azure.Extensions \
  --version 2.0 \
  --name CustomScript \
  --resource-group myResourceGroup \
  --vmss-name yourScaleSet \
  --settings @yourConfigV1.json

# view the current upgrade policy for the scale set
az vmss show \
    --name webServerScaleSet \
    --resource-group scalesetrg \
    --query upgradePolicy.mode

# apply the update script
az vmss extension set \
    --publisher Microsoft.Azure.Extensions \
    --version 2.0 \
    --name CustomScript \
    --vmss-name webServerScaleSet \
    --resource-group scalesetrg \
    --settings "{\"commandToExecute\": \"echo This is the updated app installed on the Virtual Machine Scale Set ! > /var/www/html/index.html\"}"

# retrieve the IP address
az network public-ip show \
    --name webServerScaleSetLBPublicIP \
    --resource-group scalesetrg \
    --output tsv \
    --query ipAddress

Source

Snapshot

Image

  • Managed disk supports creating a managed Custome image
  • We can create image from custom VHD in a storage account or directly from generalized VM (via sysprepped VM command)
    • This process capture a single image
    • this image contains all managed disks associated with a VM, including both OS, and Data.

Image vs. Snapshot

ImageSnapshot
With managed disks, you can take an image of a generalized VM that has been deallocated.It’s copy of disk in a specific point of time.
This image includes all managed disks attached to this VM. it applies only to one disk.
This image can be used to create a Vm.Sanpshot doesn’t have awareness of any disk except the one it contains.

If a VM has only one OS disk, we can take a snapshot of the disk or take image of VM and create a VM from either snapshot or the image.

Deploy VM from VHD

  • a vm can have some configurations like installed software -> we can create a new Virtual Hard Disk (VHD) from this vm.
  • VHD
    • is like physical hard disk
    • A VHD can also hold databases and other user-defined folders, files, and data
    • A virtual machine can contain multiple VHDs
    • Typically, a virtual machine has an operating system VHD on which the operating system is installed. 
    • It also has one or more data VHDs that contain the applications and other user-specific data used by the virtual machine.
  • VHD advantages
    • high availability
    • physical security
    • Durability
    • scalability
    • cost and performance
  • VM image
    • vm image is an original image without preconfigured items
    • VHD contains configurations
    • vm image and vhds can be created via Microsoft Hyper-V -> then upload to cloud
  • Generalized image
    • it’s customized vm image
    • and then some server-specific information must be remove and create a general image
      • The host name of your virtual machine.
      • The username and credentials that you provided when you installed the operating system on the virtual machine.
      • Log files.
      • Security identifiers for various operating system services.
    • The process of resetting this data is called generalization, and the result is a generalized image.
    •  For Windows, use the Microsoft System Preparation (Sysprep) tool. For Linux, use the Windows Azure Linux Agent (waagent) tool.
  • specialized virtual image
    • use a specialized virtual image as a backup of your system at a particular point in time. If you need to recover after a catastrophic failure, or you need to roll back the virtual machine, you can restore your virtual machine from this image.
    • is snapshot of vm at a point in time
Generalize a server
  1. use a generalized image to build pre-configured virtual machines (VMs)
  2. To generalize a Windows VM, follow these steps:
    • Sign in to the Windows virtual machine.
    • Open a command prompt as an administrator.
    • Browse to the directory \windows\system32\sysprep.
    • Run sysprep.exe.
    • In the System Preparation Tool dialog box, select the following settings, and then select OK.TABLE 1PropertyValueSystem Cleanup ActionEnter System Out-of-Box Experience (OOBE)GeneralizeSelectShutdown OptionsShutdown

Running Sysprep is a destructive process, and you can’t easily reverse its effects. Back up your virtual machine first.

When you create a virtual machine image in this way, the original virtual machine becomes unusable. You can’t restart it. Instead, you must create a new virtual machine from the image, as described later in this unit.

Source

High-performance computing

Scenario: Suppose you work for an engineering organization that has an application that creates 3D models of the facilities they design. Your organization also has another system that stores a large amount of project-related statistical data. They want to use Azure to modernize the aging high-performance compute platforms that support these applications. Your organization needs to understand the solutions available on Azure, and how they fit into their plans.

  • Azure HPC choices
    • Azure batch
    • Azure VM HPC Instances
    • Microsoft HPC Pack
  • they are for specialized tasks
    • In genetic sciences, gene sequencing.
    • In oil and gas exploration, reservoir simulations.
    • In finance, market modeling.
    • In engineering, physical system modeling.
    • In meteorology, weather modeling.
  • Azure batch
    • for working with large-scale parallel and computationally intensive tasks 
    • batch is managed service
    • The Batch scheduling and management service is free
    • batch components
      • batch account
        • pools pf vms / notes
        • batch job
          • tasks / units of work
    • batch can associate with storage for input/ourput
    • the scheduling and management engine determines the optimal plan for allocating and scheduling tasks across the specified compute capacity
    • suggested for embarrassingly parallel tasks (https://www.youtube.com/watch?v=cadoD0aSQoM)
  • Azure VM HPC
    • H-series
    • HB-Series
    • HC-series
    • N -> NVIDIA GPUs
    • NC -> NVIDIA GPUs + CUDA
    • ND -> optimized for AI and deep learning workloads for are fast at running single-precision floating point operations, which are used by AI frameworks including Microsoft Cognitive Toolkit, TensorFlow, and Caffe.
  • Microsoft HPC Pack
    • for migrate from on-prem to azure
    • have full control of the management and scheduling of your clusters of VMs
    • HPC Pack has the flexibility to deploy to on-premises and the cloud.
    • HPC Pack offers a series of installers for Windows that allows you to configure your own control and management plane, and highly flexible deployments of on-premises and cloud nodes.
    •  Deployment of HPC Pack requires Windows Server 2012 or later, and takes careful consideration to implement.
    • Prerequisites:
      • You need SQL Server and an Active Directory controlle, and a topology
      • specify the count of heads/controller nodes and workers
      • pre-provision Azure nodes as part of the cluster
      • The size of the main machines that make up the control plane (head and control nodes, SQL Server, and Active Directory domain controller) will depend on the projected cluster size
      • install HPC PAck -> the you have job scheduler  for both HPC and parallel jobs
      • scheduler appears in the Microsoft Message Passing Interface
      • HPC Pack is highly integrated with Windows
      • can see all the application, networking, and operating system events from the compute nodes in the cluster in a single, debugger view.

Source

Azure Batch

Scenario: Imagine you’re a software developer at a non-profit organization whose mission is to give every human on the planet access to clean water. To reach this goal, every citizen is asked to take a picture of their water purification meter and text it to you. Each day, you have to scan pictures from over 500,000 households, and record each reading against the sender phone number. The data is used to detect water quality trends and to dispatch the mobile water quality team to investigate the worst cases across each region. Time is of the essence, but processing each image with Optical Character Recognition (OCR) is time-intensive. With Azure Batch, you can scale out the amount of compute needed to handle this task on a daily basis, saving your non-profit the expense of fixed resources.

  • Azure Batch is an Azure service that enables you to run large-scale parallel and high-performance computing (HPC) applications efficiently in the cloud.
  • no need to manage infrastructure
  • Azure Batch to execute large-scale, high-intensity computation jobs
  • for running parallel tasks
  • flexible and scalable compute solution, such as Azure Batch, to provide the computational power
  • for compute-intensive tasks
    • heavy workloads can be broken down into separate subtasks and run in parallel
  • components
    • azure batch account
    • batch account is container for all batch resources
    • batch account contains many batch pools
    • azure batch workflow
# define variables
RESOURCE_GROUP=<your resource group>
BATCH_ACCOUNT=batchaccount$RANDOM
LOCATION=westeurope

# create azure batch account
az batch account create \
 --name $BATCH_ACCOUNT \
 --resource-group $RESOURCE_GROUP \
 --location <choose a location from the list above>

# login to azure batch account
az batch account login \
 --name $BATCH_ACCOUNT \
 --resource-group $RESOURCE_GROUP \
 --shared-key-auth

# create azure batch bool
az batch pool create \
 --id mypool --vm-size Standard_A1_v2 \
 --target-dedicated-nodes 3 \
 --image canonical:ubuntuserver:16.04-LTS \
 --node-agent-sku-id "batch.node.ubuntu 16.04"

# verify the nodes
az batch pool show --pool-id mypool \
 --query "allocationState"

# create a job
az batch job create \
 --id myjob \
 --pool-id mypool

# create tasks
for i in {1..10}
do
   az batch task create \
    --task-id mytask$i \
    --job-id myjob \
    --command-line "/bin/bash -c 'echo \$(printenv | grep \AZ_BATCH_TASK_ID) processed by; echo \$(printenv | grep \AZ_BATCH_NODE_ID)'"
done


# delete batch job
az batch job delete --job-id myjob -y

Source

Monitor Azure Batch job
  • to monitor the progress ob the tasks
# create a job for monitoring
az batch job create \
 --id myjob2 \
 --pool-id mypool

# create tasks of the job
for i in {1..10}
do
   az batch task create \
    --task-id mytask$i \
    --job-id myjob2 \
    --command-line "/bin/bash -c 'echo \$(printenv | grep \AZ_BATCH_TASK_ID) processed by; echo \$(printenv | grep \AZ_BATCH_NODE_ID)'"
done

# check status
az batch task show \
 --job-id myjob2 \
 --task-id mytask1

# list tasks output
az batch task file list \
 --job-id myjob2 \
 --task-id mytask5 \
 --output table

# create a folder for output and change to this folder
mkdir taskoutputs && cd taskoutputs

# download tasks output
for i in {1..10}
do
az batch task file download \
    --job-id myjob2 \
    --task-id mytask$i \
    --file-path stdout.txt \
    --destination ./stdout$i.txt
done

# show content
cat stdout1.txt && cat stdout2.txt

# delte job
az batch job delete --job-id myjob2 -y

Automate business processes

  • Modern businesses run on multiple applications and services
  • send the right data to the rigth task impact the efficiency
  • azure features to build and implement workflows that integrate multiple systems
    • Logic Apps
    • Microsoft Power Automate
    • WebJobs
    • Azure Functions
  • similarities of them
    • They can all accept inputs. An input is a piece of data or a file that is supplied to the workflow.
    • They can all run actions. An action is a simple operation that the workflow executes and may often modify data or cause another action to be performed.
    • They can all include conditions. A condition is a test, often run against an input, that may decide which action to execute next.
    • They can all produce outputs. An output is a piece of data or a file that is created by the workflow.
    • In addition, workflows created with these technologies can either start based on a schedule or they can be triggered by some external event.
    • They have design-first approach
      • Logic app
      • Power automate
    • They have code-first technology
      • webjob
      • Azure functions

Logic Apps

  • to automate, orchestrate, and integrate disparate components of a distributed application.
  • Visual designer / Json Code Editor
  • over 200 connectors to external services
  • If you have an unusual or unique system that you want to call from a Logic Apps, you can create your own connector if your system exposes a REST API.

Microsoft Power Automate

  • create workflows even when you have no development or IT Pro experience
  • support four different types of flow
  • is built on Logic Apps
  • support same connectors and custom connectors

Webjobs

  • is a background tasks for app service
  • Onboarding : Modern Applications
  • kinds
    • continous
    • triggered
  • webjob can be written in several languages.
  • The WebJobs SDK only supports C# and the NuGet package manager.

Azure Functions

  • small pieces of code
  • pay for the time when the code runs
  • Azure automatically scales the function 
  • has available template
  • Microsoft Power Automate supported flows
    • Automated: A flow that is started by a trigger from some event. For example, the event could be the arrival of a new tweet or a new file being uploaded.
    • Button: Use a button flow to run a repetitive task with a single click from your mobile device.
    • Scheduled: A flow that executes on a regular basis such as once a week, on a specific date, or after 10 hours.
    • Business process: A flow that models a business process such as the stock ordering process or the complaints procedure.
  • Azure function available templates
    • HTTPTrigger. Use this template when you want the code to execute in response to a request sent through the HTTP protocol.
    • TimerTrigger. Use this template when you want the code to execute according to a schedule.
    • BlobTrigger. Use this template when you want the code to execute when a new blob is added to an Azure Storage account.
    • CosmosDBTrigger. Use this template when you want the code to execute in response to new or updated documents in a NoSQL database.
  • WebJobs for these reasons
    • You want the code to be a part of an existing App Service application and to be managed as part of that application, for example in the same Azure DevOps environment.
    • You need close control over the object that listens for events that trigger the code. This object in question is the JobHost class, and you have more flexibility to modify its behavior in WebJobs

design-first comparison

Microsoft Power AutomateLogic Apps
Intended usersOffice workers and business analystsDevelopers and IT pros
Intended scenariosSelf-service workflow creationAdvanced integration projects
Design toolsGUI only. Browser and mobile appBrowser and Visual Studio designer. Code editing is possible
Application Lifecycle ManagementPower Automate includes testing and production environmentsLogic Apps source code can be included in Azure DevOps and source code management systems

code-first comparison

Azure WebJobsAzure Functions
Supported languagesC# if you are using the WebJobs SDKC#, Java, JavaScript, PowerShell, etc.
Automatic scalingNoYes
Development and testing in a browserNoYes
Pay-per-use pricingNoYes
Integration with Logic AppsNoYes
Package managersNuGet if you are using the WebJobs SDKNuget and NPM
Can be part of an App Service applicationYesNo
Provides close control of JobHostYesNo
Diagram of decision flow chart that will be described in depth in the text that follows.
[Source]

Source


You owe your dreams your courage.

Koleka Putuma


Clouds : Solution Architecting

Consideration by architecting

We should ask this questions ourselves by architecting a solution by designing its monitoring solution

  • how would you diagnose issues with an application
  • how would you understand it’s health
  • what are it’s choke points
  • how would you identify them and what would you do when something breaks

Like the firefighting maneuver that must be executed half-yearly or yearly in each company, we have to use “chaos engineering” technique to intentionally cause breakage in the environments in a controlled manner to test monitoring, alerts, react of the architecture and resiliency of our solution.

Decide for the right resource and architecture for youe product

  • Choose the appropriate architecture based on your requirements
  • Know which compute options is right for your workload
  • Identify the right storage solution that meets your needs
  • Decide how you’re going to manage all your resources
  • Optimize your application for the cloud
  • Secure your Infrastructure

Documents

  • Security document
  • Holistic Monitor Strategy for application & infrustructure
    • explains about the alerts: for which failures an alert is necessary
    • explain about the dashboard: which values can be monitored only via dashboard
    • explain how to meet SLA and how to mange with alert
  • Busines Continuity and Disaster Recovery document
  • The cloud solution architect must consider the framework and provide a buisiness plan for migration.

You owe your dreams your courage.

Koleka Putuma


Onboarding : Azure Secure APIs/Services

Topics

Related topics

Azure API Management Service [Source]

With Azure API Management Service we can:

  • Secure our backends APIs/Services
  • Expose the API/Service Products for external customers (exposes an OpenAPI endpoint)
  • Includes a secure API gateway
  • In case of Premium tier includes an Azure Traffic Manager
  • Throtteling the requests to prevent resource exhaustion
  • Set policies
  • Set Cache

Key concepts

Secure and isolate access to azure resources by using Network Security Group and Application Security Group

This section is only “what should we know about NSG and ASG”. To see the configuration refer to “Configure NSG and ASG“.

By using Network Security Group (NSG) can be specified which computer can be connected to application server [Source].
Network Security Group: is to secure network traffic for virtual machines
Virtual Network Service Endpoint: is for controlling network traffic to and from azure services e.g. storage, database
– Application Security Group:

Network security group
  • filter network traffic to or from azure resources
  • contains security rules that are configured to allow or deny inbound and outbound traffic.
  • can be used to filter traffic between virtual machines or subnets, both within a vnet and from the internet.
  • The allowed IP addresses can be configured in NSG as well.
  • NSG rules are applied to connection between on-prem to vnet or vnet to vnet.
Diagram of network security groups
Source

Network security group assignment

  • NSG is assigned to a network interface or subnet
  • NSG of a subnet is applied to all NIC in this subnet
  • NSG of subnet and NIC are evaluated separately
  • NSG on subnet instead of NIC reduces administration and management effort.
  • Each subnet and NIC can habe only one NSG
  • NSG supports TCP, UDP, ICMP, and operates at layer 4 of the OSI model.
  • Vnet and NSG must be in the same region

Network security group security rules

  • NSG contains one or more rules
  • Rules are allow or deny
  • Rule properites
    • Name
    • Priority 100..4096
    • Source [Any, IP Addresses|Service Tag|Application Security Group]
    • Source Port range
    • Protocol [Any|TCP|UDP|ICMP]
    • Destination [Any, IP Addresses|Service Tag|Application Security Group]
    • Destination Port range
    • Action [Allow|Deny]
  • Rules are evaluated by priority using 5-tuple information (Source, SourcePort, Destination, DestinationPort, Protocol)
  • The rule with lower priority will takeplace e.g. 200 (Allow 3389 RDP) and 150 (Deny 3389 RDP). 150 will takeplace.
  • With NSG, connections are stateful. It means, return traffic is automatically allowed for the same TCP/UDP session e.g. inbound rule allows traffic on port 80 also allows the vm to response the request. A corresponding outbound rule is not needed.
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Add Inbound rule pane
  • Service tag can allow or deny traffic to a spesific azure service either globally or per region. Therefore you don’t need to know the IP address and port os the service because azure does it for you.
  • Microosft create the service tags (you cannot create your own)
  • Some examples of the tags are:
    • VirtualNetwork – This tag represents all virtual network addresses anywhere in Azure, and in your on-premises network if you’re using hybrid connectivity.
    • AzureLoadBalancer – This tag denotes Azure’s infrastructure load balancer. The tag translates to the virtual IP address of the host (168.63.129.16) where Azure health probes originate.
    • Internet – This tag represents anything outside the virtual network address that is publicly reachable, including resources that have public IP addresses. One such resource is the Web Apps feature of Azure App Service.
    • AzureTrafficManager – This tag represents the IP address for Azure Traffic Manager.
    • Storage – This tag represents the IP address space for Azure Storage. You can specify whether traffic is allowed or denied. You can also specify if access is allowed only to a specific region, but you can’t select individual storage accounts.
    • SQL – This tag represents the address for Azure SQL Database, Azure Database for MySQL, Azure Database for PostgreSQL, and Azure SQL Data Warehouse services. You can specify whether traffic is allowed or denied, and you can limit to a specific region.
    • AppService – This tag represents address prefixes for Azure App Service.
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service Tag

Scenario: We have a WebServer in Subnet1 and SQL Server in Subnet2. NSG must only allow 1433 for SQL.

Scenario: Suppose your company wants to restrict access to resources in your datacenter, spread across several network address ranges. With augmented rules, you can add all these ranges into a single rule, reducing the administrative overhead and complexity in your network security groups.

Network security group default rules

  • default rules connot be deleted or changed but can be overriden
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NSG Overview
Application Security Group (ASG)

Scenario: your company has a number of front-end servers in a virtual network. The web servers must be accessible over ports 80 and 8080. Database servers must be accessible over port 1433. You assign the network interfaces for the web servers to one application security group, and the network interfaces for the database servers to another application security group. You then create two inbound rules in your network security group. One rule allows HTTP traffic to all servers in the web server application security group. The other rule allows SQL traffic to all servers in the database server application security group.

  • Application security group let you configure network security for resources used by specific application.
  • It’s for grouping Vms logically, no matter what ip address is or in which subnet assigned
  • Using ASG within NSG to apply a security rule to a group of resources, after that should only the resources be added to ASG.
  • ASG let us to group network interfaces together and the ASG can be used as Source or Destination in NSG.
Diagram of application security groups

Secure and isolate access to azure resources by using Service Enpoints

Coming soon…

Source

Secure backend API by using API Management

Transformation Policies
  • Companies that publish web APIs often need to control the behavior of those APIs without recoding them.
  • Technical informations have to be removed from responses/header.
  • with api management we can do it without changing the code and only with policies
Response Headers.
Response Header [Source]

Scenario: The agency has created an API to make recent and historical census data available. They want to prevent any unnecessary back-end information from being exposed that could be used in malicious attacks. They would also like to prevent abuse of the APIs in the form of a large volume of requests and need a mechanism to throttle requests if they exceed an allowed amount. They are serving their APIs on the Azure API Management service and would like to implement policies to address these concerns.

  • add a policy to remove the X-Powered-By header from responses via adding a policy to outbound
<outbound>
   <set-header name="X-Powered-By" exists-action="delete" />
   <base />
</outbound>

List of some of the available policies

TransformDetail
Convert JSON to XMLConverts a request or response body from JSON to XML.
Convert XML to JSONConverts a request or response body from XML to JSON.
Find and replace string in bodyFinds a request or response substring and replaces it with a different substring.
Mask URLs in contentRewrites links in the response body so that they point to the equivalent link through the gateway.
by adding <redirect-content-urls /> in outbount section, all backend urls are replaced with apim endpoint url.
Set backend serviceChanges the backend service for an incoming request.
Set bodySets the message body for incoming and outgoing requests.
Set HTTP headerAssigns a value to an existing response or request header, or adds a new response or request header.
Set query string parameterAdds, replaces the value of, or deletes a request query string parameter.
Rewrite URLConverts a request URL from its public form to the form expected by the web service.
Transform XML using an XSLTApplies an XSL transformation to the XML in the request or response body.
Throttling policies
ThrottlingDetail
Throttle API requestsa few users over-use an API to the extent that you incur extra costs or that responsiveness to other uses is reduced. You can use throttling to limit access to API endpoints by putting limits on the number of times an API can be called within a specified period of time
<rate-limit calls=”3″ renewal-period=”15″ /> and user receives 429 error when that limit was reached
#  applies to all API operations
<rate-limit calls="3" renewal-period="15" />

# target a particular API operation
<rate-limit calls="number" renewal-period="seconds">
    <api name="API name" id="API id" calls="number" renewal-period="seconds" />
        <operation name="operation name" id="operation id" calls="number" renewal-period="seconds" />
    </api>
</rate-limit>

#it applies the limit to a specified request key, often the client IP address. It gives every client equal bandwidth for calling the API
<rate-limit-by-key calls="number"
                   renewal-period="seconds"
                   increment-condition="condition"
                   counter-key="key value" />

# limit rate limit by a requests IP Address
<rate-limit-by-key calls="10"
              renewal-period="60"
              increment-condition="@(context.Response.StatusCode == 200)"
              counter-key="@(context.Request.IpAddress)"/>
# When you choose to throttle by key, you will need to decide on specific requirements for rate limiting. For example, the table below lists three common ways of specifying the counter-key:
Value	                          Detail
context.Request.IpAddress	  Rates limited by client IP address
context.Subscription.Id	          Rates limited by subscription ID
context.Request.Headers.GetValue("My-Custom-Header-Value")	Rates limited by a specified client request header value

Note: The <rate-limit-by-key> policy is not available when your API Management gateway is in the Consumption tier. You can use <rate-limit>instead.

Authentication policies

Source: https://docs.microsoft.com/en-us/learn/modules/protect-apis-on-api-management/

Onboarding: Resilient and scaleable application

Key components for scaleable and resilient applications

  • Application Gateway
  • Azure Load balancer
  • Availability Set
    • logical grouping for isolating VM resources from each other (run across multiple physical servers, racks, storage units, and network switches)
    • For building reliable cloud solutions
  • Availability Zone
    • Groups of data centers that have independent power, cooling, and networking
    • VMs in availability zone are placed in different physical locations within the same region
    • It doesn’t support all VM sizes
    • It’s available in all regions
A diagram that shows an overview of availability sets in Azure
Availability Set [Source]
A diagram that shows an overview of availability zones in Azure
Availability Zone [Source]
  • Traffic Manager: provides DNS load balancing to your application, so you improve your ability to distribute your application around the world. Use Traffic Manager to improve the performance and availability of your application.

Application Gateway vs. Traffic Manager: The traffic manager only directs the clients to the IP address of the service that they want to go to and the Traffic Manager cannot see the traffic. But Gateway sees the traffic.

Load balancing the web service with the application gateway

Improve application resilience by distributing the load across multiple servers and using path-based routing to direct web traffic.

  • Application gateway works based on Layer 7

Scenario: you work for the motor vehicle department of a governmental organization. The department runs several public websites that enable drivers to register their vehicles and renew their driver’s licenses online. The vehicle registration website has been running on a single server and has suffered multiple outages because of server failures.

Application Gateway features

  • Application delivery controller
  • Load balancing HTTP traffic
  • Web Application Firewall
  • Support SSL
  • Encrypt end-to-end traffic with TLS

Microsoft Learn offers many different learning materials. This learning module is about Application Gateway Theory and this learning module is the Practical part of the learning module. Microsoft Learn for the Application Gateway and Encryption.

Source code

Link to a sample code
– Terraform implementation of Azure Application Gateway
– Terraform implementation of Azure Application Gateway’ Backend pool with VM
– Terraform implementation of Azure Application Gateway’s HTTPS with Keyvault as Ceritficate Store

Load balancing with Azure Load Balancer

  • Azure load balancer for resilient applications against failure and for easily scaling
  • Azure load balancer works in layer 4
  • LB spreads/distributes requests to multiple VMs and services (user gets service even when a VM is failed) automatically
  • LB provides high availability
  • LB uses a Hash-based distribution algorithm (5-tuple)
  • 5-tuple hash map traffic to available services (Source IP, Source Port, Destination IP, Destination Port, Protocol Type)
  • supports an inbound, and outbound scenario
  • Low latency, high throughput, scale up to millions of flows for all TCP and UDP applications
  • Isn’t a physical instance but only an object for configuring infrastructure
  • For high availability, we can use LB with availability set (protect for hardware failure) and availability zones (for data center failure)

Scenario: You work for a healthcare organization that’s launching a new portal application in which patients can schedule appointments. The application has a patient portal and web application front end and a business-tier database. The database is used by the front end to retrieve and save patient information.
The new portal needs to be available around the clock to handle failures. The portal must adjust to fluctuations in load by adding and removing resources to match the load. The organization needs a solution that distributes work to virtual machines across the system as virtual machines are added. The solution should detect failures and reroute jobs to virtual machines as needed. Improved resiliency and scalability help ensure that patients can schedule appointments from any location [Source].

Source code

Link to a sample code to deploy simple Nginx web servers with Availability Set and Public Load Balancer.

Load Balancer SKU
  • Basic Load Balancer
    • Port forwarding
    • Automatic reconfiguration
    • Health Probe
    • Outbound connections through source network address translation (SNAT)
    • Diagnostics through Azure log analytics for public-facing load balancers
    • Can be used only with availability set
  • Standard Load Balancer
    • Supports all the basic LB features
    • Https health probe
    • Availability zone
    • Diagnostics through Azure monitor, for multidimensional metrics
    • High availability (HA) ports
    • outbound rules
    • guaranteed SLA (99,99% for two or more VMs)
Load Balancer Types

Internal LB

  • distributes the load from internal Azure resources to other Azure resources
  • no traffic from the internet is allowed

External/Public LB

  • Distributes client traffic across multiple VMS.
  • Permits traffic from the internet (browser, module app, other resources)
  • public LB maps the public IP and port of incoming traffic to the private IP address and port number of the VM in the back-end pool.
  • Distribute traffic by applying the load-balancing rule
Distribution modes
  • Lb distributes traffic equally among vms
  • distribution modes are for creating different behavior
  • When you create the load balancer endpoint, you must specify the distribution mode in the load balancer rule
  • Prerequisites for load balancer rule
    • must have at least one backend
    • must have at least one health probe

Five tuple hash

  • default of LB
  • As the source port is included in the hash and can be changed for each session, the client might be directed to a different VM for each session.

source IP affinity / Session Affinity / Client IP affinity

  • this distribution is known as session affinity/client IP affinity
  • to map traffic to the server, the 2-tuple hash is used (Source IP, Destination IP) or the 3-tuple (Source IP, Destination IP, Protocol)
  • Hash ensures that requests from specific clients are always sent to the same VM.

Scenario: Remote Desktop Protocol is incompatible with 5-tuple hash

Scenario: for uploading media files this distribution must be used because for uploading a file the same TCP session is used to monitor the progress and a separate UDP session uploads the file.

Scenario: The requirement of the presentation tier is to use in-memory sessions to store the logged user’s profile as the user interacts with the portal. In this scenario, the load balancer must provide source IP affinity to maintain a user’s session. The profile is stored only on the virtual machine that the client first connects to because that IP address is directed to the same server.

Enhance service availability and data locality with Traffic Manager

Scenario:  a company that provides a global music streaming web application. You want your customers, wherever they are in the world, to experience near-zero downtime. The application needs to be responsive. You know that poor performance might drive your customers to your competitors. You’d also like to have customized experiences for customers who are in specific regions for user interface, legal, and operational reasons.
Your customers require 24×7 availability of your company’s streaming music application. Cloud services in one region might become unavailable because of technical issues, such as planned maintenance or scheduled security updates. In these scenarios, your company wants to have a failover endpoint so your customers can continue to access its services. 

  • traffic manager is a DNS-based traffic load balancer
  • Traffic Manager distributes traffic to different regions for high availability, resilience, and responsiveness
  • it resolves the DNS name of the service as an IP address (directs to the service endpoint based on the rules of the traffic routing method)
  • it’s a proxy or gateway
  • it doesn’t see the traffic that a client sends to a server
  • it only gives the client the IP address of where they need to go
  • it’s created only Global.
The location cannot be specified because it’s Global
Traffic Manager Profile’s routing methods
  • each profile has only one routing method
Weighted routing
  • distribute traffic across a set of endpoints, either evently or based on different weights
  • weights between 1 to 1000
  • for each DNS query received, the traffic manager randomly chooses an available endpoint
  • probability of choosing an endpoint is based on the weights assigned to endpoints
Performance routing
  • with endpoints in different geographic locations, the best performance endpoint for the user is sent
  • it uses an internet latency table, which actively track network latencies to the endpoints
Example of a setup where a client connects to Traffic Manager and their traffic is routed based on relative performance of three endpoints.
Geographic routing
  • based on where the DNS query originated, the specific endpoint of the region is sent to the user
  • it’s good for geo-fence content e.g. it’s good for countries with specific terms and conditions for regional compliance
Example of a setup where a client connects to Traffic Manager and their traffic is routed based on the geographic location of four endpoints.
Multivalue routing
  • to obtain multiple healthy endpoints in a single DNS query
  • caller can make client-side retries if endpoint is unresponsive
  • it can increase availability of service and reduce latency associated with a new DNS query
Subnet routing
  • maps a set of user ip addresses to specific endpoints e.g. can be used for testing an app before release (internal test), or to block users from specific ISPs.
Priority routing
  • traffic manager profile contains a prioritized list of services
Example of a setup where a client connects to Traffic Manager and their traffic is routed based on the priority given to three endpoints.
Traffic Manager Profile’s endpoints
  • endpoint is the destination location that is returned to the client
  • Types are
    • Azure endpoints: for services hosted in azure
      • Azure App Service
      • public ip resources that are associated with load balancers, or vms
    • External endpoints
      • for ip v4/v6
      • FQDNs
      • services hosted outside azure either on-prem or other cloud
    • Nested endpoints: are used to combine Traffic Manager profiles to create more flexible traffic-routing schemes to support the needs of larger, more complex deployments.
Endpoints Types/Targets
  • Each traffic manager profile can have serveral endpoints with different types

Source code

Link to a sample code to deploy a Traffic Manager.

Source: https://docs.microsoft.com/en-us/learn/modules/distribute-load-with-traffic-manager/


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