Introduction to Azure Kubernetes
Azure Kubernetes Service (AKS) is a managed Kubernetes service provided by Microsoft Azure. It is used for deploying and managing containerized applications on a cloud platform. Kubernetes is an open-source platform for automating containerized applications' deployment, scaling, and management.
AKS enables developers to focus on building and deploying applications, rather than managing the infrastructure needed to run them. It integrates with other Azure services, such as Azure Container Registry and Azure DevOps, to provide a complete cloud-native development and deployment platform.
Getting Started with Azure Kubernetes
Creating an Azure Account:
Go to the Azure website (https://azure.microsoft.com/en-us/) and click on “Start free” or “Sign in” if you already have an account.
You will be asked to sign in with your Microsoft account. If you do not have one, you can create one by clicking on “Create one!”
Follow the steps to create a Microsoft account and sign in to the Azure website.
Once signed in, click on the “Create a resource” button in the upper left corner.
In the search bar, type “Kubernetes” and select “Kubernetes Service” from the results.
Click on “Create” on the Kubernetes Service page.
You will be prompted to enter some basic information such as the subscription, resource group, name, and region for your AKS cluster.
You can choose to use an existing resource group or create a new one. Click “Create new” if you want to create a new resource group.
Select a name and location for your resource group.
Choose a cluster name, node size, and node count for your AKS cluster. The node size determines the hardware configuration for each node in the cluster, while the node count determines the number of nodes that will be available.
Under “Authentication,” select “System-assigned managed identity.”
Click on “Review + create” to review your cluster configuration.
Once you are satisfied with the configuration, click on “Create” to start the deployment process.
It may take a few minutes for the AKS cluster to be provisioned. You can monitor the status of the deployment in the Azure portal or through the notification email you will receive.
Required tools and dependencies:
Azure Account — As mentioned above, you need an Azure account to create and manage AKS clusters.
Microsoft Azure CLI — The Azure CLI is a command-line tool that allows you to manage resources in Azure from your local machine. You can download and install it from the official documentation (https://docs.microsoft.com/en-us/cli/azure/install-azure-cli).
Kubernetes CLI (kubectl) — kubectl is a command-line tool for interacting with Kubernetes clusters. You can install it through the Azure CLI or download and install it separately (https://kubernetes.io/docs/tasks/tools/install-kubectl/).
Docker — AKS supports deploying containerized applications, so you will need to have Docker installed on your machine in order to build and push your container images to a registry that AKS can access.
Azure Container Registry — You can use Azure Container Registry to store your container images and pull them into your AKS cluster. You can create a container registry in the Azure portal or through the Azure CLI.
AKS Architecture and Components:
AKS is a managed Kubernetes service on Azure, which means that Azure handles the deployment, management, and scaling of the Kubernetes cluster and its underlying infrastructure. The following are the main components of an AKS cluster:
Control plane — This is the cluster’s management plane, which contains the main Kubernetes control components such as the API server, scheduler, and controller manager. This is where all the cluster-level operations are performed.
Nodes — Nodes are the worker machines in the cluster that run your application containers. These are virtual machines that are automatically provisioned and managed by Azure.
Pods — Pods are the smallest deployable unit in Kubernetes. They are composed of one or more containers that share a network and storage space.
Container runtime — The container runtime is responsible for managing the lifecycle of application containers on the nodes. AKS supports various container runtimes such as Docker and contained.
Virtual network — AKS creates a virtual network for the cluster.
Deploying Applications on AKS
Containerization has revolutionized the way applications are deployed and managed in the modern software development landscape. It provides a lightweight and efficient way to package and run applications, making them easily portable and deployable across different environments. Kubernetes, an open-source container orchestration system, has become the go-to solution for managing containerized applications at scale. In this section, we will walk you through the process of deploying a containerized application on Azure Kubernetes Service (AKS) using Kubernetes manifests and YAML files. We will also discuss some best practices for deploying applications that are scalable and reliable.
Prerequisites:
An Azure account (to create an AKS cluster)
Basic knowledge of containers and Kubernetes concepts
A containerized application to deploy (you can use a sample application or one of your own)
Step 1: Create an AKS cluster
The first step is to create an AKS cluster where we will be deploying our application. To create an AKS cluster in Azure, you can follow these steps:
Log in to the Azure portal and click on “Create a resource” on the navigation pane.
Search for “Azure Kubernetes Service” and select the AKS option.
Click on “Create” and provide the necessary details such as cluster name, node size, and number of nodes.
Review and confirm the settings and click on “Create” to start the cluster creation process.
Note: It may take a few minutes for the cluster to be provisioned.
Step 2: Build and push your containerized application
Before we can deploy our application on AKS, we need to build and push our container image to a container registry. A container image is a packaged and runnable version of your application that is used by Kubernetes to create containers. You can follow these steps to build and push your containerized application to a container registry (such as Azure Container Registry or Docker Hub):
Build your application using a Dockerfile. If you are using a sample application, the Dockerfile might already be provided.
Once the build is successful, tag the image with the registry name and repository name. For example, if using Azure Container Registry, the tag might look like “myregistry.azurecr.io/myapp:latest”
Push the image to the registry using the “docker push” command.
Step 3: Create a deployment YAML file
A YAML file (YAML stands for “You Ain’t Markup Language”) is a human-readable data serialization language. In Kubernetes, YAML files are used to create and manage resources such as deployments, services, and pods. To deploy our application on AKS, we need to create a deployment YAML file. The deployment YAML file defines the properties of our application and how it should be deployed on the cluster. You can follow these steps to create a deployment YAML file: 1. In your code editor, create a new file named “deployment.yaml” (or any name of your choice).
In your code editor, create a new file named “deployment.yaml” (or any name of your choice).
Start with the “apiVersion” property, which defines the version of Kubernetes API to be used. You can find the latest version on the Kubernetes documentation website.
Next, give a name to your deployment using the “kind” property. In this case, it will be “Deployment”.
Specify the metadata of your deployment using the “metadata” property. This includes the name of the deployment, labels, and annotations.
In the “spec” section, define the “replicas” property with the desired number of instances of your application to be deployed.
Specify the “selector” property, which is used to match the pods with the deployment.
Finally, specify the “template” section, which defines the properties of the pods that will be created. This includes the image name, ports, volumes, and other configurations specific to your application.
An example of a deployment YAML file:
```
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-deployment
labels:
app: myapp
spec:
replicas: 3
selector:
matchLabels:
app: myapp
template:
metadata:
labels:
app: myapp
spec:
containers:
- name: myapp-container
image: myregistry.azurecr.io/myapp:latest
ports:
- containerPort: 8080
restartPolicy: Always
```
Step 4: Create a service YAML file
A service in Kubernetes is an abstraction layer that exposes an application running on a set of pods as a network service. Creating a service allows other applications to access your application running on AKS. To create a service, we need to define a service YAML file. You can follow these steps to create a service YAML file:
In your code editor, create a new file named “service.yaml” (or any name of your choice).
Start with the “apiVersion” property, which defines the version of Kubernetes API to be used. You can find the latest version on the Kubernetes documentation website.
Next, give a name to your service using the “kind” property. In this case, it will be “Service”.
Specify the metadata of your service using the “metadata” property.
Managing and Scaling AKS
Horizontal Scaling (Scaling Out): Horizontal scaling involves adding more nodes (virtual machines) to an AKS cluster to support increased traffic and workload. This can be achieved by increasing the node count in the cluster manually or by using Horizontal Pod Autoscaler (HPA) to automatically add or remove nodes based on the resource usage of pods in the cluster.
Vertical Scaling (Scaling Up): Vertical scaling involves increasing the computing power and resources of individual nodes in the AKS cluster to handle increased traffic and workload. This can be achieved by upgrading the VM size of existing nodes or by using a Cluster Autoscaler to replace existing nodes with larger ones.
Node Pool Scaling: Node pool scaling involves creating multiple node pools within an AKS cluster and assigning different types of nodes to each pool based on their resources. This allows for a more targeted and efficient scaling approach, where certain workloads can be directed to specific node pools with the appropriate resources to handle them.
Cluster Scaling: AKS clusters can also be scaled by increasing the number of clusters. This is suitable for scenarios where different sets of applications have varying resource requirements, and managing them in separate clusters can help with better resource allocation and management.
Scheduled Scaling: In AKS, it is possible to schedule automatic scaling events based on anticipated increases or decreases in traffic and workload. This can be achieved by configuring a Scheduled Kubernetes Horizontal Pod Autoscaler, which allows for scaling up or down the cluster at scheduled intervals.
Monitoring and Managing AKS Clusters:
Cluster Metrics: AKS clusters can be monitored by using the built-in metrics provided by Azure Monitor. These metrics include CPU, memory, and network usage of nodes and clusters, as well as monitoring of pods and containers running on the cluster.
Cluster Logging: AKS clusters can also be configured to capture and store log data from pods and containers running on the cluster. This data can be used for troubleshooting and performance tuning.
Autoscaling: AKS clusters can be optimized for efficiency and cost savings by setting up Cluster Autoscaling. This feature automatically scales the number of nodes in a cluster based on actual resource usage, ensuring that the cluster only uses the necessary resources and doesn’t incur unnecessary costs.
Health Monitoring: AKS clusters can be monitored for health and availability by setting up health probes and alerts. This enables proactive monitoring, and alerts can be configured to trigger actions when certain thresholds are exceeded.
Resource Quotas: AKS clusters can be configured with resource quotas to manage resource consumption and prevent overloading of the cluster. This ensures that each application or team within the cluster has a fair share of resources to work with.
Integration with Azure App Services
Azure App Service is a fully managed platform as a service (PaaS) offering from Microsoft Azure that allows developers to quickly and easily build, deploy, and manage web and mobile applications. It supports a wide range of programming languages, frameworks, and tools, making it a popular choice for a variety of applications.
Some key features of Azure App Service include:
Easy deployment and management: With Azure App Service, developers can easily deploy their applications from source control, such as GitHub or Azure DevOps. App Service also provides a streamlined management experience through its web-based portal and command-line interface (CLI).
Built-in scalability: App Service automatically scales up or down based on the demand for your application, ensuring that your application is always available and performing well.
Custom domains and SSL certificates: App Service allows you to use your own custom domain for your application, and it also supports SSL certificates for secure communications.
Integration with Azure services: App Service integrates with other Azure services, such as Azure Active Directory and Azure Monitor, making it easy to add additional functionality to your applications.
DevOps integration: App Service is designed to work well with modern DevOps practices, including continuous integration and continuous deployment (CI/CD).
Integrating AKS with App Services:
One of the key benefits of using Azure App Service is its seamless integration with other Azure services, such as Azure Kubernetes Service (AKS). This allows developers to easily deploy their applications to AKS and take advantage of its powerful capabilities, while still using App Service’s management and scaling features.
To integrate AKS with App Services, follow these steps:
Create an AKS cluster: Create an AKS cluster using the Azure portal or CLI.
Create an App Service plan: Create a new App Service plan or use an existing one.
Configure App Service to use the AKS cluster: In the App Service plan settings, select the AKS cluster as the deployment source.
Configure the AKS cluster to use App Service: In the AKS cluster settings, enable the App Service add-on. This will allow the AKS cluster to communicate with the App Service instance.
Deploy the application: Deploy your application to the AKS cluster. App Service will handle the scaling and management of the application.
Advanced Features of Azure App Service:
In addition to its basic features, Azure App Service also offers a range of advanced features that can help developers better manage and deploy their applications.
Custom domains: With App Service, you can use your own custom domain for your application, which gives your application a more professional and branded look.
SSL certificates: App Service supports SSL certificates, allowing you to secure your application and protect sensitive data transmitted between the server and the user.
Auto-scaling: App Service can automatically scale up or down your application based on demand, ensuring that your application has the resources it needs to handle traffic spikes.
Staging environments: App Service allows you to create multiple staging environments for your application, making it easy to test new features or changes before deploying them to production.
Continuous deployment: With App Service, you can set up continuous deployment from sources like GitHub, Bitbucket, or Azure DevOps, enabling you to quickly and easily deploy updates to your application.
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