What is Kubernetes

Modern applications are increasingly built using containers—microservices packaged with their dependencies and configurations. Kubernetes or k8s for short, is open-source software for deploying and managing those containers at scale. With Kubernetes, you can build, deliver and scale containerised apps faster.

Azure Kubernetes Service (AKS) makes it simple to deploy a managed Kubernetes cluster in Azure. AKS reduces the complexity and operational overhead of managing Kubernetes by offloading much of that responsibility to Azure. As a hosted Kubernetes service, Azure handles critical tasks like health monitoring and maintenance for you. The Kubernetes masters are managed by Azure. You only manage and maintain the agent nodes. As a managed Kubernetes service, AKS is free - you only pay for the agent nodes within your clusters, not for the masters.

You can create an AKS cluster in the Azure portal, with the Azure CLI, or template driven deployment options such as Resource Manager templates and Terraform. When you deploy an AKS cluster, the Kubernetes master and all nodes are deployed and configured for you. Additional features such as advanced networking, Azure Active Directory integration, and monitoring can also be configured during the deployment process. Windows Server containers support is currently in preview in AKS.

For more information on Kubernetes basics, see Kubernetes core concepts for AKS.

To get started, complete the AKS quickstart in the Azure portal or with the Azure CLI.

Access, security, and monitoring

For improved security and management, AKS lets you integrate with Azure Active Directory and use Kubernetes role-based access controls. You can also monitor the health of your cluster and resources.

Identity and security management

To limit access to cluster resources, AKS supports Kubernetes role-based access control (RBAC). RBAC lets you control access to Kubernetes resources and namespaces, and permissions to those resources. You can also configure an AKS cluster to integrate with Azure Active Directory (AD). With Azure AD integration, Kubernetes access can be configured based on existing identity and group membership. Your existing Azure AD users and groups can be provided access to AKS resources and with an integrated sign-on experience.

For more information on identity, see Access and identity options for AKS.

To secure your AKS clusters, see Integrate Azure Active Directory with AKS.

Integrated logging and monitoring

To understand how your AKS cluster and deployed applications are performing, Azure Monitor for container health collects memory and processor metrics from containers, nodes, and controllers. Container logs are available, and you can also review the Kubernetes master logs. This monitoring data is stored in an Azure Log Analytics workspace, and is available through the Azure portal, Azure CLI, or a REST endpoint.

For more information, see Monitor Azure Kubernetes Service container health.

Clusters and nodes

AKS nodes run on Azure virtual machines. You can connect storage to nodes and pods, upgrade cluster components, and use GPUs. AKS supports Kubernetes clusters that run multiple node pools to support mixed operating systems and Windows Server containers (currently in preview). Linux nodes run a customized Ubuntu OS image, and Windows Server nodes run a customized Windows Server 2019 OS image.

Cluster node and pod scaling

As demand for resources change, the number of cluster nodes or pods that run your services can automatically scale up or down. You can use both the horizontal pod autoscaler or the cluster autoscaler. This approach to scaling lets the AKS cluster automatically adjust to demands and only run the resources needed.

For more information, see Scale an Azure Kubernetes Service (AKS) cluster.

Cluster node upgrades

Azure Kubernetes Service offers multiple Kubernetes versions. As new versions become available in AKS, your cluster can be upgraded using the Azure portal or Azure CLI. During the upgrade process, nodes are carefully cordoned and drained to minimize disruption to running applications.

To learn more about lifecycle versions, see Supported Kubernetes versions in AKS. For steps on how to upgrade, see Upgrade an Azure Kubernetes Service (AKS) cluster.

GPU enabled nodes

AKS supports the creation of GPU enabled node pools. Azure currently provides single or multiple GPU enabled VMs. GPU enabled VMs are designed for compute-intensive, graphics-intensive, and visualization workloads.

For more information, see Using GPUs on AKS.

Storage volume support

To support application workloads, you can mount storage volumes for persistent data. Both static and dynamic volumes can be used. Depending on how many connected pods are to share the storage, you can use storage backed by either Azure Disks for single pod access, or Azure Files for multiple concurrent pod access.

For more information, see Storage options for applications in AKS.

Get started with dynamic persistent volumes using Azure Disks or Azure Files.

Virtual networks and ingress

An AKS cluster can be deployed into an existing virtual network. In this configuration, every pod in the cluster is assigned an IP address in the virtual network, and can directly communicate with other pods in the cluster, and other nodes in the virtual network. Pods can connect also to other services in a peered virtual network, and to on-premises networks over ExpressRoute or site-to-site (S2S) VPN connections.

For more information, see the Network concepts for applications in AKS.

To get started with ingress traffic, see HTTP application routing.

Ingress with HTTP application routing

The HTTP application routing add-on makes it easy to access applications deployed to your AKS cluster. When enabled, the HTTP application routing solution configures an ingress controller in your AKS cluster. As applications are deployed, publicly accessible DNS names are auto configured. The HTTP application routing configures a DNS zone and integrates it with the AKS cluster. You can then deploy Kubernetes ingress resources as normal.

To get started with ingress traffic, see HTTP application routing.

Development tooling integration

Kubernetes has a rich ecosystem of development and management tools such as Helm, Draft, and the Kubernetes extension for Visual Studio Code. These tools work seamlessly with AKS.

Additionally, Azure Dev Spaces provides a rapid, iterative Kubernetes development experience for teams. With minimal configuration, you can run and debug containers directly in AKS. To get started, see Azure Dev Spaces.

The Azure DevOps project provides a simple solution for bringing existing code and Git repository into Azure. The DevOps project automatically creates Azure resources such as AKS, a release pipeline in Azure DevOps Services that includes a build pipeline for CI, sets up a release pipeline for CD, and then creates an Azure Application Insights resource for monitoring.

For more information, see Azure DevOps project.

Docker image support and private container registry

AKS supports the Docker image format. For private storage of your Docker images, you can integrate AKS with Azure Container Registry (ACR).

To create private image store, see Azure Container Registry.