Running Kubernetes on Microsoft Azure

This is in continuation on Kubernetes article series.In the earlier posts, we have seen how to create & deploy simple cluster.Now in this post,we are going to look at recently launched offering from Microsoft Azure.

For more posts on Kubernetes,check out here & here.

Azure Container Service (AKS) is managed Kubernetes offering from Azure.As a hosted Kubernetes service, Azure handles all heavy lifting of all the complexity, operational overhead of managing a Kubernetes cluster for you.

As a managed Kubernetes service, AKS provides:

Once registration is complete, we are now ready to create a Kubernetes cluster with AKS.

Step#3.Resource group creation

Before we create the cluster & nodes,we would need to create Azure resource group which is nothing but a logical group in which Azure resources are deployed and managed.

Create new resource using below command.

az group create --name k8SResourceGroup --location westus2

Before proceeding to the next step,check the provisioningState on the ouput.It should be “Succeeded”

Step#4.Kubernetes cluster creation

Creates a sample cluster named myK8sCluster with one node.

az aks create --resource-group k8SResourceGroup --name myK8sCluster --node-count 1 --generate-ssh-keys

Above command would take sometime to create the cluster, once the command completes and returns JSON-formatted information about the cluster.

Step#5.Connect to Kubernetes cluster

For us to connect, manage Kubernetes cluster, we are going to use kubectl, the Kubernetes command-line client.Azure cloud shell has already built-in kubectl so we don’t have to install them separately.

To configure kubectl to connect to our Kubernetes cluster, run the following command. This step downloads credentials and configures the Kubernetes CLI to use them.

az aks get-credentials --resource-group k8SResourceGroup --name myK8sCluster

To verify kubectl configuration, check the version of kubectl

Step#6. Deploy new application on the cluster

Now we are going to create new Kubernetes manifest file that defines a desired state for the cluster, including what container images should be running etc.,

Create file named Deployment.yml,you can use vi editor to create this file.

apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80

Use the kubectl create command to deploy the application.

In this example:

• A Deployment named nginx-deployment is created, indicated by the metadata: name field.
• The Deployment creates 1 replicated Pods, indicated by the replicas field.
• The Pod template’s specification, or template: spec field, indicates that the Pods run one container, nginx, which runs the nginx Docker Hub latest image (you can also specify the version ex.1.7.9.)
• The Deployment opens port 80 for use by the Pods.

Now that deployment is created,lets check the deployment information using kubectl get deployment command :

When you inspect the Deployments in your cluster, the following fields are displayed:

• NAME lists the names of the Deployments in the cluster.
• DESIRED displays the desired number of replicas of the application, which you define when you create the Deployment. This is the desired state.
• CURRENT displays how many replicas are currently running.
• UP-TO-DATE displays the number of replicas that have been updated to achieve the desired state.
• AVAILABLE displays how many replicas of the application are available to your users.
• AGE displays the amount of time that the application has been running.

Describe the deployment using kubectl describe deployment command to check the details on the deployment.

Step#7. Create service

Kubernetes Service is an abstraction which defines a logical set of Pods and a policy by which to access them  (micro-service). The set of Pods targeted by a Service is determined by a Label Selector

Kubernetes has powerful networking capabilities that control how applications communicate. These networking configurations can also be controlled via YAML.The Service selects all applications with the label ngnix. As multiple replicas, or instances, are deployed, they will be automatically load balanced based on this common label. The Service makes the application available via a NodePort.

Create new file named svc.yml to define load balancers & apps.

apiVersion: v1
kind: Service
metadata:
 name: nginx-svc
 labels:
 app: nginx
spec:
 type: LoadBalancer
 ports:
 - port: 80
 selector:
 app: nginx

Use kubectl create command to create new service based on the svc.yaml file created in the previous step.

Once the External-IP is available,we can browse the ngnix page.

 

Step#8. Clean up

Finally now its time to clean up the resources what we have created:

kubectl delete service my-nginx
kubectl delete deployment my-nginx

 

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Additional Resources :

• Azure CLI commands
• Kubectl cheat sheet