azure

Kubernetes ACI connector with AKS

Azure Container Instances (ACI) provide a hosted environment for running containers in Azure. When using ACI, there is no need to manage the underlying compute infrastructure, Azure handles this management for you. When running containers in ACI, you are charged by the second for each running container.

The Azure Container Instances connector for Kubernetes configures an ACI instance as a node in any Kubernetes cluster. When using the ACI connector for Kubernetes, pods can be scheduled on an ACI instance as if the ACI instance is a standard Kubernetes node. This configuration allows you to take advantage of both the capabilities of Kubernetes and the management value and cost benefit of ACI.

This document details configuring the ACI connector for Kubernetes on an Azure Container Service (AKS) cluster.

Prerequisite

The steps detailed in this document assume that you have created an AKS Kubernetes cluster and have established a kubectl connection with the cluster. If you need these items see, the Azure Container Service (AKS) quickstart.

You also need the Azure CLI version 2.0.22 or later. Run az --version to find the version. If you need to install or upgrade, see Install Azure CLI.

Installation

To install the ACI connector for an AKS cluster, run the following Azure CLI command. Replace the values for the following arguments:

• resource-group - the resource group of the AKS cluster.
• name - the name of the AKS cluster.
• connector-name - the name given to the ACI connector.

az aks install-connector --resource-group myResourceGroup --name myAKSCluster --connector-name myaciconnector

Output:

NAME:   myaciconnector-linux
LAST DEPLOYED: Thu Jan 18 13:58:05 2018
NAMESPACE: default
STATUS: DEPLOYED

RESOURCES:
==> v1/Secret
NAME                                  TYPE    DATA  AGE
myaciconnector-linux-virtual-kubelet  Opaque  1     0s

==> v1beta1/Deployment
NAME                                  DESIRED  CURRENT  UP-TO-DATE  AVAILABLE  AGE
myaciconnector-linux-virtual-kubelet  1        1        1           0          0s

==> v1/Pod(related)
NAME                                                   READY  STATUS             RESTARTS  AGE
myaciconnector-linux-virtual-kubelet-4187386653-t01x3  0/1    ContainerCreating  0         0s


NOTES:
The virtual kubelet is getting deployed on your cluster.

To verify that virtual kubelet has started, run:

  kubectl --namespace=default get pods -l "app=myaciconnector-linux-virtual-kubelet"

Validate the ACI connector

To validate that the ACI connector has been installed, return a list of Kubernetes nodes using the kubectl get nodes command. You should see a node that matches the name given to the ACI connector.

kubectl get nodes

Output:

NAME                                        STATUS    ROLES     AGE       VERSION
virtual-kubelet-myaciconnector-linux        Ready     <none>    2m        v1.8.3
aks-nodepool1-39289454-0                    Ready     agent     22h       v1.7.7
aks-nodepool1-39289454-1                    Ready     agent     22h       v1.7.7
aks-nodepool1-39289454-2                    Ready     agent     22h       v1.7.7

Schedule a pod in ACI

Create a file named aci-connector-test.yaml and copy in the following YAML. Replace the nodeName value with the name given to the ACI connector.

apiVersion: v1
kind: Pod
metadata:
  name: helloworld
spec:
  containers:
  - image: microsoft/aci-helloworld
    imagePullPolicy: Always
    name: helloworld
    resources:
      requests:
        memory: 1G
        cpu: 1
    ports:
    - containerPort: 80
      name: http
      protocol: TCP
    - containerPort: 443
      name: https
  dnsPolicy: ClusterFirst
  nodeName: virtual-kubelet-myaciconnector-linux
  tolerations:
  - key: azure.com/aci
    effect: NoSchedule

Run the application with the kubectl create command.

kubectl create -f aci-connector-test.yml

Use the kubectl get pods command with the -o wide argument to output a list of pods with the scheduled node.

kubectl get pods -o wide

Notice that the kube-aci-demo pod is running on the myACIConnector node.

NAME                                            READY     STATUS    RESTARTS   AGE       IP             NODE
aci-helloworld-2559879000-8vmjw                 1/1       Running   0          39s       52.179.3.180   virtual-kubelet-myaciconnector-linux

To validate that the container is running in an Azure Container Instance, use the az container list Azure CLI command.

az container list -o table

Output:

Name                             ResourceGroup    ProvisioningState    Image                     IP:ports         CPU/Memory       OsType    Location
-------------------------------  ---------------  -------------------  ------------------------  ---------------  ---------------  --------  ----------
aci-helloworld-2559879000-8vmjw  myResourceGroup    Succeeded            microsoft/aci-helloworld  52.179.3.180:80  1.0 core/1.5 gb  Linux     eastus

Updating the ACI Connector version

We are currently running v1beta but to run v2beta follow these steps. Run the following command on the ACI Connector deployment.

kubectl edit deploy myaciconnector-linux-virtual-kubelet

Update the pod spec to add an env variable.

       - name: KUBELET_PORT
         value: "10250"

Also, edit the image tag to represent the latest version.

      image: microsoft/virtual-kubelet:0.2-beta-3

This will deploy a new connector but be aware that the ACI pods deployed on your previous connector will be deleted.

Remove the ACI connector

To remove the ACI connector, run the following command. Replace the argument values with the name of the connector, AKS cluster, and the AKS cluster resource group.

az aks remove-connector --resource-group myResourceGroup --name myAKSCluster --connector-name myaciconnector