Deploying the Kubernetes Metrics Server

16.2 Deploying the Kubernetes Metrics Server

Before deploying Horizontal Pod Autoscaler (HPA) you must deploy the Kubernetes Metrics Server.

Check to see if the Kubernetes Metrics Server is already deployed:
```
kubectl get pods -n kube-system | grep metric
```
If a row is returned as follows, then Kubernetes Metric Server is deployed and you can move to Deploying HPA:
```
metrics-server-d9694457-mf69d           1/1     Running   0             5m13s
```
If no rows are returned by the previous command, then the Kubernetes Metric Server needs to be deployed. Run the following commands to get the components.yaml:
```
mkdir $WORKDIR/kubernetes/hpa
```
```
cd $WORKDIR/kubernetes/hpa
```
```
wget https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml
```

Deploy the Kubernetes Metrics Server by running the following command:

kubectl apply -f components.yaml

The output will look similar to the following:

serviceaccount/metrics-server created
clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created
clusterrole.rbac.authorization.k8s.io/system:metrics-server created
rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created
clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created
clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created
service/metrics-server created
deployment.apps/metrics-server created
apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created

Run the following command to check Kubernetes Metric Server is running:
```
kubectl get pods -n kube-system | grep metric
```
Make sure the pod has a READY status of 1/1:
```
metrics-server-d9694457-mf69d           1/1     Running   0             39s
```