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The etcd operator manages etcd clusters deployed to Kubernetes and automates tasks related to operating an etcd cluster.

• Create and Destroy
• Resize
• Failover
• Rolling upgrade
• Backup and Restore

There are more spec examples on setting up clusters with different configurations

Read Best Practices for more information on how to better use etcd operator.

Read RBAC docs for how to setup RBAC rules for etcd operator if RBAC is in place.

Read Developer Guide for setting up a development environment if you want to contribute.

See the Resources and Labels doc for an overview of the resources created by the etcd-operator.

• Kubernetes 1.8+
• etcd 3.2.13+

See instructions on how to install/uninstall etcd operator .

$ kubectl create -f example/example-etcd-cluster.yaml

A 3 member etcd cluster will be created.

$ kubectl get pods
NAME                            READY     STATUS    RESTARTS   AGE
example-etcd-cluster-gxkmr9ql7z   1/1       Running   0          1m
example-etcd-cluster-m6g62x6mwc   1/1       Running   0          1m
example-etcd-cluster-rqk62l46kw   1/1       Running   0          1m

See client service for how to access etcd clusters created by the operator.

If you are working with minikube locally, create a nodePort service and test that etcd is responding:

$ kubectl create -f example/example-etcd-cluster-nodeport-service.json
$ export ETCDCTL_API=3
$ export ETCDCTL_ENDPOINTS=$(minikube service example-etcd-cluster-client-service --url)
$ etcdctl put foo bar

Destroy the etcd cluster:

$ kubectl delete -f example/example-etcd-cluster.yaml

Create an etcd cluster:

$ kubectl apply -f example/example-etcd-cluster.yaml

In example/example-etcd-cluster.yaml the initial cluster size is 3. Modify the file and change size from 3 to 5.

$ cat example/example-etcd-cluster.yaml
apiVersion: "etcd.database.coreos.com/v1beta2"
kind: "EtcdCluster"
metadata:
  name: "example-etcd-cluster"
spec:
  size: 5
  version: "3.2.13"

Apply the size change to the cluster CR:

$ kubectl apply -f example/example-etcd-cluster.yaml

The etcd cluster will scale to 5 members (5 pods):

$ kubectl get pods
NAME                            READY     STATUS    RESTARTS   AGE
example-etcd-cluster-cl2gpqsmsw   1/1       Running   0          5m
example-etcd-cluster-cx2t6v8w78   1/1       Running   0          5m
example-etcd-cluster-gxkmr9ql7z   1/1       Running   0          7m
example-etcd-cluster-m6g62x6mwc   1/1       Running   0          7m
example-etcd-cluster-rqk62l46kw   1/1       Running   0          7m

Similarly we can decrease the size of the cluster from 5 back to 3 by changing the size field again and reapplying the change.

$ cat example/example-etcd-cluster.yaml
apiVersion: "etcd.database.coreos.com/v1beta2"
kind: "EtcdCluster"
metadata:
  name: "example-etcd-cluster"
spec:
  size: 3
  version: "3.2.13"

$ kubectl apply -f example/example-etcd-cluster.yaml

We should see that etcd cluster will eventually reduce to 3 pods:

$ kubectl get pods
NAME                            READY     STATUS    RESTARTS   AGE
example-etcd-cluster-cl2gpqsmsw   1/1       Running   0          6m
example-etcd-cluster-gxkmr9ql7z   1/1       Running   0          8m
example-etcd-cluster-rqk62l46kw   1/1       Running   0          9mp

If the minority of etcd members crash, the etcd operator will automatically recover the failure. Let's walk through this in the following steps.

Create an etcd cluster:

$ kubectl create -f example/example-etcd-cluster.yaml

Wait until all three members are up. Simulate a member failure by deleting a pod:

$ kubectl delete pod example-etcd-cluster-cl2gpqsmsw --now

The etcd operator will recover the failure by creating a new pod example-etcd-cluster-n4h66wtjrg:

$ kubectl get pods
NAME                            READY     STATUS    RESTARTS   AGE
example-etcd-cluster-gxkmr9ql7z   1/1       Running   0          10m
example-etcd-cluster-n4h66wtjrg   1/1       Running   0          26s
example-etcd-cluster-rqk62l46kw   1/1       Running   0          10m

Destroy etcd cluster:

$ kubectl delete -f example/example-etcd-cluster.yaml

Let's walk through operator recovery in the following steps.

Create an etcd cluster:

$ kubectl create -f example/example-etcd-cluster.yaml

Wait until all three members are up. Then stop the etcd operator and delete one of the etcd pods:

$ kubectl delete -f example/deployment.yaml
deployment "etcd-operator" deleted

$ kubectl delete pod example-etcd-cluster-8gttjl679c --now
pod "example-etcd-cluster-8gttjl679c" deleted

Next restart the etcd operator. It should recover itself and the etcd clusters it manages.

$ kubectl create -f example/deployment.yaml
deployment "etcd-operator" created

$ kubectl get pods
NAME                              READY     STATUS    RESTARTS   AGE
example-etcd-cluster-m8gk76l4ns   1/1       Running   0          3m
example-etcd-cluster-q6mff85hml   1/1       Running   0          3m
example-etcd-cluster-xnfvm7lg66   1/1       Running   0          11s

Create and have the following yaml file ready:

$ cat upgrade-example.yaml
apiVersion: "etcd.database.coreos.com/v1beta2"
kind: "EtcdCluster"
metadata:
  name: "example-etcd-cluster"
spec:
  size: 3
  version: "3.1.10"
  repository: "quay.io/coreos/etcd"

Create an etcd cluster with the version specified (3.1.10) in the yaml file:

$ kubectl apply -f upgrade-example.yaml
$ kubectl get pods
NAME                              READY     STATUS    RESTARTS   AGE
example-etcd-cluster-795649v9kq   1/1       Running   1          3m
example-etcd-cluster-jtp447ggnq   1/1       Running   1          4m
example-etcd-cluster-psw7sf2hhr   1/1       Running   1          4m

The container image version should be 3.1.10:

$ kubectl get pod example-etcd-cluster-795649v9kq -o yaml | grep "image:" | uniq
    image: quay.io/coreos/etcd:v3.1.10

Now modify the file upgrade-example and change the version from 3.1.10 to 3.2.13:

$ cat upgrade-example
apiVersion: "etcd.database.coreos.com/v1beta2"
kind: "EtcdCluster"
metadata:
  name: "example-etcd-cluster"
spec:
  size: 3
  version: "3.2.13"

Apply the version change to the cluster CR:

$ kubectl apply -f upgrade-example

Wait ~30 seconds. The container image version should be updated to v3.2.13:

$ kubectl get pod example-etcd-cluster-795649v9kq -o yaml | grep "image:" | uniq
    image: gcr.io/etcd-development/etcd:v3.2.13

Check the other two pods and you should see the same result.

Note: The provided etcd backup/restore operators are example implementations.

Follow the etcd backup operator walkthrough to backup an etcd cluster.

Follow the etcd restore operator walkthrough to restore an etcd cluster on Kubernetes from backup.

See instructions on clusterwide feature.