unit/integration:
e2e (Kubernetes stable):
e2e (Kubernetes master):
Major planned features have been completed and while no breaking API changes are currently planned, we reserve the right to address bugs and API changes in a backwards incompatible way before the project is declared stable. Any breaking changes introduced will be documented in release notes.
Currently user face etcd cluster objects are created as Kubernetes Third Party Resources, however, taking advantage of User Aggregated API Servers to improve reliability, validation and versioning is planned. The use of Aggregated API should be minimally disruptive to existing users but may change what Kubernetes objects are created or how users deploy the etcd operator.
We expect to consider the etcd operator stable soon; backwards incompatible changes will not be made once the project reaches stability.
The etcd operator manages etcd clusters deployed to Kubernetes and automates tasks related to operating an etcd cluster.
There are more spec examples on setting up clusters with backup, restore, and other 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 development environment if you want to contribute.
- Kubernetes 1.5.3+
- etcd 3.0+
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-0000 1/1 Running 0 1m
example-etcd-cluster-0001 1/1 Running 0 1m
example-etcd-cluster-0002 1/1 Running 0 1m
$ kubectl get services
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
example-etcd-cluster-0000 10.0.6.23 <none> 2380/TCP,2379/TCP 2m
example-etcd-cluster-0001 10.0.64.204 <none> 2380/TCP,2379/TCP 1m
example-etcd-cluster-0002 10.0.199.80 <none> 2380/TCP,2379/TCP 1m
If you are working with minikube locally create a nodePort service and test out 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 etcd cluster:
$ kubectl delete -f example/example-etcd-cluster.yaml
kubectl apply
doesn't work for TPR at the moment. See kubernetes/#29542.
As a workaround, we use cURL to resize the cluster.
Create an etcd cluster:
$ kubectl create -f example/example-etcd-cluster.yaml
Use kubectl to create a reverse proxy:
$ kubectl proxy --port=8080
Starting to serve on 127.0.0.1:8080
Now we can talk to apiserver via "http://127.0.0.1:8080".
Create a json file with the new configuration:
$ cat body.json
{
"apiVersion": "etcd.coreos.com/v1beta1",
"kind": "Cluster",
"metadata": {
"name": "example-etcd-cluster",
"namespace": "default"
},
"spec": {
"size": 5
}
}
In another terminal, use the following command to change the cluster size from 3 to 5.
$ curl -H 'Content-Type: application/json' -X PUT --data @body.json http://127.0.0.1:8080/apis/etcd.coreos.com/v1beta1/namespaces/default/clusters/example-etcd-cluster
We should see
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
example-etcd-cluster-0000 1/1 Running 0 1m
example-etcd-cluster-0001 1/1 Running 0 1m
example-etcd-cluster-0002 1/1 Running 0 1m
example-etcd-cluster-0003 1/1 Running 0 1m
example-etcd-cluster-0004 1/1 Running 0 1m
Now we can decrease the size of cluster from 5 back to 3.
Create a json file with cluster size of 3:
$ cat body.json
{
"apiVersion": "etcd.coreos.com/v1beta1",
"kind": "Cluster",
"metadata": {
"name": "example-etcd-cluster",
"namespace": "default"
},
"spec": {
"size": 3
}
}
Apply it to API Server:
$ curl -H 'Content-Type: application/json' -X PUT --data @body.json http://127.0.0.1:8080/apis/etcd.coreos.com/v1beta1/namespaces/default/clusters/example-etcd-cluster
We should see that etcd cluster will eventually reduce to 3 pods:
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
example-etcd-cluster-0002 1/1 Running 0 1m
example-etcd-cluster-0003 1/1 Running 0 1m
example-etcd-cluster-0004 1/1 Running 0 1m
If the minority of etcd members crash, the etcd operator will automatically recover the failure. Let's walk through 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-0000 --now
The etcd operator will recover the failure by creating a new pod example-etcd-cluster-0003
:
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
example-etcd-cluster-0001 1/1 Running 0 1m
example-etcd-cluster-0002 1/1 Running 0 1m
example-etcd-cluster-0003 1/1 Running 0 1m
Destroy etcd cluster:
$ kubectl delete -f example/example-etcd-cluster.yaml
If the etcd operator restarts, it can recover its previous state. Let's walk through in the following steps.
$ kubectl create -f example/example-etcd-cluster.yaml
Wait until all three members are up. Then
$ kubectl delete -f example/deployment.yaml
deployment "etcd-operator" deleted
$ kubectl delete pod example-etcd-cluster-0000 --now
pod "example-etcd-cluster-0000" deleted
Then 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-0001 1/1 Running 0 1m
example-etcd-cluster-0002 1/1 Running 0 1m
example-etcd-cluster-0003 1/1 Running 0 1m
If the majority of etcd members crash, but at least one backup exists for the cluster, the etcd operator can restore the entire cluster from the backup.
By default, the etcd operator creates a storage class on initialization:
$ kubectl get storageclass
NAME TYPE
etcd-backup-gce-pd kubernetes.io/gce-pd
This is used to request the persistent volume to store the backup data. See other backup options.
To enable backup, create an etcd cluster with backup enabled spec.
$ kubectl create -f example/example-etcd-cluster-with-backup.yaml
A persistent volume claim is created for the backup pod:
$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESSMODES AGE
example-etcd-cluster-with-backup-pvc Bound pvc-79e39bab-b973-11e6-8ae4-42010af00002 1Gi RWO 9s
Let's try to write some data into etcd:
$ kubectl run --rm -i --tty fun --image quay.io/coreos/etcd --restart=Never -- /bin/sh
/ # ETCDCTL_API=3 etcdctl --endpoints http://example-etcd-cluster-with-backup-0002:2379 put foo bar
OK
(ctrl-D to exit)
Now let's kill two pods to simulate a disaster failure:
$ kubectl delete pod example-etcd-cluster-with-backup-0000 example-etcd-cluster-with-backup-0001 --now
pod "example-etcd-cluster-with-backup-0000" deleted
pod "example-etcd-cluster-with-backup-0001" deleted
Now quorum is lost. The etcd operator will start to recover the cluster by:
- Creating a new seed member to recover from the backup
- Add more members until the size reaches to specified number
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
example-etcd-cluster-with-backup-0003 0/1 Init:0/2 0 11s
example-etcd-cluster-with-backup-backup-sidecar-e9gkv 1/1 Running 0 18m
...
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
example-etcd-cluster-with-backup-0003 1/1 Running 0 3m
example-etcd-cluster-with-backup-0004 1/1 Running 0 3m
example-etcd-cluster-with-backup-0005 1/1 Running 0 3m
example-etcd-cluster-with-backup-backup-sidecar-e9gkv 1/1 Running 0 22m
Finally, besides destroying the cluster, also cleanup the backup if you don't need it anymore:
$ kubectl delete pvc example-etcd-cluster-with-backup-pvc
Note: There could be a race that it will fall to single member recovery if a pod is recovered before another is deleted.
Have the following yaml file ready:
$ cat 3.0-etcd-cluster.yaml
apiVersion: "etcd.coreos.com/v1beta1"
kind: "Cluster"
metadata:
name: "example-etcd-cluster"
spec:
size: 3
version: "3.0.16"
Create an etcd cluster with the version specified (3.0.16) in the yaml file:
$ kubectl create -f 3.0-etcd-cluster.yaml
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
example-etcd-cluster-0000 1/1 Running 0 37s
example-etcd-cluster-0001 1/1 Running 0 25s
example-etcd-cluster-0002 1/1 Running 0 14s
The container image version should be 3.0.16:
$ kubectl get pod example-etcd-cluster-0000 -o yaml | grep "image:" | uniq
image: quay.io/coreos/etcd:v3.0.16
kubectl apply
doesn't work for TPR at the moment. See kubernetes/#29542.
We use cURL to update the cluster as a workaround.
Use kubectl to create a reverse proxy:
$ kubectl proxy --port=8080
Starting to serve on 127.0.0.1:8080
Have following json file ready: (Note that the version field is changed from 3.0.16 to 3.1.4)
$ cat body.json
{
"apiVersion": "etcd.coreos.com/v1beta1",
"kind": "Cluster",
"metadata": {
"name": "example-etcd-cluster"
},
"spec": {
"size": 3,
"version": "3.1.4"
}
}
Then we update the version in spec.
$ curl -H 'Content-Type: application/json' -X PUT --data @body.json \
http://127.0.0.1:8080/apis/etcd.coreos.com/v1beta1/namespaces/default/clusters/example-etcd-cluster
Wait ~30 seconds. The container image version should be updated to v3.1.4:
$ kubectl get pod example-etcd-cluster-0000 -o yaml | grep "image:" | uniq
image: quay.io/coreos/etcd:v3.1.4
Check the other two pods and you should see the same result.
-
The etcd operator only manages the etcd cluster created in the same namespace. Users need to create multiple operators in different namespaces to manage etcd clusters in different namespaces.
-
Backup works only for data in etcd3 storage, not for data in etcd2 storage.
-
PV Backup only works on GCE(kubernetes.io/gce-pd) and AWS(kubernetes.io/aws-ebs) for now.
-
Migration, the process of allowing the etcd operator to manage existing etcd3 clusters, only supports a single-member cluster, with its node running in the same Kubernetes cluster.
The operator collects anonymous usage statistics to help us learn how the software is being used and how we can improve it. To disable collection, run the operator with the flag -analytics=false
.