How to run an etcd cluster among pod replicas?

You can deploy etcd on kubernetes using an Operator (from the extensions/v1beta1) and the quay.io/coreos/etcd-operator image.

An example deployment with a cluster size of 3 looks like this:

apiVersion: extensions/v1beta1kind: Deploymentmetadata:  name: etcd-operatorspec:  replicas: 1  template:    metadata:      name: etcd-operator      labels:        app: etcd        component: operator    spec:      containers:      - name: etcd-operator        image: quay.io/coreos/etcd-operator:v0.3.0        env:        - name: MY_POD_NAMESPACE          valueFrom: { fieldRef: { fieldPath: metadata.namespace } }        - name: MY_POD_NAME          valueFrom: { fieldRef: { fieldPath: metadata.name } }---apiVersion: etcd.coreos.com/v1beta1kind: Clustermetadata:  name: etcd-cluster  labels:    app: etcd    component: clusterspec:  size: 3  version: "3.1.8"

Please be aware of the beta status of this project. However according to the maintainers the operator is now stable. I have deployed the configuration above successfully but I didn't run any of this in production.

The operator code is available on github. You can find additional documentation there.

There's a pretty good example of a three node etcd cluster here: https://github.com/coreos/etcd/tree/master/hack/kubernetes-deploy

They make use of separate rc's and services for each replica as a workaround until nominal services are added.

I added your question to kubernetes/kubernetes#5017

If someone knows the answer, they will hopefully post it there.

I think it may require the "nominal services" feature (kubernetes/kubernetes#260) which is not implemented yet, but I'm not sure.