coreos/etcd-operator

Name: etcd-operator

Owner: CoreOS

Description: etcd operator creates/configures/manages etcd clusters atop Kubernetes

Created: 2016-08-04 23:54:58.0

Updated: 2018-01-18 15:31:42.0

Pushed: 2018-01-18 21:44:57.0

Homepage: https://coreos.com/blog/introducing-the-etcd-operator.html

Size: 2992

Language: Go

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README

etcd operator

unit/integration: e2e (Kubernetes stable): e2e (upgrade):

Project status: beta

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. See upgrade guide for a safe upgrade process.

Currently user facing etcd cluster objects are created as Kubernetes Custom 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.

Overview

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.

Requirements

• Kubernetes 1.8+
• etcd 3.2.13+

Demo

Getting started

Deploy etcd operator

See instructions on how to install/uninstall etcd operator .

Create and destroy an etcd cluster

bectl create -f example/example-etcd-cluster.yaml

A 3 member etcd cluster will be created.

bectl get pods
                            READY     STATUS    RESTARTS   AGE
ple-etcd-cluster-gxkmr9ql7z   1/1       Running   0          1m
ple-etcd-cluster-m6g62x6mwc   1/1       Running   0          1m
ple-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:

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

Destroy the etcd cluster:

bectl delete -f example/example-etcd-cluster.yaml

Resize an etcd cluster

Create an etcd cluster:

bectl 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.

t example/example-etcd-cluster.yaml
ersion: "etcd.database.coreos.com/v1beta2"
: "EtcdCluster"
data:
me: "example-etcd-cluster"
:
ze: 5
rsion: "3.2.13"

Apply the size change to the cluster CR:

bectl apply -f example/example-etcd-cluster.yaml

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

bectl get pods
                            READY     STATUS    RESTARTS   AGE
ple-etcd-cluster-cl2gpqsmsw   1/1       Running   0          5m
ple-etcd-cluster-cx2t6v8w78   1/1       Running   0          5m
ple-etcd-cluster-gxkmr9ql7z   1/1       Running   0          7m
ple-etcd-cluster-m6g62x6mwc   1/1       Running   0          7m
ple-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.

t example/example-etcd-cluster.yaml
ersion: "etcd.database.coreos.com/v1beta2"
: "EtcdCluster"
data:
me: "example-etcd-cluster"
:
ze: 3
rsion: "3.2.13"

bectl apply -f example/example-etcd-cluster.yaml

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

bectl get pods
                            READY     STATUS    RESTARTS   AGE
ple-etcd-cluster-cl2gpqsmsw   1/1       Running   0          6m
ple-etcd-cluster-gxkmr9ql7z   1/1       Running   0          8m
ple-etcd-cluster-rqk62l46kw   1/1       Running   0          9mp

Failover

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:

bectl create -f example/example-etcd-cluster.yaml

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

bectl delete pod example-etcd-cluster-cl2gpqsmsw --now

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

bectl get pods
                            READY     STATUS    RESTARTS   AGE
ple-etcd-cluster-gxkmr9ql7z   1/1       Running   0          10m
ple-etcd-cluster-n4h66wtjrg   1/1       Running   0          26s
ple-etcd-cluster-rqk62l46kw   1/1       Running   0          10m

Destroy etcd cluster:

bectl delete -f example/example-etcd-cluster.yaml

etcd operator recovery

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

Create an etcd cluster:

bectl 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:

bectl delete -f example/deployment.yaml
oyment "etcd-operator" deleted

bectl delete pod example-etcd-cluster-8gttjl679c --now
"example-etcd-cluster-8gttjl679c" deleted

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

bectl create -f example/deployment.yaml
oyment "etcd-operator" created

bectl get pods
                              READY     STATUS    RESTARTS   AGE
ple-etcd-cluster-m8gk76l4ns   1/1       Running   0          3m
ple-etcd-cluster-q6mff85hml   1/1       Running   0          3m
ple-etcd-cluster-xnfvm7lg66   1/1       Running   0          11s

Upgrade an etcd cluster

Create and have the following yaml file ready:

t upgrade-example.yaml
ersion: "etcd.database.coreos.com/v1beta2"
: "EtcdCluster"
data:
me: "example-etcd-cluster"
:
ze: 3
rsion: "3.1.10"
pository: "quay.io/coreos/etcd"

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

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

The container image version should be 3.1.10:

bectl 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:

t upgrade-example
ersion: "etcd.database.coreos.com/v1beta2"
: "EtcdCluster"
data:
me: "example-etcd-cluster"
:
ze: 3
rsion: "3.2.13"

Apply the version change to the cluster CR:

bectl apply -f upgrade-example

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

bectl 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.

Backup and Restore an etcd cluster

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.

Manage etcd clusters in all namespaces

See instructions on clusterwide feature.