kops/docs/etcd/manager.md

etcd-manager

etcd-manager is a kubernetes-associated project that kops will use to manage etcd (at least that is the plan per the roadmap).

etcd-manager uses many of the same ideas as the existing etcd implementation built into kops, but it addresses some limitations also:

• separate from kops - can be used by other projects
• allows etcd2 -> etcd3 upgrade (along with minor upgrades)
• allows cluster resizing (e.g. going from 1 to 3 nodes)

etcd-manager is currently in early alpha - it is undergoing testing. However, if you have a test cluster where you don't mind if it erases all your data, please do try it out and provide feedback.

If using kubernetes >= 1.12 (which will not formally be supported until kops 1.12), note that etcd-manager will be used by default. You can override this with the cluster.spec.etcdClusters[*].provider=Legacy override. This can be specified:

• as an argument to kops create cluster: --overrides cluster.spec.etcdClusters[*].provider=Legacy
• on an existing cluster with kops set cluster cluster.spec.etcdClusters[*].provider=Legacy
• by setting the field using kops edit or kops replace, manually making the same change as kops set cluster ...

(Note you will probably have to export KOPS_FEATURE_FLAGS=SpecOverrideFlag)

How to use etcd-manager

Reminder: etcd-manager is alpha, and may cause you to lose the data in your kubernetes cluster.

To create a test cluster:

kops create cluster test.k8s.local --zones us-east-1c --master-count 3
kops update cluster test.k8s.local --yes

# Wait for cluster to boot up
kubectl get nodes

You can enable the etcd-manager - it will adopt the existing etcd data, though it won't change the configuration:

# Enable etcd-manager
kops set cluster cluster.spec.etcdClusters[*].manager.image=kopeio/etcd-manager:latest

kops update cluster --yes
kops rolling-update cluster --yes

After the masters restart, you will still be running etcd 2.2. You can change the version of etcd:

kops set cluster cluster.spec.etcdClusters[*].version=3.2.18

kops update cluster --yes
kops rolling-update cluster --yes

It should be safe to combine the etcd-manager adoption and etcd upgrade into a single restart, but we are working on boosting test coverage.

When you're done, you can shut down the cluster:

kops delete cluster example.k8s.local --yes

You can also do this for existing clusters. though remember that this is still an early alpha, so don't use for clusters with important data. You just run the two kops set cluster commands. Note that kops set cluster is just an easy command line way to set some fields in the cluster spec - if you're using a GitOps approach you can change the manifest files directly. You can also kops edit cluster.