## 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.

## 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:
```bash
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:

```bash
# 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:

```bash
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:

```bash
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`.