# How to Rescue Your Kubernetes Cluster with etcd Backups

### **How to perform a backup of the etcd datastore**

To back up the cluster store, or `etcd`, we can create a snapshot file using the CLI tool `etcdctl`. This lab assumes a successful installation of the `etcdctl` tool and that prior knowledge of what `etcd` is and its purpose exists.

```bash
# First perform the backup with snapshot option 
$ etcdctl snapshot save etcd-backup --cacert /etc/kubernetes/pki/etcd/ca.crt --cert /etc/kubernetes/pki/etcd/server.crt --key /etc/kubernetes/pki/etcd/server.crt

# ... Output omitted
Snapshot saved at etcd-backup
```

`--cacert` verifies certificates using the k8s Certificate Authority (CA) `--cert` identifies secure client using the `etcd` server certificate `--key` identifies secure client using the `etcd` key file

### **Restoring the etcd backup**

To restore the backup we use again the `etcdctl` CLI tool and the `snapshot` command. What's key in this task is that the backup will be **restored to an** `etcd` directory. That's why we use the `--data-dir` option with the command.

```bash
# Second perform the restore operation
# The command here will restore the backup to the /var/lib/etcd-backup directory
$ etcdctl snapshot restore etcd-backup --data-dir /var/lib/etcd-backup

# ... Output omitted
```

### **Change the location of the etcd data**

Once the backup and restore operations are completed, the next step is to change the location where Kubernetes looks for the `etcd` data.

To do this, we need to change the YAML file for the `etcd.yaml` manifest which is located in `/etc/kubernetes/manifests/`. Why in this directory? Because any YAML placed in this directory will be scheduled by the `kube-scheduler` process.

The part of the file that needs to be changed is at the bottom.

```yaml
volumes:
- hostPath:
    path: /etc/kubernetes/pki/etcd
    type: DirectoryOrCreate
  name: etcd-certs
- hostPath:
    path: /var/lib/etcd-backup # <--- This is the directory where we stored the snapshot
    type: DirectoryOrCreate
  name: etcd-data
```

With that done, Kubernetes will perform the necessary actions and receive an API response from the server with the new cluster data.