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Update etcd-backup-and-restore.md

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vpalazhi 2021-03-25 18:51:42 -04:00 committed by GitHub
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practice-questions-answers/cluster-maintenance/backup-etcd/etcd-backup-and-restore.md
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@ -52,17 +52,10 @@ ETCDCTL_API=3 etcdctl --data-dir /var/lib/etcd-from-backup \
Note: In this case, we are restoring the snapshot to a different directory but in the same server where we took the backup (**the controlplane node)**
As a result, the only required option for the restore command is the **--data-dir**.
# 4. Modify /etc/kubernetes/manifests/etcd.yaml
Update --data-dir to use new target location
```
--data-dir=/var/lib/etcd-from-backup
```
Update ETCD POD to use the new hostPath directory `/var/lib/etcd-from-backup` by modifying the pod definition file at `/etc/kubernetes/manifests/etcd.yaml`. When this file is updated, the ETCD pod is automatically re-created as this is a static pod placed under the `/etc/kubernetes/manifests` directory.
Update volumes and volume mounts to point to new path
We have now restored the etcd snapshot to a new path on the controlplane - **/var/lib/etcd-from-backup**, so the only change to be made in the YAML file is to change the hostPath for the volume called **etcd-data** from old directory (/var/lib/etcd) to the new directory **/var/lib/etcd-from-backup**.
```
volumes:
@ -70,12 +63,16 @@ Update volumes and volume mounts to point to new path
path: /var/lib/etcd-from-backup
type: DirectoryOrCreate
name: etcd-data
- hostPath:
path: /etc/kubernetes/pki/etcd
type: DirectoryOrCreate
name: etcd-certs
```
With this change, /var/lib/etcd on the **container** points to /var/lib/etcd-from-backup on the host (which is what we want)
When this file is updated, the ETCD pod is automatically re-created as this is a static pod placed under the `/etc/kubernetes/manifests` directory.
> Note: as the ETCD pod has changed it will automatically restart, and also kube-controller-manager and kube-scheduler. Wait 1-2 to mins for this pods to restart. You can make a `watch "docker ps | grep etcd"` to see when the ETCD pod is restarted.
> Note2: If the etcd pod is not getting `Ready 1/1`, then restart it by `kubectl delete pod -n kube-system etcd-controlplane` and wait 1 minute.
> Note3: This is the simplest way to make sure that ETCD uses the restored data after the ETCD pod is recreated. You **don't** have to change anything else.
**If** you change **--data-dir** to **/var/lib/etcd-from-backup** in the YAML file, make sure that the **volumeMounts** for **etcd-data** is updated as well, with the mountPath pointing to /var/lib/etcd-from-backup (THIS COMPLETE STEP IS OPTIONAL AND NEED NOT BE DONE FOR COMPLETING THE RESTORE)