Add docs for etcd backups and set default for etcd backup restore ima…

…ge (#221)

* Add docs for etcd backups and set default for etcd backup restore image

docs/src/topics/backups.md

@@ -8,7 +8,15 @@ Enabling this addon requires enabling Object Storage in the account where the re
 
 ## Enabling Backups
 
-TODO
+To enable backups, use the addon flag during provisioning to select the etcd-backup-restore addon
+```sh
+clusterctl generate cluster $CLUSTER_NAME \
+  --kubernetes-version v1.29.1 \
+  --infrastructure linode:0.0.0 \
+  --flavor etcd-backup-restore \
+  | kubectl apply -f -
+```
+For more fine-grain control and to know more about etcd backups, refere [backups.md](../topics/etcd.md)
 
 ## Object Storage
 
@@ -41,13 +49,13 @@ The bucket label must be unique within the region across all accounts. Otherwise
 
 ### Access Keys Creation
 
-CAPL will also create `read_write` and `read_only` access keys for the bucket and store credentials in a secret in the same namespace where the `LinodeObjectStorageBucket` was created:
+CAPL will also create `read_write` and `read_only` access keys for the bucket and store credentials in a secret in the same namespace where the `LinodeObjectStorageBucket` was created alongwith other details about the Linode OBJ Bucket:
 
 ```yaml
 apiVersion: v1
 kind: Secret
 metadata:
-  name: <unique-bucket-label>-access-keys
+  name: <unique-bucket-label>-bucket-details
   namespace: <same-namespace-as-object-storage-bucket>
   ownerReferences:
     - apiVersion: infrastructure.cluster.x-k8s.io/v1alpha1
@@ -56,13 +64,15 @@ metadata:
       controller: true
 data:
   bucket_name: <unique-bucket-label>
+  bucket_region: <linode-obj-bucket-region>
+  bucket_endpoint: <hostname-to-access-bucket>
   access_key_rw: <base64-encoded-access-key>
   secret_key_rw: <base64-encoded-secret-key>
   access_key_ro: <base64-encoded-access-key>
   secret_key_ro: <base64-encoded-secret-key>
 ```
 
-The access key secret is owned and managed by CAPL during the life of the `LinodeObjectStorageBucket`.
+The bucket-details secret is owned and managed by CAPL during the life of the `LinodeObjectStorageBucket`.
 
 ### Access Keys Rotation
 
@@ -105,7 +115,7 @@ status:
   hostname: <hostname-for-bucket>
   creationTime: <bucket-creation-timestamp>
   lastKeyGeneration: 0
-  keySecretName: <unique-bucket-label>-access-keys
+  keySecretName: <unique-bucket-label>-bucket-details
   accessKeyRefs:
     - <access-key-rw-id>
     - <access-key-ro-id>

docs/src/topics/etcd.md

@@ -7,3 +7,32 @@ This guide covers etcd configuration for the control plane of provisioned CAPL c
 By default, etcd is configured to be on a separate device from the root filesystem on
 control plane nodes. The etcd disk is automatically sized at 10 GB with a quota backend of 8 GB per
 recommendation from [the etcd documentation](https://etcd.io/docs/latest/dev-guide/limit/#storage-size-limit)
+
+## ETCD Backups
+
+By default, etcd is not backed-up. To enable backups, users need to choose the etcd-backup-restore flavor.
+
+To begin with, this will deploy a Linode OBJ bucket. This serves as the S3-compatible target to store backups.
+
+Next up, on provisioning the cluster, [etcd-backup-restore](https://github.com/gardener/etcd-backup-restore) is deployed as a statefulset.
+The pod will need the bucket details like the name, region, endpoints and access credentials which are passed using the 
+bucket-details secret that is created when the OBJ bucket gets created.
+
+### Enabling SSE
+Users can also enable SSE(Server_side encryption) by passing a SSE AES-256 Key as an env var. All env vars [here](../../../templates/addons/etcd-backup-restore/etcd-backup-restore.yaml) on the pod can be controlled during the provisioning process.
+
+> [!WARNING]  
+> This is currently under development and will be available for use once the upstream [PR](https://github.com/gardener/etcd-backup-restore/pull/719) is merged and an official image is made available
+
+For eg:
+```sh
+export CLUSTER_NAME=test
+export OBJ_BUCKET_REGION=us-ord-1
+export ETCDBR_IMAGE=docker.io/username/your-custom-image:version
+export SSE_KEY=cdQdZ3PrKgm5vmqxeqwQCuAWJ7pPVyHg
+clusterctl generate cluster $CLUSTER_NAME \
+  --kubernetes-version v1.29.1 \
+  --infrastructure linode:0.0.0 \
+  --flavor etcd-backup-restore \
+  | kubectl apply -f -
+```

docs/src/topics/flavors/etcd-backup-restore.md

@@ -0,0 +1,15 @@
+# etcd-backup-restore
+
+## Specification
+| Control Plane | CNI    | Default OS   | Installs ClusterClass | Installs etcd backup |
+|---------------|--------|--------------|-----------------------|----------------------|
+| Kubeadm       | Cilium | Ubuntu 22.04 | No                    | Yes                  |
+
+## Prerequisites
+[Quickstart](../topics/getting-started.md) completed
+
+## Notes
+This flavor is identical to the default flavor with the addon etcd-backup-restore enabled
+
+## Usage
+Refer [backups.md](../backups.md)