Enable parameterized kubelet mount path during node-agent installation (#9074)

Enable parameterized kubelet mount path during node-agent installation

Signed-off-by: longyuxiang <longyuxiang@kylinos.cn>

site/content/docs/main/customize-installation.md

@@ -31,6 +31,9 @@ For some use cases, Velero node-agent requires to run under privileged mode. For
 
 If you've already run `velero install` without the `--use-node-agent` or `--privileged-node-agent` flag, you can run the same command again, including the `--use-node-agent` or `--privileged-node-agent` flag, to add CSI snapshot data movement to your existing install.
 
+## Customize the kubelet root path of the node-agent
+When installing with the `--use-node-agent` flag, the node-agent will mount the default kubelet paths `/var/lib/kubelet/pods` and `/var/lib/kubelet/plugins` (hostPath). To customize these kubelet mount paths, use the `--kubelet-root-dir` flag.
+
 ## Default Pod Volume backup to file system backup
 
 By default, `velero install` does not enable the use of File System Backup (FSB) to take backups of all pod volumes. You must apply an [annotation](file-system-backup.md/#using-opt-in-pod-volume-backup) to every pod which contains volumes for Velero to use FSB for the backup.

site/content/docs/main/velero-install.md

@@ -21,6 +21,7 @@ velero install \
     --velero-pod-mem-request <MEMORY_REQUEST> \
     --velero-pod-cpu-limit <CPU_LIMIT> \
     --velero-pod-mem-limit <MEMORY_LIMIT> \
+    --kubelet-root-dir <PATH_TO_KUBELET_ROOT_DIR> \
     [--use-node-agent] \
     [--default-volumes-to-fs-backup] \
     [--node-agent-pod-cpu-request <CPU_REQUEST>] \