Project: Velero (Runtime / Cloud Native Storage)
File: file-system-backup.md

title: "File System Backup" layout: docs Velero supports backing up and restoring Kubernetes volumes attached to pods from the file system of the volumes, called File System Backup (FSB shortly) or Pod Volume Backup. The data movement is fulfilled by using modules from free open-source backup tools to understand if it fits your use case. Velero allows you to take snapshots of persistent volumes as part of your backups if youre using one of the supported cloud providers block storage offerings (Amazon EBS Volumes, Azure Managed Disks, Google Persistent Disks). It also provides a plugin model that enables anyone to implement additional object and block storage backends, outside the main Velero repository. If your storage supports CSI (Container Storage Interface) snapshots, Velero also allows you to take snapshots through CSI and then optionally move the snapshot data to a different storage location. Velero's File System Backup is an addition to the aforementioned snapshot approaches. Its pros and cons are listed below: Pros: It is capable of backing up and restoring almost any type of Kubernetes volume. Therefore, if you need a volume snapshot plugin for your storage platform, or if you're using EFS, AzureFile, NFS, emptyDir, local, or any other volume type that doesn't have a native snapshot concept, FSB might be for you. It is not tied to a specific storage platform, so you could save the backup data to a different storage platform from the one backing Kubernetes volumes, for example, a durable storage. Cons: It backs up data from the live file system, in which way the data is not captured at the same point in time, so is less consistent than the snapshot approaches. It access the file system from the mounted hostpath directory, so Velero Node Agent pods need to run as root user and even under privileged mode in some environments. NOTE: hostPath volumes are not supported, but the is supported. Understand how Velero performs . the latest Velero release. Kubernetes v1.16.0 or later are required. Velero's File System Backup requires the Kubernetes . Velero Node Agent is a Kubernetes daemonset that hosts FSB modules, i.e., restic, kopia uploader & repository. To install Node Agent, use the `--use-node-agent` flag in the `velero install` command. See the for more details on other flags for the install command. ``` velero install --use-node-agent ``` When using FSB on a storage that doesn't have Velero support for snapshots, the `--use-volume-snapshots=false` flag prevents an unused `VolumeSnapshotLocation` from being created on installation. At present, Velero FSB supports object storage as the backup storage only. Velero gets the parameters from the to compose the URL to the backup storage. Velero's known object storage providers are include here , for which, Velero pre-defines the endpoints; if you want to use a different backup storage, make sure it is S3 compatible and you provide the correct bucket name and endpoint in BackupStorageLocation. Alternatively, for Restic, you could set the `resticRepoPrefix` value in BackupStorageLocation. For example, on AWS, `resticRepoPrefix` is something like `s3:s3-us-west-2.amazonaws.com/bucket` (note that `resticRepoPrefix` doesn't work for Kopia). Velero handles the creation of the backup repo prefix in the backup storage, so make sure it is specified in BackupStorageLocation correctly. Velero creates one backup repo per

For example, if backing up 2 namespaces, namespace1 and namespace2, using kopia repository on AWS S3, the full backup repo path for namespace1 would be `https://s3-us-west-2.amazonaws.com/bucket/kopia/ns1` and for namespace2 would be `https://s3-us-west-2.amazonaws.com/bucket/kopia/ns2`. There may be additional installation steps depending on the cloud provider plugin you are using. You should refer to the for the most up to date information. Note: Currently, Velero creates a secret named `velero-repo-credentials` in the velero install namespace, containing a default backup repository password. You can update the secret with your own password encoded as base64 prior to the first backup (i.e., FS Backup, data mover) targeting to the backup repository. The value of the key to update is ``` data: repository-password: <custom-password> ``` Backup repository is created during the first execution of backup targeting to it after installing Velero with node agent. If you update the secret password after the first backup which created the backup repository, then Velero will not be able to connect with the older backups. After installation, some PaaS/CaaS platforms based on Kubernetes also require modifications the node-agent DaemonSet spec. The steps in this section are only needed if you are installing on RancherOS, Nutanix, OpenShift, VMware Tanzu Kubernetes Grid Integrated Edition (formerly VMware Enterprise PKS), or Microsoft Azure. RancherOS Update the host path for volumes in the node-agent DaemonSet in the Velero namespace from `/var/lib/kubelet/pods` to `/opt/rke/var/lib/kubelet/pods`. ```yaml hostPath: path: /var/lib/kubelet/pods ``` to ```yaml hostPath: path: /opt/rke/var/lib/kubelet/pods ``` Nutanix Update the host path for volumes in the node-agent DaemonSet in the Velero namespace from `/var/lib/kubelet/pods` to `/var/nutanix/var/lib/kubelet`. ```yaml hostPath: path: /var/lib/kubelet/pods ``` to ```yaml hostPath: path: /var/nutanix/var/lib/kubelet ``` OpenShift To mount the correct hostpath to pods volumes, run the node-agent pod in `privileged` mode. Add the `velero` ServiceAccount to the `privileged` SCC: ``` oc adm policy add-scc-to-user privileged -z velero -n velero ``` Install Velero with the '--privileged-node-agent' option to request a privileged mode: ``` velero install --use-node-agent --privileged-node-agent ``` If node-agent is not running in a privileged mode, it will not be able to access pods volumes within the mounted hostpath directory because of the default enforced SELinux mode configured in the host system level. You can to relax the security in your cluster so that node-agent pods are allowed to use the hostPath volume plugin without granting them access to the `privileged` SCC. By default a userland openshift namespace will not schedule pods on all nodes in the cluster. To schedule on all nodes the namespace needs an annotation: ``` oc annotate namespace <velero namespace> openshift.io/node-selector="" ``` This should be done before velero installation. Or the ds needs to be deleted and recreated: ``` oc get ds node-agent -o yaml -n <velero namespace> > ds.yaml oc annotate namespace <velero namespace> openshift.io/node-selector="" oc create -n <velero namespace> -f ds.yaml ``` VMware Tanzu Kubernetes Grid Integrated Edition (formerly VMware Enterprise PKS) You need to enable the `Allow Privileged` option in your plan configuration so that Velero is able to mount the hostpath. The hostPath should be changed from `/var/lib/kubelet/pods` to `/var/vcap/data/kubelet/pods` ```yaml hostPath: path: /var/vcap/data/kubelet/pods ``` Velero supports two approaches of discovering pod volumes that need to be backed up using FSB: Opt-in approach: Where every pod containing a volume to be backed up using FSB must be annotated with the volume's name. Opt-out approach: Where all pod volumes are backed up using FSB, with the ability to opt-out any volumes that should not be backed

The following sections provide more details on the two approaches. In this approach, Velero will back up all pod volumes using FSB with the exception of: Volumes mounting the default service account token, Kubernetes Secrets, and ConfigMaps Hostpath volumes It is possible to exclude volumes from being backed up using the `backup.velero.io/backup-volumes-excludes` annotation on the pod. Instructions to back up using this approach are as follows: Run the following command on each pod that contains volumes that should not be backed up using FSB ```bash kubectl -n YOURPODNAMESPACE annotate pod/YOURPODNAME backup.velero.io/backup-volumes-excludes=YOURVOLUMENAME1,YOURVOLUMENAME2,... ``` where the volume names are the names of the volumes in the pod spec. For example, in the following pod: ```yaml apiVersion: v1 kind: Pod metadata: name: app1 namespace: sample spec: containers: image: k8s.gcr.io/test-webserver name: test-webserver volumeMounts: name: pvc1-vm mountPath: /volume-1 name: pvc2-vm mountPath: /volume-2 volumes: name: pvc1-vm persistentVolumeClaim: claimName: pvc1 name: pvc2-vm claimName: pvc2 ``` to exclude FSB of volume `pvc1-vm`, you would run: ```bash kubectl -n sample annotate pod/app1 backup.velero.io/backup-volumes-excludes=pvc1-vm ``` Take a Velero backup: ```bash velero backup create BACKUPNAME --default-volumes-to-fs-backup OTHEROPTIONS ``` The above steps uses the opt-out approach on a per backup basis. Alternatively, this behavior may be enabled on all velero backups running the `velero install` command with the `--default-volumes-to-fs-backup` flag. Refer for details. When the backup completes, view information about the backups: ```bash velero backup describe YOURBACKUPNAME ``` ```bash kubectl -n velero get podvolumebackups -l velero.io/backup-name=YOURBACKUPNAME -o yaml ``` Velero, by default, uses this approach to discover pod volumes that need to be backed up using FSB. Every pod containing a volume to be backed up using FSB must be annotated with the volume's name using the `backup.velero.io/backup-volumes` annotation. Instructions to back up using this approach are as follows: Run the following for each pod that contains a volume to back up: ```bash kubectl -n YOURPODNAMESPACE annotate pod/YOURPODNAME backup.velero.io/backup-volumes=YOURVOLUMENAME1,YOURVOLUMENAME2,... ``` where the volume names are the names of the volumes in the pod spec. For example, for the following pod: ```yaml apiVersion: v1 kind: Pod metadata: name: sample namespace: foo spec: containers: image: k8s.gcr.io/test-webserver name: test-webserver volumeMounts: name: pvc-volume mountPath: /volume-1 name: emptydir-volume mountPath: /volume-2 volumes: name: pvc-volume persistentVolumeClaim: claimName: test-volume-claim name: emptydir-volume emptyDir: {} ``` You'd run: ```bash kubectl -n foo annotate pod/sample backup.velero.io/backup-volumes=pvc-volume,emptydir-volume ``` This annotation can also be provided in a pod template spec if you use a controller to manage your pods. Take a Velero backup: ```bash velero backup create NAME OPTIONS... ``` When the backup completes, view information about the backups: ```bash velero backup describe YOURBACKUPNAME ``` ```bash kubectl -n velero get podvolumebackups -l velero.io/backup-name=YOURBACKUPNAME -o yaml ``` Regardless of how volumes are discovered for backup using FSB, the process of restoring remains the same. Restore from your Velero backup: ```bash velero restore create --from-backup BACKUP_NAME OPTIONS... ``` When the restore completes, view information about your pod volume restores: ```bash velero restore describe YOURRESTORENAME ``` ```bash kubectl -n velero get podvolumerestores -l velero.io/restore-name=YOURRESTORENAME -o yaml ``` `hostPath` volumes are not supported. are supported. At present, Velero uses a static, common encryption key for all backup repositories it creates. This means that anyone who has access to your backup storage can decrypt your backup data. Make sure that you limit access to the backup storage appropriately. An incremental backup chain will be maintained across pod reschedules for

However, for pod volumes that are not PVCs, such as `emptyDir` volumes, when a pod is deleted/recreated (for example, by a ReplicaSet/Deployment), the next backup of those volumes will be full rather than incremental, because the pod volume's lifecycle is assumed to be defined by its pod. Even though the backup data could be incrementally preserved, for a single file data, FSB leverages on deduplication to find the difference to be saved. This means that large files (such as ones storing a database) will take a long time to scan for data deduplication, even if the actual difference is small. You may need to to make sure backups complete successfully for massive small files or large backup size cases, for more details refer to . Velero's File System Backup reads/writes data from volumes by accessing the node's filesystem, on which the pod is running. For this reason, FSB can only backup volumes that are mounted by a pod and not directly from the PVC. For orphan PVC/PV pairs (without running pods), some Velero users overcame this limitation running a staging pod (i.e. a busybox or alpine container with an infinite sleep) to mount these PVC/PV pairs prior taking a Velero backup. Velero File System Backup expects volumes to be mounted under `<hostPath>/<pod UID>` (`hostPath` is configurable as mentioned in ). Some Kubernetes systems (i.e., ) don't mount volumes under the `<pod UID>` sub-dir, Velero File System Backup is not working with them. File system restores of the same pod won't start until all the volumes of the pod get bound, even though some of the volumes have been bound and ready for restore. An a result, if a pod has multiple volumes, while only part of the volumes are restored by file system restore, these file system restores won't start until the other volumes are restored completely by other restore types (i.e., , ), the file system restores won't happen concurrently with those other types of restores. Velero uses a helper init container when performing a FSB restore. By default, the image for this container is `velero/velero-restore-helper:<VERSION>`, where `VERSION` matches the version/tag of the main Velero image. You can customize the image that is used for this helper by creating a ConfigMap in the Velero namespace with the alternate image. In addition, you can customize the resource requirements for the init container, should you need. The ConfigMap must look like the following: ```yaml apiVersion: v1 kind: ConfigMap metadata: name: fs-restore-action-config namespace: velero labels: velero.io/plugin-config: "" velero.io/pod-volume-restore: RestoreItemAction data: image: myregistry.io/my-custom-helper-image[:OPTIONAL_TAG] cpuRequest: 200m memRequest: 128Mi cpuLimit: 200m memLimit: 128Mi secCtxRunAsUser: 1001 secCtxRunAsGroup: 999 secCtxAllowPrivilegeEscalation: false secCtx: | capabilities: drop: ALL add: [] allowPrivilegeEscalation: false readOnlyRootFilesystem: true runAsUser: 1001 runAsGroup: 999 ``` Run the following checks: Are your Velero server and daemonset pods running? ```bash kubectl get pods -n velero ``` Does your backup repository exist, and is it ready? ```bash velero repo get velero repo get REPO_NAME -o yaml ``` Are there any errors in your Velero backup/restore? ```bash velero backup describe BACKUP_NAME velero backup logs BACKUP_NAME velero restore describe RESTORE_NAME velero restore logs RESTORE_NAME ``` What is the status of your pod volume backups/restores? ```bash kubectl -n velero get podvolumebackups -l velero.io/backup-name=BACKUP_NAME -o yaml kubectl -n velero get podvolumerestores -l

-o yaml ``` Is there any useful information in the Velero server or daemon pod logs? ```bash kubectl -n velero logs deploy/velero kubectl -n velero logs DAEMONPODNAME ``` NOTE: You can increase the verbosity of the pod logs by adding `--log-level=debug` as an argument to the container command in the deployment/daemonset pod template spec. Velero integrate Restic binary directly, so the operations are done by calling Restic commands: Run `restic init` command to initialize the Run `restic prune` command periodically to prune restic repository Run `restic backup` commands to backup pod volume data Run `restic restore` commands to restore pod volume data Velero integrate Kopia modules into Velero's code, primarily two modules: Kopia Uploader: Velero makes some wrap and isolation around it to create a generic file system uploader, which is used to backup pod volume data Kopia Repository: Velero integrates it with Velero's Unified Repository Interface, it is used to preserve the backup data and manage the backup storage For more details, refer to and Velero's Velero has three custom resource definitions and associated controllers: `BackupRepository` - represents/manages the lifecycle of Velero's backup repositories. Velero creates a backup repository per namespace when the first FSB backup/restore for a namespace is requested. The backup repository is backed by restic or kopia, the `BackupRepository` controller invokes restic or kopia internally, refer to and for details. You can see information about your Velero's backup repositories by running `velero repo get`. `PodVolumeBackup` - represents a FSB backup of a volume in a pod. The main Velero backup process creates one or more of these when it finds an annotated pod. Each node in the cluster runs a controller for this resource (in a daemonset) that handles the `PodVolumeBackups` for pods on that node. `PodVolumeBackup` is backed by restic or kopia, the controller invokes restic or kopia internally, refer to and for details. `PodVolumeRestore` - represents a FSB restore of a pod volume. The main Velero restore process creates one or more of these when it encounters a pod that has associated FSB backups. Each node in the cluster runs a controller for this resource (in the same daemonset as above) that handles the `PodVolumeRestores` for pods on that node. `PodVolumeRestore` is backed by restic or kopia, the controller invokes restic or kopia internally, refer to and for details. Velero's FSB supports two data movement paths, the restic path and the kopia path. Velero allows users to select between the two paths: For backup, the path is specified at the installation time through the `uploader-type` flag, the valid value is either `restic` or `kopia`, or default to `kopia` if the value is not specified. The selection is not allowed to be changed after the installation. For restore, the path is decided by the path used to back up the data, it is automatically selected. For example, if you've created a backup with restic path, then you reinstall Velero with `uploader-type=kopia`, when you create a restore from the backup, the restore still goes with restic path. Based on configuration, the main Velero backup process uses the opt-in or opt-out approach to check each pod that it's backing up for the volumes to be backed up using

When found, Velero first ensures a backup repository exists for the pod's namespace, by: checking if a `BackupRepository` custom resource already exists if not, creating a new one, and waiting for the `BackupRepository` controller to init/connect it Velero then creates a `PodVolumeBackup` custom resource per volume listed in the pod annotation The main Velero process now waits for the `PodVolumeBackup` resources to complete or fail Meanwhile, each `PodVolumeBackup` is handled by the controller on the appropriate node, which: has a hostPath volume mount of `/var/lib/kubelet/pods` to access the pod volume data finds the pod volume's subdirectory within the above volume based on the path selection, Velero invokes restic or kopia for backup updates the status of the custom resource to `Completed` or `Failed` As each `PodVolumeBackup` finishes, the main Velero process adds it to the Velero backup in a file named `<backup-name>-podvolumebackups.json.gz`. This file gets uploaded to object storage alongside the backup tarball. It will be used for restores, as seen in the next section. The main Velero restore process checks each existing `PodVolumeBackup` custom resource in the cluster to backup from. For each `PodVolumeBackup` found, Velero first ensures a backup repository exists for the pod's namespace, by: checking if a `BackupRepository` custom resource already exists if not, creating a new one, and waiting for the `BackupRepository` controller to connect it (note that in this case, the actual repository should already exist in backup storage, so the Velero controller will simply check it for integrity and make a location connection) Velero adds an init container to the pod, whose job is to wait for all FSB restores for the pod to complete (more on this shortly) Velero creates the pod, with the added init container, by submitting it to the Kubernetes API. Then, the Kubernetes scheduler schedules this pod to a worker node. If the pod fails to be scheduled for some reason (i.e. lack of cluster resources), the FSB restore will not be done. Velero creates a `PodVolumeRestore` custom resource for each volume to be restored in the pod The main Velero process now waits for each `PodVolumeRestore` resource to complete or fail Meanwhile, each `PodVolumeRestore` is handled by the controller on the appropriate node, which: has a hostPath volume mount of `/var/lib/kubelet/pods` to access the pod volume data waits for the pod to be running the init container finds the pod volume's subdirectory within the above volume based on the path selection, Velero invokes restic or kopia for restore on success, writes a file into the pod volume, in a `.velero` subdirectory, whose name is the UID of the Velero restore that this pod volume restore is for updates the status of the custom resource to `Completed` or `Failed` The init container that was added to the pod is running a process that waits until it finds a file within each restored volume, under `.velero`, whose name is the UID of the Velero restore being run Once all such files are found, the init container's process terminates successfully and the pod moves on to running other init containers/the main containers. Velero won't restore a resource if a that resource is scaled to 0 and already exists in the cluster. If Velero restored the requested pods in this scenario, the Kubernetes reconciliation loops that manage resources would delete the running pods because its scaled to be 0. Velero will be able to restore once the resources is scaled up, and the pods are created and remain running. Velero does not provide a mechanism to detect persistent volume claims that are missing the File System Backup annotation. To solve this,