RestoreBatch

What is RestoreBatch

A RestoreBatch is a Kubernetes CustomResourceDefinition(CRD) which allows you to restore multiple co-related components( eg, workloads, databases, etc.) together that were backed up via a BackupBatch.

RestoreBatch CRD Specification

Like any official Kubernetes resource, a RestoreBatch has TypeMeta, ObjectMeta, Spec and Status sections. A sample RestoreBatch object to restore multiple co-related components is shown below:

apiVersion: stash.appscode.com/v1beta1
kind: RestoreBatch
metadata:
  name: batch-restore
  namespace: demo
spec:
  driver: Restic
  repository:
    name: minio-repo
  executionOrder: Parallel
  members:
  - target:
      alias: app
      ref:
        apiVersion: apps/v1
        kind: Deployment
        name: wordpress
      rules:
      - paths:
        - /var/www/html
      volumeMounts:
      - mountPath: /var/www/html
        name: wordpress-persistent-storage
  - target:
      alias: db
      ref:
        apiVersion: appcatalog.appscode.com/v1alpha1
        kind: AppBinding
        name: wordpress-mysql
      rules:
      - snapshots:
        - latest
    task:
      name: mysql-restore-8.0.14
status:
  phase: Succeeded
  sessionDuration: 15.145032437s
  conditions:
  - lastTransitionTime: "2020-07-25T17:41:52Z"
    message: Repository demo/minio-repo exist.
    reason: RepositoryAvailable
    status: "True"
    type: RepositoryFound
  - lastTransitionTime: "2020-07-25T17:41:52Z"
    message: Backend Secret demo/minio-secret exist.
    reason: BackendSecretAvailable
    status: "True"
    type: BackendSecretFound
  members:
  - conditions:
    - lastTransitionTime: "2020-07-25T17:41:52Z"
      message: Restore target apps/v1 deployment/wordpress
        found.
      reason: TargetAvailable
      status: "True"
      type: RestoreTargetFound
    - lastTransitionTime: "2020-07-25T17:41:52Z"
      message: Successfully injected stash init-container.
      reason: InitContainerInjectionSucceeded
      status: "True"
      type: StashInitContainerInjected
    phase: Succeeded
    ref:
      apiVersion: apps/v1
      kind: Deployment
      name: wordpress
    stats:
    - duration: 822.861322ms
      hostname: app
      phase: Succeeded
    totalHosts: 1
  - conditions:
    - lastTransitionTime: "2020-07-25T17:41:52Z"
      message: Restore target appcatalog.appscode.com/v1alpha1 appbinding/wordpress-mysql
        found.
      reason: TargetAvailable
      status: "True"
      type: RestoreTargetFound
    - lastTransitionTime: "2020-07-25T17:41:52Z"
      message: Successfully created restore job.
      reason: RestoreJobCreationSucceeded
      status: "True"
      type: RestoreJobCreated
    phase: Succeeded
    ref:
      apiVersion: appcatalog.appscode.com/v1alpha1
      kind: AppBinding
      name: wordpress-mysql
    stats:
    - duration: 4.597812876s
      hostname: db
      phase: Succeeded
    totalHosts: 1

Here, we are going to describe the various sections of RestoreBatch crd.

RestoreBatch Spec

A RestoreBatch object has the following fields in the spec section.

spec.driver

spec.driver indicates the mechanism used to restore. Currently, Stash supports Restic and VolumeSnapshotter as drivers. The default value of this field is Restic. For more details, please see here.

spec.repository

spec.repository.name indicates the Repository crd name that holds necessary backend information from where data will be restored.

spec.executionOrder

spec.executionOrder specifies whether Stash should restore the targets sequentially or parallelly. If spec.executionOrder is set to Parallel, Stash will start to restore of all the targets simultaneously. If it is set to Sequential, Stash will not start restoring a target until all the previous members have completed their restore process. The default value of this field is Parallel.

spec.members

spec.members field specifies a list of targets to restore. Each member consists of the following fields:

• target : Each member has a target specification. The target specification of a member is the same as the target specification of a RestoreSession explained here.

• task : task specifies the name and parameters of the Task crd to use to restore the member. For more details, please see here.

• runtimeSettings : runtimeSettings allows to configure runtime environment for the restore init-container or job. You can specify runtime settings at both pod level and container level. For more details, please see here.

• tempDir : Stash mounts an emptyDir for holding temporary files. It is also used for caching for faster restore performance. You can configure the emptyDir using tempDir section. You can also disable caching using this field. For more details, please see here.

• interimVolumeTemplate : For some targets (i.e. some databases), Stash can’t directly pipe the restored data into the target. In this case, it has to store the restored data temporarily before injecting into the target. spec.interimVolumeTemplate specifies a PVC template for holding those data temporarily. Stash will create a PVC according to the template and use it to store the data temporarily. This PVC will be deleted automatically if you delete the RestoreBatch.

• hooks : Each member has it’s own hooks field which allows you to execute member-specific pre-restore or post-restore hooks. For more details about hooks, please visit here.

spec.hooks

spec.hooks allows performing some global actions before and after the restoration process. You can send HTTP requests to a remote server via httpGet or httpPost. You can check whether a TCP port is open using tcpSocket hooks. You can also execute some commands using exec hook.

• spec.hooks.preRestore: spec.hooks.preRestore hooks are executed before restoring any of the members.
• spec.hooks.postRestore: spec.hooks.postRestore hooks are executed after restoring all the members.

For more details on how hooks work in Stash and how to configure different types of hook, please visit here.

RestoreBatch Status

A RestoreBatch object has the following fields in the status section.

• phase : phase shows the overall phase of the restore process. It will be Succeeded only if all the targets are restored successfully.

• sessionDuration : sessionDuration shows the total time taken to complete the entire restoration process.

• conditions : The conditions field shows conditions of different steps of the restore process. The following conditions are set by the Stash operator for a RestoreBatch:

• members : members section shows the restore status of the individual members. Each entry has the following fields:
  • ref : ref points to the respective target whose status is shown here.
  • phase : phase shows the restore phase of the member.
  • conditions: conditions shows the conditions of different steps of restoring this member. Stash set the following conditions for each restore members.

• totalHosts : totalHosts field specifies the total number of hosts that will be restored for this member.
• stats : stats section is an array of restore statistics of individual hosts. Individual host stats entry consists of the following fields:
  • hostname : hostname indicates the name of the host. Usually it is the alias or alias-<workload-specific-suffix>. For more details, please visit here.
  • phase : phase indicates the restore phase of this host.
  • duration : duration indicates the total time taken to complete the restore process for this host.
  • error : error shows the reason for failure if the restore process fails for this host.