Backing up and Restoring of Kubernetes Block and File Volumes Flashcards
(35 cards)
What is the main focus of High Availability (HA)?
Minimizing downtime of data and services during component failures.
HA does not protect against data loss.
What does Disaster Recovery (DR) enable?
Recovery from catastrophic events affecting application and data availability or integrity.
DR solutions replicate data to ensure fast recovery and minimal data loss.
Define Backup in the context of data protection.
Creating periodic copies or snapshots of data for restoration if lost, corrupted, or deleted.
Backups are stored separately from primary data to protect against corruption.
What are common backup methods for applications that do not use low-level operations?
Stopping the application and using tools for copying and archiving data, such as rsync and tar.
This ensures data integrity during the backup process.
List specialized backup tools for database applications.
- mysqldump for MariaDB
- pg_dump for PostgreSQL
- mongodump for MongoDB
What alternative methods can be used to back up different applications?
- File-system backup with dump or xfsdump
- Volume snapshots from LVM or a storage controller
- Virtual Machine snapshots or clones
How do backup strategies differ for containerized application workloads?
They depend on whether the application is stateless or stateful and the type of storage used (block, file, or object).
What is a method to back up stateless applications in OpenShift?
Saving the original resource definitions in YAML or JSON format and redeploying the application.
What operations can be performed to back up stateful applications in Kubernetes?
*cloning
* snapshot
What can be created to synchronize objects from one object bucket to another?
A Job or a CronJob resource.
What does the OpenShift API for Data Protection (OADP) provide?
A native backup solution for applications running on OpenShift.
What components does OADP use for backing up Kubernetes resources?
- Velero
- Kopia
- Data Mover
What limitations might the OADP have?
Lack of graphical user interface and multitenancy support.
What is the purpose of creating volume snapshots?
To restore or duplicate storage volumes
Volume snapshots enable system administrators to back up and restore data for containerized application workloads.
What does the Container Storage Interface (CSI) do?
Defines APIs for integrating storage solutions in Kubernetes clusters
Vendors develop CSI plug-ins to support storage back ends like Ceph RBD or CephFS.
How are CSI plug-ins distributed?
As container images
These images serve as a bridge between the Kubernetes cluster and the storage driver.
What is a volume snapshot?
A point-in-time copy of a Persistent Volume (PV)
It takes no additional space until the volume snapshot and the source volume diverge.
What must you do to use a volume snapshot in OpenShift?
Clone the volume snapshot to a Persistent Volume (PV)
OpenShift cannot directly use volume snapshots.
What is a volume clone?
An exact replica of an existing volume
Volume cloning allows duplication of a cluster volume.
What command do you use to list CSI storage classes?
oc get storageclasses | grep -E ‘^NAME|csi’
This command helps identify available CSI storage classes in the cluster.
What are the two storage classes mentioned in the text?
- ocs-storagecluster-ceph-rbd
- ocs-storagecluster-cephfs
What is a key feature of volume snapshots in terms of storage efficiency?
No need for a full PV copy each time
Volume snapshots help with storage efficiency by capturing the state of a PV at a specific time.
What happens if you create a volume snapshot while a pod is using the PVC?
Unwritten or cached data is excluded from the snapshot
It’s recommended to stop or quiesce the applications before creating a snapshot.
How can you verify the readiness of a volume snapshot for use?
By using the command oc get volumesnapshots
