How to configure backup for containerized applications in Docker and Kubernetes?

Containerization has changed the approach to software deployment, making infrastructure ephemeral. Docker containers themselves and Kubernetes pods can be deleted and recreated at any time, so classical backup of the container's internal file system makes no practical sense.

To organize reliable backups in such environments, it is necessary to clearly separate application code and the data it stores. All persistent information should be moved outside the containers using persistent volume mechanisms, such as Docker Volumes or Persistent Volumes in Kubernetes.

The backup process in Kubernetes is usually implemented using specialized operators and utilities that integrate with the storage management interface. These tools know how to make consistent snapshots of disk volumes, as well as save the configuration manifests of the cluster itself in YAML format.

An important aspect is ensuring data consistency before creating a volume snapshot. For databases running in containers, it is necessary to first put them into write-lock mode or execute a special transaction commit command to prevent file corruption during restoration.