Simple restic image for kubernetes

• Meant to be added as sidecar container in kubernetes deployment, statefulset, or daemonset

• Used for backing up kubernetes PVC/PV data to some form of external storage

  • External storage can be:
    • kubernetes PVC backed by NFS or hostPath
    • Supported restic storage (S3, B2, etc) - see restic documentation, https://restic.readthedocs.io/en/stable/030_preparing_a_new_repo.html

• For restores, a simple initContainer based on https://hub.docker.com/r/restic/restic can be used

  • For this, it's sufficient to run a single restic restore command - see https://restic.readthedocs.io/en/stable/050_restore.html

Usage

• Set environment variables for container as follows:
  • BACKUP_SOURCE: folder to be backed up (defaults to /data)
  • RESTIC_REPOSITORY: folder for restic repository (backup storage location, defaults to /repo)
  • RESTIC_PASSWORD: password for restic repository
  • BACKUP_CRON: cron expression for backup timing (defaults to 00 */24 * * *)
  • CHECK_CRON: cron expression for backup integrity checks (defaults to 00 04 * * 1)
  • RESTIC_FORGET_ARGS: arguments for restic forget command (defaults to --keep-last 7)
    • if set to "", no restic forget command is ever run
  • NICE_ADJUST: nice priority adjustment, defaults to 10 for ~50% CPU time of normal-priority process
  • IONICE_CLASS: ionice scheduling class, defaults to 2 for best-effort IO
  • IONICE_PRIO: ionice priority, defaults to 7 for lowest priority IO
    • ionice is used for restic backup, restic forget and restic check commands
• Occationally check container logs to see backup results

TODO

• Prometheus metrics
• Alerts for failed backups