Frostyard

Update system to a new container image using A/B partitions

Synopsis

Update the system by installing a new container image to the inactive root partition.

This command performs an A/B system update:

  1. Auto-detects the boot device (or use --device to override)
  2. Detects which root partition is currently active
  3. Checks if an update is available (compares image digests)
  4. Pulls the new container image (unless --skip-pull is specified)
  5. Extracts the new filesystem to the inactive root partition
  6. Updates the bootloader to boot from the new partition
  7. Keeps the old partition as a rollback option

Use --check to only check if an update is available without installing.

After update, reboot to activate the new system. The previous system remains available in the boot menu for rollback if needed.

Use --download-only to download an update without applying it. The update will be staged in /var/cache/nbc/staged-update/ and can be applied later with --local-image or --auto.

With --json flag, outputs streaming JSON Lines for progress updates.

Example: nbc update nbc update --check # Just check if update available nbc update --download-only # Download but don't apply nbc update --local-image # Apply staged update nbc update --auto # Use staged update if available, else pull nbc update --image quay.io/example/myimage:v2.0 nbc update --skip-pull nbc update --device /dev/sda # Override auto-detection nbc update --force # Reinstall even if up-to-date nbc update --json # Machine-readable streaming output

nbc update [flags]

Options

      --auto               Automatically use staged update if available, otherwise pull from registry
  -c, --check              Only check if an update is available (don't install)
  -d, --device string      Target disk device (auto-detected if not specified)
      --download-only      Download update to cache without applying
  -f, --force              Force reinstall even if system is up-to-date
  -h, --help               help for update
  -i, --image string       Container image reference (uses saved config if not specified)
  -k, --karg stringArray   Kernel argument to pass (can be specified multiple times)
      --local-image        Apply update from staged cache (/var/cache/nbc/staged-update/)
      --skip-pull          Skip pulling the image (use already pulled image)

Options inherited from parent commands

  -n, --dry-run   dry run mode (no actual changes)
      --json      output in JSON format for machine-readable output
  -v, --verbose   verbose output

SEE ALSO

  • nbc - A bootc container installer for physical disks