Workflow with Persistent Partition#

The persistent partition workflow consists of the flashing phase and the filesystem phase.

Flashing#

  1. If the bootburn utility is executed with the --init-persistent-partitions option, the prebuilt user metadata and data images are flashed to persistent partitions (as specified in PCT configuration in global_storage.cfg).

  2. If the bootburn utility is executed without the --init-persistent-partitions option, there are no changes to persistent partitions.

Filesystem Boot#

  1. Filesystem mounts the existing user metadata and data persistent partitions.

  2. Filesystem checks for the stamp /etc/nvidia/oem-config/oem_config_completed. - If yes, proceeds to the next step. - If no, OEM-config is executed to set up user accounts.

After oem-config is executed, the stamp /etc/nvidia/oem-config/oem_config_completed is added, and this is written to persistent metadata partition.

  1. Check if /var/rootfs_first_boot_completed exists. - If yes, applies fix-up for persistent partition. - If no, proceeds to the next step.

After the fix-up is complete, /var/rootfs_first_boot_completed is deleted.

  1. Filesystem proceeds to reach the command-line login prompt.

Default Behaviors in NVIDIA DriveOS Linux#

  1. When the bootburn utility is run with the --init-persistent-partitions option: a. The /etc/nvidia/oem-config/oem_config_completed should not exist. b. The OEM-config shall be executed to set up user accounts. c. After oem-config is executed, the stamp /etc/nvidia/oem-config/oem_config_completed is added, and this is written to persistent metadata partition. d. The fix-up is executed (as the filesystem image contains the stamp /var/rootfs_first_boot_completed) but is equivalent to a no-op.

  2. When the bootburn utility is run without the --init-persistent-partitions option: a. /etc/nvidia/oem-config/oem_config_completed should already exist and oem-config is skipped. b. The fix-up is executed, and this cleans up persistent metadata partition by removing everything other than the necessary files, such as /etc/passwd|group|shadow|gshadow|subuid|subgid, /etc/ssh/ssh_host_key*, and /etc/nvidia/oem-config/oem_config_completed.

  3. Cleanup is required because all files added /etc go to the persistent partition (even if they apply to the rootfs partition) due to overlayfs limitation.

Note

These are the default behaviors in NVIDIA DriveOS™ Linux. However, filesystem users can always change the behavior by removing or adding stamps again (/etc/nvidia/oem-config/oem_config_completed or /var/rootfs_first_boot_completed).

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