How to use the command 'bootc' (with examples)

The bootc command offers a modern approach to managing and updating operating systems using container images. It facilitates both system upgrades and base OS changes seamlessly while adhering to transactional update principles. Using bootc, administrators can leverage container technologies such as OCI/Docker to handle upgrades, ensuring efficiency and reliability during the update process. This command transforms traditional OS management by integrating container-based methodologies, providing a robust mechanism for upgrading and managing operating systems.

Use case 1: Show deployments in the order they will appear in the bootloader

Code:

bootc status

Motivation for using this example:
When an administrator needs to verify which deployments are configured for booting, checking their order as they will appear in the bootloader is crucial. This ensures that the intended operating system version is set to boot first, aiding in troubleshooting and planning for updates or rollbacks.

Explanation:

• bootc: This is the main command invoking the bootc tool.
• status: This argument requests a display of the active and available deployments, showing their sequence for bootloader prioritization.

Example output:

NAME                VERSION        OSBASE
bootc-fedora-coreos 36.20220410.3.1 fedora-coreos
bootc-fcos-previous 36.20220328.3.2 fedora-coreos

Here, the output displays deployments such as “bootc-fedora-coreos” and “bootc-fcos-previous,” indicating their respective versions and OS bases.

Use case 2: Check if any updates are available

Code:

bootc upgrade --check

Motivation for using this example:
Before applying updates, checking for their availability is a standard operational task. By determining if new updates are present, administrators can decide when to schedule system maintenance or upgrade, thus minimizing downtime.

Explanation:

• bootc: The command used to initiate boot container operations.
• upgrade: This argument specifies the tool’s action of checking or applying updates.
• --check: This flag prompts the system to investigate whether an update exists, without making any modifications.

Example output:

Checking for updates...
Updates available: Yes
New version: 37.20221010.3.1

This output confirms the presence of an update, noting the new version’s release.

Use case 3: Prepare a new update and reboot into it

Code:

bootc upgrade --apply

Motivation for using this example:
Upon confirmation of updates, applying them is the next logical step. By utilizing the --apply flag, bootc automates the process of downloading and deploying the update, including necessary reboots, ensuring system operations remain current without manual intervention.

Explanation:

• bootc: The identifier for the command suite used.
• upgrade: Implies the commencement of an update process.
• --apply: Instructs the system to apply any available updates and prepare the system to reboot into the updated environment.

Example output:

Applying update...
Download complete for version 37.20221010.3.1
Rebooting into new deployment...

The above output details the successful downloading and preparation of the update, culminating in an automatic system reboot.

Use case 4: Change OS base to new container image

Code:

bootc switch image

Motivation for using this example:
There are situations where an overarching change in the operating system’s base image becomes necessary, perhaps due to new features or compliance requirements. By switching to a new container image, administrators can overhaul the system foundation efficiently.

Explanation:

• bootc: This element initiates the boot container process.
• switch: Directs the command to enact a change in operating system attributes.
• image: Represents the new base OS image the system will adopt.

Example output:

Switching OS base...
New OS base set to fedora-coreos-latest

The output signifies the system’s transition to a newly specified operating system base image.

Use case 5: Reboot into the previous ostree deployment

Code:

bootc rollback

Motivation for using this example:
In scenarios where updates cause issues, such as system instability or incompatibility, reverting to a prior stable deployment is necessary. The rollback feature enables a swift return to a known well-functioning state.

Explanation:

• bootc: The primary command utilized for system operations.
• rollback: Directs the operation to undo recent updates and shift back to a former system state.

Example output:

Rolling back to previous deployment...
System will boot into version 36.20220328.3.2

This output indicates that the system will return to the last established deployment upon reboot.

Conclusion:

The bootc command is a powerful tool that simplifies modern operating system management through container-driven methodologies. Each use case demonstrates specific tasks essential for maintaining system robustness, from deployment orders and updates to image switches and rollback functionalities. By integrating bootc into operational routines, administrators are equipped to handle complex updates and environment changes with ease.