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Chapter 16. Package mode and image mode hosts
Image mode simplifies enterprise operations by enabling development, operations, and solution providers to use the same container-native tools and techniques to manage both applications and the underlying operating system. Satellite supports image mode for hosts in addition to package mode.
16.1. Overview of image mode for hosts
Satellite identifies an image mode host as any system that reports a container image from its bootc status through Subscription Manager. It classifies all other hosts as package mode hosts.
In image mode, users can install and manage packages, but with limitations. Job templates run the bootc usr-overlay command or use the dnf --transient flag to ensure that packages are installed correctly. Any packages installed on image mode hosts are temporary and disappear after a reboot. Because of this, installing packages is generally discouraged, except for debugging purposes or, in some cases, when applying critical security patches. If you need new packages on an image mode host, consider building a new container image the includes the necessary packages. After upgrading the image mode host to this image, the new packages will be installed permanently.
On the All Hosts page, you can display the Type column, which includes a mode indicator. This column is disabled by default.
Image mode hosts include additional fields that reflect their boot status. These fields track the container images used in various scenarios:
- Booted Image & Digest: Indicates the container image the host is currently using.
- Staged Image & Digest: Indicates the container image the host uses after the next reboot.
-
Available Image & Digest: Represents the container image cached by running
bootc upgrade --check. -
Rollback Image & Digest: Represents the container image the host reverts to after the next reboot if
Bootc rollbackis applied.
Additional resources
16.2. Viewing booted container images by using Satellite web UI
These actions streamline the management of image mode hosts, providing flexibility and control over host operations through Satellite.
Procedure
- In the Satellite web UI, navigate to Content > Booted Container Images to view all images used by image mode hosts. This page displays the spread of digests under specific image paths. More digests under an image path indicate greater drift in the host ecosystem, ideally minimized by ensuring all hosts run the most up-to-date image version.
- Click the host count to navigate to the All Hosts page, which identifies the hosts associated with each specific image and displays the number of hosts using each digest.
-
Select a host and on the Details tab, use the image mode Details card to see the current
bootcstatus. -
Click the link to the Bootc Action - Script Default remote execution job in this card to perform a Bootc action on the host. For pull-mode remote execution, the
foreman_ygg_workerpackage must be included in the container image of the image mode hosts.
16.3. Viewing booted container images by using Hammer CLI
These actions streamline the management of image mode hosts, providing flexibility and control over host operations through Satellite.
Procedure
-
Run the
hammer host bootc imagescommand.
16.4. Remote execution jobs for image mode hosts
You can use the remote execution jobs under the Bootc job category to manage image mode hosts:
- Bootc Action - Script Default: Select any Bootc action from the dropdown menu, enter arguments, and specify a target.
- Bootc Rollback - Script Default: Run Bootc rollback to revert to a previous image.
- Bootc Status - Script Default: Run Bootc status with optional extra parameters to check the status.
- Bootc Switch - Script Default: Run Bootc switch with a mandatory image input and optional extra parameters to switch to a different image.
- Bootc Upgrade - Script Default: Run Bootc upgrade with optional extra parameters to update the image.
For pull-mode remote execution, the foreman_ygg_worker package must be included in the container image of the image mode hosts.
Additional resources
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