Red Hat Summit第1章 Using image mode for RHEL with MicroShift
You can embed MicroShift into an operating system image using image mode for Red Hat Enterprise Linux (RHEL).
Image mode for RHEL is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see the following link:
1.1. Image mode for Red Hat Enterprise Linux (RHEL)
Image mode for Red Hat Enterprise Linux (RHEL) is a Technology Preview deployment method that uses a container-native approach to build, deploy, and manage the operating system as a bootc image. By using bootc, you can build, deploy, and manage the operating system as if it is any other container.
- This container image uses standard OCI or Docker containers as a transport and delivery format for base operating system updates.
- A bootc image includes a Linux kernel that is used to start the operating system.
- By using bootc containers, developers, operations administrators, and solution providers can all use the same container-native tools and techniques.
Image mode splits the creation and installation of software changes into two steps: one on a build system and one on a running target system.
- In the build-system step, a Podman build inspects the RPM files available for installation, determines any dependencies, and creates an ordered list of chained steps to complete, with the end result being a new operating system available to install.
- In the running-target-system step, a bootc update downloads, unpacks, and makes the new operating system bootable alongside the currently running system. Local configuration changes are carried forward to the new operating system, but do not take effect until the system is rebooted and the new operating system image replaces the running image.
1.1.1. Using image mode for RHEL with MicroShift
To use image mode for RHEL, ensure that the following resources are available:
- A RHEL 9.4 host with an active Red Hat subscription for building MicroShift bootc images.
- A remote registry for storing and accessing bootc images.
- You can use image mode for RHEL with a MicroShift cluster on AArch64 or x86_64 system architectures.
The workflow for using image mode with MicroShift includes the following steps:
- Build the MicroShift bootc image.
- Publish the image.
- Run the image. This step includes configuring MicroShift networking and storage.
The rpm-ostree file system is not supported in image mode and must not be used to make changes to deployments that use image mode.
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