- Introduction
- Unsupported scenarios
- Maintenance Warning
- Upgrade from Clear Containers
- Upgrade from runV
- Upgrade Kata Containers
- Appendices
This document explains how to upgrade from Clear Containers and runV to Kata Containers and how to upgrade an existing Kata Containers system to the latest version.
Upgrading a Clear Containers system on the following distributions is not supported since the installation process for these distributions makes use of unpackaged components:
Additionally, upgrading Clear Linux is not supported as Kata Containers packages do not yet exist.
The Clear Containers codebase is no longer being developed. Only new releases will be considered for significant bug fixes.
The main development focus is now on Kata Containers. All Clear Containers users are encouraged to switch to Kata Containers.
Since Kata Containers can co-exist on the same system as Clear Containers, if you already have Clear Containers installed, the upgrade process is simply to install Kata Containers. However, since Clear Containers is no longer being actively developed, you are encouraged to remove Clear Containers from your systems.
Assuming a Docker* system, to stop all currently running Clear Containers:
$ for container in $(sudo docker ps -q); do sudo docker stop $container; done
The automatic migration of Clear Containers configuration to Kata Containers configuration is not supported.
If you have made changes to your Clear Containers configuration, you should review those changes and decide whether to manually apply those changes to the Kata Containers configuration.
Note: This step must be completed before continuing to remove the Clear Containers packages since doing so will delete the default Clear Containers configuration file from your system.
Warning: If you have modified your Clear Containers configuration, you might want to make a safe copy of the configuration file before removing the packages since doing so will delete the default configuration file
$ sudo -E dnf remove cc-runtime\* cc-proxy\* cc-shim\* linux-container clear-containers-image qemu-lite cc-ksm-throttler
$ sudo rm /etc/yum.repos.d/home:clearcontainers:clear-containers-3.repo
$ sudo apt-get purge cc-runtime\* cc-proxy\* cc-shim\* linux-container clear-containers-image qemu-lite cc-ksm-throttler
$ sudo rm /etc/apt/sources.list.d/clear-containers.list
Assuming a Docker installation, remove the docker configuration for Clear Containers:
$ sudo rm /etc/systemd/system/docker.service.d/clear-containers.conf
Follow one of the installation guides.
$ sudo docker run -ti busybox sh
runV and Kata Containers can run together on the same system without affecting each other, as long as they are
not configured to use the same container root storage. Currently, runV defaults to /run/runv and Kata Containers
defaults to /var/run/kata-containers.
Now, to upgrade from runV you need to fresh install Kata Containers by following one of the installation guides.
As shown in the installation instructions, Kata Containers provide binaries for popular distributions in their native packaging formats. This allows Kata Containers to be upgraded using the standard package management tools for your distribution.
Kata Containers requires additional resources to create a virtual machine container. These resources are called Kata Containers assets, which comprise a guest kernel and a root filesystem or initrd image. This section describes when these components are updated.
Since the official assets are packaged, they are automatically upgraded when new package versions are published.
Warning: Note that if you use custom assets (by modifying the Kata Runtime configuration > file), it is your responsibility to ensure they are updated as necessary.
The kata-linux-container package contains a Linux* kernel based on the
latest vanilla version of the
long-term kernel
plus a small number of
patches.
The Longterm branch is only updated with
important bug fixes
meaning this package is only updated when necessary.
The guest kernel package is updated when a new long-term kernel is released and when any patch updates are required.
The kata-containers-image package is updated only when critical updates are
available for the packages used to create it, such as:
- systemd
- Kata Containers Agent
To see which versions of the assets being used:
$ kata-runtime kata-env