Repositories
There are three official package repositories available in Alpine Linux. apk loads repository definitions from /etc/apk/repositories file first and has various sub-commands to query and manipulate world and package repositories.
Official repositories
Main
Packages in main repository are the software that have direct support and updates from the Alpine core team. Alpine Linux tries to limit the amount of packages in main to only include base system packages, i.e packages which are needed by other packages or are needed to setup a basic system. Packages in main must not have dependencies in other repositories.
Packages in main repository also have official special documentation, are always available for all releases and will have substitutions if some are not continued from upstream. Commonly these packages are selected due to their responsibility and stability with respect to upstream availability. Packages from community or (rarely) testing can be accepted into the main repository.
Community
Packages in community repository are those made by users in team with the official developers and close to the Alpine package process. They are supported by those user(s) contributions and could end if the user(s) stops; they may also be removed in a future release due to lack of support by upstream authors.
The community repository was introduced with Alpine Linux version 3.3.0. Packages from testing that are accepted go to the community repository.
Testing
The testing repository is only available on edge branch i.e development branch and this is where new packages go. These are made by any contributor to Alpine Linux. Packages from testing that are accepted go to the community repository or (rarely) to the main repository. Packages in testing have no support (staging only) and only built for edge. If it stays here long enough it gets moved to unmaintained/purged (gets cleaned up every 6 months).
Before a package can move from testing to main or community, the following requirements must be met:
- Package must work correctly, including the init.d script (if provided) and default configuration.
- Packaging must be done correctly, with files installed in the right places, e.g. configs are in
/etc/and not in/usr/etc. - Package dependencies are handled correctly. Abuild can (and should) autodetect shared libs, for example sqlite-libs provides so:libsqlite3.so.0. Any package linked to sqlite should have an automatically (by abuild) added
depend=so:libsqlite3.so.0and the user should not have to manually add adepend="sqlite-libs"in the APKBUILD. - There is a maintainer who claims responsibility for the maintenance of the package and can help fix things if they break in the future.
Release Branches
There are several release branches for Alpine Linux available at the same time. Each May and November we make a stable release branch from edge. The current release branch of Alpine Linux is 3.21.
Each stable release branch has its own main and community repositories. The main repository of every release branch is supported for 2 years. The community repository of any release branch is supported until next stable release i.e six months. Security fixes beyond that can be made on request, if there are patches available. Support entails security patches for the given feature versions.
To upgrade to the latest release branch, follow the steps in Upgrading Alpine Linux.
Edge
edge is the name given to the current development tree of Alpine Linux. edge can be considered as rolling release version of Alpine Linux. This version contains the latest build of all available Alpine Linux packages. Those packages are updated on a regular basis.
Similar to release branches edge consists of main and community repositories in addition to the third repository i.e testing.
Since edge is a development branch, many changes are not heavily tested (or tested at all) and packages in edge can and sometimes do break without warning. However, testing edge is a very valuable activity which helps the Alpine Linux development to ensure that the quality of the stable releases is high.
Managing repositories
The package repositories that apk uses to retrieve package files for installation are specified in file /etc/apk/repositories. To automatically configure the repositories file /etc/apk/repositories, use the setup-apkrepos script:
# setup-apkrepos -cf
After making changes to /etc/apk/repositories you should update the package index using:
# apk update
Each line of /etc/apk/repositories specifies the location of a package repository, one repository per line and optionally a tag. Lines that start with a hash character (#) are ignored.
The location may be an http:// or https:// URL, or the path to a directory on the local filesystem. If you booted from a USB stick (/media/sda1) or CD-ROM (/media/cdrom), your repository file probably looks something like this:
Contents of /etc/apk/repositories
In a properly configured Alpine Linux system, the default will look something like:
Contents of /etc/apk/repositories
Tagged repository
A tagged repository is prefixed with the @tag specifier, followed by a space and the repository location in the /etc/apk/repositories file as follows.
Contents of /etc/apk/repositories
The optional @tag, when used as shown above indicates that the tagged repository should not be used by default.
apk will by default only use the untagged repositories. However for constraints with a tag, untagged repositories are also considered. The tag is inherited to all dependencies as an allowed repository. That is, the dependencies are selected from the tagged repository if the name@tag has a dependency with version constraint requiring a version available only from the tagged repository. If the dependency can be satisfied from untagged repository it will be preferred.
For eg: apk add busybox@personal enables selection of busybox from a tagged repository @personal. The above command allows installation of busybox and it's dependencies from the tagged repository @personal. Since tagged repositories are not prioritized, if a version of busybox or it's dependencies from an untagged repository is a better fit, it will be used.
Upgrading to edge
An upgrade of Alpine Linux from a stable version to the rolling development version edge basically requires the same steps as Upgrading to latest release.
The crucial difference is, that when editing the /etc/apk/repositories file, all referenced repository versions (such as v3.21 or latest-stable) therein need to be pointing to edge as follows.
Contents of /etc/apk/repositories
When using edge branch, testing repository can be added as shown above. Installing packages from testing repository with Edge branch and submitting bug reports is one of the best ways to contribute to Alpine Linux. Remember that, packages in testing repository have no support.
After upgrading to edge, the currently installed edge version i.e the build date that is attached to the edge release may be checked with command:
$ cat /etc/alpine-release
Using testing repository
Using testing repository with Edge branch is explained in the previous sections. However, installing packages from testing repository in a stable release branch is not recommended and not guaranteed to work. To do this, add testing repository as a tagged repository by editing the file /etc/apk/repositories as follows:
Contents of /etc/apk/repositories
Do this only if you need package(s) which are available only in testing repository. Ensure that the package does not have version dependencies on the other two repositories of the edge branch. In the example command # apk add wireguard-go@testing, the tag @testing allows apk to pull the necessary package(s) from that repository without potentially messing up your installation (too badly).