1. Install or build apk-autoupdate

We'll be using a program named apk-autoupdate. If you're running on the edge branch of Alpine, the package is available via apk add apk-autoupdate; otherwise, you'll have to build from source. Fortunately, it's a tiny program.

First, get the build dependencies.

# apk add make gcc asciidoctor musl-dev

Clone the repository.

$ git clone https://github.com/jirutka/apk-autoupdate.git

There are no tags, so you'll be building from the master branch.

$ cd ./apk-autoupdate
$ make
# make install

2. Setup the cron job

Configure cron to regularly run apk-autoupdate. The crontab line below will run it daily at 2 AM, assuming that the system is running at that time.

# min   hour   day   month   weekday   command
0       2      *     *       *         apk-autoupdate

See the man page autoupdate.conf(5) for (optional) configuration.