Armbian Linux Kernel Caching

Preface

• Full, non-shallow clones of Linux kernel trees are multiple gigabytes in size, and take a lot of time to process,
• Shallow clones are much smaller, but cloning/fetching shallow trees impose a huge load on the git server (eg: kernel.org),
• kernel.org has git bundles available for download over HTTPS/CDN (simple file download). In fact they recommend their use and have instructions

What this repo does?

• it does the heavy lifting - grabbing bundles, updating them from live git servers, and makes them shallow and ready for consumption,
  • Produced shallow bundles are around 250mb as of 5.18,
  • Produced shallow bundles include all tags for the version involved, including -rc tags,
  • Scheduled runs update the bundles every 24hs, using GitHub actions, including caching,
  • They are deployed to two locations, as Github releases and uploaded to main Armbian CDN

How to use

• Example for 5.17:

# Download the bundle from this repo's Github releases.
wget --continue --progress=dot:giga -O "linux-5.17.gitbundle" "https://github.com/armbian/gitutils/releases/download/latest/linux-5.17.gitbundle"
git init linux-5.17 # init an empty repo
cd linux-5.17 # go into it
git remote add "linux-5.17-bundle" "../linux-5.17.gitbundle" # add the downloaded bundle as a remote
wget -O ".git/shallow" "https://github.com/armbian/gitutils/releases/download/latest/linux-5.17.gitshallow" # download .git/shallow
git fetch linux-5.17-bundle # fetch from the bundle.
git checkout FETCH_HEAD # checkout from the bundle's HEAD
git tag -l # look at the available tags (all 5.17-related tags)