testbed.bits

The test community for bits and bits-console. It is used to re-run another community's real build, unchanged, and publish the result to the self-contained CVMFS publishing testbed (cvmfs-testbed: its own gateway, cvmfs-prepub, Stratum 0/1 and object store, serving the repository test.cvmfs.io) instead of the production repository bits.cern.ch. Publishing changes can therefore be tried end to end without touching production and without recompiling a stack.

The repository holds no package recipes, only one defaults file, defaults-testbed.sh. It is an overlay that changes a single setting, system.cvmfs_repository: test.cvmfs.io, so a group's tree moves from /cvmfs/bits.cern.ch/<group>/... to /cvmfs/test.cvmfs.io/<group>/... and everything below the repository name stays as in production. In the bits-providers registry, testbed.bits is listed as the test community and requires stacks.bits, which in turn requires lcg.bits.

Getting started: trying the overlay locally

You can add the overlay to a group's build on your own machine to check what it resolves to. Get bits as described in the bits README, then put this repository on the recipe search path of the group's build and add testbed at the end of its defaults chain:

bits init testbed.bits                # or: git clone https://github.com/bitsorg/testbed.bits
bits init lhcb.bits && cd lhcb.bits   # the group whose build you want to re-run

bits build --dry-run --search-path "$PWD/../testbed.bits" \
           --defaults lhcb::gcc14::opt::testbed --set release=LCG_110 \
           --architecture x86_64-el9 lcg-view

Because the hashes are unchanged, the plan lists the same packages as the build without testbed. For ALICE the chain is alidist::o2::testbed. To see the CVMFS path a package would be published to, run bits cvmfs-path with the same --search-path, --defaults and --set options.

Notes for testbed users

Why the overlay changes nothing else

A package's hash comes from its recipe, sources, patches, dependencies and the merged env: of the defaults, not from where it is published. The system: block is never hashed, so a build with testbed added has the same package hashes as the production build: the certified store is reused and only the publish destination changes. Adding env:, requires:, disable: or overrides: to defaults-testbed.sh would change every hash and turn a publishing test into a full rebuild; such settings belong in the group's own defaults.

defaults-testbed.sh is marked valid_defaults_exempt: true, so packages that restrict their defaults with valid_defaults (for example ALICE's O2) accept it as a structural layer rather than a build flavour.

How it is used in testing

The Testbed community in bits-console (communities/Testbed/ui-config.yaml) is set up as follows:

• group_recipes is this repository, and the community whose build is re-run (for example lhcb.bits or alice.bits) is added as an extra provider in Settings -> Providers; the CI job puts it on the recipe search path.
• defaults_overlay: testbed: the console appends testbed as the last element of whatever defaults chain the build selects, e.g. alidist::o2 becomes alidist::o2::testbed. It must come last, because later profiles win when the chain is merged; the build form shows the full --defaults value that will be passed.
• cvmfs_repo: test.cvmfs.io and cvmfs_prefix: /cvmfs/test.cvmfs.io: bits refuses to publish unless the destination lies under this prefix. The same check is what stops the overlay from redirecting a build in a production community.
• prepub_url and stratum0_url point the publish job at the testbed's cvmfs-prepub and object store instead of the production ones.
• Platforms use the bits-containers image names: x86_64-el9, x86_64-el10, aarch64-el9, x86_64-ubuntu2404, x86_64-ubuntu2604.
• Publish options that the production communities do not offer yet, such as staged publishing and direct upload to S3, are enabled here so they can be compared and tested.

The testbed services must be running for a publish to succeed; see the cvmfs-testbed README and DEPLOYMENT.md.

More information

• cvmfs-testbed: the testbed stack; lhcb.bits and alice.bits: communities whose builds are re-run here; bits Effect on build hashes
• stacks.bits and lcg.bits READMEs: profiles, releases, CVMFS layout and the recipe pool
• bits User Guide, Cookbook, Reference
• bits-console: community configuration and the publish pipeline

License

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