Kraken dogfoods agents builds; prod deploy stays on main

Root cause category: CI/CD — decoupling “what we test” from “what we ship” Module: repo plumbing (CI), Deploy Debian Repo.yml, Install Agents Build on Kraken.yml

What happened

In the direct-to-main model, Deploy Debian Repo.yml packaged the release and then a second job (upgrade-runner-host) installed it on the kraken box from S3. With the release train, code lands on agents first and ships to main only when Ben merges the integration PR — so the kraken box was no longer continuously running the freshest agent-built code, and the deploy job was doing double duty (publish + self-install).

Fix

• Removed the upgrade-runner-host job from Deploy Debian Repo.yml (packaging
  • S3 publish on main are unchanged).
• Added Install Agents Build on Kraken.yml: on every merge to agents (loop- guarded to skip the mechanical Bump version merge), the kraken runner builds the krill server deb at agents-HEAD and dpkg -is it locally + restarts krill.service. So kraken always runs agents-HEAD before any prod release.

Prevention

• When a branch model separates “integrate” from “ship”, make the test/dogfood install follow the integrate branch, not the ship branch — otherwise your canary box silently lags the code under test.
• Scope a per-merge build to what the box actually runs (server deb here), not the full release matrix; the full matrix stays on the deliberate main deploy.
• Loop-guard any push: [agents] build against the mechanical version-bump commit so a no-code-change merge doesn’t trigger an expensive rebuild.