m/n/k/reconciler: implement leader election

Before this change, the reconciler runs on all Kubernetes controllers. 
When we are in a rolling upgrade of the cluster where a reconciled 
object changes, this will cause the old and new versions of the 
reconciler to fight each other, constantly updating the object back and 
forth.

Now, the reconciler is elected among nodes of the latest release. The 
status of the reconciliation is communicated to all Kubernetes 
controllers through a new key-value in etcd.

Additionally, compatibility constraints can be expressed by changing the 
constants minReconcilerRelease and minApiserverRelease, allowing 
reconciliation to happen in a controlled way that ensures compatibility 
even during rolling upgrades.

Change-Id: Iaf7c27702bd9809a13d47bcf041b71438353bef2
Reviewed-on: https://review.monogon.dev/c/monogon/+/3062
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
16 files changed
tree: 52eeeb7917b79220ad0f0cb34447525f7c21341b
  1. .github/
  2. build/
  3. cloud/
  4. go/
  5. intellij/
  6. metropolis/
  7. net/
  8. third_party/
  9. tools/
  10. version/
  11. .bazelignore
  12. .bazelproject
  13. .bazelrc
  14. .bazelrc.ci
  15. .bazelrc.sandboxroot
  16. .bazelversion
  17. .git-ignore-revs
  18. .gitignore
  19. BUILD.bazel
  20. CODING_STANDARDS.md
  21. go.mod
  22. go.sum
  23. LICENSE
  24. MODULE.bazel
  25. MODULE.bazel.lock
  26. README.md
  27. SETUP.md
  28. shell.nix
  29. WORKSPACE
README.md

Monogon Monorepo

This is the main repository containing the source code for the Monogon Platform.

This is pre-release software - take a look, and check back later! In the meantime, join us on Matrix: #monogon-os-community:matrix.org.

Environment

Our build environment is self-contained and requires only minimal host dependencies:

  • A Linux machine or VM.
  • Bazelisk >= v1.15.0 (or a working Nix environment).
  • A reasonably recent kernel with user namespaces enabled.
  • Working KVM with access to /dev/kvm (if you want to run tests).

Our docs assume that Bazelisk is available as bazel on your PATH.

Refer to SETUP.md for detailed instructions.

Monogon OS

The source code lives in //metropolis (Metropolis is the codename of Monogon OS).

See the //metropolis/README.md for a developer quick start guide, or see the Monogon OS Handbook for user documentation.