Greenhouse is our bazel remote caching setup. We use this to provide faster build & test presubmits with a Globally shared cache (per repo).

Most Bazel users should probably visit the official docs and select one of the options outlined there, with Prow/Kubernetes we are using a custom setup to explore:

• better support for multiple repos / cache invalidation by changing the cache URL suffix (see also: images/bootstrap/create_bazel_cache_rcs.sh)
• customized cache eviction / management
• integration with our logging and metrics stacks

We use this with Prow, to set it up we do the following:

• Install kubectl and bazel and Point KUBECONFIG at your cluster.
  • for k8s.io use make -C prow get-build-cluster-credentials
• Create a dedicated node. We use a GKE node-pool with a single node. Tag this node with label dedicated=greenhouse and taint dedicated=greenhouse:NoSchedule so your other tasks don't schedule on it.
  • for k8s.io (running on GKE) this is:

  gcloud beta container node-pools create greenhouse --cluster=prow --project=k8s-prow-builds --zone=us-central1-f --node-taints=dedicated=greenhouse:NoSchedule --node-labels=dedicated=greenhouse --machine-type=n1-standard-32 --num-nodes=1
  
  • if you're not on GKE you'll probably want to pick a node to dedicate and do something like:

  kubectl label nodes $GREENHOUSE_NODE_NAME dedicated=greenhouse
  kubectl taint nodes $GREENHOUSE_NODE_NAME dedicated=greenhouse:NoSchedule
  
• Create the Kubernetes service so jobs can talk to it conveniently: kubectl apply -f greenhouse/service.yaml
• Create a StorageClass / PersistentVolumeClaim for fast cache storage, we use kubectl apply -f greenhouse/gce-fast-storage.yaml for 3TB of pd-ssd storage
• Finally build, push, and deploy with bazel run //greenhouse:production.apply --platforms=@io_bazel_rules_go//go/toolchain:linux_amd64
  • NOTE: other uses will likely need to tweak this step to their needs, particular the service and storage definitions

• tweak metrics-service.yaml and point prometheus at this service to collect metrics

See ./../images/bootstrap/create_bazel_cache_rcs.sh for our cache keying algorithm.

In short:

• we locate a number of host binaries known to be used by bazel (eg the system c compiler) within our image
• we then lookup the package that owns each binary
• from that we lookup the package's exact installed version
• we use these in conjunction with the repo under test / built to compute a primary cache key

This avoids bazel#4558.

For operational details on working with greenhouse, see Greenhouse Playbook