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greenhouse

Greenhouse

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

Setup (on a Kubernetes Cluster)

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 deploy with kubectl apply -f greenhouse/deployment.yaml
    • NOTE: other uses will likely need to tweak this step to their needs, in particular the service and storage definitions

Optional Setup:

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

Cache Keying

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.

Playbook

For operational details on working with greenhouse, see Greenhouse Playbook