locality-checker

locality-checker

Locality checker is a container for detecting the region and availability zone of a CockroachDB pod running in a public Kubernetes cloud offering.

It is meant to be run as an init container, which writes the region and zone values of the pod to a volume mounted at /etc/cockroach-locality. These values are then read by the CockroachDB pod at startup, to fill in its --locality flag value. This allows CockroachDB to be aware of its pods' region and zone placements within a Kubernetes deployment.

A complete locality flag which can be passed into cockroach start is written to /etc/cockroach-locality/locality. For users that want more control of the locality flag, the region a pod is running in is written to /etc/cockroach-locality/region, and the zone is written to /etc/cockroach-locality/zone.

See examples for an example StatefulSet spec which uses the locality-checker container to supply the --locality flag argument to CockroachDB.