I am trying to understand a problem that currently arises with buildx, its Kubernetes driver, GitLab CI/CD, and parallel jobs. What is the suffix 0 that appears in builder instances's pod names?
It looks like an index, but seems unrelated to replicas. For instance I tried this (notice the suffix 0 behind test and before the first hyphen):
$ docker buildx create --name test --driver kubernetes --driver-opt namespace=ci,replicas=2 --use
$ echo "FROM scratch" | docker buildx build -
$ kubectl get pod -n ci
NAME READY STATUS RESTARTS AGE
test0-xxxxxxxxxx-xxxxx 1/1 Running 0 xxxxx
test0-yyyyyyyyyy-yyyyy 1/1 Running 0 yyyyyIt's related to nodes. By default, docker buildx create creates a single node. After creating a new builder, you can also append new nodes to it.
The relevant code is in store/nodegroup.go:
func (ng *NodeGroup) nextNodeName() string {
i := 0
for {
name := fmt.Sprintf("%s%d", ng.Name, i)
if ii := ng.findNode(name); ii != -1 {
i++
continue
}
return name
}
}
docker buildx ls lists all builders with their respective node(s).