Ensure kind cluster has RFC1123 compliant name (#20627)

When creating a kind cluster, we must use a cluster name that is a valid
Kubernetes resource name, and by extension, a valid DNS name. If not,
kind cluster provisioning can fail when kind tries to create resources
with invalid names.

For example, if trying to create a cluster called "a_b" (underscores
are not permitted), control-plane provisioning will fail with:

  host 'a_b-control-plane' must be [...] a valid RFC-1123 DNS subdomain

dev-tools/mage/kubernetes/kind.go

@@ -65,7 +65,7 @@ func (m *KindIntegrationTestStep) Setup(env map[string]string) error {
  return nil
  }
 
- clusterName := kubernetesPodName()
+ clusterName := kubernetesClusterName()
  stdOut := ioutil.Discard
  stdErr := ioutil.Discard
  if mg.Verbose() {

dev-tools/mage/kubernetes/kubernetes.go

@@ -24,6 +24,7 @@ import (
  "log"
  "os"
  "path/filepath"
+ "regexp"
  "strings"
  "time"
 
@@ -132,7 +133,7 @@ func (d *KubernetesIntegrationTester) Test(dir string, mageTarget string, env ma
 
  destDir := filepath.Join("/go/src", repo.CanonicalRootImportPath)
  workDir := filepath.Join(destDir, repo.SubDir)
- remote, err := NewKubeRemote(kubeConfig, "default", kubernetesPodName(), workDir, destDir, repo.RootDir)
+ remote, err := NewKubeRemote(kubeConfig, "default", kubernetesClusterName(), workDir, destDir, repo.RootDir)
  if err != nil {
  return err
  }
@@ -172,8 +173,8 @@ func waitKubeStateMetricsReadiness(env map[string]string, stdOut, stdErr io.Writ
  return nil
 }
 
-// kubernetesPodName returns the pod name to use with kubernetes.
-func kubernetesPodName() string {
+// kubernetesClusterName generates a name for the Kubernetes cluster.
+func kubernetesClusterName() string {
  commit, err := mage.CommitHash()
  if err != nil {
  panic(errors.Wrap(err, "failed to construct kind cluster name"))
@@ -183,13 +184,29 @@ func kubernetesPodName() string {
  if err != nil {
  panic(errors.Wrap(err, "failed to construct kind cluster name"))
  }
- version = strings.NewReplacer(".", "_").Replace(version)
+ version = strings.NewReplacer(".", "-").Replace(version)
 
- clusterName := "{{.BeatName}}_{{.Version}}_{{.ShortCommit}}-{{.StackEnvironment}}"
+ clusterName := "{{.BeatName}}-{{.Version}}-{{.ShortCommit}}-{{.StackEnvironment}}"
  clusterName = mage.MustExpand(clusterName, map[string]interface{}{
  "StackEnvironment": mage.StackEnvironment,
  "ShortCommit": commit[:10],
  "Version": version,
  })
+
+ // The cluster name may be used as a component of Kubernetes resource names.
+ // kind does this, for example.
+ //
+ // Since Kubernetes resources are required to have names that are valid DNS
+ // names, we should ensure that the cluster name also meets this criterion.
+ subDomainPattern := `^[A-Za-z0-9](?:[A-Za-z0-9\-]{0,61}[A-Za-z0-9])?$`
+ // Note that underscores, in particular, are not permitted.
+ matched, err := regexp.MatchString(subDomainPattern, clusterName)
+ if err != nil {
+ panic(errors.Wrap(err, "error while validating kind cluster name"))
+ }
+ if !matched {
+ panic("constructed invalid kind cluster name")
+ }
+
  return clusterName
 }