KubernetesClusterDomain looks up the Kubernetes cluster domain name.
(ctx context.Context)
| 70 | |
| 71 | // KubernetesClusterDomain looks up the Kubernetes cluster domain name. |
| 72 | func KubernetesClusterDomain(ctx context.Context) string { |
| 73 | ctx, span := tracing.Start(ctx, "kubernetes-domain-lookup") |
| 74 | defer span.End() |
| 75 | |
| 76 | // Lookup an existing Service to determine its fully qualified domain name. |
| 77 | // This is inexpensive because the "net" package uses OS-level DNS caching. |
| 78 | // - https://golang.org/issue/24796 |
| 79 | api := "kubernetes.default.svc" |
| 80 | cname, err := net.DefaultResolver.LookupCNAME(ctx, api) |
| 81 | |
| 82 | if tracing.Check(span, err) { |
| 83 | return strings.TrimPrefix(cname, api+".") |
| 84 | } |
| 85 | |
| 86 | // The kubeadm default is "cluster.local" and is adequate when not running |
| 87 | // in an actual Kubernetes cluster. |
| 88 | return "cluster.local." |
| 89 | } |