kind: fix setup on HA clusters

when there are multiple control plane nodes,
kind creates an LB node in front of them.

before this change, we would try
to configure the registry on the LB node,
which is unnecessary and doesn't work.

fixes #356

Signed-off-by: Nick Santos <nick.santos@docker.com>

pkg/cluster/admin_kind.go

@@ -187,7 +187,19 @@ func (a *kindAdmin) applyContainerdPatchRegistryApiV2(ctx context.Context, desir
 	if err != nil {
 		return errors.Wrap(err, "configuring registry")
 	}
-	return applyContainerdPatchRegistryApiV2(ctx, a.runner, a.iostreams, nodes, desired, registry)
+	filtered := []string{}
+	for _, node := range nodes {
+		if strings.HasSuffix(node, "external-load-balancer") {
+			// Ignore the external load balancers.
+			// These load-balance traffic to the control plane nodes.
+			// They don't need registry configuration.
+			continue
+		}
+		filtered = append(filtered, node)
+	}
+
+	return applyContainerdPatchRegistryApiV2(ctx, a.runner, a.iostreams,
+		filtered, desired, registry)
 }
 
 func (a *kindAdmin) getNodes(ctx context.Context, cluster string) ([]string, error) {

pkg/cluster/admin_kind_test.go

@@ -9,6 +9,7 @@ import (
 	"k8s.io/cli-runtime/pkg/genericclioptions"
 
 	"github.com/tilt-dev/ctlptl/internal/exec"
+	"github.com/tilt-dev/ctlptl/pkg/api"
 )
 
 func TestNodeImage(t *testing.T) {
@@ -43,3 +44,41 @@ func TestNodeImage(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, "kindest/node:v1.16.9@sha256:7175872357bc85847ec4b1aba46ed1d12fa054c83ac7a8a11f5c268957fd5765", img)
 }
+
+func TestPatchRegistryConfig(t *testing.T) {
+	nodeExec := []string{}
+	runner := exec.NewFakeCmdRunner(func(argv []string) string {
+		if argv[0] == "kind" && argv[1] == "get" && argv[2] == "nodes" {
+			return `kind-external-load-balancer
+kind-control-plane
+kind-control-plane2
+`
+		}
+		if argv[0] == "docker" && argv[1] == "exec" && argv[2] == "-i" {
+			nodeExec = append(nodeExec, argv[3])
+		}
+		return ""
+	})
+	iostreams := genericclioptions.IOStreams{
+		In:     os.Stdin,
+		Out:    os.Stdout,
+		ErrOut: os.Stderr,
+	}
+	a := newKindAdmin(iostreams, runner, &fakeDockerClient{})
+	ctx := context.Background()
+
+	err := a.applyContainerdPatchRegistryApiV2(
+		ctx,
+		&api.Cluster{Name: "test-cluster"},
+		&api.Registry{Name: "test-registry"})
+	assert.NoError(t, err)
+
+	// Assert that we only executed commands
+	// in the control plane nodes, not the LB.
+	assert.Equal(t, []string{
+		"kind-control-plane",
+		"kind-control-plane",
+		"kind-control-plane2",
+		"kind-control-plane2",
+	}, nodeExec)
+}