Make control plane instance IDs label-safe

Author: bill-ph

controlplane/multitenant.go

@@ -146,6 +146,9 @@ func SetupMultiTenant(
 	}
 
 	cpID := cfg.K8s.ControlPlaneID
+	if cpID == "" {
+		cpID = os.Getenv("POD_NAME")
+	}
 	if cpID == "" {
 		cpID, _ = os.Hostname()
 	}
@@ -158,7 +161,7 @@ func SetupMultiTenant(
 		return nil, nil, nil, nil, nil, fmt.Errorf("generate control plane boot id: %w", err)
 	}
 	bootIDHex := hex.EncodeToString(bootID)
-	cpInstanceID := podUID + ":" + bootIDHex
+	cpInstanceID := makeControlPlaneInstanceID(podUID, bootIDHex)
 
 	baseCfg := K8sWorkerPoolConfig{
 		Namespace:             namespace,
@@ -326,3 +329,13 @@ func parseNodeSelector(s string) map[string]string {
 	}
 	return m
 }
+
+func makeControlPlaneInstanceID(podUID, bootIDHex string) string {
+	if podUID == "" {
+		podUID = "cp"
+	}
+	if len(bootIDHex) > 16 {
+		bootIDHex = bootIDHex[:16]
+	}
+	return controlPlaneIDLabelValue(podUID + "-" + bootIDHex)
+}

controlplane/multitenant_cp_instance_id_test.go

@@ -0,0 +1,24 @@
+//go:build kubernetes
+
+package controlplane
+
+import "testing"
+
+func TestMakeControlPlaneInstanceID_StaysKubernetesSafe(t *testing.T) {
+	t.Parallel()
+
+	id := makeControlPlaneInstanceID(
+		"duckgres-control-plane-7fb9dd69c6-dcgzw",
+		"14cd8dd9eb353e609c7a4387a594a418",
+	)
+
+	if len(id) > 63 {
+		t.Fatalf("expected cp_instance_id length <= 63, got %d (%q)", len(id), id)
+	}
+	if id == "duckgres-control-plane-7fb9dd69c6-dcgzw:14cd8dd9eb353e609c7a4387a594a418" {
+		t.Fatalf("expected shortened cp_instance_id, got original %q", id)
+	}
+	if id != "duckgres-control-plane-7fb9dd69c6-dcgzw-14cd8dd9eb353e60" {
+		t.Fatalf("unexpected cp_instance_id %q", id)
+	}
+}

k8s/control-plane-deployment.yaml

@@ -30,6 +30,15 @@ spec:
           # Replace with your duckgres image built with -tags kubernetes
           image: duckgres:latest
           imagePullPolicy: IfNotPresent
+          env:
+            - name: POD_NAME
+              valueFrom:
+                fieldRef:
+                  fieldPath: metadata.name
+            - name: POD_UID
+              valueFrom:
+                fieldRef:
+                  fieldPath: metadata.uid
           args:
             - "--mode"
             - "control-plane"

k8s/control-plane-multitenant-local.yaml

@@ -29,6 +29,15 @@ spec:
         - name: control-plane
           image: duckgres:test
           imagePullPolicy: IfNotPresent
+          env:
+            - name: POD_NAME
+              valueFrom:
+                fieldRef:
+                  fieldPath: metadata.name
+            - name: POD_UID
+              valueFrom:
+                fieldRef:
+                  fieldPath: metadata.uid
           args:
             - "--mode"
             - "control-plane"

k8s/kind/control-plane.yaml

@@ -29,6 +29,15 @@ spec:
         - name: control-plane
           image: duckgres:test
           imagePullPolicy: IfNotPresent
+          env:
+            - name: POD_NAME
+              valueFrom:
+                fieldRef:
+                  fieldPath: metadata.name
+            - name: POD_UID
+              valueFrom:
+                fieldRef:
+                  fieldPath: metadata.uid
           args:
             - "--mode"
             - "control-plane"