kube-agent-updater fixes (#24468)

* helm: set TELEPORT_EXT_UPGRADER when updater is enabled

* integrations/updater: exit when agent name or namespace is missing

examples/chart/teleport-kube-agent/templates/deployment.yaml

@@ -119,8 +119,12 @@ spec:
         {{- if .Values.imagePullPolicy }}
         imagePullPolicy: {{ toYaml .Values.imagePullPolicy }}
         {{- end }}
-        {{- if or .Values.extraEnv .Values.tls.existingCASecretName }}
+        {{- if or .Values.extraEnv .Values.tls.existingCASecretName .Values.updater.enabled }}
         env:
+        {{- if .Values.updater.enabled }}
+        - name: TELEPORT_EXT_UPGRADER
+          value: kube
+        {{- end }}
         {{- if (gt (len .Values.extraEnv) 0) }}
           {{- toYaml .Values.extraEnv | nindent 8 }}
         {{- end }}

examples/chart/teleport-kube-agent/templates/statefulset.yaml

@@ -132,6 +132,10 @@ spec:
                 fieldPath: metadata.namespace
           - name: RELEASE_NAME
             value: {{ .Release.Name }}
+          {{- if .Values.updater.enabled }}
+          - name: TELEPORT_EXT_UPGRADER
+            value: kube
+          {{- end }}
           {{- if .Values.tls.existingCASecretName }}
           - name: SSL_CERT_FILE
             value: /etc/teleport-tls-ca/ca.pem

examples/chart/teleport-kube-agent/tests/statefulset_test.yaml

@@ -678,3 +678,15 @@ tests:
       - equal:
           path: spec.template.spec.containers[0].securityContext
           value: null
+
+  - it: should enable maintenance schedule export when updater is enabled
+    template: statefulset.yaml
+    values:
+      - ../.lint/existing-tls-secret-with-ca.yaml
+      - ../.lint/updater.yaml
+    asserts:
+      - contains:
+          path: spec.template.spec.containers[0].env
+          content:
+            name: TELEPORT_EXT_UPGRADER
+            value: kube

integrations/kube-agent-updater/cmd/teleport-kube-agent-updater/main.go

@@ -84,9 +84,11 @@ func main() {
 
 	if agentName == "" {
 		ctrl.Log.Error(trace.BadParameter("--agent-name empty"), "agent-name must be provided")
+		os.Exit(1)
 	}
 	if agentNamespace == "" {
 		ctrl.Log.Error(trace.BadParameter("--agent-namespace empty"), "agent-namespace must be provided")
+		os.Exit(1)
 	}
 
 	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{