Restart a Topology on Kubernetes

deploy/kubernetes/helm/templates/tools.yaml

@@ -296,6 +296,12 @@ rules:
   - patch
   - update
   - watch
+- apiGroups:
+  - ""
+  resources:
+  - pods
+  verbs:
+  - deletecollection
 - apiGroups:
   - ""
   resources:

heron/schedulers/src/java/org/apache/heron/scheduler/kubernetes/V1Controller.java

@@ -156,12 +156,23 @@ boolean killTopology() {
     return true;
   }
 
+  /**
+   * Restarts a topology by deleting the Pods associated with it using <code>Selector Labels</code>.
+   * @param shardId Not used but required because of interface.
+   * @return Indicator of successful submission of restart request to Kubernetes cluster.
+   */
   @Override
   boolean restart(int shardId) {
-    final String message = "Restarting the whole topology is not supported yet. "
-        + "Please kill and resubmit the topology.";
-    LOG.log(Level.SEVERE, message);
-    return false;
+    try {
+      coreClient.deleteCollectionNamespacedPod(getNamespace(), null, null, null, null,
+          0, createTopologySelectorLabels(), null, null, null, null,
+          null, null, null);
+      LOG.log(Level.WARNING, String.format("Restarting topology '%s'...", getTopologyName()));
+    } catch (ApiException e) {
+      LOG.log(Level.SEVERE, String.format("Failed to restart topology '%s'...", getTopologyName()));
+      return false;
+    }
+    return true;
   }
 
   @Override
@@ -839,4 +850,14 @@ protected V1ConfigMap getConfigMap(String configMapName) {
       throw new TopologySubmissionException(String.format("%s: %s", message, e.getMessage()));
     }
   }
+
+  /**
+   * Generates the <code>Selector</code> match labels with which resources in this topology can be found.
+   * @return A label of the form <code>app=heron,topology=topology-name</code>.
+   */
+  private String createTopologySelectorLabels() {
+    return String.format("%s=%s,%s=%s",
+        KubernetesConstants.LABEL_APP, KubernetesConstants.LABEL_APP_VALUE,
+        KubernetesConstants.LABEL_TOPOLOGY, getTopologyName());
+  }
 }