Handle serverless components

- Skip serverless components when allocating VMs

- Add node affinity traits to components with `type: knative-serving` to
  refer to a node with `type: serverless-platform`.

Fixes #14

nebulous-requirements-extractor/src/main/java/eu/nebulouscloud/optimiser/kubevela/KubevelaAnalyzer.java

@@ -19,6 +19,7 @@
 import java.util.Set;
 import java.util.Spliterator;
 import java.util.Spliterators;
+import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 
 /**
@@ -30,11 +31,9 @@ public class KubevelaAnalyzer {
     private static final ObjectMapper yamlMapper = new ObjectMapper(new YAMLFactory());
 
     /**
-     * Return true if a component is a volume storage node.  If true, such a
-     * node should not be rewritten during deployment, and no virtual machine
-     * should be created.<p>
+     * Return true if a component is a persistent volume storage node.<p>
      *
-     * We currently look for one of the following structures in a component:
+     * We look for one of the following structures:
      *
      * <pre>{@code
      * type: raw
@@ -56,15 +55,12 @@ public class KubevelaAnalyzer {
      * Note: In the two samples above, the objects will have other attributes
      * as well, which we omit for brevity.<p>
      *
-     * Note: This method should be redesigned once we discover other kinds of
-     * nodes (currently we have compute nodes and volume storage nodes).<p>
-     *
      * @param component The component; should be a child of the {@code spec:}
      *  top-level array in the KubeVela YAML.
      *
-     * @return true if component is a volume storage node.
+     * @return true if component is a persisten volume component, false if not
      */
-    public static final boolean isVolumeStorageComponent(JsonNode component) {
+    public static boolean isVolumeComponent(JsonNode component) {
         boolean form1 = component.at("/type").asText().equals("raw")
             && component.at("/properties/kind").asText().equals("PersistentVolumeClaim");
         boolean form2 = component.at("/type").asText().equals("k8s-objects")
@@ -77,6 +73,76 @@ public static final boolean isVolumeStorageComponent(JsonNode component) {
         return form1 || form2;
     }
 
+    /**
+     * Return true if the component is a serverless component.<p>
+     *
+     * A component is serverless if it has {@code type: knative-serving}.
+     *
+     * @param component The component; should be a child of the {@code spec:}
+     *  top-level array in the KubeVela YAML.
+     *
+     * @return true if component is serverless, false if not.
+     */
+    public static final boolean isServerlessComponent(JsonNode component) {
+        return component.at("/type").asText().equals("knative-serving");
+    }
+
+    /**
+     * Return true if a component should not be rewritten during deployment,
+     * and no virtual machine should be generated.<p>
+     *
+     * Currently, we do not deploy volume storage nodes and serverless
+     * nodes.<p>
+     *
+     * <pre>{@code
+     * type: knative-serving
+     * }</pre>
+     *
+     * @param component The component; should be a child of the {@code spec:}
+     *  top-level array in the KubeVela YAML.
+     *
+     * @return true if component should get a VM, false if not.
+     */
+    public static boolean componentNeedsNode(JsonNode component) {
+        return !isVolumeComponent(component) && !isServerlessComponent(component);
+    }
+
+    public static boolean hasServerlessComponents(JsonNode kubevela) {
+        return StreamSupport.stream(
+            Spliterators.spliteratorUnknownSize(
+                kubevela.withArray("/components").elements(), Spliterator.ORDERED),
+            false)
+            .anyMatch(KubevelaAnalyzer::isServerlessComponent);
+    }
+
+    /**
+     * Return true if the component is a serverless-platform component.<p>
+     *
+     * A component is a serverless platform, i.e., should run serverless
+     * components, if it has {@code type: serverless-platform}.
+     *
+     * @param component The component; should be a child of the {@code spec:}
+     *  top-level array in the KubeVela YAML.
+     *
+     * @return true if component is a serverless platform, false if not.
+     */
+    public static final boolean isServerlessPlatform(JsonNode component) {
+        return component.at("/type").asText().equals("serverless-platform");
+    }
+
+    /**
+     * Find the names of all {@code serverless-platform} nodes.
+     */
+    public static final List<String> findServerlessPlatformNames(JsonNode kubevela) {
+        return StreamSupport.stream(
+            Spliterators.spliteratorUnknownSize(
+                kubevela.withArray("/components").elements(), Spliterator.ORDERED),
+            false)
+            .filter(KubevelaAnalyzer::isServerlessPlatform)
+            .map((component) -> component.at("/name").asText())
+            .collect(Collectors.toUnmodifiableList());
+    }
+
     /**
      * Given a KubeVela file, extract how many nodes to deploy for each
      * component.  Note that this can be zero when the component should not be
@@ -101,7 +167,7 @@ public static Map<String, Integer> getNodeCount(JsonNode kubevela) {
         Map<String, Integer> result = new HashMap<>();
         ArrayNode components = kubevela.withArray("/spec/components");
         for (final JsonNode c : components) {
-            if (isVolumeStorageComponent(c)) continue;
+            if (!componentNeedsNode(c)) continue;
             result.put(c.get("name").asText(), 1); // default value; might get overwritten
             for (final JsonNode t : c.withArray("/traits")) {
                 if (t.at("/type").asText().equals("scaler")
@@ -290,7 +356,7 @@ public static Map<String, List<Requirement>> getBoundedRequirements(JsonNode kub
         Map<String, List<Requirement>> result = new HashMap<>();
         ArrayNode components = kubevela.withArray("/spec/components");
         for (final JsonNode c : components) {
-            if (isVolumeStorageComponent(c)) continue;
+            if (!componentNeedsNode(c)) continue;
             String componentName = c.get("name").asText();
             ArrayList<Requirement> reqs = new ArrayList<>();
             if (includeNebulousRequirements) {

optimiser-controller/src/main/java/eu/nebulouscloud/optimiser/controller/AMPLGenerator.java

@@ -41,7 +41,7 @@ public static List<String> getMetricList(NebulousApp app) {
      * @param kubevela the kubevela file, used to obtain default variable values.
      * @return AMPL code for the solver.
      */
-    public static String generateAMPL(NebulousApp app, ObjectNode kubevela) {
+    public static String generateAMPL(NebulousApp app, JsonNode kubevela) {
         final StringWriter result = new StringWriter();
         final PrintWriter out = new PrintWriter(result);
         out.format("# AMPL file for application '%s' with id %s%n", app.getName(), app.getUUID());
@@ -231,7 +231,7 @@ private static Set<String> usedMetrics(NebulousApp app) {
         return result;
     }
 
-    private static void generateVariablesSection(NebulousApp app, ObjectNode kubevela, PrintWriter out) {
+    private static void generateVariablesSection(NebulousApp app, JsonNode kubevela, PrintWriter out) {
         out.println("# Variables");
         for (final JsonNode p : app.getKubevelaVariables().values()) {
             ObjectNode param = (ObjectNode) p;

optimiser-controller/src/main/java/eu/nebulouscloud/optimiser/controller/NebulousApp.java

@@ -195,7 +195,7 @@ public enum State {
 
     /** The KubeVela as it was most recently sent to the app's controller. */
     @Getter
-    private ObjectNode deployedKubevela = null;
+    private JsonNode deployedKubevela = null;
 
     /**
      * The EXN connector for this class.  At the moment all apps share the
@@ -379,7 +379,7 @@ public boolean setStateDeploying() {
     /** Set state from DEPLOYING to RUNNING and update app cluster information.
       * @return false if not in state deploying, otherwise true. */
     @Synchronized
-    public boolean setStateDeploymentFinished(Map<String, List<Requirement>> componentRequirements, Map<String, Integer> nodeCounts, Map<String, Set<String>> componentNodeNames, Map<String, NodeCandidate> nodeEdgeCandidates, ObjectNode deployedKubevela) {
+    public boolean setStateDeploymentFinished(Map<String, List<Requirement>> componentRequirements, Map<String, Integer> nodeCounts, Map<String, Set<String>> componentNodeNames, Map<String, NodeCandidate> nodeEdgeCandidates, JsonNode deployedKubevela) {
         if (state != State.DEPLOYING) {
             return false;
         } else {

optimiser-controller/src/main/java/eu/nebulouscloud/optimiser/controller/NebulousAppDeployer.java

@@ -56,7 +56,7 @@ public static List<Requirement> getControllerRequirements(String jobID, Set<Stri
      * During deployment and redeployment, we label all nodes with {@code
      * nebulouscloud.eu/<componentname>=yes}.  (Note that with this scheme, a
      * node can have labels for multiple components if desired.)  We add the
-     * following trait to all components:
+     * following trait to all normal components:
      *
      * <pre>{@code
      * traits:
@@ -71,30 +71,60 @@ public static List<Requirement> getControllerRequirements(String jobID, Set<Stri
      *               values: "yes"
      * }</pre>
      *
+     * Persistent volume components do not get an affinity trait.  Serverless
+     * components get an affinity for the {@code type: serverless-platform}
+     * node.
+     *
      * @param kubevela the KubeVela specification to modify. This parameter is
      *  not modified.
      * @return a fresh KubeVela specification with added nodeAffinity traits.
      */
-    public static ObjectNode createDeploymentKubevela(JsonNode kubevela) {
-        ObjectNode result = kubevela.deepCopy();
-        for (final JsonNode c : result.withArray("/spec/components")) {
-            // Do not add trait to components that define a volume
-            if (c.at("/type").asText().equals("raw")) continue;
-            String name = c.get("name").asText();
-            // Add traits
-            ArrayNode traits = c.withArray("traits");
-            ObjectNode trait = traits.addObject();
-            trait.put("type", "affinity");
-            ArrayNode nodeSelectorTerms = trait.withArray("/properties/nodeAffinity/required/nodeSelectorTerms");
-            ArrayNode matchExpressions = nodeSelectorTerms.addObject().withArray("matchExpressions");
-            ObjectNode term = matchExpressions.addObject();
-            term.put("key", "nebulouscloud.eu/" + name)
-                .put("operator", "In")
-                .withArray("values").add("yes");
-            // Remove resources
-            c.withObject("/properties").remove("memory");
-            c.withObject("/properties").remove("cpu");
-            c.withObject("/properties/resources").remove("requests");
+    public static ObjectNode createDeploymentKubevela(JsonNode kubevela) throws IllegalStateException {
+        final ObjectNode result = kubevela.deepCopy();
+        final ArrayNode components = result.withArray("/spec/components");
+        final List<String> serverlessPlatformNodes = KubevelaAnalyzer.findServerlessPlatformNames(result);
+        if (serverlessPlatformNodes.size() > 1) {
+            log.warn("More than one serverless platform node found, serverless components will run on {}", serverlessPlatformNodes.get(0));
+        }
+        for (final JsonNode c : components) {
+            if (KubevelaAnalyzer.isVolumeComponent(c)) {
+                // Persistent volume component: skip
+                continue;
+            } else if (KubevelaAnalyzer.isServerlessComponent(c)) {
+                // Serverless component: add trait to deploy on serverless-platform node
+                if (serverlessPlatformNodes.isEmpty()) {
+                    throw new IllegalStateException("Trying to deploy serverless component without defining a serverless platform node");
+                }
+                ArrayNode traits = c.withArray("traits");
+                ObjectNode trait = traits.addObject();
+                trait.put("type", "affinity");
+                ArrayNode nodeSelectorTerms = trait.withArray("/properties/nodeAffinity/required/nodeSelectorTerms");
+                ArrayNode matchExpressions = nodeSelectorTerms.addObject().withArray("matchExpressions");
+                ObjectNode term = matchExpressions.addObject();
+                // TODO: figure out how to express multiple affinities; in
+                // case of multiple serverless-platform nodes, we want
+                // kubernetes to choose an arbitrary one.
+                term.put("key", "nebulouscloud.eu/" + serverlessPlatformNodes.get(0))
+                    .put("operator", "In")
+                    .withArray("values").add("yes");
+            } else {
+                // Normal component: add trait to deploy on its own machine
+                String name = c.get("name").asText();
+                // Add traits
+                ArrayNode traits = c.withArray("traits");
+                ObjectNode trait = traits.addObject();
+                trait.put("type", "affinity");
+                ArrayNode nodeSelectorTerms = trait.withArray("/properties/nodeAffinity/required/nodeSelectorTerms");
+                ArrayNode matchExpressions = nodeSelectorTerms.addObject().withArray("matchExpressions");
+                ObjectNode term = matchExpressions.addObject();
+                term.put("key", "nebulouscloud.eu/" + name)
+                    .put("operator", "In")
+                    .withArray("values").add("yes");
+                // Remove resources
+                c.withObject("/properties").remove("memory");
+                c.withObject("/properties").remove("cpu");
+                c.withObject("/properties/resources").remove("requests");
+            }
         }
         return result;
     }
@@ -267,7 +297,14 @@ public static void deployApplication(NebulousApp app, JsonNode kubevela) {
 
         // ------------------------------------------------------------
         // Rewrite KubeVela
-        ObjectNode rewritten = createDeploymentKubevela(kubevela);
+        JsonNode rewritten;
+        try {
+            rewritten = createDeploymentKubevela(kubevela);
+        } catch (IllegalStateException e) {
+            log.error("Failed to create deployment kubevela", e);
+            app.setStateFailed();
+            return;
+        }
         String rewritten_kubevela = "---\n# Did not manage to create rewritten KubeVela";
         try {
             rewritten_kubevela = yamlMapper.writeValueAsString(rewritten);
@@ -544,7 +581,14 @@ public static void redeployApplication(NebulousApp app, ObjectNode updatedKubeve
 
         // ------------------------------------------------------------
         // Rewrite KubeVela
-        JsonNode rewritten = createDeploymentKubevela(updatedKubevela);
+        JsonNode rewritten;
+        try {
+            rewritten = createDeploymentKubevela(updatedKubevela);
+        } catch (IllegalStateException e) {
+            log.error("Failed to create deployment kubevela", e);
+            app.setStateFailed();
+            return;
+        }
         String rewritten_kubevela = "---\n# Did not manage to create rewritten KubeVela";
         try {
             rewritten_kubevela = yamlMapper.writeValueAsString(rewritten);

optimiser-controller/src/test/java/eu/nebulouscloud/optimiser/controller/NebulousAppTests.java

@@ -3,6 +3,7 @@
 import org.junit.jupiter.api.Test;
 import org.ow2.proactive.sal.model.Requirement;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
@@ -22,6 +23,7 @@
 
 import static org.junit.Assert.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class NebulousAppTests {
@@ -85,7 +87,7 @@ void replaceValueInKubevela() throws IOException, URISyntaxException {
     }
 
     @Test
-    void calculateNodeRequirements() throws IOException, URISyntaxException {
+    void calculateNodeRequirementsSize() throws IOException, URISyntaxException {
         String kubevela_str = Files.readString(getResourcePath("vela-deployment-v2.yml"),
             StandardCharsets.UTF_8);
         JsonNode kubevela = yaml_mapper.readTree(kubevela_str);
@@ -98,6 +100,20 @@ void calculateNodeRequirements() throws IOException, URISyntaxException {
         assertTrue(requirements.size() == kubevela.withArray("/spec/components").size());
     }
 
+    @Test
+    void calculateServerlessRequirementsSize() throws IOException, URISyntaxException {
+        JsonNode kubevela = KubevelaAnalyzer.parseKubevela(Files.readString(getResourcePath("serverless-deployment.yaml"), StandardCharsets.UTF_8));
+        Map<String, List<Requirement>> requirements = KubevelaAnalyzer.getBoundedRequirements(kubevela, null);
+        // We have one serverless component, so we need n-1 VMs
+        assertTrue(requirements.size() == kubevela.withArray("/spec/components").size() - 1);
+    }
+
+    @Test
+    void checkInvalidServerlessDeployment() throws JsonProcessingException, IOException, URISyntaxException {
+        JsonNode kubevela = KubevelaAnalyzer.parseKubevela(Files.readString(getResourcePath("invalid-serverless-deployment.yaml"), StandardCharsets.UTF_8));
+        assertThrows(IllegalStateException.class, () -> NebulousAppDeployer.createDeploymentKubevela(kubevela));
+    }
+
     // @Test
     void calculateRewrittenNodeRequirements() throws IOException, URISyntaxException {
         // TODO: reinstate with `app-creation-message-mercabana.json` after we

optimiser-controller/src/test/resources/invalid-serverless-deployment.yaml

@@ -0,0 +1,29 @@
+apiVersion: core.oam.dev/v1beta1
+kind: Application
+metadata:
+  name: first-app
+spec:
+  components:
+    - name: helloworld
+      type: webservice
+      properties:
+        image: oamdev/helloworld-python:v1
+        env:
+          - name: "TARGET"
+            value: "KubeVela"
+        port: 8080
+    - name: serverless-backend
+      type: webservice
+      properties:
+        resources:
+          requests:
+            cpu: "2"    # Requests for CPU in cores
+            memory: "2Gi" # Requests for memory in GiB
+        replicas: 3   # Number of replicas
+    - name: backend
+      type: knative-serving
+      properties:
+        image: gcr.io/knative-samples/helloworld-go
+        env:
+          - name: TARGET
+            value: "Go Sample v1"

optimiser-controller/src/test/resources/serverless-deployment.yaml

@@ -0,0 +1,29 @@
+apiVersion: core.oam.dev/v1beta1
+kind: Application
+metadata:
+  name: first-app
+spec:
+  components:
+    - name: helloworld
+      type: webservice
+      properties:
+        image: oamdev/helloworld-python:v1
+        env:
+          - name: "TARGET"
+            value: "KubeVela"
+        port: 8080
+    - name: serverless-backend
+      type: serverless-platform
+      properties:
+        resources:
+          requests:
+            cpu: "2"    # Requests for CPU in cores
+            memory: "2Gi" # Requests for memory in GiB
+        replicas: 3   # Number of replicas
+    - name: backend
+      type: knative-serving
+      properties:
+        image: gcr.io/knative-samples/helloworld-go
+        env:
+          - name: TARGET
+            value: "Go Sample v1"