Use interlink-apptainer-plugin with ConfigMap-based configuration

README.md

@@ -60,15 +60,37 @@ InterlinkMachine
 The controller creates a Pod and ClusterIP Service named `<machine-name>-plugin`,
 then derives the address as `http://<machine>-plugin.<namespace>.svc.cluster.local:<port>`.
 
+The [interlink-apptainer-plugin](https://github.com/interlink-hq/interlink-apptainer-plugin)
+reads its configuration from a YAML file.  Create a ConfigMap with the file and
+mount it into the plugin container via `volumes` / `volumeMounts`:
+
 ```yaml
+# ConfigMap holding the Apptainer plugin configuration.
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: apptainer-plugin-config
+  namespace: default
+data:
+  ApptainerConfig.yaml: |
+    SidecarPort: "4000"
+    DataRootFolder: "/tmp/.interlink/"
+    ApptainerPath: "/usr/bin/apptainer"
+    ApptainerDefaultOptions:
+      - "--no-eval"
+      - "--containall"
+    ImagePrefix: "docker://"
+    BashPath: /bin/bash
+    ExportPodData: true
+    VerboseLogging: false
+    ErrorsOnlyLogging: false
+    EnableProbes: false
+---
 apiVersion: infrastructure.cluster.x-k8s.io/v1alpha1
 kind: InterlinkMachine
 metadata:
   name: my-virtual-node
 spec:
-  # Optional: override the derived interLinkAddress
-  # interLinkAddress: "http://custom-endpoint:3000"
-
   nodeName: "my-virtual-node"
   resources:
     cpu: "8"
@@ -82,8 +104,8 @@ spec:
     effect: NoSchedule
 
   pluginSpec:
-    # Container image running the interLink plugin binary.
-    image: "ghcr.io/interlink-hq/interlink/plugin-apptainer:latest"
+    # Apptainer plugin image from https://github.com/interlink-hq/interlink-apptainer-plugin.
+    image: "ghcr.io/interlink-hq/interlink-apptainer-plugin:latest"
 
     # TCP port the plugin listens on (default: 4000).
     port: 4000
@@ -99,10 +121,20 @@ spec:
       operator: Exists
       effect: NoSchedule
 
-    # Plugin-specific environment variables.
+    # Point the plugin at the mounted configuration file.
     env:
-    - name: INTERLINK_PORT
-      value: "4000"
+    - name: APPTAINERCONFIGPATH
+      value: "/etc/interlink/ApptainerConfig.yaml"
+
+    # Mount the ConfigMap so the plugin can read its configuration.
+    volumes:
+    - name: plugin-config
+      configMap:
+        name: apptainer-plugin-config
+    volumeMounts:
+    - name: plugin-config
+      mountPath: /etc/interlink
+      readOnly: true
 
     # Compute resources for the plugin container.
     resources:

api/v1alpha1/interlinkmachine_types.go

@@ -85,6 +85,18 @@ type PluginPodSpec struct {
 	// Resources specifies the compute resources required by the plugin container.
 	// +optional
 	Resources corev1.ResourceRequirements `json:"resources,omitempty"`
+
+	// VolumeMounts describe volume mounts for the plugin container.
+	// Use this together with Volumes to inject files (e.g. a ConfigMap containing
+	// ApptainerConfig.yaml) into the container at a specific path.
+	// +optional
+	VolumeMounts []corev1.VolumeMount `json:"volumeMounts,omitempty"`
+
+	// Volumes is a list of volumes that can be mounted by the plugin container.
+	// Use this to make ConfigMaps, Secrets, or host paths available inside
+	// the container (e.g. mounting an apptainer configuration file).
+	// +optional
+	Volumes []corev1.Volume `json:"volumes,omitempty"`
 }
 
 // VirtualNodeResources describes the capacity of a virtual node.

controllers/controllers_test.go

@@ -582,3 +582,87 @@ func TestInterlinkMachineReconciler_PluginPodMode_DefaultPort(t *testing.T) {
 }
 
 func boolPtr(b bool) *bool { return &b }
+
+func TestInterlinkMachineReconciler_PluginPodMode_VolumesAndMounts(t *testing.T) {
+	g := NewWithT(t)
+	scheme := buildScheme(t)
+
+	cluster := &clusterv1.Cluster{
+		ObjectMeta: metav1.ObjectMeta{Name: "test-cluster", Namespace: "default"},
+	}
+	machine := &clusterv1.Machine{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "apptainer-machine",
+			Namespace: "default",
+			Labels:    map[string]string{clusterv1.ClusterNameLabel: "test-cluster"},
+		},
+		Spec: clusterv1.MachineSpec{ClusterName: "test-cluster"},
+	}
+	interlinkMachine := &infrav1.InterlinkMachine{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "apptainer-machine",
+			Namespace: "default",
+			OwnerReferences: []metav1.OwnerReference{
+				{APIVersion: clusterv1.GroupVersion.String(), Kind: "Machine", Name: machine.Name, UID: machine.UID, Controller: boolPtr(true)},
+			},
+		},
+		Spec: infrav1.InterlinkMachineSpec{
+			NodeName: "virtual-node-apptainer",
+			PluginSpec: &infrav1.PluginPodSpec{
+				Image: "ghcr.io/interlink-hq/interlink-apptainer-plugin:latest",
+				Port:  4000,
+				Env: []corev1.EnvVar{
+					{Name: "APPTAINERCONFIGPATH", Value: "/etc/interlink/ApptainerConfig.yaml"},
+				},
+				Volumes: []corev1.Volume{
+					{
+						Name: "plugin-config",
+						VolumeSource: corev1.VolumeSource{
+							ConfigMap: &corev1.ConfigMapVolumeSource{
+								LocalObjectReference: corev1.LocalObjectReference{Name: "apptainer-plugin-config"},
+							},
+						},
+					},
+				},
+				VolumeMounts: []corev1.VolumeMount{
+					{Name: "plugin-config", MountPath: "/etc/interlink", ReadOnly: true},
+				},
+			},
+		},
+	}
+
+	fakeClient := fake.NewClientBuilder().
+		WithScheme(scheme).
+		WithObjects(cluster, machine, interlinkMachine).
+		WithStatusSubresource(interlinkMachine).
+		Build()
+
+	reconciler := &controllers.InterlinkMachineReconciler{
+		Client: fakeClient,
+		Scheme: scheme,
+		Log:    ctrl.Log.WithName("test"),
+	}
+
+	result, err := reconciler.Reconcile(context.Background(), ctrl.Request{
+		NamespacedName: types.NamespacedName{Namespace: "default", Name: "apptainer-machine"},
+	})
+	g.Expect(err).ToNot(HaveOccurred())
+	// Plugin pod is not Running yet; should requeue.
+	g.Expect(result.RequeueAfter).ToNot(BeZero())
+
+	// Verify the plugin Pod has the expected volumes and volumeMounts.
+	pod := &corev1.Pod{}
+	g.Expect(fakeClient.Get(context.Background(), types.NamespacedName{Namespace: "default", Name: "apptainer-machine-plugin"}, pod)).To(Succeed())
+	g.Expect(pod.Spec.Containers[0].Image).To(Equal("ghcr.io/interlink-hq/interlink-apptainer-plugin:latest"))
+	g.Expect(pod.Spec.Volumes).To(HaveLen(1))
+	g.Expect(pod.Spec.Volumes[0].Name).To(Equal("plugin-config"))
+	g.Expect(pod.Spec.Volumes[0].ConfigMap).ToNot(BeNil())
+	g.Expect(pod.Spec.Volumes[0].ConfigMap.Name).To(Equal("apptainer-plugin-config"))
+	g.Expect(pod.Spec.Containers[0].VolumeMounts).To(HaveLen(1))
+	g.Expect(pod.Spec.Containers[0].VolumeMounts[0].Name).To(Equal("plugin-config"))
+	g.Expect(pod.Spec.Containers[0].VolumeMounts[0].MountPath).To(Equal("/etc/interlink"))
+	g.Expect(pod.Spec.Containers[0].VolumeMounts[0].ReadOnly).To(BeTrue())
+	g.Expect(pod.Spec.Containers[0].Env).To(ContainElement(
+		corev1.EnvVar{Name: "APPTAINERCONFIGPATH", Value: "/etc/interlink/ApptainerConfig.yaml"},
+	))
+}

controllers/interlinkmachine_controller.go

@@ -451,6 +451,7 @@ func buildPluginPodSpec(spec *infrav1.PluginPodSpec, port int32) corev1.PodSpec
 		NodeSelector:  spec.NodeSelector,
 		Tolerations:   spec.Tolerations,
 		RestartPolicy: corev1.RestartPolicyAlways,
+		Volumes:       spec.Volumes,
 		Containers: []corev1.Container{
 			{
 				Name:  "plugin",
@@ -462,8 +463,9 @@ func buildPluginPodSpec(spec *infrav1.PluginPodSpec, port int32) corev1.PodSpec
 						Protocol:      corev1.ProtocolTCP,
 					},
 				},
-				Env:       spec.Env,
-				Resources: spec.Resources,
+				Env:          spec.Env,
+				Resources:    spec.Resources,
+				VolumeMounts: spec.VolumeMounts,
 			},
 		},
 	}

examples/pilot.yaml

@@ -1,8 +1,9 @@
 ---
-# Pilot-mode example: on-demand interLink plugin instantiation.
+# Pilot-mode example: on-demand interLink plugin instantiation using the
+# Apptainer plugin (https://github.com/interlink-hq/interlink-apptainer-plugin).
 #
 # In this mode the controller creates a Pod (and a ClusterIP Service) that runs
-# the interLink plugin binary on an *existing* virtual node that has access to
+# the interLink apptainer plugin on an *existing* virtual node that has access to
 # the remote resource provider (e.g. an HPC cluster running Apptainer).
 # The Service address is automatically used as the interLinkAddress for the
 # VirtualNode, so no external interLink deployment is required beforehand.
@@ -18,6 +19,30 @@
 # The same InterlinkMachineTemplate can be referenced by a MachineDeployment
 # and scaled by the Cluster Autoscaler.
 
+# -- Apptainer plugin configuration ------------------------------------------
+# The apptainer plugin reads its configuration from a YAML file.
+# Mount this ConfigMap into the plugin Pod as /etc/interlink/ApptainerConfig.yaml.
+# Adjust the values below to match your environment.
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: apptainer-plugin-config
+  namespace: default
+data:
+  ApptainerConfig.yaml: |
+    SidecarPort: "4000"
+    DataRootFolder: "/tmp/.interlink/"
+    ApptainerPath: "/usr/bin/apptainer"
+    ApptainerDefaultOptions:
+      - "--no-eval"
+      - "--containall"
+    ImagePrefix: "docker://"
+    BashPath: /bin/bash
+    ExportPodData: true
+    VerboseLogging: false
+    ErrorsOnlyLogging: false
+    EnableProbes: false
+---
 # -- Cluster -----------------------------------------------------------------
 apiVersion: cluster.x-k8s.io/v1beta1
 kind: Cluster
@@ -105,8 +130,10 @@ spec:
           effect: NoSchedule
       # Pilot-mode configuration.
       pluginSpec:
-        # Image that runs the interLink plugin binary (e.g. Apptainer plugin).
-        image: "ghcr.io/interlink-hq/interlink/plugin-apptainer:latest"
+        # Apptainer plugin image from https://github.com/interlink-hq/interlink-apptainer-plugin.
+        # Build the image from source and push it to a registry accessible from the cluster,
+        # or use a pre-built image if one is available.
+        image: "ghcr.io/interlink-hq/interlink-apptainer-plugin:latest"
         # TCP port the plugin listens on inside the container (default: 4000).
         port: 4000
         # Schedule the plugin Pod onto an existing virtual node backed by the
@@ -118,12 +145,21 @@ spec:
           - key: virtual-node.interlink.eu
             operator: Exists
             effect: NoSchedule
-        # Plugin-specific configuration passed as environment variables.
+        # Environment variables for the apptainer plugin.
+        # APPTAINERCONFIGPATH tells the plugin where to find its config file.
+        # SHARED_FS=true enables shared-filesystem mode (set by the container entrypoint).
         env:
-          - name: INTERLINK_PORT
-            value: "4000"
-          - name: APPTAINER_TMPDIR
-            value: "/tmp/apptainer"
+          - name: APPTAINERCONFIGPATH
+            value: "/etc/interlink/ApptainerConfig.yaml"
+        # Mount the ConfigMap defined above so the plugin can read its configuration.
+        volumes:
+          - name: plugin-config
+            configMap:
+              name: apptainer-plugin-config
+        volumeMounts:
+          - name: plugin-config
+            mountPath: /etc/interlink
+            readOnly: true
         resources:
           requests:
             cpu: "500m"