Allow disabling /runner emptydir mounts and setting storage volume (#674)

* Allow disabling /runner emptydir mounts

* Support defining storage medium for emptydirs

* Fix typos

README.md

@@ -961,13 +961,13 @@ spec:
 
 As it is based on `StatefulSet`, `selector` and `template.medatada.labels` needs to be defined and haev the exact same set of labels. `serviceName` must be set to some non-empty string as it is also required by `StatefulSet`.
 
-Runner-related fields like `ephemeral`, `repository`, `organiåtion`, `enterprise`, and so on should be written directly under `spec`.
+Runner-related fields like `ephemeral`, `repository`, `organization`, `enterprise`, and so on should be written directly under `spec`.
 
-Fields like `volumeClaimTemplates` that originates from `StatefulSet` shuold also be written directly under `spec`.
+Fields like `volumeClaimTemplates` that originates from `StatefulSet` should also be written directly under `spec`.
 
 Pod-related fields like security contexts and volumes are written under `spec.template.spec` like `StatefulSet`.
 
-Simillarly, container-related fields like resource requests and limits, container image names and tags, security context, and so on are written under `spec.template.spec.containers`. There are two reserved container `name`, `runner` and `docker`. The former is for the container that runs [actions runner](https://github.com/actions/runner) and the latter is for the container that runs a dockerd.
+Similarly, container-related fields like resource requests and limits, container image names and tags, security context, and so on are written under `spec.template.spec.containers`. There are two reserved container `name`, `runner` and `docker`. The former is for the container that runs [actions runner](https://github.com/actions/runner) and the latter is for the container that runs a dockerd.
 
 For a more complex example, see the below:
 
@@ -1018,7 +1018,7 @@ https://github.com/actions-runner-controller/actions-runner-controller/pull/629
 
 Under the hood, `RunnerSet` relies on Kubernetes's `StatefulSet` and Mutating Webhook. A statefulset is used to create a number of pods that has stable names and dynamically provisioned persistent volumes, so that each statefulset-managed pod gets the same persisntet volume even after restarting. A mutating webhook is used to dynamically inject a runner's "registration token" which is used to call GitHub's "Create Runner" API.
 
-We envision that `RunnerSet` will eventually replaces `RunnerDeployment`, as `RunnerSet` provides a more standard API that is easy to learn and use because it is based on `StatefulSet`, and it has a support for `volumeClaimTemplates` which is crucial to manage dynamically provisioned persistent volumes.
+We envision that `RunnerSet` will eventually replace `RunnerDeployment`, as `RunnerSet` provides a more standard API that is easy to learn and use because it is based on `StatefulSet`, and it has a support for `volumeClaimTemplates` which is crucial to manage dynamically provisioned persistent volumes.
 
 ### Software Installed in the Runner Image
 

api/v1alpha1/runner_types.go

@@ -69,6 +69,8 @@ type RunnerConfig struct {
 	DockerRegistryMirror *string `json:"dockerRegistryMirror,omitempty"`
 	// +optional
 	VolumeSizeLimit *resource.Quantity `json:"volumeSizeLimit,omitempty"`
+	// +optional
+	VolumeStorageMedium *string `json:"volumeStorageMedium,omitempty"`
 }
 
 // RunnerPodSpec defines the desired pod spec fields of the runner pod

api/v1alpha1/zz_generated.deepcopy.go

@@ -408,6 +408,11 @@ func (in *RunnerConfig) DeepCopyInto(out *RunnerConfig) {
 		x := (*in).DeepCopy()
 		*out = &x
 	}
+	if in.VolumeStorageMedium != nil {
+		in, out := &in.VolumeStorageMedium, &out.VolumeStorageMedium
+		*out = new(string)
+		**out = **in
+	}
 }
 
 // DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new RunnerConfig.

charts/actions-runner-controller/crds/actions.summerwind.dev_runnerdeployments.yaml

@@ -984,6 +984,8 @@ spec:
                             - type: string
                           pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                           x-kubernetes-int-or-string: true
+                        volumeStorageMedium:
+                          type: string
                         volumes:
                           items:
                             description: Volume represents a named volume in a pod that may be accessed by any container in the pod.

charts/actions-runner-controller/crds/actions.summerwind.dev_runnerreplicasets.yaml

@@ -981,6 +981,8 @@ spec:
                             - type: string
                           pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                           x-kubernetes-int-or-string: true
+                        volumeStorageMedium:
+                          type: string
                         volumes:
                           items:
                             description: Volume represents a named volume in a pod that may be accessed by any container in the pod.

charts/actions-runner-controller/crds/actions.summerwind.dev_runners.yaml

@@ -927,6 +927,8 @@ spec:
                     - type: string
                   pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                   x-kubernetes-int-or-string: true
+                volumeStorageMedium:
+                  type: string
                 volumes:
                   items:
                     description: Volume represents a named volume in a pod that may be accessed by any container in the pod.

charts/actions-runner-controller/crds/actions.summerwind.dev_runnersets.yaml

@@ -7113,6 +7113,8 @@ spec:
                 - type: string
                 pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                 x-kubernetes-int-or-string: true
+              volumeStorageMedium:
+                type: string
               workDir:
                 type: string
             required:

config/crd/bases/actions.summerwind.dev_runnerdeployments.yaml

@@ -984,6 +984,8 @@ spec:
                             - type: string
                           pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                           x-kubernetes-int-or-string: true
+                        volumeStorageMedium:
+                          type: string
                         volumes:
                           items:
                             description: Volume represents a named volume in a pod that may be accessed by any container in the pod.

config/crd/bases/actions.summerwind.dev_runnerreplicasets.yaml

@@ -981,6 +981,8 @@ spec:
                             - type: string
                           pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                           x-kubernetes-int-or-string: true
+                        volumeStorageMedium:
+                          type: string
                         volumes:
                           items:
                             description: Volume represents a named volume in a pod that may be accessed by any container in the pod.

config/crd/bases/actions.summerwind.dev_runners.yaml

@@ -927,6 +927,8 @@ spec:
                     - type: string
                   pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                   x-kubernetes-int-or-string: true
+                volumeStorageMedium:
+                  type: string
                 volumes:
                   items:
                     description: Volume represents a named volume in a pod that may be accessed by any container in the pod.

config/crd/bases/actions.summerwind.dev_runnersets.yaml

@@ -7113,6 +7113,8 @@ spec:
                 - type: string
                 pattern: ^(\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))(([KMGTPE]i)|[numkMGTPE]|([eE](\+|-)?(([0-9]+(\.[0-9]*)?)|(\.[0-9]+))))?$
                 x-kubernetes-int-or-string: true
+              volumeStorageMedium:
+                type: string
               workDir:
                 type: string
             required:

controllers/runner_controller.go

@@ -886,32 +886,49 @@ func newRunnerPod(template corev1.Pod, runnerSpec v1alpha1.RunnerConfig, default
 	// When you're NOT using dindWithinRunner=true,
 	// it must also be shared with the dind container as it seems like required to run docker steps.
 	//
+	// Setting VolumeSizeLimit to zero will disable /runner emptydir mount
+	//
+	// VolumeStorageMedium defines ways that storage can be allocated to a volume: "", "Memory", "HugePages", "HugePages-<size>"
+	//
 
 	runnerVolumeName := "runner"
 	runnerVolumeMountPath := "/runner"
 	runnerVolumeEmptyDir := &corev1.EmptyDirVolumeSource{}
 
+	if runnerSpec.VolumeStorageMedium != nil {
+		runnerVolumeEmptyDir.Medium = corev1.StorageMedium(*runnerSpec.VolumeStorageMedium)
+	}
+
 	if runnerSpec.VolumeSizeLimit != nil {
 		runnerVolumeEmptyDir.SizeLimit = runnerSpec.VolumeSizeLimit
 	}
 
-	pod.Spec.Volumes = append(pod.Spec.Volumes,
+	if runnerSpec.VolumeSizeLimit == nil || !runnerSpec.VolumeSizeLimit.IsZero() {
-		corev1.Volume{
+		pod.Spec.Volumes = append(pod.Spec.Volumes,
-			Name: runnerVolumeName,
+			corev1.Volume{
-			VolumeSource: corev1.VolumeSource{
+				Name: runnerVolumeName,
-				EmptyDir: runnerVolumeEmptyDir,
+				VolumeSource: corev1.VolumeSource{
+					EmptyDir: runnerVolumeEmptyDir,
+				},
 			},
-		},
+		)
-	)
 
-	runnerContainer.VolumeMounts = append(runnerContainer.VolumeMounts,
+		runnerContainer.VolumeMounts = append(runnerContainer.VolumeMounts,
-		corev1.VolumeMount{
+			corev1.VolumeMount{
-			Name:      runnerVolumeName,
+				Name:      runnerVolumeName,
-			MountPath: runnerVolumeMountPath,
+				MountPath: runnerVolumeMountPath,
-		},
+			},
-	)
+		)
+	}
 
 	if !dockerdInRunner && dockerEnabled {
+		if runnerSpec.VolumeSizeLimit != nil && runnerSpec.VolumeSizeLimit.IsZero() {
+			return *pod, fmt.Errorf(
+				"%s volume can't be disabled because it is required to share the working directory between the runner and the dockerd containers",
+				runnerVolumeName,
+			)
+		}
+
 		pod.Spec.Volumes = append(pod.Spec.Volumes,
 			corev1.Volume{
 				Name: "work",

main.go

@@ -203,7 +203,7 @@ func main() {
 
 	log.Info(
 		"Initializing actions-runner-controller",
-		"github-api-cahce-duration", gitHubAPICacheDuration,
+		"github-api-cache-duration", gitHubAPICacheDuration,
 		"sync-period", syncPeriod,
 		"runner-image", runnerImage,
 		"docker-image", dockerImage,