Add ability to set the MTU size of the docker in docker container (#385)

* adding abilitiy to set docker in docker MTU size

* safeguards to only set MTU env var if it is set

api/v1alpha1/runner_types.go

@@ -92,6 +92,8 @@ type RunnerSpec struct {
 	DockerdWithinRunnerContainer *bool `json:"dockerdWithinRunnerContainer,omitempty"`
 	// +optional
 	DockerEnabled *bool `json:"dockerEnabled,omitempty"`
+	// +optional
+	DockerMTU *int64 `json:"dockerMTU,omitempty"`
 }
 
 // ValidateRepository validates repository field.

api/v1alpha1/zz_generated.deepcopy.go

@@ -689,6 +689,11 @@ func (in *RunnerSpec) DeepCopyInto(out *RunnerSpec) {
 		*out = new(bool)
 		**out = **in
 	}
+	if in.DockerMTU != nil {
+		in, out := &in.DockerMTU, &out.DockerMTU
+		*out = new(int64)
+		**out = **in
+	}
 }
 
 // DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new RunnerSpec.

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

@@ -433,6 +433,9 @@ spec:
                       type: array
                     dockerEnabled:
                       type: boolean
+                    dockerMTU:
+                      format: int64
+                      type: integer
                     dockerdContainerResources:
                       description: ResourceRequirements describes the compute resource requirements.
                       properties:

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

@@ -433,6 +433,9 @@ spec:
                       type: array
                     dockerEnabled:
                       type: boolean
+                    dockerMTU:
+                      format: int64
+                      type: integer
                     dockerdContainerResources:
                       description: ResourceRequirements describes the compute resource requirements.
                       properties:

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

@@ -398,6 +398,9 @@ spec:
               type: array
             dockerEnabled:
               type: boolean
+            dockerMTU:
+              format: int64
+              type: integer
             dockerdContainerResources:
               description: ResourceRequirements describes the compute resource requirements.
               properties:

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

@@ -433,6 +433,9 @@ spec:
                       type: array
                     dockerEnabled:
                       type: boolean
+                    dockerMTU:
+                      format: int64
+                      type: integer
                     dockerdContainerResources:
                       description: ResourceRequirements describes the compute resource requirements.
                       properties:

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

@@ -433,6 +433,9 @@ spec:
                       type: array
                     dockerEnabled:
                       type: boolean
+                    dockerMTU:
+                      format: int64
+                      type: integer
                     dockerdContainerResources:
                       description: ResourceRequirements describes the compute resource requirements.
                       properties:

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

@@ -398,6 +398,9 @@ spec:
               type: array
             dockerEnabled:
               type: boolean
+            dockerMTU:
+              format: int64
+              type: integer
             dockerdContainerResources:
               description: ResourceRequirements describes the compute resource requirements.
               properties:

controllers/runner_controller.go

@@ -530,6 +530,15 @@ func (r *RunnerReconciler) newPod(runner v1alpha1.Runner) (corev1.Pod, error) {
 		},
 	}
 
+	if mtu := runner.Spec.DockerMTU; mtu != nil && dockerdInRunner {
+		pod.Spec.Containers[0].Env = append(pod.Spec.Containers[0].Env, []corev1.EnvVar{
+			{
+				Name:  "MTU",
+				Value: fmt.Sprintf("%d", *runner.Spec.DockerMTU),
+			},
+		}...)
+	}
+
 	if !dockerdInRunner && dockerEnabled {
 		runnerVolumeName := "runner"
 		runnerVolumeMountPath := "/runner"
@@ -612,6 +621,15 @@ func (r *RunnerReconciler) newPod(runner v1alpha1.Runner) (corev1.Pod, error) {
 			Resources: runner.Spec.DockerdContainerResources,
 		})
 
+		if mtu := runner.Spec.DockerMTU; mtu != nil {
+			pod.Spec.Containers[1].Env = append(pod.Spec.Containers[1].Env, []corev1.EnvVar{
+				{
+					Name:  "DOCKERD_ROOTLESS_ROOTLESSKIT_MTU",
+					Value: fmt.Sprintf("%d", *runner.Spec.DockerMTU),
+				},
+			}...)
+		}
+
 	}
 
 	if len(runner.Spec.Containers) != 0 {

runner/startup.sh

@@ -33,5 +33,9 @@ for process in "${processes[@]}"; do
     fi
 done
 
+if [ -n "${MTU}" ]; then
+  ifconfig docker0 mtu ${MTU} up
+fi
+
 # Wait processes to be running
 entrypoint.sh