Add emptyDir volume support to kube play

When a kube yaml has a volume set as empty dir, podman
will create an anonymous volume with the empty dir name and
attach it to the containers running in the pod. When the pod
is removed, the empy dir volume created is also removed.

Add tests and docs for this as well.

Signed-off-by: Urvashi Mohnani <[email protected]>

docs/source/markdown/podman-kube-play.1.md.in

@@ -21,7 +21,7 @@ Currently, the supported Kubernetes kinds are:
 
 `Kubernetes Pods or Deployments`
 
-Only two volume types are supported by kube play, the *hostPath* and *persistentVolumeClaim* volume types. For the *hostPath* volume type, only the  *default (empty)*, *DirectoryOrCreate*, *Directory*, *FileOrCreate*, *File*, *Socket*, *CharDevice* and *BlockDevice* subtypes are supported. Podman interprets the value of *hostPath* *path* as a file path when it contains at least one forward slash, otherwise Podman treats the value as the name of a named volume. When using a *persistentVolumeClaim*, the value for *claimName* is the name for the Podman named volume.
+Only three volume types are supported by kube play, the *hostPath*, *emptyDir*, and *persistentVolumeClaim* volume types. For the *hostPath* volume type, only the  *default (empty)*, *DirectoryOrCreate*, *Directory*, *FileOrCreate*, *File*, *Socket*, *CharDevice* and *BlockDevice* subtypes are supported. Podman interprets the value of *hostPath* *path* as a file path when it contains at least one forward slash, otherwise Podman treats the value as the name of a named volume. When using a *persistentVolumeClaim*, the value for *claimName* is the name for the Podman named volume. When using an *emptyDir* volume, podman creates an anonymous volume that is attached the containers running inside the pod and is deleted once the pod is removed.
 
 Note: When playing a kube YAML with init containers, the init container will be created with init type value `once`. To change the default type, use the `io.podman.annotations.init.container.type` annotation to set the type to `always`.
 

libpod/container.go

@@ -237,6 +237,9 @@ type ContainerNamedVolume struct {
 	Dest string `json:"dest"`
 	// Options are fstab style mount options
 	Options []string `json:"options,omitempty"`
+	// IsAnonymous sets the named volume as anonymous even if it has a name
+	// This is used for emptyDir volumes from a kube yaml
+	IsAnonymous bool `json:"setAnonymous,omitempty"`
 }
 
 // ContainerOverlayVolume is a overlay volume that will be mounted into the

libpod/options.go

@@ -1413,9 +1413,10 @@ func WithNamedVolumes(volumes []*ContainerNamedVolume) CtrCreateOption {
 			}
 
 			ctr.config.NamedVolumes = append(ctr.config.NamedVolumes, &ContainerNamedVolume{
-				Name:    vol.Name,
-				Dest:    vol.Dest,
-				Options: mountOpts,
+				Name:        vol.Name,
+				Dest:        vol.Dest,
+				Options:     mountOpts,
+				IsAnonymous: vol.IsAnonymous,
 			})
 		}
 

libpod/runtime_ctr.go

@@ -474,6 +474,11 @@ func (r *Runtime) setupContainer(ctx context.Context, ctr *Container) (_ *Contai
 				return nil, fmt.Errorf("error retrieving named volume %s for new container: %w", vol.Name, err)
 			}
 		}
+		if vol.IsAnonymous {
+			// If SetAnonymous is true, make this an anonymous volume
+			// this is needed for emptyDir volumes from kube yamls
+			isAnonymous = true
+		}
 
 		logrus.Debugf("Creating new volume %s for container", vol.Name)
 
@@ -814,11 +819,11 @@ func (r *Runtime) removeContainer(ctx context.Context, c *Container, force, remo
 					// Ignore error, since podman will report original error
 					volumesFrom, _ := c.volumesFrom()
 					if len(volumesFrom) > 0 {
-						logrus.Debugf("Cleaning up volume not possible since volume is in use (%s)", v)
+						logrus.Debugf("Cleaning up volume not possible since volume is in use (%s)", v.Name)
 						continue
 					}
 				}
-				logrus.Errorf("Cleaning up volume (%s): %v", v, err)
+				logrus.Errorf("Cleaning up volume (%s): %v", v.Name, err)
 			}
 		}
 	}
@@ -968,7 +973,7 @@ func (r *Runtime) evictContainer(ctx context.Context, idOrName string, removeVol
 				continue
 			}
 			if err := r.removeVolume(ctx, volume, false, timeout, false); err != nil && err != define.ErrNoSuchVolume && err != define.ErrVolumeBeingUsed {
-				logrus.Errorf("Cleaning up volume (%s): %v", v, err)
+				logrus.Errorf("Cleaning up volume (%s): %v", v.Name, err)
 			}
 		}
 	}

pkg/domain/infra/abi/play.go

@@ -436,7 +436,7 @@ func (ic *ContainerEngine) playKubePod(ctx context.Context, podName string, podY
 	}
 
 	// Go through the volumes and create a podman volume for all volumes that have been
-	// defined by a configmap
+	// defined by a configmap or secret
 	for _, v := range volumes {
 		if (v.Type == kube.KubeVolumeTypeConfigMap || v.Type == kube.KubeVolumeTypeSecret) && !v.Optional {
 			vol, err := ic.Libpod.NewVolume(ctx, libpod.WithVolumeName(v.Source))

pkg/k8s.io/api/core/v1/types.go

@@ -58,6 +58,10 @@ type VolumeSource struct {
 	ConfigMap *ConfigMapVolumeSource `json:"configMap,omitempty"`
 	// Secret represents a secret that should be mounted as a volume
 	Secret *SecretVolumeSource `json:"secret,omitempty"`
+	// emptyDir represents a temporary directory that shares a pod's lifetime.
+	// More info: https://kubernetes.io/docs/concepts/storage/volumes#emptydir
+	// +optional
+	EmptyDir *EmptyDirVolumeSource `json:"emptyDir,omitempty"`
 }
 
 // PersistentVolumeClaimVolumeSource references the user's PVC in the same namespace.

pkg/specgen/generate/container_create.go

@@ -387,9 +387,10 @@ func createContainerOptions(rt *libpod.Runtime, s *specgen.SpecGenerator, pod *l
 		var vols []*libpod.ContainerNamedVolume
 		for _, v := range volumes {
 			vols = append(vols, &libpod.ContainerNamedVolume{
-				Name:    v.Name,
-				Dest:    v.Dest,
-				Options: v.Options,
+				Name:        v.Name,
+				Dest:        v.Dest,
+				Options:     v.Options,
+				IsAnonymous: v.IsAnonymous,
 			})
 		}
 		options = append(options, libpod.WithNamedVolumes(vols))

pkg/specgen/generate/kube/kube.go

@@ -406,8 +406,15 @@ func ToSpecGen(ctx context.Context, opts *CtrSpecGenOptions) (*specgen.SpecGener
 				Name:    volumeSource.Source,
 				Options: options,
 			}
-
 			s.Volumes = append(s.Volumes, &secretVolume)
+		case KubeVolumeTypeEmptyDir:
+			emptyDirVolume := specgen.NamedVolume{
+				Dest:        volume.MountPath,
+				Name:        volumeSource.Source,
+				Options:     options,
+				IsAnonymous: true,
+			}
+			s.Volumes = append(s.Volumes, &emptyDirVolume)
 		default:
 			return nil, errors.New("unsupported volume source type")
 		}

pkg/specgen/generate/kube/volume.go

@@ -32,6 +32,7 @@ const (
 	KubeVolumeTypeBlockDevice
 	KubeVolumeTypeCharDevice
 	KubeVolumeTypeSecret
+	KubeVolumeTypeEmptyDir
 )
 
 //nolint:revive
@@ -219,8 +220,13 @@ func VolumeFromConfigMap(configMapVolumeSource *v1.ConfigMapVolumeSource, config
 	return kv, nil
 }
 
+// Create a kubeVolume for an emptyDir volume
+func VolumeFromEmptyDir(emptyDirVolumeSource *v1.EmptyDirVolumeSource, name string) (*KubeVolume, error) {
+	return &KubeVolume{Type: KubeVolumeTypeEmptyDir, Source: name}, nil
+}
+
 // Create a KubeVolume from one of the supported VolumeSource
-func VolumeFromSource(volumeSource v1.VolumeSource, configMaps []v1.ConfigMap, secretsManager *secrets.SecretsManager) (*KubeVolume, error) {
+func VolumeFromSource(volumeSource v1.VolumeSource, configMaps []v1.ConfigMap, secretsManager *secrets.SecretsManager, volName string) (*KubeVolume, error) {
 	switch {
 	case volumeSource.HostPath != nil:
 		return VolumeFromHostPath(volumeSource.HostPath)
@@ -230,8 +236,10 @@ func VolumeFromSource(volumeSource v1.VolumeSource, configMaps []v1.ConfigMap, s
 		return VolumeFromConfigMap(volumeSource.ConfigMap, configMaps)
 	case volumeSource.Secret != nil:
 		return VolumeFromSecret(volumeSource.Secret, secretsManager)
+	case volumeSource.EmptyDir != nil:
+		return VolumeFromEmptyDir(volumeSource.EmptyDir, volName)
 	default:
-		return nil, errors.New("HostPath, ConfigMap, and PersistentVolumeClaim are currently the only supported VolumeSource")
+		return nil, errors.New("HostPath, ConfigMap, EmptyDir, and PersistentVolumeClaim are currently the only supported VolumeSource")
 	}
 }
 
@@ -240,7 +248,7 @@ func InitializeVolumes(specVolumes []v1.Volume, configMaps []v1.ConfigMap, secre
 	volumes := make(map[string]*KubeVolume)
 
 	for _, specVolume := range specVolumes {
-		volume, err := VolumeFromSource(specVolume.VolumeSource, configMaps, secretsManager)
+		volume, err := VolumeFromSource(specVolume.VolumeSource, configMaps, secretsManager, specVolume.Name)
 		if err != nil {
 			return nil, fmt.Errorf("failed to create volume %q: %w", specVolume.Name, err)
 		}

pkg/specgen/volumes.go

@@ -23,6 +23,9 @@ type NamedVolume struct {
 	Dest string
 	// Options are options that the named volume will be mounted with.
 	Options []string
+	// IsAnonymous sets the named volume as anonymous even if it has a name
+	// This is used for emptyDir volumes from a kube yaml
+	IsAnonymous bool
 }
 
 // OverlayVolume holds information about a overlay volume that will be mounted into

test/e2e/play_kube_test.go

@@ -509,6 +509,9 @@ spec:
   volumes:
   {{ range . }}
   - name: {{ .Name }}
+    {{- if (eq .VolumeType "EmptyDir") }}
+    emptyDir: {}
+    {{- end }}
     {{- if (eq .VolumeType "HostPath") }}
     hostPath:
       path: {{ .HostPath.Path }}
@@ -1242,12 +1245,15 @@ type ConfigMap struct {
 	Optional bool
 }
 
+type EmptyDir struct{}
+
 type Volume struct {
 	VolumeType string
 	Name       string
 	HostPath
 	PersistentVolumeClaim
 	ConfigMap
+	EmptyDir
 }
 
 // getHostPathVolume takes a type and a location for a HostPath
@@ -1289,6 +1295,14 @@ func getConfigMapVolume(vName string, items []map[string]string, optional bool)
 	}
 }
 
+func getEmptyDirVolume() *Volume {
+	return &Volume{
+		VolumeType: "EmptyDir",
+		Name:       defaultVolName,
+		EmptyDir:   EmptyDir{},
+	}
+}
+
 type Env struct {
 	Name      string
 	Value     string
@@ -2762,6 +2776,43 @@ VOLUME %s`, ALPINE, hostPathDir+"/")
 		Expect(kube).Should(Exit(0))
 	})
 
+	It("podman play kube with emptyDir volume", func() {
+		podName := "test-pod"
+		ctrName1 := "vol-test-ctr"
+		ctrName2 := "vol-test-ctr-2"
+		ctr1 := getCtr(withVolumeMount("/test-emptydir", false), withImage(BB), withName(ctrName1))
+		ctr2 := getCtr(withVolumeMount("/test-emptydir-2", false), withImage(BB), withName(ctrName2))
+		pod := getPod(withPodName(podName), withVolume(getEmptyDirVolume()), withCtr(ctr1), withCtr(ctr2))
+		err = generateKubeYaml("pod", pod, kubeYaml)
+		Expect(err).To(BeNil())
+
+		kube := podmanTest.Podman([]string{"play", "kube", kubeYaml})
+		kube.WaitWithDefaultTimeout()
+		Expect(kube).Should(Exit(0))
+
+		emptyDirCheck1 := podmanTest.Podman([]string{"exec", podName + "-" + ctrName1, "ls", "/test-emptydir"})
+		emptyDirCheck1.WaitWithDefaultTimeout()
+		Expect(emptyDirCheck1).Should(Exit(0))
+
+		emptyDirCheck2 := podmanTest.Podman([]string{"exec", podName + "-" + ctrName2, "ls", "/test-emptydir-2"})
+		emptyDirCheck2.WaitWithDefaultTimeout()
+		Expect(emptyDirCheck2).Should(Exit(0))
+
+		volList1 := podmanTest.Podman([]string{"volume", "ls", "-q"})
+		volList1.WaitWithDefaultTimeout()
+		Expect(volList1).Should(Exit(0))
+		Expect(volList1.OutputToString()).To(Equal(defaultVolName))
+
+		remove := podmanTest.Podman([]string{"pod", "rm", "-f", podName})
+		remove.WaitWithDefaultTimeout()
+		Expect(remove).Should(Exit(0))
+
+		volList2 := podmanTest.Podman([]string{"volume", "ls", "-q"})
+		volList2.WaitWithDefaultTimeout()
+		Expect(volList2).Should(Exit(0))
+		Expect(volList2.OutputToString()).To(Equal(""))
+	})
+
 	It("podman play kube applies labels to pods", func() {
 		var numReplicas int32 = 5
 		expectedLabelKey := "key1"