Merge pull request #19579 from danishprakash/generate-daemonset-support

kube: add DaemonSet support for generate

cmd/podman/kube/play.go

@@ -46,7 +46,7 @@ var (
 	playOptions        = playKubeOptionsWrapper{}
 	playDescription    = `Reads in a structured file of Kubernetes YAML.
 
-  Creates pods or volumes based on the Kubernetes kind described in the YAML. Supported kinds are Pods, Deployments and PersistentVolumeClaims.`
+  Creates pods or volumes based on the Kubernetes kind described in the YAML. Supported kinds are Pods, Deployments, DaemonSets and PersistentVolumeClaims.`
 
 	playCmd = &cobra.Command{
 		Use:               "play [options] KUBEFILE|-",

docs/kubernetes_support.md

@@ -173,3 +173,15 @@ Note: **N/A** means that the option cannot be supported in a single-node Podman
 | revisionHistoryLimit                    | no                                                    |
 | progressDeadlineSeconds                 | no                                                    |
 | paused                                  | no                                                    |
+
+## DaemonSet Fields
+
+| Field                                   | Support                                               |
+|-----------------------------------------|-------------------------------------------------------|
+| selector                                | ✅                                                    |
+| template                                | ✅                                                    |
+| minReadySeconds                         | no                                                    |
+| strategy\.type                          | no                                                    |
+| strategy\.rollingUpdate\.maxSurge       | no                                                    |
+| strategy\.rollingUpdate\.maxUnavailable | no                                                    |
+| revisionHistoryLimit                    | no                                                    |

docs/source/markdown/podman-kube-generate.1.md

@@ -30,6 +30,8 @@ Note that the generated Kubernetes YAML file can be used to re-run the deploymen
 
 Note that if the pod being generated was created with the **--infra-name** flag set, then the generated kube yaml will have the **io.podman.annotations.infra.name** set where the value is the name of the infra container set by the user.
 
+Also note that both Deployment and DaemonSet can only have `restartPolicy` set to `Always`.
+
 ## OPTIONS
 
 #### **--filename**, **-f**=*filename*
@@ -54,9 +56,9 @@ Note: this can only be set with the option `--type=deployment`.
 
 Generate a Kubernetes service object in addition to the Pods. Used to generate a Service specification for the corresponding Pod output. In particular, if the object has portmap bindings, the service specification includes a NodePort declaration to expose the service. A random port is assigned by Podman in the specification.
 
-#### **--type**, **-t**=*pod | deployment*
+#### **--type**, **-t**=*pod* | *deployment* | *daemonset*
 
-The Kubernetes kind to generate in the YAML file. Currently, the only supported Kubernetes specifications are `Pod` and `Deployment`. By default, the `Pod` specification is generated.
+The Kubernetes kind to generate in the YAML file. Currently, the only supported Kubernetes specifications are `Pod`, `Deployment` and `DaemonSet`. By default, the `Pod` specification is generated.
 
 ## EXAMPLES
 

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

@@ -23,6 +23,7 @@ Currently, the supported Kubernetes kinds are:
 - PersistentVolumeClaim
 - ConfigMap
 - Secret
+- DaemonSet
 
 `Kubernetes Pods or Deployments`
 

libpod/define/container.go

@@ -45,4 +45,6 @@ const (
 	K8sKindPod = "pod"
 	// A Deployment kube yaml spec
 	K8sKindDeployment = "deployment"
+	// A DaemonSet kube yaml spec
+	K8sKindDaemonSet = "daemonset"
 )

libpod/kube.go

@@ -119,6 +119,61 @@ func (p *Pod) getInfraContainer() (*Container, error) {
 	return p.runtime.GetContainer(infraID)
 }
 
+func GenerateForKubeDaemonSet(ctx context.Context, pod *YAMLPod, options entities.GenerateKubeOptions) (*YAMLDaemonSet, error) {
+	// Restart policy for DaemonSets can only be set to Always
+	if !(pod.Spec.RestartPolicy == "" || pod.Spec.RestartPolicy == v1.RestartPolicyAlways) {
+		return nil, fmt.Errorf("k8s DaemonSets can only have restartPolicy set to Always")
+	}
+
+	// Error out if the user tries to set replica count
+	if options.Replicas > 1 {
+		return nil, fmt.Errorf("k8s DaemonSets don't allow setting replicas")
+	}
+
+	// Create label map that will be added to podSpec and DaemonSet metadata
+	// The matching label lets the daemonset know which pod to manage
+	appKey := "app"
+	matchLabels := map[string]string{appKey: pod.Name}
+	// Add the key:value (app:pod-name) to the podSpec labels
+	if pod.Labels == nil {
+		pod.Labels = matchLabels
+	} else {
+		pod.Labels[appKey] = pod.Name
+	}
+
+	depSpec := YAMLDaemonSetSpec{
+		DaemonSetSpec: v1.DaemonSetSpec{
+			Selector: &v12.LabelSelector{
+				MatchLabels: matchLabels,
+			},
+		},
+		Template: &YAMLPodTemplateSpec{
+			PodTemplateSpec: v1.PodTemplateSpec{
+				ObjectMeta: pod.ObjectMeta,
+			},
+			Spec: pod.Spec,
+		},
+	}
+
+	// Create the DaemonSet object
+	dep := YAMLDaemonSet{
+		DaemonSet: v1.DaemonSet{
+			ObjectMeta: v12.ObjectMeta{
+				Name:              pod.Name + "-daemonset",
+				CreationTimestamp: pod.CreationTimestamp,
+				Labels:            pod.Labels,
+			},
+			TypeMeta: v12.TypeMeta{
+				Kind:       "DaemonSet",
+				APIVersion: "apps/v1",
+			},
+		},
+		Spec: &depSpec,
+	}
+
+	return &dep, nil
+}
+
 // GenerateForKubeDeployment returns a YAMLDeployment from a YAMLPod that is then used to create a kubernetes Deployment
 // kind YAML.
 func GenerateForKubeDeployment(ctx context.Context, pod *YAMLPod, options entities.GenerateKubeOptions) (*YAMLDeployment, error) {
@@ -262,6 +317,28 @@ type YAMLDeploymentSpec struct {
 	Strategy *v1.DeploymentStrategy `json:"strategy,omitempty"`
 }
 
+// YAMLDaemonSetSpec represents the same k8s API core DeploymentSpec with a small
+// change and that is having Template as a pointer to YAMLPodTemplateSpec and Strategy
+// as a pointer to k8s API core DaemonSetStrategy.
+// Because Go doesn't omit empty struct and we want to omit Strategy and any fields in the Pod YAML
+// if it's empty.
+type YAMLDaemonSetSpec struct {
+	v1.DaemonSetSpec
+	Template *YAMLPodTemplateSpec        `json:"template,omitempty"`
+	Strategy *v1.DaemonSetUpdateStrategy `json:"strategy,omitempty"`
+}
+
+// YAMLDaemonSet represents the same k8s API core DaemonSet with a small change
+// and that is having Spec as a pointer to YAMLDaemonSetSpec and Status as a pointer to
+// k8s API core DaemonSetStatus.
+// Because Go doesn't omit empty struct and we want to omit Status and any fields in the DaemonSetSpec
+// if it's empty.
+type YAMLDaemonSet struct {
+	v1.DaemonSet
+	Spec   *YAMLDaemonSetSpec  `json:"spec,omitempty"`
+	Status *v1.DaemonSetStatus `json:"status,omitempty"`
+}
+
 // YAMLDeployment represents the same k8s API core Deployment with a small change
 // and that is having Spec as a pointer to YAMLDeploymentSpec and Status as a pointer to
 // k8s API core DeploymentStatus.

pkg/domain/infra/abi/generate.go

@@ -232,14 +232,24 @@ func (ic *ContainerEngine) GenerateKube(ctx context.Context, nameOrIDs []string,
 				return nil, err
 			}
 			typeContent = append(typeContent, b)
+		case define.K8sKindDaemonSet:
+			dep, err := libpod.GenerateForKubeDaemonSet(ctx, libpod.ConvertV1PodToYAMLPod(po), options)
+			if err != nil {
+				return nil, err
+			}
+			b, err := generateKubeYAML(dep)
+			if err != nil {
+				return nil, err
+			}
+			typeContent = append(typeContent, b)
 		case define.K8sKindPod:
 			b, err := generateKubeYAML(libpod.ConvertV1PodToYAMLPod(po))
 			if err != nil {
 				return nil, err
 			}
 			typeContent = append(typeContent, b)
 		default:
-			return nil, fmt.Errorf("invalid generation type - only pods and deployments are currently supported")
+			return nil, fmt.Errorf("invalid generation type - only pods, deployments and daemonsets are currently supported: %+v", options.Type)
 		}
 
 		if options.Service {
@@ -289,14 +299,24 @@ func getKubePods(ctx context.Context, pods []*libpod.Pod, options entities.Gener
 				return nil, nil, err
 			}
 			out = append(out, b)
+		case define.K8sKindDaemonSet:
+			dep, err := libpod.GenerateForKubeDaemonSet(ctx, libpod.ConvertV1PodToYAMLPod(po), options)
+			if err != nil {
+				return nil, nil, err
+			}
+			b, err := generateKubeYAML(dep)
+			if err != nil {
+				return nil, nil, err
+			}
+			out = append(out, b)
 		case define.K8sKindPod:
 			b, err := generateKubeYAML(libpod.ConvertV1PodToYAMLPod(po))
 			if err != nil {
 				return nil, nil, err
 			}
 			out = append(out, b)
 		default:
-			return nil, nil, fmt.Errorf("invalid generation type - only pods and deployments are currently supported")
+			return nil, nil, fmt.Errorf("invalid generation type - only pods, deployments and daemonsets are currently supported")
 		}
 
 		if options.Service {