podman-kube-generate(1)

NAME

podman-kube-generate - Generate Kubernetes YAML based on containers, pods or volumes

SYNOPSIS

podman kube generate [options] container... | pod... | volume...

DESCRIPTION

podman kube generate generates Kubernetes YAML (v1 specification) from Podman containers, pods or volumes. Regardless of whether the input is for containers or pods, Podman generates the specification as a Pod by default. The input may be in the form of one or more containers, pods or volumes names or IDs.

Podman Containers or Pods

Volumes appear in the generated YAML according to two different volume types. Bind-mounted volumes become hostPath volume types and named volumes become persistentVolumeClaim volume types. Generated hostPath volume types are one of three subtypes depending on the state of the host path: DirectoryOrCreate when no file or directory exists at the host, Directory when host path is a directory, or File when host path is a file. The value for claimName for a persistentVolumeClaim is the name of the named volume registered in Podman.

Potential name conflicts between volumes are avoided by using a standard naming scheme for each volume type. The hostPath volume types are named according to the path on the host machine, replacing forward slashes with hyphens less any leading and trailing forward slashes. The special case of the filesystem root, /, translates to the name root. Additionally, the name is suffixed with -host to avoid naming conflicts with persistentVolumeClaim volumes. Each persistentVolumeClaim volume type uses the name of its associated named volume suffixed with -pvc.

Note that if an init container is created with type once and the pod has been started, it does not show up in the generated kube YAML as once type init containers are deleted after they are run. If the pod has only been created and not started, it is in the generated kube YAML. Init containers created with type always are always generated in the kube YAML as they are never deleted, even after running to completion.

Note: When using volumes and generating a Kubernetes YAML for an unprivileged and rootless podman container on an SELinux enabled system, one of the following options must be completed:
  * Add the "privileged: true" option to the pod spec
  * Add type: spc_t under the securityContext seLinuxOptions in the pod spec
  * Relabel the volume via the CLI command chcon -t container_file_t -R <directory>

Once completed, the correct permissions are in place to access the volume when the pod/container is created in a Kubernetes cluster.

Note that the generated Kubernetes YAML file can be used to re-run the deployment via podman-play-kube(1).

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

Output to the given file instead of STDOUT. If the file already exists, kube generate refuses to replace it and returns an error.

  --podman-only

Add podman-only reserved annotations in generated YAML file (Cannot be used by Kubernetes)

  --replicas, -r=replica count

The value to set replicas to when generating a Deployment kind. Note: this can only be set with the option --type=deployment.

  --service, -s

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 | daemonset

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

Create Kubernetes Pod YAML for the specified container.
    $ podman kube generate some-mariadb
    # Save the output of this file and use kubectl create -f to import
    # it into Kubernetes.
    #
    # Created with podman-4.8.2
    # NOTE: If you generated this yaml from an unprivileged and rootless podman container on an SELinux
    # enabled system, check the podman generate kube man page for steps to follow to ensure that your pod/container
    # has the right permissions to access the volumes added.
    ---
    apiVersion: v1
    kind: Pod
    metadata:
      creationTimestamp: "2024-01-09T02:24:55Z"
      labels:
        app: some-mariadb-pod
      name: some-mariadb-pod
    spec:
      containers:
      - args:
        - mariadbd
        env:
        - name: MARIADB_ROOT_PASSWORD
          value: x
        image: docker.io/library/mariadb:10.11
        name: some-mariadb
        ports:
        - containerPort: 3306
          hostPort: 34891
        volumeMounts:
        - mountPath: /var/lib/mysql
          name: mariadb_data-pvc
      volumes:
      - name: mariadb_data-pvc
        persistentVolumeClaim:
          claimName: mariadb_data

Create Kubernetes Deployment YAML with 3 replicas for the specified container.
    $ podman kube generate --type deployment --replicas 3 dep-ct
    r
    # Save the output of this file and use kubectl create -f to import
    # it into Kubernetes.
    #
    # Created with podman-4.5.0-dev
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      creationTimestamp: "2023-03-27T20:45:08Z"
      labels:
        app: dep-ctr-pod
      name: dep-ctr-pod-deployment
    spec:
      replicas: 3
      selector:
        matchLabels:
          app: dep-ctr-pod
      template:
        metadata:
          annotations:
            io.podman.annotations.ulimit: nofile=524288:524288,nproc=127332:127332
          creationTimestamp: "2023-03-27T20:45:08Z"
          labels:
            app: dep-ctr-pod
          name: dep-ctr-pod
        spec:
          containers:
          - command:
            - top
            image: docker.io/library/alpine:latest
            name: dep-ctr

Create Kubernetes Pod YAML for the specified container with the host directory /home/user/my-data bind-mounted onto the container path /volume.
    $ podman kube generate my-container-with-bind-mounted-data
    # Save the output of this file and use kubectl create -f to import
    # it into Kubernetes.
    #
    # Created with podman-3.1.0-dev
    apiVersion: v1
    kind: Pod
    metadata:
      creationTimestamp: "2021-03-18T16:26:08Z"
      labels:
        app: my-container-with-bind-mounted-data
      name: my-container-with-bind-mounted-data
    spec:
      containers:
      - command:
        - /bin/sh
        image: docker.io/library/alpine:latest
        name: test-bind-mount
        volumeMounts:
        - mountPath: /volume
          name: home-user-my-data-host
      restartPolicy: Never
      volumes:
      - hostPath:
          path: /home/user/my-data
          type: Directory
        name: home-user-my-data-host

Create Kubernetes Pod YAML for the specified container with named volume priceless-data mounted onto the container path /volume.
    $ podman kube generate my-container-using-priceless-data
    # Save the output of this file and use kubectl create -f to import
    # it into Kubernetes.
    #
    # Created with podman-3.1.0-dev
    apiVersion: v1
    kind: Pod
    metadata:
      creationTimestamp: "2021-03-18T16:26:08Z"
      labels:
        app: my-container-using-priceless-data
      name: my-container-using-priceless-data
    spec:
      containers:
      - command:
        - /bin/sh
        image: docker.io/library/alpine:latest
        name: test-bind-mount
        volumeMounts:
        - mountPath: /volume
          name: priceless-data-pvc
      restartPolicy: Never
      volumes:
      - name: priceless-data-pvc
        persistentVolumeClaim:
          claimName: priceless-data

Create Kubernetes Pod YAML for the specified pod and include a service.
    $ sudo podman kube generate -s demoweb
    # Save the output of this file and use kubectl create -f to import
    # it into Kubernetes.
    #
    # Created with podman-0.12.2-dev
    apiVersion: v1
    kind: Pod
    metadata:
      creationTimestamp: 2018-12-18T15:16:06Z
      labels:
        app: demoweb
      name: demoweb-libpod
    spec:
      containers:
      - command:
        - python3
        - /root/code/graph.py
        image: quay.io/baude/demoweb:latest
        name: practicalarchimedes
        tty: true
        workingDir: /root/code
    ---
    apiVersion: v1
    kind: Service
    metadata:
      creationTimestamp: 2018-12-18T15:16:06Z
      labels:
        app: demoweb
      name: demoweb-libpod
    spec:
      ports:
      - name: "8050"
        nodePort: 31269
        port: 8050
        targetPort: 0
      selector:
        app: demoweb
      type: NodePort
    status:
      loadBalancer: {}

SEE ALSO

podman(1), podman-container(1), podman-pod(1), podman-kube-play(1), podman-kube-down(1)

HISTORY

December 2018, Originally compiled by Brent Baude (bbaude at redhat dot com)