podman-generate-kube(1)

NAME

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

SYNOPSIS

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

DESCRIPTION

podman generate kube will generate Kubernetes YAML (v1 specification) from Podman containers, pods or volumes. Whether the input is for containers or pods, Podman will always generate the specification as a Pod. 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 will be 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, the init container will 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 will be in the generated kube YAML. Init containers created with type always will always be 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 context -R <directory> Once completed, the correct permissions will be 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).

OPTIONS

  --filename, -f=filename

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

  --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 will include a NodePort declaration to expose the service. A random port is assigned by Podman in the specification.

EXAMPLES

Create Kubernetes Pod YAML for a container called some-mariadb.

    $ sudo podman generate kube some-mariadb
    # Save the output of this file and use kubectl create -f to import
    # it into Kubernetes.
    #
    # Created with podman-0.11.2-dev
    apiVersion: v1
    kind: Pod
    metadata:
      creationTimestamp: 2018-12-03T19:07:59Z
      labels:
        app: some-mariadb
      name: some-mariadb-libpod
    spec:
      containers:
      - command:
        - docker-entrypoint.sh
        - mysqld
        env:
        - name: HOSTNAME
        - name: GOSU_VERSION
          value: "1.10"
        - name: GPG_KEYS
          value: "199369E5404BD5FC7D2FE43BCBCB082A1BB943DB \t177F4010FE56CA3336300305F1656F24C74CD1D8
            \t430BDF5C56E7C94E848EE60C1C4CBDCDCD2EFD2A \t4D1BB29D63D98E422B2113B19334A25F8507EFA5"
        - name: MARIADB_MAJOR
          value: "10.3"
        - name: MARIADB_VERSION
          value: 1:10.3.10+maria~bionic
        - name: MYSQL_ROOT_PASSWORD
          value: x
        image: quay.io/baude/demodb:latest
        name: some-mariadb
        ports:
        - containerPort: 3306
          hostPort: 36533
        resources: {}
        securityContext:
          capabilities:
            drop:
            - CAP_MKNOD
            - CAP_NET_RAW
            - CAP_AUDIT_WRITE
        tty: true
    status: {}

Create Kubernetes Pod YAML for a container with the directory /home/user/my-data on the host bind-mounted in the container to /volume.

    $ podman generate kube 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
        resources: {}
        securityContext:
          capabilities:
            drop:
            - CAP_MKNOD
            - CAP_NET_RAW
            - CAP_AUDIT_WRITE
        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
    status: {}

Create Kubernetes Pod YAML for a container with the named volume priceless-data mounted in the container at /volume.

    $ podman generate kube 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
        resources: {}
        securityContext:
          capabilities:
            drop:
            - CAP_MKNOD
            - CAP_NET_RAW
            - CAP_AUDIT_WRITE
        volumeMounts:
        - mountPath: /volume
          name: priceless-data-pvc
      restartPolicy: Never
      volumes:
      - name: priceless-data-pvc
        persistentVolumeClaim:
          claimName: priceless-data
    status: {}

Create Kubernetes Pod YAML for a pod called demoweb and include a service.

    $ sudo podman generate kube -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
        resources: {}
        tty: true
        workingDir: /root/code
    status: {}
    ---
    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-play-kube(1)

HISTORY

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