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.

--no-trunc

Don’t truncate annotations to the Kubernetes maximum length of 63 characters. Note: enabling this flag means the generated YAML file is not Kubernetes compatible and can only be used with podman kube play

--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)