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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 will generate Kubernetes YAML (v1 specification) from Podman containers, pods or volumes. Regardless of 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 -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, kube generate 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 kube generate 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 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
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 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
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 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
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-kube-play(1), podman-kube-down(1)
HISTORY¶
December 2018, Originally compiled by Brent Baude (bbaude at redhat dot com)