Difference between revisions of "Kubernetes Pod Manifest"

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(imagePullPolicy)
(External)
 
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=External=
 
=External=
  
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* https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.16/#pod-v1-core
 +
* https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.15/#pod-v1-core
 
* https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.14/#pod-v1-core
 
* https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.14/#pod-v1-core
  

Latest revision as of 00:00, 6 November 2019

External

Internal

Overview

Example

apiVersion: v1
kind: Pod
metadata:
  name: loop
  labels:
    color: blue
spec:
  dnsPolicy: ClusterFirst
  restartPolicy: Always
  schedulerName: default-scheduler
  terminationGracePeriodSeconds: 120
  containers:
  - name: loop-container
    image: docker.io/ovidiufeodorov/loop:latest
    imagePullPolicy: Always
    resources:
      limits:
        memory: '4096Mi'
        cpu: '1000m'
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File
    command: ...
    ports:
    - containerPort: 8080
      protocol: TCP
    - containerPort: 8787
      protocol: TCP
    env:
    - name: SOMETHING
      value: 'something else'
    volumeMounts:
    - name: 'mount-0'
      mountPath: '/red'
      # 'orange' must exist in the root of the volume identified by 'mount-0'; the content of that
      # directory will be exposed in the container under the '/red' directory.
      subPath: 'orange' 
    readinessProbe:
      # See Probe Template
    livenessProbe:
      # See Probe Template
  initContainers:
  - name: init-container1
    image: busybox
    command: ['sh', '-c', 'until nslookup myservice; do echo waiting for myservice; sleep 2; done;']
  volumes:
  - name: mount-0
    hostPath:
      # '/yellow' must contain an 'orange' sub-directory
      path: '/yellow'

.spec Elements

https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.14/#podspec-v1-core

hostname

Optional field. If not specified, the hostname exposed to the processes running inside the pod will be the name of the pod.

restartPolicy

Optional field. See:
Container Restart Policy

containers

name

image

imagePullPolicy

https://kubernetes.io/docs/concepts/containers/images/

This is configuration that tells the container runtime how to pull the container image prior to starting the container There are three possible values:

  • Always
  • IfNotPresent - pull the image if it does not already exist on the node.
  • Never

This attribute is optional, and if it is not specified, it is inferred based on the image tag. The default is "Always" if ":latest" tag is specified, or "IfNotPresent" otherwise.

volumeMounts

Pod volumes to mount into the container's filesystem.

name

The identifier of the volume. Must match the name the volume specification was declared under, in the volumes section of the specification.

If we need to use the same volume for multiple mount points, those mount points should refer the same volume name.

mountPath

Specifies the path within the container where the volume will be mounted. Must not contain ':'.

The mount will succeed even if some or all intermediate path elements of the "mountPath" does not exist as directories in the container's file system - they will be created as necessary.

subPath

Specifies the path within the volume (it needs to exist inside the external volume) from which the container's volume should be mounted. Defaults to "" (volume's root).

readOnly

Mounted read-only if true, read-write otherwise (false or unspecified). Defaults to false.

readinessProbe, livenessProbe

command

https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#running-a-command-in-a-shell

Optional field. If not present, the docker image's ENTRYPOINT is used. If present, represents the entrypoint array of the container. Not executed within a shell, so if a shell is required, must be specified as below. Variable references $(VAR_NAME) are expanded using the container's environment. If a variable cannot be resolved, the reference in the input string will be unchanged. The $(VAR_NAME) syntax can be escaped with a double $$, ie: $$(VAR_NAME). Escaped references will never be expanded, regardless of whether the variable exists or not.

Example:

command: ['sh', '-c', 'while true; do echo .; sleep 1; done']
Also see:
Dockerfile ENTRYPOINT and CMD

initContainers

init Containers

volumes

List of volumes that can be mounted by containers belonging to the pod.

TODO: https://kubernetes.io/docs/concepts/storage/volumes

TODO