= k8s Pods =

 * PODs
   * smallest object in k8s, contains containers, can contain one or more containers
   * scale service by creating more pod instances.
   * additional container could be helper container. 
   * network space is shared between containers in the same pod, they can communicate on localhost.

 
 * Static Pods
   * On standalone VM, the '''kubelet''' can be configured to 
     * read pod definitions from
       1. (Option:--pod-manifest-path=/etc/kubernetes/manifests).
           * {{{ ps ax | grep kubeconfig }}}
       2. kubeconfig.yaml  staticPodPath: /etc/kubernetes/manifest.
     * It also assures they stay alive.
     * Only POD's , nothing else.
     * view with {{{ docker ps }}}
     * the kubeadm k8s setup uses static pods to run the k8s management software as pods on nodes.
  * Static Pods and DaemonSets are ignored by the Kube-Scheduler

 * Pod, eq in Docker ENTRYPOINT->command & CMD->args {{{
apiVersion: v1
kind: Pod
metadata:
  name: ubuntu-sleeper-pod
spec:
  containers:
    - name: ubuntu-sleeper
      image: ubuntu-sleeper
      command: ["sleep2.0"]
      args: ["10",]
      ...
      envFrom:
        - configMapRef:
             name: app-conf-map
        - secretRef:
             name: app-secret
      ...
      env:
        - name: APP_COLOR1
          value: pink

        - name: App_COLOR2
          valueFrom:
               configMapKeyRef:

        - name: App_PWD
          valueFrom:
               secretKeyRef:
                  name: app-secret
                  key: DB_Password    

      ...
  volumes:
    - name: app-secret-volume
      secret:
         secretName: app-secret  
}}}

 * Multi-container pods
   * Types
     1. SideCar
     1. Adapter
     1. Ambassador
   * All containers are expected to stay alive in POD. If any fail, the POD restarts.
     * InitContainers:  separate section in line with containers:
       * Runs one at a time, before Containers: and must all complete before real container starts.
         * if an InitContainer fails, Pod restarts

{{{
}}}