Qfyilyi

I use CentOs 7.4 virtual machine which has 32Gb memory.

I have docker composer, it has following configurations:

version: "2"

services:

  shiny-cas-server:

    image: shiny-cas

    command: puma -C config/puma.rb

    volumes:

      - ./cas-server/logs:/app/logs

      - ./cas-server/config:/app/config

      - ./cas-server/public:/app/public

With above docker level configuartions, I make kubernetes configuration:

cas-server-depl.yaml:

apiVersion: extensions/v1beta1   

kind: Deployment                 

metadata:                        

  name: cas-server-depl          

spec:                            

  replicas: 1                    

  template:                      

    metadata:                    

      labels:                    

        app: cas-server-pod

    spec:                        

      containers:                

      - name: cas-server-pod     

        image: shiny-cas         

        imagePullPolicy: Never

        command: ["puma -C /cas-server/config/puma.rb"]

        ports:

          - containerPort: 100

        volumeMounts:

          - mountPath: /app/logs

            name: cas-server-logs

          - mountPath: /app/config

            name: cas-server-config

          - mountPath: /app/public

            name: cas-server-public

      volumes:

        - name: cas-server-logs

          hostPath:

            path: /cas-server/logs

        - name: cas-server-config

          hostPath:

            path: /cas-server/config

        - name: cas-server-public

          hostPath:

            path: /cas-server/public

In virtual machine, I copy ./cas-server directory to /cas-server, and changed chown and chgrp as my login name k8s, when I do sudo kubectl apply -f cas-server-depl.yaml, it has following response:

[k8s@k8s config]$ sudo kubectl get po

NAME                               READY     STATUS              RESTARTS   AGE

cas-server-depl-7f849bf94c-srg77   0/1       RunContainerError   1          5s

Then I use following command to see why:

[k8s@k8s config]$ sudo kubectl describe po cas-server-depl-7988d6b447-ffff5

Name:               cas-server-depl-7988d6b447-ffff5

Namespace:          default

Priority:           0



IP:                 100.68.142.72

Controlled By:      ReplicaSet/cas-server-depl-7988d6b447

Containers:

  cas-server-pod:



    Command:

      puma -C /cas-server/config/puma.rb

    State:          Waiting

      Reason:       CrashLoopBackOff

    Last State:     Terminated

      Reason:       ContainerCannotRun

      Message:      OCI runtime create failed: container_linux.go:348: starting container process caused "exec: "puma -C /cas-server/config/puma.rb": stat puma -C /cas-server/config/puma.rb: no such file or directory": unknown

      Exit Code:    128

      ...

    Ready:          False

    Restart Count:  2

    Environment:    <none>

    Mounts:

      /app/config from cas-server-config (rw)

      /app/logs from cas-server-logs (rw)

      /app/public from cas-server-public (rw)

      /var/run/secrets/kubernetes.io/serviceaccount from default-token-mrkdx (ro)

Conditions:

  Type              Status

  Initialized       True

  Ready             False

  ContainersReady   False

  PodScheduled      True

Volumes:

  cas-server-logs:

    Type:          HostPath (bare host directory volume)

    Path:          /cas-server/logs

    HostPathType:



    HostPathType:

  default-token-mrkdx:

    Type:        Secret (a volume populated by a Secret)

    SecretName:  default-token-mrkdx

    Optional:    false





  Normal   Created    15s (x3 over 29s)  kubelet, k8s.xxx.com.cn  Created container

  Warning  Failed     15s (x3 over 28s)  kubelet, k8s.xxx.com.cn  Error: failed to start container "cas-server-pod": Error response from daemon: OCI runtime create failed: container_linux.go:348: starting container process caused "exec: "puma -C /cas-server/config/puma.rb": stat puma -C /cas-server/config/puma.rb: no such file or directory": unknown

  Warning  BackOff    1s (x3 over 26s)   kubelet, k8s.shinyinfo.com.cn  Back-off restarting failed container

It says:

Message:      OCI runtime create failed: container_linux.go:348: starting container process caused "exec: "puma -C /cas-server/config/puma.rb": stat puma -C /cas-server/config/puma.rb: no such file or directory": unknown

I tried /app/config/puma.rb and config/puma.rb in command, both have same error message. which directory I shall write? I could see puma.rb do exists.

My cas-server-svc.yaml is pasted as reference:

apiVersion: v1

kind: Service

metadata:

  name: cas-server-svc

  labels:

    name: cas-server-svc

spec:

  selector:

    app: cas-server-pod

  type: NodePort

  ports:

  - port: 100

    nodePort: 31101

    name: tcp

When you say

command: ["puma -C /cas-server/config/puma.rb"]

You are telling Kubernetes to tell Docker to look for a single executable named puma -C ..., where what you think are the command-line options are actually part of the filename. You need to split out the arguments into separate elements in the YAML list syntax, something like

command: ["puma", "-C", "/cas-server/config/puma.rb"]

or

command:

  - puma

  - -C

  - /cas-server/config/puma.rb

Path should be /app/config/puma.rb instead of /cas-server/config/puma.rb, since you mounted cas-server-config in /app/config/. Also make sure /cas-server/config/puma.rb file exist in host path.

spec:                        

  containers:                

  - name: cas-server-pod     

    image: shiny-cas         

    imagePullPolicy: Never

    command: ["puma -C /app/config/puma.rb"]

    ports:

      - containerPort: 100

    volumeMounts:

      - mountPath: /app/logs

        name: cas-server-logs

      - mountPath: /app/config

        name: cas-server-config

      - mountPath: /app/public

        name: cas-server-public

  volumes:

    - name: cas-server-logs

      hostPath:

        path: /cas-server/logs

    - name: cas-server-config

      hostPath:

        path: /cas-server/config

    - name: cas-server-public

      hostPath:

        path: /cas-server/public

@David Maze, @nightfury1204 Thanks both your answer. Each answered the part of the question.

Path shall be /app/config, command line is as follows:

command: ["/bin/sh"]

args: ["-c","puma -C /app/config/puma.rb"]

What's more, one shall also notice /app/config access rights to login user.