How to set multiple commands in one yaml file with Kubernetes

Question

In this official document  it can run command in a yaml config file      https   kubernetes io docs tasks configure-pod-container    apiVersion  v1 kind  Pod metadata    name  hello-world spec     specification of the pod   s contents   restartPolicy  Never   containers    - name  hello     image   ubuntu 14 04      env      - name  MESSAGE       value   hello world      command     bin sh   -c       args     bin echo     MESSAGE        If I want to run more than one command  how to do

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command     bin sh   -c   args    command one  command two  amp  amp  command three     Explanation  The command    bin sh    -c   says  run a shell  and execute the following instructions   The args are then passed as commands to the shell  In shell scripting a semicolon separates commands  and  amp  amp  conditionally runs the following command if the first succeed  In the above example  it always runs command one followed by command two  and only runs command three if command two succeeded   Alternative  In many cases  some of the commands you want to run are probably setting up the final command to run  In this case  building your own Dockerfile is the way to go  Look at the RUN directive in particular

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Here is my successful run  apiVersion  v1 kind  Pod metadata    labels      run  busybox   name  busybox spec    containers    - command      -  bin sh     - -c     -         echo  quot running below scripts quot        i 0         while true         do          echo  quot  i    date  quot            i    i 1             sleep 1         done     name  busybox     image  busybox

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My preference is to multiline the args  this is simplest and easiest to read  Also  the script can be changed without affecting the image  just need to restart the pod  For example  for a mysql dump  the container spec could be something like this    containers    - name  mysqldump     image  mysql     command     bin sh    -c       args        - echo starting          ls -la  backups          mysqldump --host     -r  backups file sql db name          ls -la  backups          echo done      volumeMounts        -       The reason this works is that yaml actually concatenates all the lines after the  -  into one  and sh runs one long string  echo starting  ls      echo done

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Just to bring another possible option  secrets can be used as they are presented to the pod as volumes   Secret example   apiVersion  v1 kind  Secret  metadata    name  secret-script type  Opaque data    script text   lt  lt your script in b64 gt  gt    Yaml extract        containers      - name  container-name       image  image-name       command     bin bash     your script sh         volumeMounts          - name  vsecret-script           mountPath   your script sh           subPath  script text        volumes      - name  vsecret-script       secret          secretName  secret-script   I know many will argue this is not what secrets must be used for  but it is an option

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I am not sure if the question is still active but due to the fact that I did not find the solution in the above answers I decided to write it down  I use the following approach  readinessProbe    exec      command      - sh     - -c     -         command1       command2  amp  amp  command3  I know my example is related to readinessProbe  livenessProbe  etc  but suspect the same case is for the container commands  This provides flexibility as it mirrors a standard script writing in Bash

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Here is how you can pass  multiple commands  amp  arguments in one YAML file with kubernetes     Write your commands here command     bin sh    -c     Write your multiple arguments in args args     usr local bin php  var www test php  amp   usr local bin php  var www vendor api php     Full containers block from yaml file       containers        - name  widc-cron   container name         image  widc-cron   custom docker image         imagePullPolicy  IfNotPresent   advisable to keep           write your command here         command     bin sh    -c             You can declare multiple arguments here  like this example         args     usr local bin php  var www tools test php  amp   usr local bin php  var www vendor api php           volumeMounts    to mount files from config-map generator           - mountPath   var www session constants inc php             subPath  constants inc php             name  widc-constants

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IMHO the best option is to use YAML s native block scalars  Specifically in this case  the folded style block   By invoking sh -c you can pass arguments to your container as commands  but if you want to elegantly separate them with newlines  you d want to use the folded style block  so that YAML will know to convert newlines to whitespaces  effectively concatenating the commands   A full working example    apiVersion  v1 kind  Pod metadata    name  myapp   labels      app  myapp spec    containers    - name  busy     image  busybox 1 28     command     bin sh    -c       args      -  gt        command 1  amp  amp        command 2  amp  amp                   command n

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If you re willing to use a Volume and a ConfigMap  you can mount ConfigMap data as a script  and then run that script   --- apiVersion  v1 kind  ConfigMap metadata    name  my-configmap data    entrypoint sh   -        bin bash     echo  Do this       echo  Do that  --- apiVersion  v1 kind  Pod metadata    name  my-pod spec    containers    - name  my-container     image   ubuntu 14 04      command      -  bin entrypoint sh     volumeMounts      - name  configmap-volume       mountPath   bin entrypoint sh       readOnly  true       subPath  entrypoint sh   volumes    - name  configmap-volume     configMap        defaultMode  0700       name  my-configmap   This cleans up your pod spec a little and allows for more complex scripting     kubectl logs my-pod Do this Do that

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If you want to avoid concatenating all commands into a single command with   or  amp  amp  you can also get true multi-line scripts using a heredoc  command    - sh  -  quot -c quot   -       bin bash  lt  lt  EOF        Normal script content possible here    echo  quot Hello world quot     ls -l    exit 123     EOF  This is handy for running existing bash scripts  but has the downside of requiring both an inner and an outer shell instance for setting up the heredoc

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Here is another way to run multi line commands   apiVersion  batch v1 kind  Job metadata    name  multiline spec    template      spec        containers        - command          -  bin bash         - -exc         -             set  x           echo  running below scripts            if    -f  if-condition sh      then             echo  Running if success            else             echo  Running if failed            fi         name  ubuntu         image  ubuntu       restartPolicy  Never   backoffLimit  1

[yaml] How to set multiple commands in one yaml file with Kubernetes?

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