Kubernetes command and args in YAML file

Question

What is the difference between the below three declarations in a Pod YAML file:

1. containers:

• name: busybox
  image: busybox
  args:
  -sleep
  -"1000"

2. containers:

   • name: busybox
     image: busybox
     command: ["/bin/sh", "-c", "sleep 1000"]

3. containers:

• name: busybox
  image: busybox
  args:
  -/bin/sh
  --c
  -sleep 1000

Also, would 1, 2 and 3 above produce same result?

---

---

I edited further. This is really getting confusing. It appears that below two will produce the same result. If so, not sure what is the purpose of each:

command:
- sleep
- "5000"

args:
- sleep
- "5000"

Answer 1

According to https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/

To run a command in a Shell

command: ["/bin/sh"]
args: ["-c", "while true; do echo hello; sleep 10; done"]

A command is required with args. Or

If you do not supply command or args for a Container, the defaults defined in the Docker image are used.

Answer 2

For first case:

If you supply only args for a Container, the default Entrypoint defined in the Docker image is run with the args that you supplied.

For second case:

If you supply a command but no args for a Container, only the supplied command is used. The default EntryPoint and the default Cmd defined in the Docker image are ignored.

So in first case busybox default entry point will execute the given argument. And in second case busybox default entry point is ignored and "/bin/sh" command will execute the given arguments.

Ref: https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#notes