Kubernetes 容器参数行为不正确

Question

I want to use Kubernetes and the postman/newman Docker image to execute my API tests.

Locally, I can execute the image with

docker run postman/newman run <url-to-collection> --env-var baseUrl=<local-hostname>

I include the Image in a Kubernetes manifest file

spec:
  containers:
    - name: newman
      image: postman/newman:latest
      args:
        - run
        - '<url-to-collection>'
        - --env-var baseUrl=<kubernetes-hostname>

When I apply the manifest and look at the logs of the container, I get the following error:

error: unknown option '--global-var baseUrl=<kubernetes-hostname>'

I tried out many things with quotes and using the command section instead of the args section, but always with the same result. I figure that Kubernetes somehow builds the command in a way, that the newman executable can not understand it. However I could not find any info about that.

(I also created an issue in the GitHub repo of Newman here )

Could anybody explain to me where this problem comes from and how I might solve this?

Thanks anyways!

Answer 1

Linux commands are made up of a sequence of words. If you type a command at a shell prompt, it takes responsibility for splitting it into words for you, but in the Kubernetes args: list, you need to split out the words yourself.

args:
  - run
  - '<url-to-collection>'
  # You want these as two separate arguments, so they need to be
  # two separate list items
  - --env-var
  - baseUrl=<kubernetes-hostname>

If the two arguments are in the same list item, they are a single "word":

# /bin/ls "/app/some directory/some file"
command:
  - /bin/ls
  # a single argument, including embedded spaces
  - /app/some directory/some file

The same basic rules apply for Docker Compose entrypoint: and command: and the JSON-syntax Dockerfile ENTRYPOINT and CMD directives, except that the Docker-native forms all also accept a plain string that they will split on spaces (using a shell in the Dockerfile case, but not in the Compose case).

In the docker run command you provide, the shell on your host system processes it first, so the --env-var option and baseUrl=... argument get split into separate words before they're passed into the container.