Passing minified yaml as an argument to a kubernetes job

Question

Here's a simplified version of a kubernetes job YAML config I use commonly:

apiVersion: batch/v1
kind: Job
metadata:
  name: myjob
spec:
  template:
    spec:
      containers:
      - name: mycontainer
        image: me/mycontainer:latest
        command: ["bash", "-c"]
        args:
          - python -u myscript.py
              --param1 abc
              --param2 xyz

The above works great, and is easy to maintain and read. But now one of my parameters needs some minified YAML:

apiVersion: batch/v1
kind: Job
metadata:
  name: myjob
spec:
  template:
    spec:
      containers:
      - name: mycontainer
        image: me/mycontainer:latest
        command: ["bash", "-c"]
        args:
          - python -u myscript.py
              --param_minified_yaml "{key: value}"

This bit of embedded minified yaml is being parsed by kubectl and causing: error: error parsing STDIN: error converting YAML to JSON: yaml: line 26: mapping values are not allowed in this context

How can the embedded yaml in args: be escaped such that it's passed as a pure text argument?

Answer 1

If the minified yaml (or the args string in general) does not include single quotes, you can wrap the whole command line in them:

apiVersion: batch/v1
kind: Job
metadata:
  name: myjob
spec:
  template:
    spec:
      containers:
      - name: mycontainer
        image: me/mycontainer:latest
        command: ["bash", "-c"]
        args:
          - 'python -u myscript.py
              --param_minified_yaml "{key: value}"'

If the arg string contains includes single quotes, the args string can be passed as a YAML multiline string:

apiVersion: batch/v1
kind: Job
metadata:
  name: myjob
spec:
  template:
    spec:
      containers:
      - name: mycontainer
        image: me/mycontainer:latest
        command: ["bash", "-c"]
        args:
          - >-
            python -u myscript.py
            --param_minified_yaml "{key: 'value'}"