Triggering child pipeline in another repo ni a multi-project downstream pipeline

Problem to solve

I have two repos A and B. B has a child pipeline (call it ChildB), which essentially contains only a single job. ChildB is triggered from the the main .gitlab-ci.yml pipeline (call it MainB) in B as a parent several times with different env vars.

I would now like to trigger ChildB from the main .gitlab-ci.yml pipeline in A (call it MainA), such that it runs the steps specified in ChildB on code in repo B.

Here are the two ways I have tried:

  • I know I can trigger the pipeline in B in form of a multi-project pipeline like so. However, that triggers MainB in B, which has stages and jobs I don’t want to trigger from MainA
  • I know I can use a child pipeline configuration from a different project like so. However, that basically just runs the steps of ChildB in repo A, i.e. A is cloned out, not B.

I cannot combine the two approaches, as the project and include keywords are mutually exclusive under trigger.

Is there any other way I can achieve this?

Many thanks for your help!

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  • GitLab: 15.11.13-ee
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