Build, Test and Deploy of a single commit do not stick to a single shared runner (CI)

Copied from https://gitlab.com/gitlab-org/gitlab-ci/issues/327

I have a job like:

build:
    stage: build
    script: make build

unit:
    stage: test
    script: make unittests

functional/integration:
    stage: test
    script: make bddtests

deploy:
   stage: deploy
   script: make push release-test
   only:
     - tags

The build task builds a Docker container that will be tested in the test steps and ultimately pushed to our orchestration to load.

The container built on the runner itself and is shared between jobs on the same runner because we're exposing the Docker socket in our CI runners.

I have 2 shared CI runners.

If the other runner picks up some of the test/deploy jobs, the container won't be available. Would it be possible to get some stickiness to launch Docker runners related to the same commit on the same CI runner?