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author | Tomasz Maczukin <tomasz@maczukin.pl> | 2017-12-12 18:42:11 +0300 |
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committer | Tomasz Maczukin <tomasz@maczukin.pl> | 2017-12-12 18:42:54 +0300 |
commit | b17c3ab63b60ed73b2bdad84f45d39da2fe9a577 (patch) | |
tree | 272b16a90d136fdf2161c979d823bab8efc3e1f5 /doc/ci/docker/using_docker_images.md | |
parent | d673628de003d1ce1402f03311066339828fb811 (diff) |
Fix entrypoint overriding documentation
Diffstat (limited to 'doc/ci/docker/using_docker_images.md')
-rw-r--r-- | doc/ci/docker/using_docker_images.md | 48 |
1 files changed, 45 insertions, 3 deletions
diff --git a/doc/ci/docker/using_docker_images.md b/doc/ci/docker/using_docker_images.md index ecb8f15c851..ed3f64ff302 100644 --- a/doc/ci/docker/using_docker_images.md +++ b/doc/ci/docker/using_docker_images.md @@ -325,7 +325,34 @@ want to execute some tests with this database binary. Let's also assume that this image is configured with `/usr/bin/super-sql run` as an entrypoint. That means, that when starting the container without additional options, it will run the database's process, while Runner expects that the image will have no -entrypoint or at least will start with a shell as its entrypoint. +entrypoint or that the entrypoint is prepared to start a shell command. + +---- + +Before showing available entrypoint overwrite methods, let's describe shortly +how Runner start's and uses Docker image for job container: + +1. Runner start's Docker container using defined entrypoint (default from `Dockerfile` + that may be overridden with `.gitlab-ci.yml`) and + [shell discovering](https://gitlab.com/gitlab-org/gitlab-runner/blob/v10.2.0/shells/bash.go#L16) + as [command](https://gitlab.com/gitlab-org/gitlab-runner/blob/v10.2.0/shells/bash.go#L215). +1. Runner attaches itself to a running container. +1. Runner prepares a script (it may be the combination of `before_script` and `script` + or the `after_script`). +1. Runner sends the script to container shell's STDIN and receives the output. + +After analyzing how works the code linked in first point, we can assume that Runner +will work if entrypoint will be either: + +- empty, +- set to `sh -c`, `bash -c` or an equivalent with shell available in the image. + +We recommend to make the entrypoint empty, so it doesn't start an useless shell +layer. However if Docker older than 17.04 is used, the empty entrypoint may not +work and for Docker older than 1.13 it will certainly not work. In that case +the `/bin/sh -c` or equal entrypoint should be used. + +---- Before the new extended Docker configuration options, you would need to create your own image based on the `super/sql:experimental` image, set the entrypoint @@ -335,9 +362,16 @@ to a shell and then use it in job's configuration, like: # my-super-sql:experimental image's Dockerfile FROM super/sql:experimental -ENTRYPOINT ["/bin/sh"] +ENTRYPOINT [""] ``` +or +```Dockerfile +# my-super-sql:experimental image's Dockerfile +FROM super/sql:experimental +ENTRYPOINT ["/bin/sh", "-c"] +``` +and ```yaml # .gitlab-ci.yml @@ -352,7 +386,15 @@ set an `entrypoint` in `.gitlab-ci.yml`, like: image: name: super/sql:experimental - entrypoint: ["/bin/sh"] + entrypoint: [""] +``` +or +```yaml +# .gitlab-ci.yml + +image: + name: super/sql:experimental + entrypoint: ["/bin/sh", "-c"] ``` As you can see the syntax of `entrypoint` is similar to |