[PATCH] gitlab-ci: Restrict jobs using Docker to runners having 'docker' tag

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

When a job is based on a Docker image [1], or is using a Docker
service, it requires a runner with Docker installed.

Gitlab shared runners provide the 'docker' tag when they have it
installed.

Are Gitlab shared runners are limited resources, we'd like to
add more runners to QEMU repositories hosted on Gitlab. If a
runner doesn't provide Docker, our jobs requiring it will fail.

Use the standard 'docker' tag to mark the jobs requiring Docker
on the runner.

[1] https://docs.gitlab.com/ee/ci/yaml/#image
[2] https://docs.gitlab.com/ee/ci/yaml/#services

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
If someone is interested in testing or filling the documentation
gap, what I ran is:

$ sudo usermod -aG docker,kvm gitlab-runner
$ sudo gitlab-runner --log-format text --log-level debug \
    register \
 --non-interactive \
 --url https://gitlab.com --registration-token MYTOKEN --description myrunner \
 --tag-list 'docker,linux,x86_64,kvm' --run-untagged --limit 2 \
 --executor docker --docker-image docker:dind --docker-cpus 4 \
 --docker-volumes /var/run/docker.sock:/var/run/docker.sock \
 --docker-dns 8.8.8.8

--docker-volumes is for docker:dind else it was not working
This comes from this 3 year old thread:
https://gitlab.com/gitlab-org/gitlab-runner/-/issues/1986

We can not use the 'docker:dind' tag for a runner having docker:dind
and /var/run/docker.sock volume because this is not a tag used by
the shared runners, so we can't use them anymore.
---
 .gitlab-ci.d/containers.yml  | 2 ++
 .gitlab-ci.d/crossbuilds.yml | 4 ++++
 .gitlab-ci.d/edk2.yml        | 4 ++++
 .gitlab-ci.d/opensbi.yml     | 4 ++++
 .gitlab-ci.yml               | 4 ++++
 5 files changed, 18 insertions(+)

diff --git a/.gitlab-ci.d/containers.yml b/.gitlab-ci.d/containers.yml
index 33e4046e233..8e2a6a99889 100644
--- a/.gitlab-ci.d/containers.yml
+++ b/.gitlab-ci.d/containers.yml
@@ -1,4 +1,6 @@
 .container_job_template: &container_job_definition
+  tags:
+  - docker
   image: docker:stable
   stage: containers
   services:
diff --git a/.gitlab-ci.d/crossbuilds.yml b/.gitlab-ci.d/crossbuilds.yml
index d5098c986b8..e59fbfdc73f 100644
--- a/.gitlab-ci.d/crossbuilds.yml
+++ b/.gitlab-ci.d/crossbuilds.yml
@@ -1,4 +1,6 @@
 .cross_system_build_job:
+  tags:
+  - docker
   stage: build
   image: $CI_REGISTRY_IMAGE/qemu/$IMAGE:latest
   timeout: 80m
@@ -18,6 +20,8 @@
 # KVM), and set extra options (such disabling other accelerators) via the
 # $ACCEL_CONFIGURE_OPTS variable.
 .cross_accel_build_job:
+  tags:
+  - docker
   stage: build
   image: $CI_REGISTRY_IMAGE/qemu/$IMAGE:latest
   timeout: 30m
diff --git a/.gitlab-ci.d/edk2.yml b/.gitlab-ci.d/edk2.yml
index ba7280605c4..afbd8e4d915 100644
--- a/.gitlab-ci.d/edk2.yml
+++ b/.gitlab-ci.d/edk2.yml
@@ -5,6 +5,8 @@ docker-edk2:
    - .gitlab-ci.d/edk2.yml
    - .gitlab-ci.d/edk2/Dockerfile
    when: always
+ tags:
+ - docker
  image: docker:19.03.1
  services:
  - docker:19.03.1-dind
@@ -24,6 +26,8 @@ docker-edk2:
  - docker push $IMAGE_TAG
 
 build-edk2:
+ tags:
+ - docker
  stage: build
  needs: ['docker-edk2']
  rules: # Only run this job when ...
diff --git a/.gitlab-ci.d/opensbi.yml b/.gitlab-ci.d/opensbi.yml
index f66cd1d9089..a4a93222c2d 100644
--- a/.gitlab-ci.d/opensbi.yml
+++ b/.gitlab-ci.d/opensbi.yml
@@ -5,6 +5,8 @@ docker-opensbi:
    - .gitlab-ci.d/opensbi.yml
    - .gitlab-ci.d/opensbi/Dockerfile
    when: always
+ tags:
+ - docker
  image: docker:19.03.1
  services:
  - docker:19.03.1-dind
@@ -24,6 +26,8 @@ docker-opensbi:
  - docker push $IMAGE_TAG
 
 build-opensbi:
+ tags:
+ - docker
  stage: build
  needs: ['docker-opensbi']
  rules: # Only run this job when ...
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f65cb11c4d3..d4511cf7dea 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -14,6 +14,8 @@ include:
   - local: '/.gitlab-ci.d/crossbuilds.yml'
 
 .native_build_job_template: &native_build_job_definition
+  tags:
+  - docker
   stage: build
   image: $CI_REGISTRY_IMAGE/qemu/$IMAGE:latest
   before_script:
@@ -38,6 +40,8 @@ include:
       fi
 
 .native_test_job_template: &native_test_job_definition
+  tags:
+  - docker
   stage: test
   image: $CI_REGISTRY_IMAGE/qemu/$IMAGE:latest
   script:
-- 
2.26.2