Merge branch '356232_adding_Runner_docker_variable_try_2' into 'master'

Adding env variable to enable parameterizing Runner Instance

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/125463



Merged-by: Mark Lapierre <mlapierre@gitlab.com>
Approved-by: Mark Lapierre <mlapierre@gitlab.com>
Reviewed-by: Mark Lapierre <mlapierre@gitlab.com>
Co-authored-by: Andy Hohenner <ahohenner@gitlab.com>

qa/qa/runtime/env.rb

@@ -562,6 +562,10 @@ def container_registry_host
         ENV.fetch('QA_CONTAINER_REGISTRY_HOST', 'registry.gitlab.com')
       end
 
+      def runner_container_image
+        ENV.fetch('QA_RUNNER_CONTAINER_IMAGE', 'gitlab-runner:alpine')
+      end
+
       # ENV variables for authenticating against a private container registry
       # These need to be set if using the
       # Service::DockerRun::Mixins::ThirdPartyDocker module

qa/qa/service/docker_run/gitlab_runner.rb

@@ -16,7 +16,7 @@ class GitlabRunner < Base
         MSG
 
         def initialize(name)
-          @image = "#{QA::Runtime::Env.container_registry_host}/gitlab-org/gitlab-runner:alpine"
+          @image = "#{QA::Runtime::Env.container_registry_host}/gitlab-org/#{QA::Runtime::Env.runner_container_image}"
           @name = name || "qa-runner-#{SecureRandom.hex(4)}"
           @run_untagged = true
           @executor = :shell