diff --git a/gitlab-runner_config_example/docker/etc/gitlab-runner/config.toml b/gitlab-runner_config_example/docker/etc/gitlab-runner/config.toml
index e28da7a..4a2329b 100644
--- a/gitlab-runner_config_example/docker/etc/gitlab-runner/config.toml
+++ b/gitlab-runner_config_example/docker/etc/gitlab-runner/config.toml
@@ -5,7 +5,7 @@
 # example setup running CI @ docker
 # with this, every commit will refresh whole python packages.. will take 1 min. ==> slow. but up to date all the time..
 
-concurrent = 2
+concurrent = 2 # this should be > 0
 check_interval = 0
 
 [session_server]