Troubleshooting GitLab Runner

This section can assist when troubleshooting GitLab Runner.

A Critical Security release will reset runner registration tokens for your group and projects. If you use an automated process (scripts that encode the value of the registration token) to register runners, this update will break that process. However, it should have no affect on previously registered runners.

General troubleshooting tips

View the logs:

  • tail -100 /var/log/syslog (Debian)
  • tail -100 /var/log/messages (RHEL)

Restart the service:

  • service gitlab-runner restart

View the Docker machines:

  • sudo docker-machine ls
  • sudo su - && docker-machine ls

Delete all Docker machines:

  • docker-machine rm $(docker-machine ls -q)

After making changes to your config.toml:

  • service gitlab-runner restart
  • docker-machine rm $(docker-machine ls -q)
  • tail -f /var/log/syslog (Debian)
  • tail -f /var/log/messages (RHEL)

Confirm your GitLab and GitLab Runner versions

GitLab aims to guarantee backward compatibility. However, as a first troubleshooting step, you should ensure your version of GitLab Runner is the same as your GitLab version.

What does coordinator mean?

The coordinator is the GitLab installation from which a job is requested.

In other words, runner is an isolated agent that request jobs from the coordinator (GitLab installation through GitLab API).

Where are logs stored when run as a service on Windows?

  • If GitLab Runner is running as a service on Windows, it creates system event logs. To view them, open the Event Viewer (from the Run menu, type eventvwr.msc or search for “Event Viewer”). Then go to Windows Logs > Application. The Source for Runner logs is gitlab-runner. If you are using Windows Server Core, run this PowerShell command to get the last 20 log entries: get-eventlog Application -Source gitlab-runner -Newest 20 | format-table -wrap -auto.

Enable debug logging mode

Debug logging can be a serious security risk. The output contains the content of all variables and other secrets available to the job.

In the GitLab Runner config.toml

From a terminal, logged in as root, run:

gitlab-runner stop
gitlab-runner --debug run

Debug logging can be enabled in the global section of the config.toml by setting the log_level setting to debug. Add the following line at the very top of your config.toml, before/after the concurrent line:

log_level = "debug"

In the Helm Chart

If GitLab Runner was installed in a Kubernetes cluster by using the GitLab Runner Helm Chart, you can enable debug logging by setting the logLevel option in the values.yaml customization:

## Configure the GitLab Runner logging level. Available values are: debug, info, warn, error, fatal, panic
## ref:
logLevel: debug

Configure DNS for a Docker executor runner

When configuring a GitLab Runner with the Docker executor, it is possible to run into a problem where the Runner daemon on the host can access GitLab but the built container cannot. This can happen when DNS is configured in the host but those configurations are not passed to the container.


GitLab service and GitLab Runner exist in two different networks that are bridged in two ways (for example, over the Internet and through a VPN). If the routing mechanism that the Runner uses to find the GitLab service queries DNS, the container’s DNS configuration doesn’t know to use the DNS service over the VPN and may default to the one provided over the Internet. This configuration would result in the following message:

Created fresh repository.
++ echo 'Created fresh repository.'
++ git -c 'http.userAgent=gitlab-runner 13.9.0 linux/amd64' fetch origin +da39a3ee5e6b4b0d3255bfef95601890afd80709:refs/pipelines/435345 +refs/heads/master:refs/remotes/origin/master --depth 50 --prune --quiet
fatal: Authentication failed for ''

In this case, the authentication failure is caused by a service in between the Internet and the GitLab service. This service uses separate credentials, which the runner could circumvent if they used the DNS service over the VPN.

You can tell Docker which DNS server to use by using the dns configuration in the [runners.docker] section of the Runner’s config.toml file.

dns           = ["",""]

I’m seeing x509: certificate signed by unknown authority

Please see the self-signed certificates.

I get Permission Denied when accessing the /var/run/docker.sock

If you want to use Docker executor, and you are connecting to Docker Engine installed on server. You can see the Permission Denied error. The most likely cause is that your system uses SELinux (enabled by default on CentOS, Fedora and RHEL). Check your SELinux policy on your system for possible denials.

Docker-machine error: Unable to query docker version: Cannot connect to the docker engine endpoint.

If you get the error Unable to query docker version: Cannot connect to the docker engine endpoint, it could be related to a TLS failure. When docker-machine is installed, it ends up with some certs that don’t work.

To fix this issue, clear out the certs and restart the runner. Upon restart, the runner notices the certs are empty and it recreates them.

sudo su -
rm -r /root/.docker/machine/certs/*
service gitlab-runner restart

Adding an AWS Instance Profile to your autoscaled runners

After you create an AWS IAM Role, in your IAM console, the role has a Role ARN and a Instance Profile ARNs. You must use the Instance Profile name, not the Role Name.

Add the following value to your [runners.machine] section: "amazonec2-iam-instance-profile=<instance-profile-name>",

The Docker executor gets timeout when building Java project

This most likely happens, because of the broken AUFS storage driver: Java process hangs on inside container. The best solution is to change the storage driver to either OverlayFS (faster) or DeviceMapper (slower).

Check this article about configuring and running Docker or this article about control and configure with systemd.

I get 411 when uploading artifacts

This happens due to fact that GitLab Runner uses Transfer-Encoding: chunked which is broken on early version of NGINX (

Upgrade your NGINX to newer version. For more information see this issue:

Error: warning: You appear to have cloned an empty repository.

When running git clone using HTTP(s) (with GitLab Runner or manually for tests) and you see the following output:

$ git clone

Cloning into 'repo'...
warning: You appear to have cloned an empty repository.

Make sure, that the configuration of the HTTP Proxy in your GitLab server installation is done properly. Especially if you are using some HTTP Proxy with its own configuration, make sure that GitLab requests are proxied to the GitLab Workhorse socket, not to the GitLab Unicorn socket.

Git protocol via HTTP(S) is resolved by the GitLab Workhorse, so this is the main entrypoint of GitLab.

If you are using Omnibus GitLab, but don’t want to use the bundled NGINX server, please read using a non-bundled web-server.

In the GitLab Recipes repository there are web-server configuration examples for Apache and NGINX.

If you are using GitLab installed from source, please also read the above documentation and examples, and make sure that all HTTP(S) traffic is going through the GitLab Workhorse.

See an example of a user issue.

Error: no such file or directory error when using Timezone or OffPeakTimezone

It’s possible to configure the time zone in which [[docker.machine.autoscaling]] periods are described. This feature should work on most Unix systems out of the box. However on some Unix systems, and probably on most non-Unix systems (including Windows, for which we’re providing GitLab Runner binaries), when used, the runner will crash at start with an error similar to:

Failed to load config Invalid OffPeakPeriods value: open /usr/local/go/lib/time/ no such file or directory

The error is caused by the time package in Go. Go uses the IANA Time Zone database to load the configuration of the specified time zone. On most Unix systems, this database is already present on one of well-known paths (/usr/share/zoneinfo, /usr/share/lib/zoneinfo, /usr/lib/locale/TZ/). Go’s time package looks for the Time Zone database in all those three paths. If it doesn’t find any of them, but the machine has a configured Go development environment, then it will fallback to the $GOROOT/lib/time/ file.

If none of those paths are present (for example on a production Windows host) the above error is thrown.

In case your system has support for the IANA Time Zone database, but it’s not available by default, you can try to install it. For Linux systems it can be done for example by:

# on Debian/Ubuntu based systems
sudo apt-get install tzdata

# on RPM based systems
sudo yum install tzdata

# on Linux Alpine
sudo apk add -U tzdata

If your system doesn’t provide this database in a native way, then you can make OffPeakTimezone working by following the steps below:

  1. Downloading the Starting with version v9.1.0 you can download the file from a tagged path. In that case you should replace latest with the tag name (e.g., v9.1.0) in the download URL.

  2. Store this file in a well known directory. We’re suggesting to use the same directory where the config.toml file is present. So for example, if you’re hosting Runner on Windows machine and your configuration file is stored at C:\gitlab-runner\config.toml, then save the at C:\gitlab-runner\

  3. Set the ZONEINFO environment variable containing a full path to the file. If you are starting the Runner using the run command, then you can do this with:

    ZONEINFO=/etc/gitlab-runner/ gitlab-runner run <other options ...>

    or if using Windows:

    C:\gitlab-runner> set ZONEINFO=C:\gitlab-runner\
    C:\gitlab-runner> gitlab-runner run <other options ...>

    If you are starting GitLab Runner as a system service then you will need to update/override the service configuration in a way that is provided by your service manager software (unix systems) or by adding the ZONEINFO variable to the list of environment variables available for the GitLab Runner user through System Settings (Windows).

Why can’t I run more than one instance of GitLab Runner?

You can, but not sharing the same config.toml file.

Running multiple instances of GitLab Runner using the same configuration file can cause unexpected and hard-to-debug behavior. In GitLab Runner 12.2, only a single instance of GitLab Runner can use a specific config.toml file at one time.

Job failed (system failure): preparing environment:

This error is often due to your shell loading your profile, and one of the scripts is causing the failure.

Example of dotfiles that are known to cause failure:

  • .bash_logout
  • .condarc
  • .rvmrc

SELinux can also be the culprit of this error. You can confirm this by looking at the SELinux audit log:

sealert -a /var/log/audit/audit.log

Helm Chart: ERROR .. Unauthorized

Before uninstalling or upgrading runners deployed with Helm, pause them in GitLab and wait for any jobs to complete.

If you remove a runner pod with helm uninstall or helm upgrade while a job is running, Unauthorized errors like the following may occur when the job completes:

ERROR: Error cleaning up pod: Unauthorized
ERROR: Error cleaning up secrets: Unauthorized
ERROR: Job failed (system failure): Unauthorized

This probably occurs because when the runner is removed, the role bindings are removed. The runner pod continues until the job completes, and then the runner tries to delete it. Without the role binding, the runner pod no longer has access.

See this issue for details.

Elasticsearch service container startup error max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

Elasticsearch has a vm.max_map_count requirement that has to be set on the instance on which Elasticsearch is run.

See the Elasticsearch Docs for how to set this value correctly depending on the platform.