Configuring runners

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If you have installed your own runners, you can configure and secure them in GitLab.

If you need to configure runners on the machine where you installed GitLab Runner, see the GitLab Runner documentation.

Set the maximum job timeout

You can specify a maximum job timeout for each runner to prevent projects with longer job timeouts from using the runner. The maximum job timeout is used if it is shorter than the job timeout defined in the project.

For an instance runner

Prerequisites:

• You must be an administrator.

On GitLab.com, you cannot override the job timeout for instance runners and must use the project defined timeout instead.

To set the maximum job timeout:

1. On the left sidebar, at the bottom, select Admin Area.
2. Select CI/CD > Runners.
3. To the right of the runner, you want to edit, select Edit ({pencil}).
4. In the Maximum job timeout field, enter a value in seconds. The minimum amount is 600 seconds (10 minutes).
5. Select Save changes.

For a group runner

Prerequisites:

• You must have the Owner role for the group.

To set the maximum job timeout:

1. On the left sidebar, select Search or go to and find your group.
2. Select Build > Runners.
3. To the right of the runner you want to edit, select Edit ({pencil}).
4. In the Maximum job timeout field, enter a value in seconds. The minimum amount is 600 seconds (10 minutes).
5. Select Save changes.

For a project runner

Prerequisites:

• You must have the Owner role for the project.

To set the maximum job timeout:

1. On the left sidebar, select Search or go to and find your project.
2. Select Settings > CI/CD.
3. Expand Runners.
4. To the right of the runner you want to edit, select Edit ({pencil}).
5. In the Maximum job timeout field, enter a value in seconds. The minimum amount is 600 seconds (10 minutes). If not defined, the job timeout for the project is used instead.
6. Select Save changes.

How maximum job timeout works

Example 1 - Runner timeout bigger than project timeout

1. You set the maximum job timeout for a runner to 24 hours.
2. You set the CI/CD Timeout for a project to 2 hours.
3. You start a job.
4. The job, if running longer, times out after 2 hours.

Example 2 - Runner timeout not configured

1. You remove the maximum job timeout configuration from a runner.
2. You set the CI/CD Timeout for a project to 2 hours.
3. You start a job.
4. The job, if running longer, times out after 2 hours.

Example 3 - Runner timeout smaller than project timeout

1. You set the maximum job timeout for a runner to 30 minutes.
2. You set the CI/CD Timeout for a project to 2 hours.
3. You start a job.
4. The job, if running longer, times out after 30 minutes.

Set script and after_script timeouts

• Introduced in GitLab Runner 16.4.

To control the amount of time script and after_script runs before it terminates, you can set specify a timeout.

For example, you can specify a timeout to terminate a long-running script early, so that artifacts and caches can still be uploaded before the job timeout is exceeded.

• To set a timeout for script, use the job variable RUNNER_SCRIPT_TIMEOUT.
• To set a timeout for after_script, and override the default of 5 minutes, use the job variable RUNNER_AFTER_SCRIPT_TIMEOUT.

Both of these variables accept Go's duration format (for example, 40s, 1h20m, 2h 4h30m30s).

For example:

job-with-script-timeouts:
  variables:
    RUNNER_SCRIPT_TIMEOUT: 15m
    RUNNER_AFTER_SCRIPT_TIMEOUT: 10m
  script:
    - "I am allowed to run for min(15m, remaining job timeout)."
  after_script:
    - "I am allowed to run for min(10m, remaining job timeout)."

job-artifact-upload-on-timeout:
  timeout: 1h                           # set job timeout to 1 hour
  variables:
     RUNNER_SCRIPT_TIMEOUT: 50m         # only allow script to run for 50 minutes
  script:
    - long-running-process > output.txt # will be terminated after 50m

  artifacts: # artifacts will have roughly ~10m to upload
    paths:
      - output.txt
    when: on_failure # on_failure because script termination after a timeout is treated as a failure

Protecting sensitive information

To avoid exposing sensitive information, you can restrict the usage of instance runners on large GitLab instances. This ensures that you control access to your GitLab instances and secure runner executors.

If certain executors run a job, the file system, the code the runner executes, and the runner authentication token may be exposed. This means that anyone who runs jobs on an instance runner can access another user's code that runs on the runner. Users with access to the runner authentication token can use it to create a clone of a runner and submit false jobs in a vector attack. For more information, see Security Considerations.

Configuring long polling

To reduce job queueing times and load on your GitLab server, configure long polling.

Using instance runners in forked projects

When a project is forked, the job settings related to jobs are copied. If you have instance runners configured for a project and a user forks that project, the instance runners serve jobs of this project.

Due to a known issue, if the runner settings of the forked project does not match the new project namespace, the following message displays: An error occurred while forking the project. Please try again..

To work around this issue, ensure that the instance runner settings are consistent in the forked project and the new namespace.

• If instance runners are enabled on the forked project, then this should also be enabled on the new namespace.
• If instance runners are disabled on the forked project, then this should also be disabled on the new namespace.

Reset the runner registration token for a project (deprecated)

WARNING: The ability to pass a runner registration token, and support for certain configuration arguments was deprecated in GitLab 15.6 and will be removed in GitLab 18.0. Authentication tokens should be used instead. For more information, see Migrating to the new runner registration workflow.

If you think that a registration token for a project was revealed, you should reset it. A registration token can be used to register another runner for the project. That new runner may then be used to obtain the values of secret variables or to clone project code.

To reset the registration token:

1. On the left sidebar, select Search or go to and find your project.
2. Select Settings > CI/CD.
3. Expand Runners.
4. To the right of New project runner, select the vertical ellipsis ({ellipsis_v}).
5. Select Reset registration token.
6. Select Reset token.

After you reset the registration token, it is no longer valid and does not register any new runners to the project. You should also update the registration token in tools you use to provision and register new values.

Authentication token security

• Introduced in GitLab 15.3 with a flag named enforce_runner_token_expires_at. Disabled by default.
• Generally available in GitLab 15.5. Feature flag enforce_runner_token_expires_at removed.

Each runner has an runner authentication token to connect with the GitLab instance.

To help prevent the token from being compromised, you can have the token rotate automatically at specified intervals. When the tokens are rotated, they are updated for each runner, regardless of the runner's status (online or offline).

No manual intervention should be required, and no running jobs should be affected. For more information about token rotation, see Runner authentication token does not update when rotated.

If you need to manually update the runner authentication token, you can run a command to reset the token.

Reset the runner authentication token

If a runner authentication token is revealed, an attacker could use the token to clone a runner.

To reset the runner authentication token:

1. Delete the runner:
   • Delete an instance runner.
   • Delete a group runner.
   • Delete a project runner.
2. Create a new runner so that it is assigned a new runner authentication token:
   • Create an instance runner.
   • Create a group runner.
   • Create a project runner.
3. Optional. To verify that the previous runner authentication token has been revoked, use the Runners API.

Automatically rotate runner authentication tokens

You can specify an interval for runner authentication tokens to rotate. This rotation helps ensure the security of the tokens assigned to your runners.

Prerequisites:

• Runners must use GitLab Runner 15.3 or later.
• You must be an administrator.

To automatically rotate runner authentication tokens:

1. On the left sidebar, at the bottom, select Admin Area.
2. Select Settings > CI/CD.
3. Expand Continuous Integration and Deployment.
4. Set a Runners expiration time for runners, leave empty for no expiration.
5. Select Save changes.

Before the interval expires, runners automatically request a new runner authentication token. For more information about token rotation, see Runner authentication token does not update when rotated.

Prevent runners from revealing sensitive information

To ensure runners don't reveal sensitive information, you can configure them to only run jobs on protected branches, or jobs that have protected tags.

Runners configured to run jobs on protected branches cannot run jobs in merge request pipelines.

For an instance runner

Prerequisites:

• You must be an administrator.

1. On the left sidebar, at the bottom, select Admin Area.
2. Select CI/CD > Runners.
3. To the right of the runner you want to protect, select Edit ({pencil}).
4. Select the Protected checkbox.
5. Select Save changes.

For a group runner

Prerequisites:

• You must have the Owner role for the group.

1. On the left sidebar, select Search or go to and find your group.
2. Select Build > Runners.
3. To the right of the runner you want to protect, select Edit ({pencil}).
4. Select the Protected checkbox.
5. Select Save changes.

For a project runner

Prerequisites:

• You must have the Owner role for the project.

1. On the left sidebar, select Search or go to and find your project.
2. Select Settings > CI/CD.
3. Expand Runners.
4. To the right of the runner you want to protect, select Edit ({pencil}).
5. Select the Protected checkbox.
6. Select Save changes.

Control jobs that a runner can run

You can use tags to control the jobs a runner can run. For example, you can specify the rails tag for runners that have the dependencies to run Rails test suites.

GitLab CI/CD tags are different to Git tags. GitLab CI/CD tags are associated with runners. Git tags are associated with commits.

For an instance runner

Prerequisites:

• You must be an administrator.

To set the maximum job timeout:

1. On the left sidebar, at the bottom, select Admin Area.
2. Select CI/CD > Runners.
3. To the right of the runner you want to edit, select Edit ({pencil}).
4. Set the runner to run tagged or untagged jobs:
   • To run tagged jobs, in the Tags field, enter the job tags separated with a comma. For example, macos, rails.
   • To run untagged jobs, select the Run untagged jobs checkbox.
5. Select Save changes.

For a group runner

Prerequisites:

• You must have the Owner role for the group.

To set the maximum job timeout:

1. On the left sidebar, select Search or go to and find your group.
2. Select Build > Runners.
3. To the right of the runner you want to edit, select Edit ({pencil}).
4. Set the runner to run tagged or untagged jobs:
   • To run tagged jobs, in the Tags field, enter the job tags separated with a comma. For example, macos, ruby.
   • To run untagged jobs, select the Run untagged jobs checkbox.
5. Select Save changes.

For a project runner

Prerequisites:

• You must have the Owner role for the project.

To set a runner to run tagged jobs:

1. On the left sidebar, select Search or go to and find your project.
2. Select Settings > CI/CD.
3. Expand Runners.
4. To the right of the runner you want to edit, select Edit ({pencil}).
5. Set the runner to run tagged or untagged jobs:
   • To run tagged jobs, in the Tags field, enter the job tags separated with a comma. For example, macos, ruby.
   • To run untagged jobs, select the Run untagged jobs checkbox.
6. Select Save changes.

How the runner uses tags

Runner runs only tagged jobs

The following examples illustrate the potential impact of the runner being set to run only tagged jobs.

Example 1:

1. The runner is configured to run only tagged jobs and has the docker tag.
2. A job that has a hello tag is executed and stuck.

Example 2:

1. The runner is configured to run only tagged jobs and has the docker tag.
2. A job that has a docker tag is executed and run.

Example 3:

1. The runner is configured to run only tagged jobs and has the docker tag.
2. A job that has no tags defined is executed and stuck.

Runner is allowed to run untagged jobs

The following examples illustrate the potential impact of the runner being set to run tagged and untagged jobs.

Example 1:

1. The runner is configured to run untagged jobs and has the docker tag.
2. A job that has no tags defined is executed and run.
3. A second job that has a docker tag defined is executed and run.

Example 2:

1. The runner is configured to run untagged jobs and has no tags defined.
2. A job that has no tags defined is executed and run.
3. A second job that has a docker tag defined is stuck.

A runner and a job have multiple tags

The selection logic that matches the job and runner is based on the list of tags defined in the job.

The following examples illustrate the impact of a runner and a job having multiple tags. For a runner to be selected to run a job, it must have all of the tags defined in the job script block.

Example 1:

1. The runner is configured with the tags [docker, shell, gpu].
2. The job has the tags [docker, shell, gpu] and is executed and run.

Example 2:

1. The runner is configured with the tags [docker, shell, gpu].
2. The job has the tags [docker, shell,] and is executed and run.

Example 3:

1. The runner is configured with the tags [docker, shell].
2. The job has the tags [docker, shell, gpu] and is not executed.

Use tags to run jobs on different platforms

You can use tags to run different jobs on different platforms. For example, if you have an OS X runner with tag osx and a Windows runner with tag windows, you can run a job on each platform.

Update the tags field in the .gitlab-ci.yml:

windows job:
  stage: build
  tags:
    - windows
  script:
    - echo Hello, %USERNAME%!

osx job:
  stage: build
  tags:
    - osx
  script:
    - echo "Hello, $USER!"

Use CI/CD variables in tags

In the .gitlab-ci.yml file, use CI/CD variables with tags for dynamic runner selection:

variables:
  KUBERNETES_RUNNER: kubernetes

  job:
    tags:
      - docker
      - $KUBERNETES_RUNNER
    script:
      - echo "Hello runner selector feature"

Configure runner behavior with variables

You can use CI/CD variables to configure runner Git behavior globally or for individual jobs:

• GIT_STRATEGY
• GIT_SUBMODULE_STRATEGY
• GIT_CHECKOUT
• GIT_CLEAN_FLAGS
• GIT_FETCH_EXTRA_FLAGS
• GIT_SUBMODULE_UPDATE_FLAGS
• GIT_SUBMODULE_FORCE_HTTPS
• GIT_DEPTH (shallow cloning)
• GIT_SUBMODULE_DEPTH
• GIT_CLONE_PATH (custom build directories)
• TRANSFER_METER_FREQUENCY (artifact/cache meter update frequency)
• ARTIFACT_COMPRESSION_LEVEL (artifact archiver compression level)
• CACHE_COMPRESSION_LEVEL (cache archiver compression level)
• CACHE_REQUEST_TIMEOUT (cache request timeout)

You can also use variables to configure how many times a runner attempts certain stages of job execution.

When using the Kubernetes executor, you can use variables to override Kubernetes CPU and memory allocations for requests and limits.

Git strategy

You can set the GIT_STRATEGY used to fetch the repository content, either globally or per-job in the variables section:

variables:
  GIT_STRATEGY: clone

There are three possible values: clone, fetch, and none. If left unspecified, jobs use the project's pipeline setting.

clone is the slowest option. It clones the repository from scratch for every job, ensuring that the local working copy is always pristine. If an existing worktree is found, it is removed before cloning.

fetch is faster as it re-uses the local working copy (falling back to clone if it does not exist). git clean is used to undo any changes made by the last job, and git fetch is used to retrieve commits made after the last job ran.

However, fetch does require access to the previous worktree. This works well when using the shell or docker executor because these try to preserve worktrees and try to re-use them by default.

This has limitations when using the Docker Machine executor.

A Git strategy of none also re-uses the local working copy, but skips all Git operations usually done by GitLab. GitLab Runner pre-clone scripts are also skipped, if present. This strategy could mean you need to add fetch and checkout commands to your .gitlab-ci.yml script.

It can be used for jobs that operate exclusively on artifacts, like a deployment job. Git repository data may be present, but it's likely out of date. You should only rely on files brought into the local working copy from cache or artifacts, and be aware that cache and artifact files from previous pipelines might still be present.

Git submodule strategy

The GIT_SUBMODULE_STRATEGY variable is used to control if / how Git submodules are included when fetching the code before a build. You can set them globally or per-job in the variables section.

There are three possible values: none, normal, and recursive:

• none means that submodules are not included when fetching the project code. This is the default, which matches the pre-v1.10 behavior.

• normal means that only the top-level submodules are included. It's equivalent to:

  git submodule sync
  git submodule update --init

• recursive means that all submodules (including submodules of submodules) are included. This feature needs Git v1.8.1 and later. When using a GitLab Runner with an executor not based on Docker, make sure the Git version meets that requirement. It's equivalent to:

  git submodule sync --recursive
  git submodule update --init --recursive

For this feature to work correctly, the submodules must be configured (in .gitmodules) with either:

• the HTTP(S) URL of a publicly-accessible repository, or
• a relative path to another repository on the same GitLab server. See the Git submodules documentation.

You can provide additional flags to control advanced behavior using GIT_SUBMODULE_UPDATE_FLAGS.

Git checkout

The GIT_CHECKOUT variable can be used when the GIT_STRATEGY is set to either clone or fetch to specify whether a git checkout should be run. If not specified, it defaults to true. You can set them globally or per-job in the variables section.

If set to false, the runner:

• when doing fetch - updates the repository and leaves the working copy on the current revision,
• when doing clone - clones the repository and leaves the working copy on the default branch.

If GIT_CHECKOUT is set to true, both clone and fetch work the same way. The runner checks out the working copy of a revision related to the CI pipeline:

variables:
  GIT_STRATEGY: clone
  GIT_CHECKOUT: "false"
script:
  - git checkout -B master origin/master
  - git merge $CI_COMMIT_SHA

Git clean flags

The GIT_CLEAN_FLAGS variable is used to control the default behavior of git clean after checking out the sources. You can set it globally or per-job in the variables section.

GIT_CLEAN_FLAGS accepts all possible options of the git clean command.

git clean is disabled if GIT_CHECKOUT: "false" is specified.

If GIT_CLEAN_FLAGS is:

• Not specified, git clean flags default to -ffdx.
• Given the value none, git clean is not executed.

For example:

variables:
  GIT_CLEAN_FLAGS: -ffdx -e cache/
script:
  - ls -al cache/

Git fetch extra flags

Use the GIT_FETCH_EXTRA_FLAGS variable to control the behavior of git fetch. You can set it globally or per-job in the variables section.

GIT_FETCH_EXTRA_FLAGS accepts all options of the git fetch command. However, GIT_FETCH_EXTRA_FLAGS flags are appended after the default flags that can't be modified.

The default flags are:

• GIT_DEPTH.
• The list of refspecs.
• A remote called origin.

If GIT_FETCH_EXTRA_FLAGS is:

• Not specified, git fetch flags default to --prune --quiet along with the default flags.
• Given the value none, git fetch is executed only with the default flags.

For example, the default flags are --prune --quiet, so you can make git fetch more verbose by overriding this with just --prune:

variables:
  GIT_FETCH_EXTRA_FLAGS: --prune
script:
  - ls -al cache/

The configuration above results in git fetch being called this way:

git fetch origin $REFSPECS --depth 50  --prune

Where $REFSPECS is a value provided to the runner internally by GitLab.

Sync or exclude specific submodules from CI jobs

• Introduced in GitLab Runner 14.0.

Use the GIT_SUBMODULE_PATHS variable to control which submodules have to be synced or updated. You can set it globally or per-job in the variables section.

The path syntax is the same as git submodule:

• To sync and update specific paths:

  variables:
     GIT_SUBMODULE_PATHS: submoduleA submoduleB

• To exclude specific paths:

  variables:
     GIT_SUBMODULE_PATHS: :(exclude)submoduleA :(exclude)submoduleB

WARNING: Git ignores nested paths. To ignore a nested submodule, exclude the parent submodule and then manually clone it in the job's scripts. For example, git clone <repo> --recurse-submodules=':(exclude)nested-submodule'. Make sure to wrap the string in single quotes so the YAML can be parsed successfully.

Git submodule update flags

Use the GIT_SUBMODULE_UPDATE_FLAGS variable to control the behavior of git submodule update when GIT_SUBMODULE_STRATEGY is set to either normal or recursive. You can set it globally or per-job in the variables section.

GIT_SUBMODULE_UPDATE_FLAGS accepts all options of the git submodule update subcommand. However, GIT_SUBMODULE_UPDATE_FLAGS flags are appended after a few default flags:

• --init, if GIT_SUBMODULE_STRATEGY was set to normal or recursive.
• --recursive, if GIT_SUBMODULE_STRATEGY was set to recursive.
• GIT_DEPTH. See the default value below.

Git honors the last occurrence of a flag in the list of arguments, so manually providing them in GIT_SUBMODULE_UPDATE_FLAGS overrides these default flags.

You can use this variable to fetch the latest remote HEAD instead of the commit tracked, in the repository, or to speed up the checkout by fetching submodules in multiple parallel jobs:

variables:
  GIT_SUBMODULE_STRATEGY: recursive
  GIT_SUBMODULE_UPDATE_FLAGS: --remote --jobs 4
script:
  - ls -al .git/modules/

The configuration above results in git submodule update being called this way:

git submodule update --init --depth 50 --recursive --remote --jobs 4

WARNING: You should be aware of the implications for the security, stability, and reproducibility of your builds when using the --remote flag. In most cases, it is better to explicitly track submodule commits as designed, and update them using an auto-remediation/dependency bot.

Rewrite submodule URLs to HTTPS

• Introduced in GitLab Runner 15.11.

Use the GIT_SUBMODULE_FORCE_HTTPS variable to force a rewrite of all Git and SSH submodule URLs to HTTPS. This allows you to clone submodules on the same GitLab instance that use absolute URLs, even if they were configured with a Git or SSH protocol.

variables:
  GIT_SUBMODULE_STRATEGY: recursive
  GIT_SUBMODULE_FORCE_HTTPS: "true"

When enabled, GitLab Runner uses a CI/CD job token to clone the submodules with the permissions of the user executing the job, and does not require SSH credentials.

Shallow cloning

You can specify the depth of fetching and cloning using GIT_DEPTH. GIT_DEPTH does a shallow clone of the repository and can significantly speed up cloning. It can be helpful for repositories with a large number of commits or old, large binaries. The value is passed to git fetch and git clone.

Newly-created projects automatically have a default git depth value of 50.

If you use a depth of 1 and have a queue of jobs or retry jobs, jobs may fail.

Git fetching and cloning is based on a ref, such as a branch name, so runners can't clone a specific commit SHA. If multiple jobs are in the queue, or you're retrying an old job, the commit to be tested must be within the Git history that is cloned. Setting too small a value for GIT_DEPTH can make it impossible to run these old commits and unresolved reference is displayed in job logs. You should then reconsider changing GIT_DEPTH to a higher value.

Jobs that rely on git describe may not work correctly when GIT_DEPTH is set since only part of the Git history is present.

To fetch or clone only the last 3 commits:

variables:
  GIT_DEPTH: "3"

You can set it globally or per-job in the variables section.

Git submodule depth

• Introduced in GitLab Runner 15.5.

Use the GIT_SUBMODULE_DEPTH variable to specify the depth of fetching and cloning submodules when GIT_SUBMODULE_STRATEGY is set to either normal or recursive. You can set it globally or for a specific job in the variables section.

When you set the GIT_SUBMODULE_DEPTH variable, it overwrites the GIT_DEPTH setting for the submodules only.

To fetch or clone only the last 3 commits:

variables:
  GIT_SUBMODULE_DEPTH: 3

Custom build directories

By default, GitLab Runner clones the repository in a unique subpath of the $CI_BUILDS_DIR directory. However, your project might require the code in a specific directory (Go projects, for example). In that case, you can specify the GIT_CLONE_PATH variable to tell the runner the directory to clone the repository in:

variables:
  GIT_CLONE_PATH: $CI_BUILDS_DIR/project-name

test:
  script:
    - pwd

The GIT_CLONE_PATH must always be within $CI_BUILDS_DIR. The directory set in $CI_BUILDS_DIR is dependent on executor and configuration of runners.builds_dir setting.

This can only be used when custom_build_dir is enabled in the runner's configuration.

Handling concurrency

An executor that uses a concurrency greater than 1 might lead to failures. Multiple jobs might be working on the same directory if the builds_dir is shared between jobs.

The runner does not try to prevent this situation. It's up to the administrator and developers to comply with the requirements of runner configuration.

To avoid this scenario, you can use a unique path within $CI_BUILDS_DIR, because runner exposes two additional variables that provide a unique ID of concurrency:

• $CI_CONCURRENT_ID: Unique ID for all jobs running within the given executor.
• $CI_CONCURRENT_PROJECT_ID: Unique ID for all jobs running within the given executor and project.

The most stable configuration that should work well in any scenario and on any executor is to use $CI_CONCURRENT_ID in the GIT_CLONE_PATH. For example:

variables:
  GIT_CLONE_PATH: $CI_BUILDS_DIR/$CI_CONCURRENT_ID/project-name

test:
  script:
    - pwd -P

The $CI_CONCURRENT_PROJECT_ID should be used in conjunction with $CI_PROJECT_PATH as the $CI_PROJECT_PATH provides a path of a repository. That is, group/subgroup/project. For example:

variables:
  GIT_CLONE_PATH: $CI_BUILDS_DIR/$CI_CONCURRENT_ID/$CI_PROJECT_PATH

test:
  script:
    - pwd -P

Nested paths

The value of GIT_CLONE_PATH is expanded once and nesting variables within is not supported.

For example, you define both the variables below in your .gitlab-ci.yml file:

variables:
  GOPATH: $CI_BUILDS_DIR/go
  GIT_CLONE_PATH: $GOPATH/src/namespace/project

The value of GIT_CLONE_PATH is expanded once into $CI_BUILDS_DIR/go/src/namespace/project, and results in failure because $CI_BUILDS_DIR is not expanded.

Job stages attempts

You can set the number of attempts that the running job tries to execute the following stages:

The default is one single attempt.

Example:

variables:
  GET_SOURCES_ATTEMPTS: 3

You can set them globally or per-job in the variables section.

System calls not available on GitLab.com instance runners

GitLab.com instance runners run on CoreOS. This means that you cannot use some system calls, like getlogin, from the C standard library.

Artifact and cache settings

Artifact and cache settings control the compression ratio of artifacts and caches. Use these settings to specify the size of the archive produced by a job.

• On a slow network, uploads might be faster for smaller archives.
• On a fast network where bandwidth and storage are not a concern, uploads might be faster using the fastest compression ratio, despite the archive produced being larger.

For GitLab Pages to serve HTTP Range requests, artifacts should use the ARTIFACT_COMPRESSION_LEVEL: fastest setting, as only uncompressed zip archives support this feature.

A meter can be enabled to provide the rate of transfer for uploads and downloads.

You can set a maximum time for cache upload and download with the CACHE_REQUEST_TIMEOUT setting. This setting can be useful when slow cache uploads substantially increase the duration of your job.

variables:
  # output upload and download progress every 2 seconds
  TRANSFER_METER_FREQUENCY: "2s"

  # Use fast compression for artifacts, resulting in larger archives
  ARTIFACT_COMPRESSION_LEVEL: "fast"

  # Use no compression for caches
  CACHE_COMPRESSION_LEVEL: "fastest"

  # Set maximum duration of cache upload and download
  CACHE_REQUEST_TIMEOUT: 5

Artifact provenance metadata

• Introduced in GitLab Runner 15.1.

NOTE: Zip archives are the only supported artifact type. Follow the issue for details.

Runners can generate and produce provenance metadata for all build artifacts.

To enable artifact provenance data, set the RUNNER_GENERATE_ARTIFACTS_METADATA environment variable to true. You can set the variable as global or for individual jobs:

variables:
  RUNNER_GENERATE_ARTIFACTS_METADATA: "true"

job1:
  variables:
    RUNNER_GENERATE_ARTIFACTS_METADATA: "true"

The metadata renders in a plain text .json file stored with the artifact. The filename is {ARTIFACT_NAME}-metadata.json. ARTIFACT_NAME is the name for the artifact defined in the .gitlab-ci.yml file. If the name is not defined, the default filename is artifacts-metadata.json.

Provenance metadata format

The provenance metadata is generated in the in-toto attestation format for spec version 0.1. The runner also produces a statement that adheres to SLSA v0.2 by default.

To opt-in to an SLSA v1.0 statement, set the SLSA_PROVENANCE_SCHEMA_VERSION=v1 variable in the .gitlab-ci.yml file. The v0.2 statement is deprecated and is planned to be removed in the GitLab 17.0 and the v1.0 statement is planned to become the new default format.

The following fields are populated by default:

An example of provenance metadata that the GitLab Runner might generate is as follows:

{
    "_type": "https://gitlab.com/gitlab-org/gitlab-runner/-/blob/v15.1.0/PROVENANCE.md",
    "subject": [
        {
            "name": "script.sh",
            "digest": {
                "sha256": "f5ae5ced234922eebe6461d32228ba8ab9c3d0c0f3983a3bef707e6e1a1ab52a"
            }
        }
    ],
    "predicateType": "https://slsa.dev/provenance/v0.2",
    "predicate": {
        "buildType": "https://gitlab.com/gitlab-org/gitlab-runner/-/blob/v15.1.0/PROVENANCE.md",
        "builder": {
            "id": "https://gitlab.com/ggeorgiev_gitlab/playground/-/runners/14811533"
        },
        "invocation": {
            "configSource": {
                "uri": "https://gitlab.com/ggeorgiev_gitlab/playground",
                "digest": {
                    "sha256": "f0582e2c9a16b5cc2cde90e8be8f1b50fd67c631"
                },
                "entryPoint": "whoami shell"
            },
            "environment": {
                "name": "local",
                "executor": "shell",
                "architecture": "amd64"
            },
            "parameters": {
                "CI_PIPELINE_ID": "",
                "CI_PIPELINE_URL": "",
                // All other CI variable names are listed here. Values are always represented as empty strings to avoid leaking secrets.
            }
        },
        "metadata": {
            "buildStartedOn": "2022-06-17T00:47:27+03:00",
            "buildFinishedOn": "2022-06-17T00:47:28+03:00",
            "completeness": {
                "parameters": true,
                "environment": true,
                "materials": false
            },
            "reproducible": false
        },
        "materials": []
    }
}

Staging directory

• Introduced in GitLab Runner 15.0.

If you do not want to archive cache and artifacts in the system's default temporary directory, you can specify a different directory.

You might need to change the directory if your system's default temporary path has constraints. If you use a fast disk for the directory location, it can also improve performance.

To change the directory, set ARCHIVER_STAGING_DIR as a variable in your CI job, or use a runner variable when you register the runner (gitlab register --env ARCHIVER_STAGING_DIR=<dir>).

The directory you specify is used as the location for downloading artifacts prior to extraction. If the fastzip archiver is used, this location is also used as scratch space when archiving.

Configure fastzip to improve performance

• Introduced in GitLab Runner 15.0.

To tune fastzip, ensure the FF_USE_FASTZIP flag is enabled. Then use any of the following environment variables.

Files in a zip archive are appended sequentially. This makes concurrent compression challenging. fastzip works around this limitation by compressing files concurrently to disk first, and then copying the result back to zip archive sequentially.

To avoid writing to disk and reading the contents back for smaller files, a small buffer per concurrency is used. This setting can be controlled with FASTZIP_ARCHIVER_BUFFER_SIZE. The default size for this buffer is 2 MiB, therefore, a concurrency of 16 allocates 32 MiB. Data that exceeds the buffer size is written to and read back from disk. Therefore, using no buffer, FASTZIP_ARCHIVER_BUFFER_SIZE: 0, and only scratch space is a valid option.

FASTZIP_ARCHIVER_CONCURRENCY controls how many files are compressed concurrency. As mentioned above, this setting therefore can increase how much memory is being used, but also how much temporary data is written to the scratch space. The default is the number of CPUs available, but given the memory ramifications, this may not always be the best setting.

FASTZIP_EXTRACTOR_CONCURRENCY controls how many files are decompressed at once. Files from a zip archive can natively be read from concurrency, so no additional memory is allocated in addition to what the decompressor requires. This defaults to the number of CPUs available.