Windows shared runners (beta)

The Windows shared runners are in beta and shouldn’t be used for production workloads.

During this beta period, the shared runner pipeline quota applies for groups and projects in the same manner as Linux runners. This may change when the beta period ends, as discussed in this related issue.

Windows shared runners on GitLab.com autoscale by launching virtual machines on the Google Cloud Platform. This solution uses an autoscaling driver developed by GitLab for the custom executor. Windows shared runners execute your CI/CD jobs on n1-standard-2 instances with 2 vCPUs and 7.5 GB RAM. You can find a full list of available Windows packages in the package documentation.

We want to keep iterating to get Windows shared runners in a stable state and generally available. You can follow our work towards this goal in the related epic.

Configuration

The full contents of our config.toml are:

noteSettings that aren’t public are shown as X.
concurrent = X
check_interval = 3

[[runners]]
  name = "windows-runner"
  url = "https://gitlab.com/"
  token = "TOKEN"
  executor = "custom"
  builds_dir = "C:\\GitLab-Runner\\builds"
  cache_dir = "C:\\GitLab-Runner\\cache"
  shell  = "powershell"
  [runners.custom]
    config_exec = "C:\\GitLab-Runner\\autoscaler\\autoscaler.exe"
    config_args = ["--config", "C:\\GitLab-Runner\\autoscaler\\config.toml", "custom", "config"]
    prepare_exec = "C:\\GitLab-Runner\\autoscaler\\autoscaler.exe"
    prepare_args = ["--config", "C:\\GitLab-Runner\\autoscaler\\config.toml", "custom", "prepare"]
    run_exec = "C:\\GitLab-Runner\\autoscaler\\autoscaler.exe"
    run_args = ["--config", "C:\\GitLab-Runner\\autoscaler\\config.toml", "custom", "run"]
    cleanup_exec = "C:\\GitLab-Runner\\autoscaler\\autoscaler.exe"
    cleanup_args = ["--config", "C:\\GitLab-Runner\\autoscaler\\config.toml", "custom", "cleanup"]

The full contents of our autoscaler/config.toml are:

Provider = "gcp"
Executor = "winrm"
OS = "windows"
LogLevel = "info"
LogFormat = "text"
LogFile = "C:\\GitLab-Runner\\autoscaler\\autoscaler.log"
VMTag = "windows"

[GCP]
  ServiceAccountFile = "PATH"
  Project = "some-project-df9323"
  Zone = "us-east1-c"
  MachineType = "n1-standard-2"
  Image = "IMAGE"
  DiskSize = 50
  DiskType = "pd-standard"
  Subnetwork = "default"
  Network = "default"
  Tags = ["TAGS"]
  Username = "gitlab_runner"

[WinRM]
  MaximumTimeout = 3600
  ExecutionMaxRetries = 0

[ProviderCache]
  Enabled = true
  Directory = "C:\\GitLab-Runner\\autoscaler\\machines"

Example

Below is a simple .gitlab-ci.yml file to show how to start using the Windows shared runners:

.shared_windows_runners:
  tags:
    - shared-windows
    - windows
    - windows-1809

stages:
  - build
  - test

before_script:
 - Set-Variable -Name "time" -Value (date -Format "%H:%m")
 - echo ${time}
 - echo "started by ${GITLAB_USER_NAME}"

build:
  extends:
    - .shared_windows_runners
  stage: build
  script:
    - echo "running scripts in the build job"

test:
  extends:
    - .shared_windows_runners
  stage: test
  script:
    - echo "running scripts in the test job"

Limitations and known issues

  • All the limitations mentioned in our beta definition.
  • The average provisioning time for a new Windows VM is 5 minutes. This means that you may notice slower build start times on the Windows shared runner fleet during the beta. In a future release we intend to update the autoscaler to enable the pre-provisioning of virtual machines. This is intended to significantly reduce the time it takes to provision a VM on the Windows fleet. You can follow along in the related issue.
  • The Windows shared runner fleet may be unavailable occasionally for maintenance or updates.
  • The Windows shared runner virtual machine instances do not use the GitLab Docker executor. This means that you can’t specify image or services in your pipeline configuration.
  • For the beta release, we have included a set of software packages in the base VM image. If your CI job requires additional software that’s not included in this list, then you must add installation commands to before_script or script to install the required software. Note that each job runs on a new VM instance, so the installation of additional software packages needs to be repeated for each job in your pipeline.
  • The job may stay in a pending state for longer than the Linux shared runners.
  • There is the possibility that we introduce breaking changes which will require updates to pipelines that are using the Windows shared runner fleet.