GitLab.com settings

In this page you will find information about the settings that are used on GitLab.com.

SSH host keys fingerprints

Below are the fingerprints for GitLab.com's SSH host keys.

Algorithm	MD5	SHA256
DSA	7a:47:81:3a:ee:89:89:64:33:ca:44:52:3d:30:d4:87	p8vZBUOR0XQz6sYiaWSMLmh0t9i8srqYKool/Xfdfqw
ECDSA	f1:d0:fb:46:73:7a:70:92:5a:ab:5d:ef:43:e2:1c:35	HbW3g8zUjNSksFbqTiUWPWg2Bq1x8xdGUrliXFzSnUw
ED25519	2e:65:6a:c8:cf:bf:b2:8b:9a:bd:6d:9f:11:5c:12:16	eUXGGm1YGsMAS7vkcx6JOJdOGHPem5gQp4taiCfCLB8
RSA	b6:03:0e:39:97:9e:d0:e7:24:ce:a3:77:3e:01:42:09	ROQFvPThGrW4RuWLoL9tq9I9zJ42fK4XywyRtbOz/EQ

Mail configuration

GitLab.com sends emails from the mg.gitlab.com domain via Mailgun and has its own dedicated IP address (198.61.254.240).

Alternative SSH port

GitLab.com can be reached via a different SSH port for git+ssh.

Setting	Value
Hostname	altssh.gitlab.com
Port	443

An example ~/.ssh/config is the following:

Host gitlab.com
  Hostname altssh.gitlab.com
  User git
  Port 443
  PreferredAuthentications publickey
  IdentityFile ~/.ssh/gitlab

GitLab Pages

Below are the settings for GitLab Pages.

Setting	GitLab.com	Default
Domain name	gitlab.io	-
IP address	35.185.44.232	-
Custom domains support	yes	no
TLS certificates support	yes	no

The maximum size of your Pages site is regulated by the artifacts maximum size which is part of GitLab CI/CD.

GitLab CI/CD

Below are the current settings regarding GitLab CI/CD.

Setting	GitLab.com	Default
Artifacts maximum size	1G	100M
Artifacts expiry time	kept forever	deleted after 30 days unless otherwise specified

Repository size limit

The maximum size your Git repository is allowed to be, including LFS. If you are near or over the size limit, you can reduce your repository size with Git.

Setting	GitLab.com	Default
Repository size including LFS	10G	Unlimited

Shared Runners

Shared Runners on GitLab.com run in autoscale mode and powered by Google Cloud Platform. Autoscaling means reduced waiting times to spin up CI/CD jobs, and isolated VMs for each project, thus maximizing security. They're free to use for public open source projects and limited to 2000 CI minutes per month per group for private projects. Read about all GitLab.com plans.

All your CI/CD jobs run on n1-standard-1 instances with 3.75GB of RAM, CoreOS and the latest Docker Engine installed. Instances provide 1 vCPU and 25GB of HDD disk space. The default region of the VMs is US East1. Each instance is used only for one job, this ensures any sensitive data left on the system can't be accessed by other people their CI jobs.

Jobs handled by the shared Runners on GitLab.com (shared-runners-manager-X.gitlab.com), will be timed out after 3 hours, regardless of the timeout configured in a project. Check the issues 4010 and 4070 for the reference.

Below are the shared Runners settings.

Setting	GitLab.com	Default
GitLab Runner	Runner versions dashboard	-
Executor	docker+machine	-
Default Docker image	ruby:2.5	-
privileged (run Docker in Docker)	true	false

config.toml

The full contents of our config.toml are:

DigitalOcean

concurrent = X
check_interval = 1
metrics_server = "X"
sentry_dsn = "X"

[[runners]]
  name = "docker-auto-scale"
  request_concurrency = X
  url = "https://gitlab.com/"
  token = "SHARED_RUNNER_TOKEN"
  executor = "docker+machine"
  environment = [
    "DOCKER_DRIVER=overlay2"
  ]
  limit = X
  [runners.docker]
    image = "ruby:2.5"
    privileged = true
  [runners.machine]
    IdleCount = 20
    IdleTime = 1800
    OffPeakPeriods = ["* * * * * sat,sun *"]
    OffPeakTimezone = "UTC"
    OffPeakIdleCount = 5
    OffPeakIdleTime = 1800
    MaxBuilds = 1
    MachineName = "srm-%s"
    MachineDriver = "digitalocean"
    MachineOptions = [
      "digitalocean-image=X",
      "digitalocean-ssh-user=core",
      "digitalocean-region=nyc1",
      "digitalocean-size=s-2vcpu-2gb",
      "digitalocean-private-networking",
      "digitalocean-tags=shared_runners,gitlab_com",
      "engine-registry-mirror=http://INTERNAL_IP_OF_OUR_REGISTRY_MIRROR",
      "digitalocean-access-token=DIGITAL_OCEAN_ACCESS_TOKEN",
    ]
  [runners.cache]
    Type = "s3"
    BucketName = "runner"
    Insecure = true
    Shared = true
    ServerAddress = "INTERNAL_IP_OF_OUR_CACHE_SERVER"
    AccessKey = "ACCESS_KEY"
    SecretKey = "ACCESS_SECRET_KEY"

Google Cloud Platform

concurrent = X
check_interval = 1
metrics_server = "X"
sentry_dsn = "X"

[[runners]]
  name = "docker-auto-scale"
  request_concurrency = X
  url = "https://gitlab.com/"
  token = "SHARED_RUNNER_TOKEN"
  executor = "docker+machine"
  environment = [
    "DOCKER_DRIVER=overlay2"
  ]
  limit = X
  [runners.docker]
    image = "ruby:2.5"
    privileged = true
  [runners.machine]
    IdleCount = 20
    IdleTime = 1800
    OffPeakPeriods = ["* * * * * sat,sun *"]
    OffPeakTimezone = "UTC"
    OffPeakIdleCount = 5
    OffPeakIdleTime = 1800
    MaxBuilds = 1
    MachineName = "srm-%s"
    MachineDriver = "google"
    MachineOptions = [
      "google-project=PROJECT",
      "google-disk-size=25",
      "google-machine-type=n1-standard-1",
      "google-username=core",
      "google-tags=gitlab-com,srm",
      "google-use-internal-ip",
      "google-zone=us-east1-d",
      "google-machine-image=PROJECT/global/images/IMAGE",
      "engine-registry-mirror=http://INTERNAL_IP_OF_OUR_REGISTRY_MIRROR"
    ]
  [runners.cache]
    Type = "s3"
    BucketName = "runner"
    Insecure = true
    Shared = true
    ServerAddress = "INTERNAL_IP_OF_OUR_CACHE_SERVER"
    AccessKey = "ACCESS_KEY"
    SecretKey = "ACCESS_SECRET_KEY"

Sidekiq

GitLab.com runs Sidekiq with arguments --timeout=4 --concurrency=4 and the following environment variables:

Setting	GitLab.com	Default
SIDEKIQ_MEMORY_KILLER_MAX_RSS	1000000	1000000
SIDEKIQ_MEMORY_KILLER_SHUTDOWN_SIGNAL	SIGKILL	-
SIDEKIQ_LOG_ARGUMENTS	1	-

Cron jobs

Periodically executed jobs by Sidekiq, to self-heal GitLab, do external synchronizations, run scheduled pipelines, etc.:

Setting	GitLab.com	Default
pipeline_schedule_worker	19 * * * *	19 * * * *

PostgreSQL

GitLab.com being a fairly large installation of GitLab means we have changed various PostgreSQL settings to better suit our needs. For example, we use streaming replication and servers in hot-standby mode to balance queries across different database servers.

The list of GitLab.com specific settings (and their defaults) is as follows:

Setting	GitLab.com	Default
archive_command	/usr/bin/envdir /etc/wal-e.d/env /opt/wal-e/bin/wal-e wal-push %p	empty
archive_mode	on	off
autovacuum_analyze_scale_factor	0.01	0.01
autovacuum_max_workers	6	3
autovacuum_vacuum_cost_limit	1000	-1
autovacuum_vacuum_scale_factor	0.01	0.02
checkpoint_completion_target	0.7	0.9
checkpoint_segments	32	10
effective_cache_size	338688MB	Based on how much memory is available
hot_standby	on	off
hot_standby_feedback	on	off
log_autovacuum_min_duration	0	-1
log_checkpoints	on	off
log_line_prefix	%t [%p]: [%l-1]	empty
log_min_duration_statement	1000	-1
log_temp_files	0	-1
maintenance_work_mem	2048MB	16 MB
max_replication_slots	5	0
max_wal_senders	32	0
max_wal_size	5GB	1GB
shared_buffers	112896MB	Based on how much memory is available
shared_preload_libraries	pg_stat_statements	empty
shmall	30146560	Based on the server's capabilities
shmmax	123480309760	Based on the server's capabilities
wal_buffers	16MB	-1
wal_keep_segments	512	10
wal_level	replica	minimal
statement_timeout	15s	60s
idle_in_transaction_session_timeout	60s	60s

Some of these settings are in the process being adjusted. For example, the value for shared_buffers is quite high and as such we are looking into adjusting it. More information on this particular change can be found at https://gitlab.com/gitlab-com/infrastructure/issues/1555. An up to date list of proposed changes can be found at https://gitlab.com/gitlab-com/infrastructure/issues?scope=all&utf8=%E2%9C%93&state=opened&label_name[]=database&label_name[]=change.

Unicorn

GitLab.com adjusts the memory limits for the unicorn-worker-killer gem.

Base default:

• memory_limit_min = 750MiB
• memory_limit_max = 1024MiB

Web front-ends:

• memory_limit_min = 1024MiB
• memory_limit_max = 1280MiB

GitLab.com at scale

In addition to the GitLab Enterprise Edition Omnibus install, GitLab.com uses the following applications and settings to achieve scale. All settings are located publicly available chef cookbooks.

ELK

We use Elasticsearch, logstash, and Kibana for part of our monitoring solution:

• gitlab-cookbooks / gitlab-elk · GitLab
• gitlab-cookbooks / gitlab_elasticsearch · GitLab

Prometheus

Prometheus complete our monitoring stack:

• gitlab-cookbooks / gitlab-prometheus · GitLab

Grafana

For the visualization of monitoring data:

• gitlab-cookbooks / gitlab-grafana · GitLab

Sentry

Open source error tracking:

• gitlab-cookbooks / gitlab-sentry · GitLab

Consul

Service discovery:

• gitlab-cookbooks / gitlab_consul · GitLab

Haproxy

High Performance TCP/HTTP Load Balancer:

• gitlab-cookbooks / gitlab-haproxy · GitLab