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debian-mirror-gitlab/doc/user/gitlab_com/index.md
Sruthi Chandran fa176ca292 New upstream version 12.2.8
2019-10-12 21:52:04 +05:30

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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

IP range

GitLab.com, CI/CD, and related services are deployed into Google Cloud Platform (GCP). Any IP based firewall can be configured by looking up all IP address ranges or CIDR blocks for GCP.

Static endpoints are being considered.

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. More minutes can be purchased, if needed. 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:

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",
    "DOCKER_TLS_CERTDIR="
  ]
  limit = X
  [runners.docker]
    image = "ruby:2.5"
    privileged = true
    volumes = [
      "/certs/client",
      "/dummy-sys-class-dmi-id:/sys/class/dmi/id:ro" # Make kaniko builds work on GCP.
    ]
  [runners.machine]
    IdleCount = 50
    IdleTime = 3600
    OffPeakPeriods = ["* * * * * sat,sun *"]
    OffPeakTimezone = "UTC"
    OffPeakIdleCount = 15
    OffPeakIdleTime = 3600
    MaxBuilds = 1 # For security reasons we delete the VM after job has finished so it's not reused.
    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",
      "engine-opt=mtu=1460", # Set MTU for container interface, for more information check https://gitlab.com/gitlab-org/gitlab-runner/issues/3214#note_82892928
      "google-machine-image=PROJECT/global/images/IMAGE",
      "engine-opt=ipv6", # This will create IPv6 interfaces in the containers.
      "engine-opt=fixed-cidr-v6=fc00::/7",
      "google-operation-backoff-initial-interval=2" # Custom flag from forked docker-machine, for more information check https://github.com/docker/machine/pull/4600
    ]
  [runners.cache]
    Type = "gcs"
    Shared = true
    [runners.cache.gcs]
      CredentialsFile = "/path/to/file"
      BucketName = "bucket-name"

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 2000000
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-specific rate limits

NOTE: Note: See Rate limits for administrator documentation.

IP blocks usually happen when GitLab.com receives unusual traffic from a single IP address that the system views as potentially malicious based on rate limit settings. After the unusual traffic ceases, the IP address will be automatically released depending on the type of block, as described below.

If you receive a 403 Forbidden error for all requests to GitLab.com, please check for any automated processes that may be triggering a block. For assistance, contact GitLab Support with details, such as the affected IP address.

HAProxy API throttle

GitLab.com responds with HTTP status code 429 to API requests that exceed 10 requests per second per IP address.

The following example headers are included for all API requests:

RateLimit-Limit: 600
RateLimit-Observed: 6
RateLimit-Remaining: 594
RateLimit-Reset: 1563325137
RateLimit-ResetTime: Wed, 17 Jul 2019 00:58:57 GMT

Source:

Rack Attack initializer

Details of rate limits enforced by Rack Attack.

Protected paths throttle

GitLab.com responds with HTTP status code 429 to POST requests at protected paths that exceed 10 requests per minute per IP address.

See the source below for which paths are protected. This includes user creation, user confirmation, user sign in, and password reset.

This header is included in responses to blocked requests:

Retry-After: 60

Source:

Git and container registry failed authentication ban

GitLab.com responds with HTTP status code 403 for 1 hour, if 30 failed authentication requests were received in a 3-minute period from a single IP address.

This applies only to Git requests and container registry (/jwt/auth) requests (combined).

This limit is reset by requests that authenticate successfully. For example, 29 failed authentication requests followed by 1 successful request, followed by 29 more failed authentication requests would not trigger a ban.

No response headers are provided.

Admin Area settings

GitLab.com does not currently use these settings.

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:

Prometheus

Prometheus complete our monitoring stack:

Grafana

For the visualization of monitoring data:

Sentry

Open source error tracking:

Consul

Service discovery:

Haproxy

High Performance TCP/HTTP Load Balancer:

Group and project settings

On GitLab.com, projects, groups, and snippets created after July 2019 have the Internal visibility setting disabled.

You can read more about the change in the relevant issue.