• Options
  • Known compatibility issues
• Configuration guides
  • Consolidated object storage configuration
    • Common parameters
  • Connection settings
    • S3-compatible connection settings
    • Oracle Cloud S3 connection settings
    • Google Cloud Storage (GCS)
      • Google example (consolidated form)
      • Google example with ADC (consolidated form)
    • Azure Blob storage
      • Azure example (consolidated form)
    • OpenStack-compatible connection settings
    • Rackspace Cloud Files
  • Object-specific configuration
    • Selectively disabling object storage
  • Transition to consolidated form
• Storage-specific configuration
  • Other alternatives to file system storage
• Warnings, limitations, and known issues
  • Use separate buckets
  • S3 API compatibility issues
  • Incremental logging is required for CI to use object storage
  • Proxy Download
  • ETag mismatch
  • Using Amazon instance profiles
    • Encrypted S3 buckets
      • Server-side encryption headers
      • Disabling the feature
    • IAM Permissions
  • Multi-threaded copying

Object storage

GitLab supports using an object storage service for holding numerous types of data. It’s recommended over NFS and in general it’s better in larger setups as object storage is typically much more performant, reliable, and scalable.

Options

GitLab has been tested on a number of object storage providers:

• Amazon S3
• Google Cloud Storage
• Digital Ocean Spaces
• Oracle Cloud Infrastructure
• OpenStack Swift
• Azure Blob storage
• On-premises hardware and appliances from various storage vendors.
• MinIO. We have a guide to deploying this within our Helm Chart documentation.

Known compatibility issues

• Dell EMC ECS: Prior to GitLab 13.3, there is a known bug in GitLab Workhorse that prevents HTTP Range Requests from working with CI job artifacts. Be sure to upgrade to GitLab 13.3.0 or above if you use S3 storage with this hardware.

• Ceph S3 prior to Kraken 11.0.2 does not support the Upload Copy Part API. You may need to disable multi-threaded copying.

Configuration guides

There are two ways of specifying object storage configuration in GitLab:

• Consolidated form: A single credential is shared by all supported object types.
• Storage-specific form: Every object defines its own object storage connection and configuration.

For more information on the differences and to transition from one form to another, see Transition to consolidated form.

Consolidated object storage configuration

Using the consolidated object storage configuration has a number of advantages:

• It can simplify your GitLab configuration since the connection details are shared across object types.
• It enables the use of encrypted S3 buckets.
• It uploads files to S3 with proper Content-MD5 headers.

Because direct upload mode must be enabled, only the following providers can be used:

• Amazon S3-compatible providers
• Google Cloud Storage
• Azure Blob storage

When consolidated object storage is used, direct upload is enabled automatically. Background upload is not supported. For storage-specific configuration, direct upload may become the default because it does not require a shared folder.

Consolidated object storage configuration can’t be used for backups or Mattermost. See the full table for a complete list.

Enabling consolidated object storage enables object storage for all object types. If you want to use local storage for specific object types, you can selectively disable object storages.

Most types of objects, such as CI artifacts, LFS files, upload attachments, and so on can be saved in object storage by specifying a single credential for object storage with multiple buckets.

When the consolidated form is:

• Used with an S3-compatible object storage, Workhorse uses its internal S3 client to upload files.
• Not used with an S3-compatible object storage, Workhorse falls back to using pre-signed URLs.

See the section on ETag mismatch errors for more details.

In Omnibus installations:

1. Edit /etc/gitlab/gitlab.rb and add the following lines, substituting the values you want:

    # Consolidated object storage configuration
    gitlab_rails['object_store']['enabled'] = true
    gitlab_rails['object_store']['proxy_download'] = true
    gitlab_rails['object_store']['connection'] = {
      'provider' => 'AWS',
      'region' => '<eu-central-1>',
      'aws_access_key_id' => '<AWS_ACCESS_KEY_ID>',
      'aws_secret_access_key' => '<AWS_SECRET_ACCESS_KEY>'
    }
    # OPTIONAL: The following lines are only needed if server side encryption is required
    gitlab_rails['object_store']['storage_options'] = {
      'server_side_encryption' => '<AES256 or aws:kms>',
      'server_side_encryption_kms_key_id' => '<arn:aws:kms:xxx>'
    }
    gitlab_rails['object_store']['objects']['artifacts']['bucket'] = '<artifacts>'
    gitlab_rails['object_store']['objects']['external_diffs']['bucket'] = '<external-diffs>'
    gitlab_rails['object_store']['objects']['lfs']['bucket'] = '<lfs-objects>'
    gitlab_rails['object_store']['objects']['uploads']['bucket'] = '<uploads>'
    gitlab_rails['object_store']['objects']['packages']['bucket'] = '<packages>'
    gitlab_rails['object_store']['objects']['dependency_proxy']['bucket'] = '<dependency-proxy>'
    gitlab_rails['object_store']['objects']['terraform_state']['bucket'] = '<terraform-state>'
    gitlab_rails['object_store']['objects']['pages']['bucket'] = '<pages>'
   

   For GitLab 9.4 or later, if you’re using AWS IAM profiles, be sure to omit the AWS access key and secret access key/value pairs. For example:

   gitlab_rails['object_store']['connection'] = {
     'provider' => 'AWS',
     'region' => '<eu-central-1>',
     'use_iam_profile' => true
   }
   

2. Save the file and reconfigure GitLab for the changes to take effect.

In installations from source:

1. Edit /home/git/gitlab/config/gitlab.yml and add or amend the following lines:

   object_store:
     enabled: true
     proxy_download: true
     connection:
       provider: AWS
       aws_access_key_id: <AWS_ACCESS_KEY_ID>
       aws_secret_access_key: <AWS_SECRET_ACCESS_KEY>
       region: <eu-central-1>
     storage_options:
       server_side_encryption: <AES256 or aws:kms>
       server_side_encryption_key_kms_id: <arn:aws:kms:xxx>
     objects:
       artifacts:
         bucket: <artifacts>
       external_diffs:
         bucket: <external-diffs>
       lfs:
         bucket: <lfs-objects>
       uploads:
         bucket: <uploads>
       packages:
         bucket: <packages>
       dependency_proxy:
         bucket: <dependency_proxy>
       terraform_state:
         bucket: <terraform>
       pages:
         bucket: <pages>
   

2. Edit /home/git/gitlab-workhorse/config.toml and add or amend the following lines:

   [object_storage]
     provider = "AWS"
   
   [object_storage.s3]
     aws_access_key_id = "<AWS_ACCESS_KEY_ID>"
     aws_secret_access_key = "<AWS_SECRET_ACCESS_KEY>"
   

3. Save the file and restart GitLab for the changes to take effect.

Common parameters

In the consolidated configuration, the object_store section defines a common set of parameters. Here we use the YAML from the source installation because it’s easier to see the inheritance:

    object_store:
      enabled: true
      proxy_download: true
      connection:
        provider: AWS
        aws_access_key_id: <AWS_ACCESS_KEY_ID>
        aws_secret_access_key: <AWS_SECRET_ACCESS_KEY>
      objects:
        ...

The Omnibus configuration maps directly to this:

gitlab_rails['object_store']['enabled'] = true
gitlab_rails['object_store']['proxy_download'] = true
gitlab_rails['object_store']['connection'] = {
  'provider' => 'AWS',
  'aws_access_key_id' => '<AWS_ACCESS_KEY_ID',
  'aws_secret_access_key' => '<AWS_SECRET_ACCESS_KEY>'
}

Connection settings

Both consolidated configuration form and storage-specific configuration form must configure a connection. The following sections describe parameters that can be used in the connection setting.

S3-compatible connection settings

The connection settings match those provided by fog-aws:

Oracle Cloud S3 connection settings

Note that Oracle Cloud S3 must be sure to use the following settings:

If enable_signature_v4_streaming is set to true, you may see the following error in production.log:

STREAMING-AWS4-HMAC-SHA256-PAYLOAD is not supported

Google Cloud Storage (GCS)

Here are the valid connection parameters for GCS:

The service account must have permission to access the bucket. Learn more in Google’s Cloud Storage authentication documentation.

Google example (consolidated form)

For Omnibus installations, this is an example of the connection setting:

gitlab_rails['object_store']['connection'] = {
  'provider' => 'Google',
  'google_project' => '<GOOGLE PROJECT>',
  'google_client_email' => '<GOOGLE CLIENT EMAIL>',
  'google_json_key_location' => '<FILENAME>'
}

Google example with ADC (consolidated form)

Google Cloud Application Default Credentials (ADC) are typically used with GitLab to use the default service account. This eliminates the need to supply credentials for the instance. For example:

gitlab_rails['object_store']['connection'] = {
  'provider' => 'Google',
  'google_project' => '<GOOGLE PROJECT>',
  'google_application_default' => true
}

If you use ADC, be sure that:

• The service account that you use has the iam.serviceAccounts.signBlob permission. Typically this is done by granting the Service Account Token Creator role to the service account.

• Your virtual machines have the correct access scopes to access Google Cloud APIs. If the machines do not have the right scope, the error logs may show:

  Google::Apis::ClientError (insufficientPermissions: Request had insufficient authentication scopes.)
  

Azure Blob storage

Although Azure uses the word container to denote a collection of blobs, GitLab standardizes on the term bucket. Be sure to configure Azure container names in the bucket settings.

Azure Blob storage can only be used with the consolidated form because a single set of credentials are used to access multiple containers. The storage-specific form is not supported. For more details, see how to transition to consolidated form.

The following are the valid connection parameters for Azure. Read the Azure Blob storage documentation to learn more.

Azure example (consolidated form)

For Omnibus installations, this is an example of the connection setting:

gitlab_rails['object_store']['connection'] = {
  'provider' => 'AzureRM',
  'azure_storage_account_name' => '<AZURE STORAGE ACCOUNT NAME>',
  'azure_storage_access_key' => '<AZURE STORAGE ACCESS KEY>',
  'azure_storage_domain' => '<AZURE STORAGE DOMAIN>',
}

Azure Workhorse settings (source installs only)

For source installations, Workhorse also needs to be configured with Azure credentials. This isn’t needed in Omnibus installs, because the Workhorse settings are populated from the previous settings.

1. Edit /home/git/gitlab-workhorse/config.toml and add or amend the following lines:

   [object_storage]
     provider = "AzureRM"
   
   [object_storage.azurerm]
     azure_storage_account_name = "<AZURE STORAGE ACCOUNT NAME>"
     azure_storage_access_key = "<AZURE STORAGE ACCESS KEY>"
   

If you are using a custom Azure storage domain, note that azure_storage_domain does not have to be set in the Workhorse configuration. This information is exchanged in an API call between GitLab Rails and Workhorse.

OpenStack-compatible connection settings

Although OpenStack Swift provides S3 compatibility, some users may want to use the Swift API.

This isn’t compatible with the consolidated object storage form. OpenStack Swift is supported only with the storage-specific form. If you want to use the consolidated form, see the S3 settings.

Here are the valid connection settings for the Swift API, provided by fog-openstack:

Rackspace Cloud Files

The following table describes the valid connection parameters for Rackspace Cloud, provided by fog-rackspace.

This isn’t compatible with the consolidated object storage form. Rackspace Cloud is supported only with the storage-specific form.

Regardless of whether the container has public access enabled or disabled, Fog uses the TempURL method to grant access to LFS objects. If you see error messages in logs that refer to instantiating storage with a temp-url-key, be sure you have set the key properly both in the Rackspace API and in gitlab.rb. You can verify the value of the key Rackspace has set by sending a GET request with token header to the service access endpoint URL and comparing the output of the returned headers.

Object-specific configuration

The following YAML shows how the object_store section defines object-specific configuration block and how the enabled and proxy_download flags can be overridden. The bucket is the only required parameter within each type:

  object_store:
      connection:
        ...
      objects:
        artifacts:
          bucket: artifacts
          proxy_download: false
        external_diffs:
          bucket: external-diffs
        lfs:
          bucket: lfs-objects
        uploads:
          bucket: uploads
        packages:
          bucket: packages
        dependency_proxy:
          enabled: false
          bucket: dependency_proxy
        terraform_state:
          bucket: terraform
        pages:
          bucket: pages

This maps to this Omnibus GitLab configuration:

gitlab_rails['object_store']['objects']['artifacts']['bucket'] = 'artifacts'
gitlab_rails['object_store']['objects']['artifacts']['proxy_download'] = false
gitlab_rails['object_store']['objects']['external_diffs']['bucket'] = 'external-diffs'
gitlab_rails['object_store']['objects']['lfs']['bucket'] = 'lfs-objects'
gitlab_rails['object_store']['objects']['uploads']['bucket'] = 'uploads'
gitlab_rails['object_store']['objects']['packages']['bucket'] = 'packages'
gitlab_rails['object_store']['objects']['dependency_proxy']['enabled'] = false
gitlab_rails['object_store']['objects']['dependency_proxy']['bucket'] = 'dependency-proxy'
gitlab_rails['object_store']['objects']['terraform_state']['bucket'] = 'terraform-state'
gitlab_rails['object_store']['objects']['pages']['bucket'] = 'pages'

This is the list of valid objects that can be used:

Within each object type, three parameters can be defined:

Selectively disabling object storage

As seen above, object storage can be disabled for specific types by setting the enabled flag to false. For example, to disable object storage for CI artifacts:

gitlab_rails['object_store']['objects']['artifacts']['enabled'] = false

A bucket is not needed if the feature is disabled entirely. For example, no bucket is needed if CI artifacts are disabled with this setting:

gitlab_rails['artifacts_enabled'] = false

Transition to consolidated form

Prior to GitLab 13.2:

• Object storage configuration for all types of objects such as CI/CD artifacts, LFS files, upload attachments, and so on had to be configured independently.
• Object store connection parameters such as passwords and endpoint URLs had to be duplicated for each type.

For example, an Omnibus GitLab install might have the following configuration:

# Original object storage configuration
gitlab_rails['artifacts_object_store_enabled'] = true
gitlab_rails['artifacts_object_store_direct_upload'] = true
gitlab_rails['artifacts_object_store_proxy_download'] = true
gitlab_rails['artifacts_object_store_remote_directory'] = 'artifacts'
gitlab_rails['artifacts_object_store_connection'] = { 'provider' => 'AWS', 'aws_access_key_id' => 'access_key', 'aws_secret_access_key' => 'secret' }
gitlab_rails['uploads_object_store_enabled'] = true
gitlab_rails['uploads_object_store_direct_upload'] = true
gitlab_rails['uploads_object_store_proxy_download'] = true
gitlab_rails['uploads_object_store_remote_directory'] = 'uploads'
gitlab_rails['uploads_object_store_connection'] = { 'provider' => 'AWS', 'aws_access_key_id' => 'access_key', 'aws_secret_access_key' => 'secret' }

Although this provides flexibility in that it makes it possible for GitLab to store objects across different cloud providers, it also creates additional complexity and unnecessary redundancy. Since both GitLab Rails and Workhorse components need access to object storage, the consolidated form avoids excessive duplication of credentials.

The consolidated object storage configuration is used only if all lines from the original form is omitted. To move to the consolidated form, remove the original configuration (for example, artifacts_object_store_enabled, or uploads_object_store_connection)

Storage-specific configuration

For configuring object storage in GitLab 13.1 and earlier, or for storage types not supported by consolidated configuration form, refer to the following guides:

Other alternatives to file system storage

If you’re working to scale out your GitLab implementation, or add fault tolerance and redundancy, you may be looking at removing dependencies on block or network file systems. See the following additional guides:

1. Make sure the git user home directory is on local disk.
2. Configure database lookup of SSH keys to eliminate the need for a shared authorized_keys file.
3. Prevent local disk usage for job logs.

Warnings, limitations, and known issues

Use separate buckets

Using separate buckets for each data type is the recommended approach for GitLab. This ensures there are no collisions across the various types of data GitLab stores. There are plans to enable the use of a single bucket in the future.

Helm-based installs require separate buckets to handle backup restorations

S3 API compatibility issues

Not all S3 providers are fully compatible with the Fog library that GitLab uses. Symptoms include an error in production.log:

411 Length Required

Incremental logging is required for CI to use object storage

If you configure GitLab to use object storage for CI logs and artifacts, you can avoid local disk usage for job logs by enabling beta incremental logging.

Proxy Download

Clients can download files in object storage by receiving a pre-signed, time-limited URL, or by GitLab proxying the data from object storage to the client. Downloading files from object storage directly helps reduce the amount of egress traffic GitLab needs to process.

When the files are stored on local block storage or NFS, GitLab has to act as a proxy. This is not the default behavior with object storage.

The proxy_download setting controls this behavior: the default is generally false. Verify this in the documentation for each use case. Set it to true if you want GitLab to proxy the files.

When not proxying files, GitLab returns an HTTP 302 redirect with a pre-signed, time-limited object storage URL. This can result in some of the following problems:

• If GitLab is using non-secure HTTP to access the object storage, clients may generate https->http downgrade errors and refuse to process the redirect. The solution to this is for GitLab to use HTTPS. LFS, for example, generates this error:

   LFS: lfsapi/client: refusing insecure redirect, https->http
  

• Clients need to trust the certificate authority that issued the object storage certificate, or may return common TLS errors such as:

   x509: certificate signed by unknown authority
  

• Clients need network access to the object storage. Network firewalls could block access. Errors that might result if this access is not in place include:

   Received status code 403 from server: Forbidden
  

Getting a 403 Forbidden response is specifically called out on the package repository documentation as a side effect of how some build tools work.

Additionally for a short time period users could share pre-signed, time-limited object storage URLs with others without authentication. Also bandwidth charges may be incurred between the object storage provider and the client.

ETag mismatch

Using the default GitLab settings, some object storage back-ends such as MinIO and Alibaba might generate ETag mismatch errors.

If you are seeing this ETag mismatch error with Amazon Web Services S3, it’s likely this is due to encryption settings on your bucket. To fix this issue, you have two options:

• Use the consolidated object configuration.
• Use Amazon instance profiles.

The first option is recommended for MinIO. Otherwise, the workaround for MinIO is to use the --compat parameter on the server.

Without consolidated object store configuration or instance profiles enabled, GitLab Workhorse uploads files to S3 using pre-signed URLs that do not have a Content-MD5 HTTP header computed for them. To ensure data is not corrupted, Workhorse checks that the MD5 hash of the data sent equals the ETag header returned from the S3 server. When encryption is enabled, this is not the case, which causes Workhorse to report an ETag mismatch error during an upload.

With the consolidated object configuration and instance profile, Workhorse has S3 credentials so that it can compute the Content-MD5 header. This eliminates the need to compare ETag headers returned from the S3 server.

Using Amazon instance profiles

Instead of supplying AWS access and secret keys in object storage configuration, GitLab can be configured to use IAM roles to set up an Amazon instance profile. When this is used, GitLab fetches temporary credentials each time an S3 bucket is accessed, so no hard-coded values are needed in the configuration.

Encrypted S3 buckets

When configured either with an instance profile or with the consolidated object configuration, GitLab Workhorse properly uploads files to S3 buckets that have SSE-S3 or SSE-KMS encryption enabled by default. Note that customer master keys (CMKs) and SSE-C encryption are not supported since this requires sending the encryption keys in every request.

Server-side encryption headers

Setting a default encryption on an S3 bucket is the easiest way to enable encryption, but you may want to set a bucket policy to ensure only encrypted objects are uploaded. To do this, you must configure GitLab to send the proper encryption headers in the storage_options configuration section:

As with the case for default encryption, these options only work when the Workhorse S3 client is enabled. One of the following two conditions must be fulfilled:

• use_iam_profile is true in the connection settings.
• Consolidated object storage settings are in use.

ETag mismatch errors occur if server side encryption headers are used without enabling the Workhorse S3 client.

Disabling the feature

The Workhorse S3 client is enabled by default when the use_iam_profile configuration option is set to true or consolidated object storage settings are configured.

The feature can be disabled using the :use_workhorse_s3_client feature flag. To disable the feature, ask a GitLab administrator with Rails console access to run the following command:

Feature.disable(:use_workhorse_s3_client)

IAM Permissions

To set up an instance profile:

1. Create an Amazon Identity Access and Management (IAM) role with the necessary permissions. The following example is a role for an S3 bucket named test-bucket:

   {
       "Version": "2012-10-17",
       "Statement": [
           {
               "Sid": "VisualEditor0",
               "Effect": "Allow",
               "Action": [
                   "s3:PutObject",
                   "s3:GetObject",
                   "s3:DeleteObject"
               ],
               "Resource": "arn:aws:s3:::test-bucket/*"
           }
       ]
   }
   

2. Attach this role to the EC2 instance hosting your GitLab instance.
3. Configure GitLab to use it via the use_iam_profile configuration option.

Multi-threaded copying

GitLab uses the S3 Upload Part Copy API to accelerate the copying of files within a bucket. Ceph S3 prior to Kraken 11.0.2 does not support this and returns a 404 error when files are copied during the upload process.

The feature can be disabled using the :s3_multithreaded_uploads feature flag. To disable the feature, ask a GitLab administrator with Rails console access to run the following command:

Feature.disable(:s3_multithreaded_uploads)