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:

Configuration guides

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

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

Consolidated object storage configuration

Introduced in GitLab 13.2.

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

Note: Only AWS S3-compatible providers and Google are supported at the moment since direct upload mode must be used. Background upload is not supported in this mode. We recommend direct upload mode because it does not require a shared folder, and this setting may become the default.
Note: Consolidated object storage configuration cannot be used for backups or Mattermost. See the full table for a complete list.

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. A different bucket for each type must be used.

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

    [object_storage]
      enabled = true
      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>'
}
Setting Description
enabled Enable/disable object storage
proxy_download Set to true to enable proxying all files served. Option allows to reduce egress traffic as this allows clients to download directly from remote storage instead of proxying all data
connection Various connection options described below
objects Object-specific configuration

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:

Setting Description Default
provider Always AWS for compatible hosts AWS
aws_access_key_id AWS credentials, or compatible  
aws_secret_access_key AWS credentials, or compatible  
aws_signature_version AWS signature version to use. 2 or 4 are valid options. Digital Ocean Spaces and other providers may need 2. 4
enable_signature_v4_streaming Set to true to enable HTTP chunked transfers with AWS v4 signatures. Oracle Cloud S3 needs this to be false. true
region AWS region us-east-1
host S3 compatible host for when not using AWS, e.g. localhost or storage.example.com. HTTPS and port 443 is assumed. s3.amazonaws.com
endpoint Can be used when configuring an S3 compatible service such as MinIO, by entering a URL such as http://127.0.0.1:9000. This takes precedence over host. (optional)
path_style Set to true to use host/bucket_name/object style paths instead of bucket_name.host/object. Leave as false for AWS S3. false
use_iam_profile Set to true to use IAM profile instead of access keys false

Oracle Cloud S3 connection settings

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

Setting Value
enable_signature_v4_streaming false
path_style true

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:

Setting Description example
provider The provider name Google
google_project GCP project name gcp-project-12345
google_client_email The email address of the service account foo@gcp-project-12345.iam.gserviceaccount.com
google_json_key_location The JSON key path /path/to/gcp-project-12345-abcde.json
Note: The service account must have permission to access the bucket. See more
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>'
}

OpenStack-compatible connection settings

Note: This is not compatible with the consolidated object storage form. OpenStack Swift is only supported with the storage-specific form. See the S3 settings if you want to use the consolidated form.

While OpenStack Swift provides S3 compatibliity, some users may want to use the Swift API. Here are the valid connection settings below for the Swift API, provided by fog-openstack:

Setting Description Default
provider Always OpenStack for compatible hosts OpenStack
openstack_username OpenStack username  
openstack_api_key OpenStack API key  
openstack_temp_url_key OpenStack key for generating temporary URLs  
openstack_auth_url OpenStack authentication endpoint  
openstack_region OpenStack region  
openstack_tenant OpenStack tenant ID  

Rackspace Cloud Files

Note: This is not compatible with the consolidated object storage form. Rackspace Cloud is only supported with the storage-specific form.

Here are the valid connection parameters for Rackspace Cloud, provided by fog-rackspace:

Setting Description example
provider The provider name Rackspace
rackspace_username The username of the Rackspace account with access to the container joe.smith
rackspace_api_key The API key of the Rackspace account with access to the container ABC123DEF456ABC123DEF456ABC123DE
rackspace_region The Rackspace storage region to use, a three letter code from the list of service access endpoints iad
rackspace_temp_url_key The private key you have set in the Rackspace API for temporary URLs. Read more here ABC123DEF456ABC123DEF456ABC123DE
Note: Regardless of whether the container has public access enabled or disabled, Fog will use the TempURL method to grant access to LFS objects. If you see errors in logs referencing instantiating storage with a temp-url-key, ensure that you have set the key properly on 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 overriden. 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

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'

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

Type Description
artifacts CI artifacts
external_diffs Merge request diffs
uploads User uploads
lfs Git Large File Storage objects
packages Project packages (e.g. PyPI, Maven, NuGet, etc.)
dependency_proxy GitLab Dependency Proxy
terraform_state Terraform state files

Within each object type, three parameters can be defined:

Setting Required? Description
bucket Yes The bucket name for the object storage.
enabled No Overrides the common parameter
proxy_download No Overrides the common parameter

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' }

While 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.

Note: The consolidated object storage configuration is only used 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, uploads_object_store_connection, and so on.)

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:

Object storage type Supported by consolidated configuration?
Backups No
Job artifacts and incremental logging Yes
LFS objects Yes
Uploads Yes
Container Registry (optional feature) No
Merge request diffs Yes
Mattermost No
Packages (optional feature) Yes
Dependency Proxy (optional feature) Yes
Pseudonymizer (optional feature) No
Autoscale Runner caching (optional for improved performance) No
Terraform state files Yes

Other alternatives to filesystem 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 filesystems. See the following guides and note that Pages requires disk storage:

  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.

Warnings, limitations, and known issues

Use separate buckets

Using separate buckets for each data type is the recommended approach for GitLab.

A limitation of our configuration is that each use of object storage is separately configured. We have an issue for improving this and easily using one bucket with separate folders is one improvement that this might bring.

There is at least one specific issue with using the same bucket: when GitLab is deployed with the Helm chart restore from backup will not properly function unless separate buckets are used.

One risk of using a single bucket would be that if your organisation decided to migrate GitLab to the Helm deployment in the future. GitLab would run, but the situation with backups might not be realised until the organisation had a critical requirement for the backups to work.

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

GitLab Pages requires NFS

If you’re working to add more GitLab servers for scaling or fault tolerance and one of your requirements is GitLab Pages this currently requires NFS. There is work in progress to remove this dependency. In the future, GitLab Pages may use object storage.

The dependency on disk storage also prevents Pages being deployed using the GitLab Helm chart.

Incremental logging is required for CI to use object storage

If you configure GitLab to use object storage for CI logs and artifacts, you must also enable 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, will generate this error:

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

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 will upload 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 will fetch temporary credentials each time an S3 bucket is accessed, so no hard-coded values are needed in the configuration.

Encrypted S3 buckets

Version history

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 yet supported since this requires supplying keys to the GitLab configuration.

Disabling the feature

The Workhorse S3 client is enabled by default when the use_iam_profile configuration option is set to true.

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:AbortMultipartUpload",
                    "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.