Merge branch 'jej/lfs-object-storage-docs' into 'master'

Documentation for LFS object storage

See merge request gitlab-org/gitlab-ee!2959

doc/workflow/lfs/lfs_administration.md

@@ -5,6 +5,7 @@ Documentation on how to use Git LFS are under [Managing large binary files with
 ## Requirements
 
 * Git LFS is supported in GitLab starting with version 8.2.
+* Support for object storage, such as AWS S3, was introduced in 10.0.
 * Users need to install [Git LFS client](https://git-lfs.github.com) version 1.0.1 and up.
 
 ## Configuration
@@ -12,13 +13,15 @@ Documentation on how to use Git LFS are under [Managing large binary files with
 Git LFS objects can be large in size. By default, they are stored on the server
 GitLab is installed on.
 
-There are two configuration options to help GitLab server administrators:
+There are various configuration options to help GitLab server administrators:
 
 * Enabling/disabling Git LFS support
 * Changing the location of LFS object storage
+* Setting up AWS S3 compatible object storage
 
 ### Omnibus packages
 
+
 In `/etc/gitlab/gitlab.rb`:
 
 ```ruby
@@ -42,6 +45,106 @@ In `config/gitlab.yml`:
     storage_path: /mnt/storage/lfs-objects
 ```
 
+## Setting up S3 compatible object storage
+
+> **Note:** [Introduced][ee-2760] in [GitLab Enterprise Edition Premium][eep] 10.0.
+
+It is possible to store LFS objects on remote object storage instead of on a local disk.
+
+This allows you to offload storage to an external AWS S3 compatible service, freeing up disk space locally. You can also host your own S3 compatible storage decoupled from GitLab, with with a service such as [Minio](https://www.minio.io/).
+
+Object storage currently transfers files first to GitLab, and then on the object storage in a second stage. This can be done either by using a rake task to transfer existing objects, or in a background job after each file is received.
+
+### Object Storage Settings
+
+For source installations the following settings are nested under `lfs:` and then `object_store:`. On omnibus installs they are prefixed by `lfs_object_store_`.
+
+| Setting | Description | Default |
+|---------|-------------|---------|
+| `enabled` | Enable/disable object storage | `false` |
+| `remote_directory` | The bucket name where LFS objects will be stored| |
+| `background_upload` | Set to false to disable automatic upload. Option may be removed once upload is direct to S3 | `true` |
+| `connection` | Various connection options described below | |
+
+#### S3 compatible connection settigns
+
+The connection settings match those provided by [Fog](https://github.com/fog), and are as follows:
+
+| 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 | |
+| `region` | AWS region | us-east-1 |
+| `host` | S3 compatible host for when not using AWS, e.g. `localhost` or `storage.example.com` | s3.amazonaws.com |
+| `endpoint` | Can be used when configuring an S3 compatible service such as [Minio](https://www.minio.io), by entering a URL such as `http://127.0.0.1:9000` | (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 |
+
+
+### From source
+
+1. Edit `/home/git/gitlab/config/gitlab.yml` and add or amend the following
+   lines:
+
+	```yaml
+	lfs:
+	enabled: true
+	object_store:
+	  enabled: false
+	  remote_directory: lfs-objects # Bucket name
+	  connection:
+	    provider: AWS
+	    aws_access_key_id: 1ABCD2EFGHI34JKLM567N
+	    aws_secret_access_key: abcdefhijklmnopQRSTUVwxyz0123456789ABCDE
+	    region: eu-central-1
+	    # Use the following options to configure an AWS compatible host such as Minio
+	    host: 'localhost'
+	    endpoint: 'http://127.0.0.1:9000'
+	    path_style: true
+	```
+
+1. Save the file and [restart GitLab][] for the changes to take effect.
+1. Migrate any existing local LFS objects to the object storage:
+
+	```bash
+	sudo -u git -H bundle exec rake gitlab:lfs:migrate RAILS_ENV=production
+	```
+
+	This will migrate existing LFS objects to object storage. New LFS objects
+	will be forwarded to object storage unless
+	`gitlab_rails['lfs_object_store_background_upload']` is set to false.
+
+### In ombnibus
+
+1. Edit `/etc/gitlab/gitlab.rb` and add the following lines by replacing with
+   the values you want:
+
+	```ruby
+	gitlab_rails['lfs_object_store_enabled'] = true
+	gitlab_rails['lfs_object_store_remote_directory'] = "lfs-objects"
+	gitlab_rails['lfs_object_store_connection'] = {
+	  'provider' => 'AWS',
+	  'region' => 'eu-central-1',
+	  'aws_access_key_id' => '1ABCD2EFGHI34JKLM567N',
+	  'aws_secret_access_key' => 'abcdefhijklmnopQRSTUVwxyz0123456789ABCDE',
+	  # The below options configure an S3 compatible host instead of AWS
+	  'host' => 'localhost',
+	  'endpoint' => 'http://127.0.0.1:9000',
+	  'path_style' => true
+	}
+	```
+
+1. Save the file and [reconfigure GitLab]s for the changes to take effect.
+1. Migrate any existing local LFS objects to the object storage:
+
+      ```bash
+      gitlab-rake gitlab:lfs:migrate
+      ```
+
+      This will migrate existing LFS objects to object storage. New LFS objects
+      will be forwarded to object storage unless
+      `gitlab_rails['lfs_object_store_background_upload']` is set to false.
+
 ## Storage statistics
 
 You can see the total storage used for LFS objects on groups and projects
@@ -50,10 +153,13 @@ and [projects APIs](../../api/projects.md).
 
 ## Known limitations
 
-* Currently, storing GitLab Git LFS objects on a non-local storage (like S3 buckets)
-  is not supported
 * Support for removing unreferenced LFS objects was added in 8.14 onwards.
 * LFS authentications via SSH was added with GitLab 8.12
 * Only compatible with the GitLFS client versions 1.1.0 and up, or 1.0.2.
 * The storage statistics currently count each LFS object multiple times for
   every project linking to it
+
+[reconfigure gitlab]: ../../administration/restart_gitlab.md#omnibus-gitlab-reconfigure "How to reconfigure Omnibus GitLab"
+[restart gitlab]: ../../administration/restart_gitlab.md#installations-from-source "How to restart GitLab"
+[eep]: https://about.gitlab.com/gitlab-ee/ "GitLab Enterprise Edition Premium"
+[ee-2760]: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/2760
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