222 lines
		
	
	
		
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			222 lines
		
	
	
		
			7.6 KiB
		
	
	
	
		
			Markdown
		
	
	
	
| ---
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| stage: Ecosystem
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| group: Integrations
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| info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
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| ---
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| 
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| # Use GitHub as an authentication provider **(FREE SELF)**
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| 
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| You can integrate your GitLab instance with GitHub.com and GitHub Enterprise.
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| You can import projects from GitHub, or sign in to GitLab
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| with your GitHub credentials.
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| 
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| ## Create an OAuth app in GitHub
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| 
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| To enable the GitHub OmniAuth provider, you need an OAuth 2.0 client ID and client
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| secret from GitHub:
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| 
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| 1. Sign in to GitHub.
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| 1. [Create an OAuth App](https://docs.github.com/en/developers/apps/building-oauth-apps/creating-an-oauth-app)
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|    and provide the following information:
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|    - The URL of your GitLab instance, such as `https://gitlab.example.com`.
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|    - The authorization callback URL, such as, `https://gitlab.example.com/users/auth`.
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|      Include the port number if your GitLab instance uses a non-default port.
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| 
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| ### Check for security vulnerabilities
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| 
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| For some integrations, the [OAuth 2 covert redirect](https://oauth.net/advisories/2014-1-covert-redirect/)
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| vulnerability can compromise GitLab accounts.
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| To mitigate this vulnerability, append `/users/auth` to the authorization
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| callback URL.
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| 
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| However, as far as we know, GitHub does not validate the subdomain part of the `redirect_uri`.
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| Therefore, a subdomain takeover, an XSS, or an open redirect on any subdomain of
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| your website could enable the covert redirect attack.
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| 
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| ## Enable GitHub OAuth in GitLab
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| 
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| 1. [Configure the initial settings](omniauth.md#configure-initial-settings) in GitLab.
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| 
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| 1. Edit the GitLab configuration file using the following information:
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| 
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|    | GitHub setting | Value in the GitLab configuration file | Description             |
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|    |----------------|----------------------------------------|-------------------------|
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|    | Client ID      | `YOUR_APP_ID`                          | OAuth 2.0 client ID     |
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|    | Client secret  | `YOUR_APP_SECRET`                      | OAuth 2.0 client secret |
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|    | URL            | `https://github.example.com/`          | GitHub deployment URL   |
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| 
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|    - **For Omnibus installations**
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| 
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|      1. Open the `/etc/gitlab/gitlab.rb` file.
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| 
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|         For GitHub.com, update the following section:
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| 
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|         ```ruby
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|         gitlab_rails['omniauth_providers'] = [
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|           {
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|             name: "github",
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|             # label: "Provider name", # optional label for login button, defaults to "GitHub"
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|             app_id: "YOUR_APP_ID",
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|             app_secret: "YOUR_APP_SECRET",
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|             args: { scope: "user:email" }
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|           }
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|         ]
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|         ```
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| 
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|         For GitHub Enterprise, update the following section and replace
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|         `https://github.example.com/` with your GitHub URL:
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| 
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|         ```ruby
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|         gitlab_rails['omniauth_providers'] = [
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|           {
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|             name: "github",
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|             # label: "Provider name", # optional label for login button, defaults to "GitHub"
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|             app_id: "YOUR_APP_ID",
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|             app_secret: "YOUR_APP_SECRET",
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|             url: "https://github.example.com/",
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|             args: { scope: "user:email" }
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|           }
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|         ]
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|         ```
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| 
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|      1. Save the file and [reconfigure](../administration/restart_gitlab.md#omnibus-gitlab-reconfigure)
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|         GitLab.
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| 
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|    - **For installations from source**
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| 
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|      1. Open the `config/gitlab.yml` file.
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| 
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|         For GitHub.com, update the following section:
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| 
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|         ```yaml
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|         - { name: 'github',
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|             # label: 'Provider name', # optional label for login button, defaults to "GitHub"
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|             app_id: 'YOUR_APP_ID',
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|             app_secret: 'YOUR_APP_SECRET',
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|             args: { scope: 'user:email' } }
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|         ```
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| 
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|         For GitHub Enterprise, update the following section and replace
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|         `https://github.example.com/` with your GitHub URL:
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| 
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|         ```yaml
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|         - { name: 'github',
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|             # label: 'Provider name', # optional label for login button, defaults to "GitHub"
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|             app_id: 'YOUR_APP_ID',
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|             app_secret: 'YOUR_APP_SECRET',
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|             url: "https://github.example.com/",
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|             args: { scope: 'user:email' } }
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|         ```
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| 
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|      1. Save the file and [restart](../administration/restart_gitlab.md#installations-from-source)
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|         GitLab.
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| 
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| 1. Refresh the GitLab sign-in page. A GitHub icon should display below the
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|    sign-in form.
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| 
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| 1. Select the icon. Sign in to GitHub and authorize the GitLab application.
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| 
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| ## Troubleshooting
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| 
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| ### Imports from GitHub Enterprise with a self-signed certificate fail
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| 
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| When you import projects from GitHub Enterprise using a self-signed
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| certificate, the imports fail.
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| 
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| To fix this issue, you must disable SSL verification:
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| 
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| 1. Set `verify_ssl` to `false` in the configuration file.
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| 
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|    - **For Omnibus installations**
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| 
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|      ```ruby
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|      gitlab_rails['omniauth_providers'] = [
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|        {
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|          name: "github",
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|          # label: "Provider name", # optional label for login button, defaults to "GitHub"
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|          app_id: "YOUR_APP_ID",
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|          app_secret: "YOUR_APP_SECRET",
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|          url: "https://github.example.com/",
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|          verify_ssl: false,
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|          args: { scope: "user:email" }
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|        }
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|      ]
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|      ```
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| 
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|    - **For installations from source**
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| 
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|      ```yaml
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|      - { name: 'github',
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|          # label: 'Provider name', # optional label for login button, defaults to "GitHub"
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|          app_id: 'YOUR_APP_ID',
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|          app_secret: 'YOUR_APP_SECRET',
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|          url: "https://github.example.com/",
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|          verify_ssl: false,
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|          args: { scope: 'user:email' } }
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|      ```
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| 
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| 1. Change the global Git `sslVerify` option to `false` on the GitLab server.
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| 
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|    - **For Omnibus installations**
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| 
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|      ```ruby
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|      omnibus_gitconfig['system'] = { "http" => ["sslVerify = false"] }
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|      ```
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| 
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|    - **For installations from source**
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| 
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|      ```shell
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|      git config --global http.sslVerify false
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|      ```
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| 
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| 1. [Reconfigure GitLab](../administration/restart_gitlab.md#omnibus-gitlab-reconfigure)
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|    if you installed using Omnibus, or [restart GitLab](../administration/restart_gitlab.md#installations-from-source)
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|    if you installed from source.
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| 
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| ### Signing in using GitHub Enterprise returns a 500 error
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| 
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| This error can occur because of a network connectivity issue between your
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| GitLab instance and GitHub Enterprise.
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| 
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| To check for a connectivity issue:
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| 
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| 1. Go to the [`production.log`](../administration/logs.md#productionlog)
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|    on your GitLab server and look for the following error:
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| 
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|    ``` plaintext
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|    Faraday::ConnectionFailed (execution expired)
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|    ```
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| 
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| 1. [Start the rails console](../administration/operations/rails_console.md#starting-a-rails-console-session)
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|    and run the following commands. Replace `<github_url>` with the URL of your
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|    GitHub Enterprise instance:
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| 
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|    ```ruby
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|    uri = URI.parse("https://<github_url>") # replace `GitHub-URL` with the real one here
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|    http = Net::HTTP.new(uri.host, uri.port)
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|    http.use_ssl = true
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|    http.verify_mode = 1
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|    response = http.request(Net::HTTP::Get.new(uri.request_uri))
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|    ```
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| 
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| 1. If a similar `execution expired` error is returned, this confirms the error is
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|    caused by a connectivity issue. Make sure the GitLab server can reach
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|    your GitHub Enterprise instance.
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| 
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| ### Signing in using your GitHub account without a pre-existing GitLab account is not allowed
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| 
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| When you sign in to GitLab, you get the following error:
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| 
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| ```plaintext
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| Signing in using your GitHub account without a pre-existing
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| GitLab account is not allowed. Create a GitLab account first,
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| and then connect it to your GitHub account
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| ```
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| 
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| To fix this issue, you must activate GitHub sign-in in GitLab:
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| 
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| 1. On the top bar, in the top right corner, select your avatar.
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| 1. Select **Edit profile**.
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| 1. On the left sidebar, select **Account**.
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| 1. In the **Social sign-in** section, select **Connect to GitHub**.
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