Remotes in GitLab

Last updated on 2025-12-12 | Edit this page

Estimated time: 45 minutes

Overview

Questions

How do I share my changes with others on the web?

Objectives

Explain what remote repositories are and why they are useful.
Push to or pull from a remote repository.

Version control really comes into its own when we begin to collaborate with other people. We already have most of the machinery we need to do this; the only thing missing is to copy changes from one repository to another.

Systems like Git allow us to move work between any two repositories. In practice, though, it’s easiest to use one copy as a central hub, and to keep it on the web rather than on someone’s laptop. Most programmers use hosting services like GitHub, Bitbucket or GitLab to hold those main copies; we’ll explore the pros and cons of this in a later episode.

Let’s start by sharing the changes we’ve made to our current project with the world. To this end we are going to create a remote repository that will be linked to our local repository.

1. Create a remote repository

We are going to create a project and connect a local Git repository to it.

To create a project, we click on the button with the “+” symbol near the top of the side menu on the right and select “New project/repository”.

Multiple options are presented for how to create the new project. In this lesson we will only look at, and use, the first option: “Create blank project”. So click on that.

This leads to the following page:

Create blank project form with text input fields labeled “Project name”, “Project URL”, “Project slug”, “Project deployment target (optional)”, a radio button element labeled “Visibility Level” with options “Private” and “Public”, and two checkboxes labeled “Initialize repository with a README” and “Enable Static Application Security Testing (SAST)”.

The “Project name” field is for just that, the project name. Its value has no other purpose and can be changed at anytime without indirect consequences (the direct consequence being, that its name will be different). We will call it “recipes”.

As we fill in the project name, a project slug gets suggested in the respective field. The project slug is the last part of the project’s, and the associated Git repository’s, URL or web address.

Callout

Project URL and Project Slug

The two fields under labels “Project URL” and “Project slug” are the only fields in this form for which changing the value later might cause problems. They determine the URL under which the project’s pages and the project’s Git repository can be found, so changing them later might brake links and bookmarks as well as connections from Git repositories on other systems, for example on contributors’ machines.

We ignore the field labeled “Project deployment target (optional)”.

The choice under label “Visibility Level” determines the project’s visibility.

Callout

Visibility

GitLab offers three settings for the visibility of a project: public, internal, and private. Publicly visible projects can be looked at by anyone that can access the GitLab instance, projects with internal visibility can be looked at by anyone logged in to the instance, while projects with private visibility can only be looked at by its members.

We choose “Private” for our project’s visibility.

Note: Since this repository will be connected to a local repository, it needs to be empty. Leave “Initialize this repository with a README” unchecked.

Callout

README

A project’s README file usually contains basic information about the project: what it contains, how it can be used (for example built or installed, if it is a software project), how to contribute, how to get help, and licensing information.

It is common to write README files in Markdown format, indicated by the filename suffix .md.

Platforms like GitLab show the contents of a project’s README file on its homepage; if it is in Markdown format, in its rendered form.

Discussion

Change Name, Description, Visibility, or Avatar

Click on the “Settings” sub-menu and select its “General” entry. Set the description to “Alfredo and Jimmy’s recipes.”.

The project description appears in many lists and on some pages under the project’s name.

Then change any of the project’s name, visibility, or avatar. Do not forget to click the “Save changes” button once you are done.

Callout

Markdown

Markdown is a markup language like HTML, on which the World Wide Web is based, or wikitext, which is used to write Wikipedia’s content. Its markup directives, indicating for example that something is a headline or a list item, are such that they serve their purpose even in the plain text form.

There are many variants (or flavors) of Markdown and GitLab has its own. Other than for rendering Markdown files in repositories on its web interface, GitLab allows for Markdown input in many of its interface’s text fields, such as issue descriptions or comments.

This effectively does the following on GitLab’s servers:

BASH

$ mkdir recipes
$ cd recipes
$ git init

If you remember back to the earlier episode where we added and committed our earlier work on guacamole.md, we had a diagram of the local repository which looked like this:

A diagram showing how "git add" registers changes in the staging area, while "git commit" moves changes from the staging area to the repository

Now that we have two repositories, we need a diagram like this:

A diagram illustrating how the GitLab "recipes" repository is also a git repository like our local repository, but that it is currently empty

Note that our local repository still contains our earlier work on guacamole.md, but the remote repository on GitLab appears empty as it doesn’t contain any files yet.

2. Connect local to remote repository

Now we connect the two repositories. We do this by making the GitLab repository a remote for the local repository. The home page of the repository on GitLab includes the URL string we need to identify it.

Callout

HTTPS vs. SSH

We use SSH here because, while it requires some additional configuration, it is a security protocol widely used by many applications. The steps below describe SSH at a minimum level for GitLab.

Clicking the "Copy to Clipboard" button on GitLab to obtain the repository's URL

Copy that URL from the browser, go into the local recipes repository, and run this command:

BASH

$ git remote add origin git@git.unistra.fr:alfin/recipes.git

Make sure to use the URL for your repository rather than Alfredo’s: the only difference should be your username instead of alflin.

origin is a local name used to refer to the remote repository. It could be called anything, but origin is a convention that is often used by default in git and GitLab (and other forges like GitHub), so it’s helpful to stick with this unless there’s a reason not to.

We can check that the command has worked by running git remote -v:

BASH

$ git remote -v

OUTPUT

origin   git@git.unistra.fr:alfin/recipes.git (fetch)
origin   git@git.unistra.fr:alfin/recipes.git (push)

We’ll discuss remotes in more detail in the next episode, while talking about how they might be used for collaboration.

3. SSH Background and Setup

Before Alfredo can connect to a remote repository, he needs to set up a way for his computer to authenticate with GitLab so it knows it’s him trying to connect to his remote repository.

We are going to set up the method that is commonly used by many different services to authenticate access on the command line. This method is called Secure Shell Protocol (SSH). SSH is a cryptographic network protocol that allows secure communication between computers using an otherwise insecure network.

SSH uses what is called a key pair. This is two keys that work together to validate access. One key is publicly known and called the public key, and the other key called the private key is kept private. Very descriptive names.

You can think of the public key as a padlock, and only you have the key (the private key) to open it. You use the public key where you want a secure method of communication, such as your GitLab account. You give this padlock, or public key, to GitLab and say “lock the communications to my account with this so that only computers that have my private key can unlock communications and send git commands as my GitLab account.”

What we will do now is the minimum required to set up the SSH keys and add the public key to a GitLab account.

The first thing we are going to do is check if this has already been done on the computer you’re on. Because generally speaking, this setup only needs to happen once and then you can forget about it.

Callout

Keeping your keys secure

You shouldn’t really forget about your SSH keys, since they keep your account secure. It’s good practice to check your SSH keys every so often to ensure they are still secure, up to date, and that there are no unauthorized keys that could compromise your account. This is especially important if you are using multiple computers to access your account.

We will run the list command to check what key pairs already exist on your computer.

BASH

$ ls -al ~/.ssh

Your output is going to look a little different depending on whether or not SSH has ever been set up on the computer you are using.

Alfredo has not set up SSH on his computer, so his output is

OUTPUT

ls: cannot access '/c/Users/Alfredo/.ssh': No such file or directory

If SSH has been set up on the computer you’re using, the public and private key pairs will be listed. The file names are either id_ed25519/id_ed25519.pub or id_rsa/id_rsa.pub depending on how the key pairs were set up. Since they don’t exist on Alfredo’s computer, he uses this command to create them.

Resolving SSH Key Conflicts: Custom Names and Paths

If you need to create an SSH key pair with a custom name or store it in a non-default location (e.g., because a default-named key like id_ed25519 already exists), Git may not automatically use it when pushing or pulling from GitLab.

One solution is to add a GitLab entry to your SSH config.

Open or create the SSH config file:

BASH


$ nano ~/.ssh/config

Add an entry for GitLab, replacing the path with your key’s actual name and location:

Host git.unistra.fr
	HostName git.unistra.fr
	User git
	IdentityFile ~/<full_path_to_SSH_key_file>/<key_name>
	IdentitiesOnly yes

Save and exit. Now Git will use the correct key when pushing to GitLab.

3.1 Create an SSH key pair

To create an SSH key pair Alfredo uses this command, where the -t option specifies which type of algorithm to use and -C attaches a comment to the key (here, Alfredo’s email):

BASH

$ ssh-keygen -t ed25519 -C "a.linguini@ratatouille.fr"

If you are using a legacy system that doesn’t support the Ed25519 algorithm, use: $ ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

OUTPUT

Generating public/private ed25519 key pair.
Enter file in which to save the key (/c/Users/Alfredo/.ssh/id_ed25519):

We want to use the default file, so just press Enter.

OUTPUT

Created directory '/c/Users/Alfredo/.ssh'.
Enter passphrase (empty for no passphrase):

Now, it is prompting Alfredo for a passphrase. Since he is using his kitchen’s laptop that other people sometimes have access to, he wants to create a passphrase. Be sure to use something memorable or save your passphrase somewhere, as there is no “reset my password” option. Note that, when typing a passphrase on a terminal, there won’t be any visual feedback of your typing. This is normal: your passphrase will be recorded even if you see nothing changing on your screen.

OUTPUT

Enter same passphrase again:

After entering the same passphrase a second time, we receive the confirmation

OUTPUT

Your identification has been saved in /c/Users/Alfredo/.ssh/id_ed25519
Your public key has been saved in /c/Users/Alfredo/.ssh/id_ed25519.pub
The key fingerprint is:
SHA256:SMSPIStNyA00KPxuYu94KpZgRAYjgt9g4BA4kFy3g1o a.linguini@ratatouille.fr
The key's randomart image is:
+--[ED25519 256]--+
|^B== o.          |
|%*=.*.+          |
|+=.E =.+         |
| .=.+.o..        |
|....  . S        |
|.+ o             |
|+ =              |
|.o.o             |
|oo+.             |
+----[SHA256]-----+

The “identification” is actually the private key. You should never share it. The public key is appropriately named. The “key fingerprint” is a shorter version of a public key.

Now that we have generated the SSH keys, we will find the SSH files when we check.

BASH

ls -al ~/.ssh

OUTPUT

drwxr-xr-x 1 Alfredo   197121   0 Jul 16 14:48 ./
drwxr-xr-x 1 Alfredo   197121   0 Jul 16 14:48 ../
-rw-r--r-- 1 Alfredo   197121 419 Jul 16 14:48 id_ed25519
-rw-r--r-- 1 Alfredo   197121 106 Jul 16 14:48 id_ed25519.pub

3.2 Copy the public key to GitLab

Now we have a SSH key pair and we can run this command to check if GitLab can read our authentication.

BASH

ssh -T git@git.unistra.fr

OUTPUT

The authenticity of host 'git.unistra.fr (192.30.255.112)' can't be established.
RSA key fingerprint is SHA256:nThbg6kXUpJWGl7E1IGOCspRomTxdCARLviKw6E5SY8.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])? y
Please type 'yes', 'no' or the fingerprint: yes
Warning: Permanently added 'git.unistra.fr' (RSA) to the list of known hosts.
git@git.unistra.fr: Permission denied (publickey).

Right, we forgot that we need to give GitLab our public key!

First, we need to copy the public key. Be sure to include the .pub at the end, otherwise you’re looking at the private key.

BASH

cat ~/.ssh/id_ed25519.pub

OUTPUT

ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIDmRA3d51X0uu9wXek559gfn6UFNF69yZjChyBIU2qKI a.linguini@ratatouille.fr

Now, going to git.unistra.fr, click on your profile icon in the top left corner to get the drop-down menu. Click “Preferences”, then on the settings page, click “SSH keys”, on the left side menu. Click the “Add new key” button on the right side. Now, you can add the title (Alfredo uses the title “Alfredo’s Kitchen Laptop” so he can remember where the original key pair files are located), paste your SSH public key into the field, and click the “Add key” to complete the setup.

Now that we’ve set that up, let’s check our authentication again from the command line.

BASH

$ ssh -T git@git.unistra.fr

OUTPUT

Welcome to GitLab, @alfredo!

Good! This output confirms that the SSH key works as intended. We are now ready to push our work to the remote repository.

4. Push local changes to a remote

Now that authentication is setup, we can return to the remote. This command will push the changes from our local repository to the repository on GitLab:

BASH

$ git push origin main

Since Alfredo set up a passphrase, it will prompt him for it. If you completed advanced settings for your authentication, it will not prompt for a passphrase.

OUTPUT

Enumerating objects: 16, done.
Counting objects: 100% (16/16), done.
Delta compression using up to 8 threads.
Compressing objects: 100% (11/11), done.
Writing objects: 100% (16/16), 1.45 KiB | 372.00 KiB/s, done.
Total 16 (delta 2), reused 0 (delta 0)
remote: Resolving deltas: 100% (2/2), done.
To https://git.unistra.fr/alflin/recipes.git
 * [new branch]      main -> main

Callout

Proxy

If the network you are connected to uses a proxy, there is a chance that your last command failed with “Could not resolve hostname” as the error message. To solve this issue, you need to tell Git about the proxy:

BASH

$ git config --global http.proxy http://user:password@proxy.url
$ git config --global https.proxy https://user:password@proxy.url

When you connect to another network that doesn’t use a proxy, you will need to tell Git to disable the proxy using:

BASH

$ git config --global --unset http.proxy
$ git config --global --unset https.proxy

Callout

Password Managers

If your operating system has a password manager configured, git push will try to use it when it needs your username and password. For example, this is the default behavior for Git Bash on Windows. If you want to type your username and password at the terminal instead of using a password manager, type:

BASH

$ unset SSH_ASKPASS

in the terminal, before you run git push. Despite the name, Git uses SSH_ASKPASS for all credential entry, so you may want to unset SSH_ASKPASS whether you are using Git via SSH or https.

You may also want to add unset SSH_ASKPASS at the end of your ~/.bashrc to make Git default to using the terminal for usernames and passwords.

Our local and remote repositories are now in this state:

A diagram showing how "git push origin" will push changes from the local repository to the remote, making the remote repository an exact copy of the local repository.

Callout

The ‘-u’ Flag

You may see a -u option used with git push in some documentation. This option is synonymous with the --set-upstream-to option for the git branch command, and is used to associate the current branch with a remote branch so that the git pull command can be used without any arguments. To do this, simply use git push -u origin main once the remote has been set up.

We can pull changes from the remote repository to the local one as well:

BASH

$ git pull origin main

OUTPUT

From git.unistra.fr:alflin/recipes
 * branch            main     -> FETCH_HEAD
Already up-to-date.

In this case, we’d see a merge conflict due to unrelated histories. When GitLab creates a README.md file, it performs a commit in the remote repository. When you try to pull the remote repository to your local repository, Git detects that they have histories that do not share a common origin and refuses to merge.

BASH

$ git pull origin main

OUTPUT

warning: no common commits
remote: Enumerating objects: 3, done.
remote: Counting objects: 100% (3/3), done.
remote: Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
Unpacking objects: 100% (3/3), done.
From https://git.unistra.fr/alflin/recipes
 * branch            main     -> FETCH_HEAD
 * [new branch]      main     -> origin/main
fatal: refusing to merge unrelated histories

You can force git to merge the two repositories with the option --allow-unrelated-histories. Be careful when you use this option and carefully examine the contents of local and remote repositories before merging.

BASH

$ git pull --allow-unrelated-histories origin main

OUTPUT

From https://git.unistra.fr/alflin/recipes
 * branch            main     -> FETCH_HEAD
Merge made by the 'recursive' strategy.
README.md | 1 +
1 file changed, 1 insertion(+)
create mode 100644 README.md

Key Points

A local Git repository can be connected to one or more remote repositories.
Use the SSH protocol to connect to remote repositories.
git push copies changes from a local repository to a remote repository.
git pull copies changes from a remote repository to a local repository.