git SSH keys

Posted 2020-07-09 霓裳依旧

An SSH key allows you to establish a secure connection between your computer and GitLab. Before generating an SSH key in your shell, check if your system already has one by running the following command:

Windows Command Line:

type %userprofile%\.ssh\id_rsa.pub

GNU/Linux/Mac/PowerShell:

cat ~/.ssh/id_rsa.pub

If you see a long string starting with ssh-rsa, you can skip the ssh-keygen step.

Note: It is a best practice to use a password for an SSH key, but it is not required and you can skip creating a password by pressing enter. Note that the password you choose here can‘t be altered or retrieved.

To generate a new SSH key, use the following command:

ssh-keygen -t rsa -C "[email protected]"

This command will prompt you for a location and filename to store the key pair and for a password. When prompted for the location and filename, just press enter to use the default. If you use a different name, the key will not be used automatically.

Use the command below to show your public key:

Windows Command Line:

type %userprofile%\.ssh\id_rsa.pub

GNU/Linux/Mac/PowerShell:

cat ~/.ssh/id_rsa.pub

Copy-paste the key to the ‘My SSH Keys‘ section under the ‘SSH‘ tab in your user profile. Please copy the complete key starting with ssh-rsa and ending with your username and host.

To copy your public key to the clipboard, use the code below. Depending on your OS you‘ll need to use a different command:

Windows Command Line:

type %userprofile%\.ssh\id_rsa.pub | clip

Windows PowerShell:

cat ~/.ssh/id_rsa.pub | clip

Mac:

pbcopy < ~/.ssh/id_rsa.pub

GNU/Linux (requires xclip):

xclip -sel clip < ~/.ssh/id_rsa.pub

Deploy keys

Deploy keys allow read-only access to multiple projects with a single SSH key.

This is really useful for cloning repositories to your Continuous Integration (CI) server. By using deploy keys, you don‘t have to setup a dummy user account.

If you are a project master or owner, you can add a deploy key in the project settings under the section ‘Deploy Keys‘. Press the ‘New Deploy Key‘ button and upload a public SSH key. After this, the machine that uses the corresponding private key has read-only access to the project.

You can‘t add the same deploy key twice with the ‘New Deploy Key‘ option. If you want to add the same key to another project, please enable it in the list that says ‘Deploy keys from projects available to you‘. All the deploy keys of all the projects you have access to are available. This project access can happen through being a direct member of the project, or through a group. See def accessible_deploy_keys in app/models/user.rb for more information.

Deploy keys can be shared between projects, you just need to add them to each project.

Applications

Eclipse

How to add your ssh key to Eclipse: https://wiki.eclipse.org/EGit/User_Guide#Eclipse_SSH_Configuration

Tip: Non-default OpenSSH key file names or locations

If, for whatever reason, you decide to specify a non-default location and filename for your GitLab SSH key pair, you must configure your SSH client to find your GitLab SSH private key for connections to your GitLab server (perhaps gitlab.com). For OpenSSH clients, this is handled in the ~/.ssh/config file with a stanza similar to the following:

#
# Main gitlab.com server
#
Host gitlab.com
RSAAuthentication yes
IdentityFile ~/my-ssh-key-directory/my-gitlab-private-key-filename
User mygitlabusername

Another example

#
# Our company‘s internal GitLab server
#
Host my-gitlab.company.com
RSAAuthentication yes
IdentityFile ~/my-ssh-key-directory/company-com-private-key-filename

Note in the gitlab.com example above a username was specified to override the default chosen by OpenSSH (your local username). This is only required if your local and remote usernames differ.

Due to the wide variety of SSH clients and their very large number of configuration options, further explanation of these topics is beyond the scope of this document.

Public SSH keys need to be unique, as they will bind to your account. Your SSH key is the only identifier you‘ll have when pushing code via SSH. That‘s why it needs to uniquely map to a single user.