Generate Ssh Key Ubuntu Gitlab

Mar 23, 2017  How to add SSH Key to GitLab. Posted on March 23, 2017 by patlatus. There is a good document about how to create ssh key for gitlab. If you don’t see the string or would like to generate a SSH key pair with a custom name continue onto the next step. Generating a new SSH key pair.

SSH keys are an access credential used in SSH protocol (Secure Shell) which is a network protocol that helps to login from one computer to another securely, as well as to manage networks, operating systems, and configurations. This snippet is going to help you add an SSH key to the ssh-agent, generate a new SSH key, learn how to find the SSH key of your PC and how to connect it with your GitHub/bitbucket account. You can also find information on the use of SSH keys.

Now let's find out how we can checkout PC's SSH keys.

To create a new key pair, select the type of key to generate from the bottom of the screen (using SSH-2 RSA with 2048 bit key size is good for most people; another good well-known alternative is ECDSA). Then click Generate, and start moving the mouse within the Window. Putty uses mouse movements to. How to Generate SSH key for Git. SSH keys are an access credential used in SSH protocol (Secure Shell) which is a network protocol that helps to login from one computer to another securely, as well as to manage networks, operating systems, and configurations. This snippet is going to help you add an SSH key to the ssh-agent, generate a new SSH key, learn how to find the SSH key of your PC.

Checking PC's SSH Keys

Type ls -al ~/.ssh so as to see your ssh keys:

By default, the filenames of the public keys are one of the following:

Generate a new SSH key

Type this below, using your GitHub's account email:

The following text will show up after which you can hit the “Enter” button:

In this section, you can hit “Enter” again or type the secure passphrase (more about passphrase).

Adding an SSH key to the ssh-agent

Now let’s find out how we can add the SSH key to ssh-agent. Before adding, check your ssh keys or generate a new key.

  • Be sure ssh-agent is enabled:
  • Add your SSH key to the ssh-agent. If you used an existing SSH key rather than generating a new SSH key, you would need to replace id_rsa in the command with the name of your existing private key file:

How To Add SSH Key To Github Account

  • Log into your Github's account. In the top right corner of any page, click your profile photo, then click Settings.
  • In the user settings sidebar, go to SSH and GPG keys.
  • Click New SSH key.
  • Type Title and your SSH Key.

You can get your ssh key by typing below.

Now you have added your PC's SSH key to your Github's account.

Back up old SSH keys

If there are existing SSH keys, but you do not want to use them for connecting to Bitbucket Server, you should back up these old keys running the following:

Why we need SSH key (for Linux and OSX)

If you use Git and want to clone anything from remote repositories, you have to choose one of these two ways: HTTPS or SSH. If you use HTTPS, you have to type your account access every time you communicate with the remote repository, or change your configs and fill your account data (access). Another modern way is to use the SSH authentication method. It is used in many Version Control Systems to have command line access into your servers, etc. SSH key pairs can be used for authentication instead of passwords. Each key pair consists of a private key and a corresponding public key. When you use SSH key for Git, you inform Git that this PC is authenticated for that Github account, and it will never ask you about any access again because you have already given it your SSH key.


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I am a new Ubuntu 18.04 LTS user and I would like to setup ssh public key authentication. How do I set up ssh keys based authentication on Ubuntu Linux 18.04 LTS server? How do I set up SSH keys on an Ubuntu Linux 18.04 LTS server? In Ubuntu 18.04 LTS, how do I set up public key authentication?
Introduction: OpenSSH is a free and open source client/server technology for secure remote login. It is an implementation of the SSH protocol. OpenSSH divided into sshd (server) and various client tools such as sftp, scp, ssh and more. One can do remote login with OpenSSH either using password or combination of private and public keys named as public key based authentication. It is an alternative security method for user passwords. This method is recommended on a VPS, cloud, dedicated or even home-based server or laptop. This page shows how to set up SSH keys on Ubuntu 18.04 LTS server.
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Ubuntu 18.04 Setup SSH Public Key Authentication

The procedure to set up secure ssh keys on Ubuntu 18.04:

  1. Create the key pair using ssh-keygen command.
  2. Copy and install the public key using ssh-copy-id command.
  3. Add yourself to sudo admin account on Ubuntu 18.04 server.
  4. Disable the password login for root account on Ubuntu 18.04.

Sample set up for SSH Keys on Ubuntu 18.04


Where,

  • 202.54.1.55 – You store your public key on the remote hosts and you have an accounts on this Ubuntu Linux 18.04 LTS server.
  • Linux/macbook laptop – Your private key stays on the desktop/laptop/computer (or local server) you use to connect to 202.54.1.55 server. Do not share or give your private file to anyone.

In public key based method you can log into remote hosts and server, and transfer files to them, without using your account passwords. Feel free to replace 202.54.1.55 and client names with your actual setup. Enough talk, let’s set up public key authentication on Ubuntu Linux 18.04 LTS.

How to create the RSA/ed25519 key pair on your local desktop/laptop

Open the Terminal and type following commands if .ssh directory does not exists:
$ mkdir -p $HOME/.ssh
$ chmod 0700 $HOME/.ssh

Next generate a key pair for the protocol, run:
$ ssh-keygen
OR
$ ssh-keygen -t rsa 4096 -C 'My key for Linode server'
These days ED25519 keys are favored over RSA keys when backward compatibility is not needed:
$ ssh-keygen -t ed25519 -C 'My key for Linux server # 42'

How to install the public key in Ubuntu 18.04 remote server

The syntax is as follows:
ssh-copy-id your-user-name@your-ubuntu-server-name
ssh-copy-id -i ~/.ssh/file.pub your-user-name@your-ubuntu-server-name

For example:
## for RSA KEY ##
ssh-copy-id -i $HOME/.ssh/id_rsa.pub user@202.54.1.55
## for ED25519 KEY ##
ssh-copy-id -i $HOME/.ssh/id_ed25519.pub user@202.54.1.55
## install SSH KEY for root user ##
ssh-copy-id -i $HOME/.ssh/id_ed25519.pub root@202.54.1.55

I am going to install ssh key for a user named vivek (type command on your laptop/desktop where you generated RSA/ed25519 keys):
$ ssh-copy-id -i ~/.ssh/id_ed25519.pub vivek@202.54.1.55

Test it

Now try logging into the Ubuntu 18.04 LTS server, with ssh command from your client computer/laptop using ssh keys:
$ ssh your-user@your-server-name-here
$ ssh vivek@202.54.1.55

What are ssh-agent and ssh-add, and how do I use them on Ubuntu 18.04?

To get rid of a passphrase for the current session, add a passphrase to ssh-agent (see ssh-agent command for more info) and you will not be prompted for it when using ssh or scp/sftp/rsync to connect to hosts with your public key. The syntax is as follows:
$ eval $(ssh-agent)
Type the ssh-add command to prompt the user for a private key passphrase and adds it to the list maintained by ssh-agent command:
$ ssh-add
Enter your private key passphrase. Now try again to log into vivek@202.54.1.55 and you will NOT be prompted for a password:
$ ssh vivek@202.54.1.55

Generate Ssh Key Ubuntu Gitlab Download

How to disable the password based login on a Ubuntu 18.04 server

Login to your server, type:
## client commands ##
$ eval $(ssh-agent)
$ ssh-add
$ ssh vivek@202.54.1.55

Now login as root user:
$ sudo -i
OR
$ su -i
Edit sshd_config file:
# vim /etc/ssh/sshd_config
OR
# nano /etc/ssh/sshd_config
Find PermitRootLogin and set it as follows:
PermitRootLogin no
Save and close the file. I am going to add a user named vivek to sudoers group on Ubuntu 18.04 server so that we can run sysadmin tasks:
# adduser vivek sudo
Restart/reload the sshd service:
# systemctl reload ssh
You can exit from all session and test it as follows:
$ ssh vivek@202.54.1.55
## become root on server for sysadmin task ##
$ sudo -i

How do I add or replace a passphrase for an existing private key?

To to change your SSH passphrase type the following command:
$ ssh-keygen -p

How do I backup my existing private/public SSH keys

Just copy files to your backup server or external USB pen/hard drive:

How do I protect my ssh keys?

  1. Always use a strong passphrase.
  2. Do not share your private keys anywhere online or store in insecure cloud storage or gitlab/github servers.
  3. Restrict privileges of the account.
Ssh key for gitlab

Tip: Create and setup an OpenSSH config file to create shortcuts for servers

See how to create and use an OpenSSH ssh_config file for more info.

How do I secure my OpenSSH server?

Gitlab Ssh Key Not Working

See “OpenSSH Server Best Security Practices” for more info.

Generate Ssh Key Ubuntu Gitlab Server

Conclusion

You learned how to create and install ssh keys for SSH key-based authentication for Ubuntu Linux 18.04 LTS server. See OpenSSH server documents here and here for more info.

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