Fingerprint has already been taken gitlab

Question

I formatted my Windows 7 laptop and in an attempt to have git setup working again, I installed git and source tree application.

I deleted the SSH Key from gitlab and regenerated the key using ssh-keygen. But when I try to add the SSH Key at gitlab, it throws the following exception :

Key is invalid Fingerprint has already been taken Fingerprint cannot be generated 

Because of this I am unable to clone the git repository from the source tree application since gitlab is unable to authenticate the SSH key.I followed queries at google groups of gitlab but none of them seem to resolve my issue. Is there any workaround or steps to get the SSH key accepted by gitlab?

Answer 1

In my case; the public key i was trying to add was already used with 'work' Gitlab account and i received the said error upon trying to use the same key with 'personal' Gitlab account.

Solution - Add another public key on the same machine and use that with 'personal' gitlab account (both on same machine).

navigate to .ssh folder in your profile (even works on windows) and run command

ssh-keygen -t rsa 

when asked for file name give another filename id_rsa_2 (or any other). enter for no passphrase (or otherwise). You will end up making id_rsa_2 and id_rsa_2.pub

use the command

cat id_rsa_2.pub 

copy and save key in 'personal' Gitlab account.

create a file with no extension in .ssh folder named 'config'

put this block of configuration in your config file

Host           gitlab.com HostName       gitlab.com IdentityFile   C:\Users\<user name>\.ssh\id_rsa User           <user name>   Host           gitlab_2 HostName       gitlab.com IdentityFile   C:\Users\<user name>\.ssh\id_rsa_2 User           <user name> 

now whenever you want to use 'personal' gitlab account simply change alias in git URLs for action to remote servers.

for example instead of using

git clone git@gitlab.com:..............

simply use

git clone git@gitlab_2:...............

doing that would use the second configuration with gitlab.com (from 'config' file) and will use the new id_rsa_2 key pair for authentication.

Find more about above commands on this link
https://clubmate.fi/how-to-setup-and-manage-multiple-ssh-keys/