Setting ssh keys

There are ssh keys needed for ssh connections and there is an ssh agent.

The ssh agent looks the keys into the ~/.ssh/config map. This file is only a map with the configurations and the keys. You can say, if the url is this, then use the key x or whatever.

creating ssh keys

You can have several keys if you want or only one for all. As you wish.

when you want to create a key, two files are created the public and the private files. The public contains the public key, and this file is used into the github for the configuration of the repositories.

Generating keys

# create the priv/pub keys
ssh-keygen -t ed25519 -C your_user@email.com" -f ~/.ssh/id_ed25519_your_user

# by default creates the id_rsa for the private key and the id_rsa_pub for the public key
# take care, if you have a previous id_rsa you are going to override them.
> Enter a file in which to save the key (/home/you/.ssh/id_rsa): [Press enter]

# do enter two times, leave it empty
> Enter passphrase (empty for no passphrase): [Type a passphrase]
> Enter same passphrase again: [Type passphrase again]

add keys to the ~/ssh/config file, adding key to the agent

The ssh-agent stores the private keys into the macosx keystore. to do that

# start the agent
eval "$(ssh-agent -s)"
# list keys
ssh-add -l
# add the key to the agent
ssh-add ~/.ssh/id_ed25519_your_user

this process will create the ~/ssh/config file with the info. If it's not, you have to create it.

Host gitlab.com
    HostName gitlab.com
    User git
    IdentityFile ~/.ssh/id_ed25519_your_user

give the permissions to the file

chmod 600 ~/.ssh/id_ed25519_your_user
chmod 644 ~/.ssh/id_ed25519_your_user

test it

ssh -T git@gitlab.com

write yes and enter

problem

git pull git@gitlab.com: Permission denied (publickey).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights and the repository exists.

Review the previos steps, and if everything is ok,

go to gitlab -> yourprofile -> settings -> SSH keys

and add the public key to the gitlab.

cat ~/.ssh/id_ed25519_your_user.pub | pbcopy

with the key copied, paste it into the gitlab ssh keys.