step 1: Create a new rsa key pair of your choice locally on you device.
ssh-keygen -t rsa
step 2 : once you have Public and private key pair available, chnage their permissions. The private key need a permission of 400 and set Public key permission as 644.
sudo chmod 600 id_rsa
sudo chmod 644 id_rsa.pub
step 3: Use SCP or SFTP protocol to connect to remote server and transfer the Pub/Private keypair to ".ssh directory". In the same directory you can fine "authorized_keys" file which has the current Public key.
step 4: Now Go to .ssh Directory and concatenate the new public key to authorized_keys file.
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
step 5: Very the new key added to authorized_keys by open reading the file.
cat authorized_keys
Repeate the steps 3 - 5 on other Server where you want to distrubute the same key pair. After that both the server will havce a commnon set of RSA keypair and you can use the private key to ssh to other devuces where the poublic key is already available.
remote-server1$ ssh -i id_rsa.pub user@remoteserver2
commit one