Multiple SSH private keys Examples

To allow multiple private keys connect to different servers, edit ~/.ssh/config :

Host 10.10.10.1 
IdentityFile ~/.ssh/linode_rsa
Host 200.20.20.2
IdentityFile ~/.ssh/id_rsa

If you SSH to 10.10.10.1, private key ~/.ssh/linode_rsa will be used.
If you SSH to 200.20.20.2, private key ~/.ssh/id_rsa will be used.

1. Single Private Key for Multiple Servers

1.1 You have following public and private keys.

$ cat ~/.ssh/
linode_rsa.pub
linode_rsa

1.2 Public key linode_rsa.pub is copied to following two servers :

1. linode-us (10.10.10.1)
2. linode-uk (10.10.10.2)

To SSH above servers with a single private key, edit .ssh/config :

Host 10.10.10.1 10.10.10.2
IdentityFile ~/.ssh/linode_rsa

Or

127.0.0.1   localhost
10.10.10.1  linode-us
10.10.10.2  linode-uk

Host linode-us linode-uk
IdentityFile ~/.ssh/linode_rsa

2. Multiple Private Keys for Multiple Servers

Create another set of public and private keys, and copy the public key new_rsa.pub to another server, for example 200.20.20.1.

$ cat ~/.ssh/
linode_rsa.pub
linode_rsa
new_rsa.pub
new_rsa

To SSH 200.20.20.1 with the new private key, update ~/.ssh/config :

Host linode-us linode-uk
IdentityFile ~/.ssh/linode_rsa
Host 200.20.20.1
IdentityFile ~/.ssh/new_rsa

3. Output

Try SSH to the servers.

# Connect with private key - linode_rsa
$ ssh username@linode-us
# Connect with private key - linode_rsa
$ ssh username@linode-uk
# Connect with private key - new_rsa
$ ssh username@200.20.20.1

References

1. OpenSSH Config File Examples