Often, when dealing with more than one database server, one needs to have an easy shell level access configured between them. For example to exchange with configuration files, make base backups, copy some maintenance scripts, etc. SSH configured with key based authorization (without password) will save a lot of time and efforts here.
Now, let us see how to set it up from user1@host1 to user2@host2.
First, generate a public key on host1 when logged in with
user1. Do not enter any passphrase.
ssh-keygen -t rsa
Then, using ssh with user2@host2, create an .ssh directory,
change an access mode to 700 on it, and append the generated key to
the end of ~/.ssh/authorized_keys (or ~/.ssh/authorized_keys2 if
SSH2 is used) there. You will need to enter user2s password two
times here.
ssh user2@host2 'mkdir ~/.ssh/ && chmod 700 ~/.ssh/'
cat ~/.ssh/id_rsa.pub | ssh user2@host2 'cat >>~/.ssh/authorized_keys'
If you do not have a password for user2@host2 than use 2 terminal
windows and clipboard to copy the content of ~/.ssh/id_rsa.pub with
user1@host1.
cat ~/.ssh/id_rsa.pub
ssh-rsa AAAAB4NbsC3xf ... user1@host1
And paste it to ~/.ssh/authorized_keys with user2@host2.
cat <<EOF >>~/.ssh/authorized_keys
> ssh-rsa AAAAB4NbsC3xf ... user1@host1
> EOF
And finally you can enjoy it without password.
ssh user2@host2
scp ~/some/file user2@host2:~/