Now it's recommended to use .ssh/config file instead of the old alias approach, but that does not mean that you've to loss the benefits of the aliases like autocompletion.

ssh_alias.sh

# copy this code to .bashrc

# This loop generates aliases for the hosts you've configured on ./ssh/config.
for x in $(grep '^Host' ~/.ssh/*config 2>/dev/null | grep -v '[?*]' | cut -d ' ' -f 2-); do
        alias "$x"="ssh $x"
done