Simple script to update all you server at the smae time, uses SSH key to work.
To use it, simply add the server you want to update with apt (Debian/Ubuntu) or with yum (Centos or aother distro with yum package manager)
server_apt=( ns1.domain.tld ns2.domain.tld srvcld01.domain.tld )
server_yum=( ns10.domain.tld )