server-update.sh

#!/bin/bash

DEBIAN_HOSTS="server1 server2 server3";
LOG_FILE="server-update-`date +%Y%m%d%H%M%S`.log"

requires_reboot="";

function execute_command()
{
    command="$1";
    # $2 = variable to store output

    if [ $# = 2 ]; then
    tmp=$(ssh -o ConnectTimeout=5 -t -t -t ${server} "$command" | tee -a $LOG_FILE)

    eval $2=\$tmp
    else
    ssh -o ConnectTimeout=5 -t -t -t ${server} "$command" | tee -a $LOG_FILE
    fi
}

function execute_command_with_password()
{
    command="$1";
    pass="$2";

    ssh -o ConnectTimeout=5 -t -t -t ${server} "sudo -S $command <<EOF
$pass
EOF
" | tee -a $LOG_FILE
}

stty -echo
read -p "* sudo password: " password; echo
stty echo

echo "NOTE: You might see a [sudo] prompt once in a while; ignore it!";

for server in $DEBIAN_HOSTS
do
    echo "* Connecting to $server" | tee -a $LOG_FILE;

    # Connect to the next server, download updates and perform safe-upgrade
    echo "* Invalidating sudo session...";
    execute_command "sudo -k"
    echo "* Updating packages...";
    execute_command_with_password "aptitude update" $password
    echo "* Upgrading packages...";
    execute_command "sudo -S aptitude safe-upgrade"

    if [ $? -ne 0 ]; then
    echo "Non-zero exit code - continue with next server (y/n)?";
    read CONTINUE
    if [ "$CONTINUE" != "y" ]; then
        exit 1;
    fi
    fi

    echo "* Checking if reboot is needed...";
    reboot_required=0;
    execute_command "[ -e /var/run/reboot-required ] && echo 1;" reboot_required

    if [ $reboot_required ]; then
    export requires_reboot="$server $requires_reboot"
    fi
done

# Print servers that requires rebooting
if [ ! "$requires_reboot" = "" ]; then
    echo "---------------------------------------";
    echo "THE FOLLOWING SERVERS MUST BE REBOOTED:";
    for server in $requires_reboot
    do
    echo "$server";
    done
    echo "---------------------------------------";
fi