ubuntu ec2 instance - apply security updates

Question

Currently, my company has several ubuntu-based instances running on Amazon EC2, being released, in the meanwhile, multiple updates, including security related.

Once all instances are ebs-based (for granting data persistence), how should I update all the running instances, rather without rebooting them?

Answer 1

• Usual security updates do not require a reboot on Linux... Updating can be done via the usual Debian-bases update mechanisms (apt-get for example).
• If you want to upgrade the kernel and other part of the OS that cannot be upgraded easily (for example to Upgrade the Ubuntu version to a newer one; or if a security flaw is found in the kernel you use and you are vulnerable to it), the usual way is simply to reinstall the EC2 instances from scratch with a newer AMI image. This can be painful but the use of computer assisted deployment tools such as Puppet, CFengine or Chef can make the task considerably simpler...