How are security updates managed on Scalarium?

Scalarium uses the default and build-in mechanisms of Ubuntu to update the OS and install patches. Scalarium by design does not install updates by itself. This is due to the fact that updates could affect your operations or briefly restart services. Imagine a security update for Apache. Installing the patch involves restarting Apache so it will be unavailable for a short time.

Another possible problem with automatic updates is that in theory patched versions of software could be incompatible with previous versions. This should not happen as within an Ubuntu release APIs should not change and only security updates are ported. But nothing is perfect, so there is a chance of a broken update.

For those two reasons Scalarium does not install updates automatically on already running instances. A newly booted instance will install all updates during the setup process.

If you want to install updates for your already running machines, there is an easy way to do this using Scalarium. You can use the "Update Dependencies" button on the cloud page to trigger a deployment that will update all Linux packages and Rubygems on every machine (essentially equivalent to apt-get update && apt-get upgrade).

Once the deployment is on its way, you can see the output of the individual instances:

If you are really paranoid you can also start a new instance. This new instance will install all updates on boot, thus have the new software in place. Then you can verify if your service is running normally on the new machine. If it is you can shutdown the old instance, effectively swapping the instances. If it is not, you can shut it down again and use the old instance until you fix the incompatibilities.