I don't really understand what the difference is between Linux running on a Linux host and Linux running on a Windows host. You're going to require updates and

I don't really understand what the difference is between Linux running on a Linux host and Linux running on a Windows host. You're going to require updates and patches for both. I haven't noticed any serious downtime on Azure for this reason. Probably 1 reboot in the last few months, with plenty of notice (and a fairly specific timespan).