Updating critical software is something not to be taken lightly. It’s nerve-wracking when your business operations rely upon such systems.
What has helped EXPLOINSIGHTS Inc. (EI) sleep better at night is the extensive use of unprivileged containers or so-called virtual machines. Most of the EI support software is installed on unprivileged LXC containers, which is a standard component of the Ubuntu 16.04 Linux distribution.
Today was a typical day for EI: an update to a major release of Nextcloud. This critical software houses EI’s data and is the hub for data sharing with customers and stakeholders. If this upgrade goes wrong, my customers can’t download their files. #Embarrassing – or maybe even worse; loss of critical data? To make it more enjoyable, I am not in the office today – so the update has to be performed remotely via secure SSH. That’s an excellent recipe for high stress…normally.
So how did EI mitigate this update risk? With the following simple command entered at the host machine terminal via secure SSH access (i.e. WITHOUT SuperUser privileges!):
LXC snapshot NC pre-13-upgrade
That’s it. Painless. Super-safe (no Superuser rights!). Blindingly fast. Very efficient. And this creates a full working snapshot of the EI current cloud configuration – files, links, settings, SSL-certs, SQL database, apache2 configs – absolutely everything needed to completely restore the setup should the upgrade process break something critical.
Breaking this command down:
- LXC – this is the command we issue to fire up the Ubuntu LXC/LXD virtual machine management hypervisor, followed by three parameters:
- snapshot – tells LXC to take a full working snapshot of the running instance;
- NC – the name of the EI container that runs the Nextcloud instance – the one we want to backup;
- pre-13-upgrade – a name assigned to the snapshot (easy to remember).
Yes, it’s that simple. After that, the Nextcloud upgrade process was initiated…and as it happens, everything went smoothly, so the snapshot was NOT actually needed to recover the pre-version-13 upgrade – but it will be kept for a while just to make sure there are no bugs waiting in the shadows. Here’s the new EI cloud instance:
If a major problem arises, then the following command entered at the same terminal, again as a non-SuperUser, restores the entire pre-version 13 instance:
LXC restore NC pre-13-upgrade
This restore command overwrites the current instance with the pre-upgraded and fully functioning snapshot. The only risk is losing files/links created since completing the upgrade process – way better than a total rebuild.
LXC makes it so convenient to update major platforms. The entire process was fast, safe; easy. And because all the work is performed in non-SuperUser unprivileged mode, it comes with the confidence of knowing you can’t accidentally break an important part of the core system on the way. It’s so good, it’s almost boring – but only almost.
Checkout using LXC to run your small business support software, it’s better than prescription-grade sleeping tablets for helping you with the upgrade process! Official documents are here. And there’s a ton of useful tutorials to get you started – Google is your friend.