HA (High availability) and clustering might be a quite unknown feature inside openSUSE (Pacemaker, Corosync, crmsh, resource agents, etc), but it provides really interesting and powerful options.
In order to explain how HA cluster works in a more visible and funnier way, I will expose a didactic demonstration with a cluster created with some Raspberries and Webcams. The main idea is to create a high available video security system with the tools provided in openSUSE (and some custom code, of course). In this use case, the cluster will host a Webcam service where if the current Webcam (or raspberry with the connected Webcam) fails the whole system is migrated to the seconde node, and the service continues working in the same address and without downtime. This will help to understand what is application or service level redundancy and some of the advantages of it.
● From the Basque Country (Spain) but living in the Canary Islands.
● Studied computer science in the University of Basque Country (UPV).
● Working at Suse since last October in the
SLES4SAP and HA team as software engineer
(with Python, Salt and Terraform mainly).
● Hobbies: Surf, time in nature, friki things
(anime, videogames, etc) .
Christmas dinner 2018...
My brother and I got a new job. Now he works in a
company that builds elevators. So as always:
“Oh!! I see. And how fast they move?
How many people can use them?
Which material do you use?”
So they talk about that until...
Dad: “Xabi, sorry, we could talk about what you do,
Me: “You don’t know what I do, right?
Mmm... you work with a computer, don’t you?
So I decided to do
something to make
what I do!
“Oh man, and now I have to configure all the
And redo everything every time I fail… So
“Dude! But you are working with Salt all the time!
Create some states to configure everything!
And finally the project was born!
HA cluster will assure that there is
● What if the Motion daemon stops working?
– I will restart the daemon!
● What if the node crashes?
– I will migrate Motion daemon to the 2n node
● But the IP address to monitor the service will be
– I will create a virtual address and migrate with Motion
How are going to do that?
Simple! HA cluster monitors resources (instead of
We can monitor a systemd daemon for example.
So, you will be thinking: “Hey! Why are you not just
using the 2 webcams together?!!”
Remember! This is just a demonstration to
show how to use Salt and HA in a more visual
So… Mom, Dad, do
you understand now
what I do?
You do… webcams?
We will try other time again….
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Design & Inspiration
openSUSE Design Team