Add secondary HA instance for High Availability / resilience

Having just experienced a SDcard failure during the night I woke up to a very cold house. It was 4 degrees outside, and not much warmer inside, I needed it back up and running fast. Additionally, I could not turn on any lights to see what I was doing.

I had to rebuild/restore HA on a RPI. Whilst I did this my entire house automation was down - including the heating. Since an HA instance is central to the function of the house the lack of a standby instance makes this a critical single point of failure, with serious consequences.

Is it possible to have a second HA instance running alongside the primary instance that can take over control when the primary goes off-line? The secondary instance could simply monitor the primary every minute, and if there is no response after 3 consecutive attempts, then the secondary will take over. Control can be transferred back to the primary when it comes on-line again. All configuration work will be done on the primary and copied to the secondary. There is no need to make changes to the secondary.

Please search for existing FRs before opening a new one. This is a duplicate. You can vote and comment here:

PS: not being able to turn your heating on without home assistant is poor design. Everything in your house should be able to be manually controlled without home assistant (lights, climate, covers, etc…).