I have HA running on a pi 4b in a remote location which has stopped working. HA is installed on an external ssd and there is no sd card attached to the pi. Is it possible to restore a backup remotely?
Your device needs to be remotely accessible already. For example, using wireguard VPN within that network and the raspi listening over the network.
With regard how to restore it kind of depends on your setup and your tolerance for scripting. For example, in Linux you can overwrite the currently running operating system while it is still running. The script should launch all of the necessary tools from a ram disk, overwrite, and reboot.
It is a pretty advanced task so it’s one of those things:
- It may (or even likely will) fail due to your lack of experience.
- Even with experience an event like a power outage at the wrong time would render it inoperable.
If you already have remote access and ability to upload what you need to the remote site, then it would be good to simulate what you’re about to do at home with similar hardware. Where mistakes can be learned from with local access to the system.
Once practiced: you do the thing for real. I do not suggest doing it blindly without a practice run.
If you do not have remote access, then you will need to set it up later; when on-site.
As well as having access to your remote network, a KVM like this can be a godsend: https://www.kickstarter.com/projects/jetkvm/jetkvm
I have one and can remotely access a PC on my network to log into it. From there I have full control as if I had a keyboard and display attached to my HA NUC, BIOS, POST and everything.
There are other options available, e.g. https://pikvm.org/ Jeff Geerling covers the pros and cons well here: https://www.youtube.com/@JeffGeerling/search?query=kvm