LXD Clustering Case Study

Hello friends,
I have a problem that I need to solve:
My company has 3 websites siteA, siteB, siteC. I have created 3 LXD containers to host those 3 cA, cB, cC sites on the same physical server. If this server loses power, or has some hardware failure, or fails to update LXD, etc., all 3 of my sites will go down. I want to use LXD’s clustering feature to create redundant LXD servers for these 3 sites. My question is what if I want all the requests to the above 3 sites to be handled on my company’s physical server, but when this server crashes, can I quickly forward all the requests? Can the next request to the backup server (also have cA, cB, cC identical to the containers on the physical server at the time of the incident) in the LXD cluster and how to set up this cluster?
Thanks everyone.