I have a server that has a bunch of domains that I've generated a common certificate for. The old server uses certbot, and uses a single multi-domain certificate, with all the domains listed. It has worked great over the years.
On the new server, I don't want to use certbot any more, and the reason is that certbot has been pressuring users to use snap to install it, and I don't want an extra daemon running on my system just for a single package, and I have other objections to snap.
I've been looking towards other methods of setting up the certificates, and have been leaning towards acme.sh, although I haven't decided for sure about this.
I am having trouble though, figuring out the procedure I need to follow. I ideally want to do this with zero downtime, I.e. I want to be able to fully set up the new web server, certificates and all, and then move the domains over one-by-one (this is going to be a many-day-long process because each domain has unique needs that need to be tested) to point to the new server's DNS. I have done this in the past, and it worked great, but back then I wasn't using a single SSL certificate, back then I had individual, privately-purchased SSL certificates.
I saw this documentation on switching from certbot to acme.sh and it has a step of revoking the certificates from Certbot. Is this necessary before issuing new certificates? I really don't want to do this, because it will result in downtime. I am especially nervous that the downtime could be significant, because I'd be migrating to a new, unfamiliar program and if I run into problems, it could be errors or days before I get the new certificates set up using acme.sh. I ideally would want to issue new certificates before revoking old ones, and I don't understand why there is a need to revoke the certificates at all, because my server hasn't been compromised and no one else has access to the certificates, the server is going to be wiped as soon as I have everything moved over, and the certificates are eventually going to expire anyway.
I initally thought that the way I would want to do this would be to set up the new certificates on the new server, and just not bother about migrating to a new script like acme.sh, on the old server, but I am wondering if this might not be possible because if the domains all point to the old server, there will be no way for the CA to verify that I own the domains. I don't know if there is a way around this?
I'm just so confused and I don't know the best way to go about this. I am open to suggestions about the process, as well as alternatives to acme.sh as, frankly, it is seeming harder to use than certbot. I am still open to the idea of installing certbot on the new server without snap, but I don't even know if this is possible or realistic.
I'm also nervous about using acme.sh for multiple domains. I don't see good examples of how to do this. The example given in the documentation has a single webroot. I figured out by reading websites and the built-in help file, that what I think I need to do is to use options like -d domain1.com -w /path/to/domain1.com/webroot/ -d domain2.com -w /path/to/domain2.com/webroot/
etc. But I'm not even sure if it's going to work or what is going to happen.