Earlier this year the CA/Browser Forum voted to make Certificate Authority Authorization (CAA) mandatory for all Certificate Authorities. What this means that domains will need to assert via DNS records (the CAA DNS RRType) which CA’s are permitted to issue certificates for your domains. Think of it as “sort of like SPF, but for SSL/TLS certs”.
You can add multiple issuers to a specific hostname and if you want to specify authority for a wildcard certificate, use the “issuewild” tag:
After which, your CAA recs will be visible via DNS:
markjr@markjr:~$ dig -t caa anarchy.fm [snip] ;; ANSWER SECTION: anarchy.fm. 10799 IN CAA 0 issue "rapidssl.com" anarchy.fm. 10799 IN CAA 0 issuewild "geotrust.com"