This one is a biggie in with 6 bugs in 1 report:
Result was webmin outage for half hour (and usermin for 1 hour) after upgrade of a server's virtualmin...
Ok, let's go through:
1) the command /etc/init.d/webmin start command gives NO ERRORs, while (fortunately) the command /etc/init.d/webmin restart gave finally the error which prevented the start of webmin:
Failed to open SSL key /home/oldmainclient/domains/domainnamethatisnowamaindomain.com/ssl.key at /usr/share/webmin/miniserv.pl line 3843.
Bug #1: start command should be as verbose as the restart command in case of error
2) such a missing file should not prevent restarting webmin imho !
Bug #2: the whole webmin can be down because of 1 missing non-essential file
3) the original bug that bombed days later now, is that the domainnamethatisnowamaindomain.com has been changed from sub-server of oldmainclient to become a main server as that domain got transfered to the oldmainclient's client, thus we moved from sub-server to main-level server. However, that sub-server had a dedicated IP and SSL certificates, that we had setup in Webmin->Usermin Config->SSL Encryption-> Add a new IP-specific SSL key.
Bug #3: when moving a server from sub-server to main-server, the usermin SSL certificates file paths are not updated (and maybe webmin's too, didn't check as we didn't set an IP-specifc key there ?)
To solve issue, we created just the folder:
then copied from
and restart worked!
4) the same issue of not updating IP-specific SSL keys is there in webmin too, but it doesn't prevent webmin to start at least.
5) webmin restart does not start usermin, when both were down.
5) webmin restart is a bit verbose, telling by default normal things:
Starting Webmin server in /usr/share/webmin Pre-loaded virtual-server/virtual-server-lib-funcs.pl in virtual_server Pre-loaded virtual-server/feature-unix.pl in virtual_server Pre-loaded virtual-server/feature-dir.pl in virtual_server Pre-loaded virtual-server/feature-dns.pl in virtual_server Pre-loaded virtual-server/feature-mail.pl in virtual_server Pre-loaded virtual-server/feature-web.pl in virtual_server Pre-loaded virtual-server/feature-webalizer.pl in virtual_server Pre-loaded virtual-server/feature-ssl.pl in virtual_server Pre-loaded virtual-server/feature-logrotate.pl in virtual_server Pre-loaded virtual-server/feature-mysql.pl in virtual_server Pre-loaded virtual-server/feature-postgres.pl in virtual_server Pre-loaded virtual-server/feature-ftp.pl in virtual_server Pre-loaded virtual-server/feature-spam.pl in virtual_server Pre-loaded virtual-server/feature-virus.pl in virtual_server Pre-loaded virtual-server/feature-status.pl in virtual_server Pre-loaded virtual-server/feature-webmin.pl in virtual_server Pre-loaded virtual-server/feature-virt.pl in virtual_server Pre-loaded virtual-server/feature-virt6.pl in virtual_server Pre-loaded WebminCore
No urgency to reply, as we managed to fix configs and restart.