Earlier this week, I decided to build a new puppetmaster for the auditlogging project. Its fqdn is puppetmaster04.auditlogging.eqiad1.wikimedia.cloud.

Following the steps at https://wikitech.wikimedia.org/wiki/Help:Standalone_puppetmaster#Step_1:_Setup_a_standalone_puppetmaster resulted in an error: puppet wasn't able to restart apache2, because apache2 couldn't listen on port 8140. And indeed, something else already claimed that port:

netstat: tcp        0      0 0.0.0.0:8140            0.0.0.0:*               LISTEN      108        93247      31195/ruby          
puppet   31195  0.0  4.8 214188 48668 ?        Ssl  20:13   0:00 /usr/bin/ruby /usr/bin/puppet master

@Andrew found out killing the aforementioned ruby process was sufficient to resume the installation. I'm not sure what the root cause is, but implementing a fix shouldn't be too hard (either preventing the process from starting, or ensuring nothing listens at 8140 before managing the apache2 service).