Since yesterday I encounter a rather strange issue. I have 2 VPS on OVH. Yesterday after the virtualmin/webmin update and a restart all the websites using PHP were throwing this kind of error:
[Sun Jul 28 11:00:19.583179 2019] [proxy:error] [pid 11605:tid 140145000912640] (111)Connection refused: AH00957: FCGI: attempt to connect to 127.0.0.1:8021 (*) failed
[Sun Jul 28 11:00:19.583228 2019] [proxy_fcgi:error] [pid 11605:tid 140145000912640] [client 220.127.116.11:38808] AH01079: failed to make connection to backend: localhost
HTML websites were working, Apache was working ok, PHP7.0-FPM was running.
This config was running ok like for 2 years ago, no issues.
user = www-data
group = www-data
listen = 9003
listen.owner = www-data
listen.group = www-data
pm = dynamic
pm.max_children = 5
pm.start_servers = 2
pm.min_spare_servers = 1
pm.max_spare_servers = 3
All the virtualhosts are using another port for proxy:fcgi
The only solution I found to work is to go for every website to Server configuration - Website options and to change from FPM, save, then change back to FPM and everything is working again.
I did this yesterday for all the websites but after midnight (probably some cron, log rotate run) all the websites were again down with:
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
I did the trick to change the execution mode and they are running again. I tried to run the log rotate again and the websites were still running.
After the trick with changing the execution mode, no config files are modified, apparently. The www.conf, the pool conf are unchanged, the Virtualhost conf, port etc are unchanged.
I'm runnin Ubuntu 16.04LTS, Linux 4.4.0-157-generic on x86_64, Apache version 2.4.18, PHP7.0-FPM