Not that much experienced in php, currently running a php app
The cluster uses an nginx ingress load balancer
The php container currently uses nginx (FROM that one https://hub.docker.com/r/wyveo/nginx-php-fpm/), so the pod is exposed via nginx
I'm having some weird behaviours by using this image, so I had in mind to give apache a shot, in case it would provide a more stable result
That is, it does not change the game; is there any other ways to run a php app in such context ? What would be the best way ?
Have you checked the official images?
For safety is better to use official images rather than other ones.
Check the php official repo, they have a version with apache installed.
I am not a php expert either, but the configurations I have made usually use apache to handle requests.
The official repo: https://hub.docker.com/_/php
Check the tags that use apache. There are versions in stretch and alpine.