Difference between apache vs fpm in PHP Docker image?

Question

At the PHP Docker hub, there's 7.3-apache-stretch and 7.3-fpm-stretch, what's the difference? Which one is suited for a webapp?

Answer 1

the apache image can be directly exposed, whereas the fpm image needs another web server that then connects to fpm

to put it into perspective - the following docker-compose are almost identical (the second one requires a vhost to be added but I think you get the idea):

php with apache:

services:
   php:
       image: php:7.3-apache-stretch
       ports:
           - 80

php with fpm (requires apache / nginx to work):

services:
   php:
       image: php:7.3-fpm-stretch
   apache:
       image: apache
       ports:
           - 80
       links:
           - php

as you can see the fpm version gives you more control - ie to use a different webserver

Answer 2

The 7.3-fpm-stretch variant contains just PHP FPM, while 7.3-apache-stretch contains also Apache httpd server and PHP configured as Apache module.

If you want to use PHP as Apache module, the apache variant may be suited for you.

If you want to use for example nginx or you just want to have FPM, you need the fpm variant.