What modules can be enable/disable in a default Apache 2.4 setup?

Question

I am setting up a new CentOS 7 server with Apache 2.4 and I am planning to add PHP-FPM trough mod_proxy_fcgi (as per this post here). I don't think all that's enabled by default is needed in this case but sadly I am not an Apache expert so I need some advice from gurus over here. This is what's enabled by default:

LoadModule access_compat_module modules/mod_access_compat.so
LoadModule actions_module modules/mod_actions.so
LoadModule alias_module modules/mod_alias.so
LoadModule allowmethods_module modules/mod_allowmethods.so
LoadModule auth_basic_module modules/mod_auth_basic.so
LoadModule auth_digest_module modules/mod_auth_digest.so
LoadModule authn_anon_module modules/mod_authn_anon.so
LoadModule authn_core_module modules/mod_authn_core.so
LoadModule authn_dbd_module modules/mod_authn_dbd.so
LoadModule authn_dbm_module modules/mod_authn_dbm.so
LoadModule authn_file_module modules/mod_authn_file.so
LoadModule authn_socache_module modules/mod_authn_socache.so
LoadModule authz_core_module modules/mod_authz_core.so
LoadModule authz_dbd_module modules/mod_authz_dbd.so
LoadModule authz_dbm_module modules/mod_authz_dbm.so
LoadModule authz_groupfile_module modules/mod_authz_groupfile.so
LoadModule authz_host_module modules/mod_authz_host.so
LoadModule authz_owner_module modules/mod_authz_owner.so
LoadModule authz_user_module modules/mod_authz_user.so
LoadModule autoindex_module modules/mod_autoindex.so
LoadModule cache_module modules/mod_cache.so
LoadModule cache_disk_module modules/mod_cache_disk.so
LoadModule data_module modules/mod_data.so
LoadModule dbd_module modules/mod_dbd.so
LoadModule deflate_module modules/mod_deflate.so
LoadModule dir_module modules/mod_dir.so
LoadModule dumpio_module modules/mod_dumpio.so
LoadModule echo_module modules/mod_echo.so
LoadModule env_module modules/mod_env.so
LoadModule expires_module modules/mod_expires.so
LoadModule ext_filter_module modules/mod_ext_filter.so
LoadModule filter_module modules/mod_filter.so
LoadModule headers_module modules/mod_headers.so
LoadModule include_module modules/mod_include.so
LoadModule info_module modules/mod_info.so
LoadModule log_config_module modules/mod_log_config.so
LoadModule logio_module modules/mod_logio.so
LoadModule mime_magic_module modules/mod_mime_magic.so
LoadModule mime_module modules/mod_mime.so
LoadModule negotiation_module modules/mod_negotiation.so
LoadModule remoteip_module modules/mod_remoteip.so
LoadModule reqtimeout_module modules/mod_reqtimeout.so
LoadModule rewrite_module modules/mod_rewrite.so
LoadModule setenvif_module modules/mod_setenvif.so
LoadModule slotmem_plain_module modules/mod_slotmem_plain.so
LoadModule slotmem_shm_module modules/mod_slotmem_shm.so
LoadModule socache_dbm_module modules/mod_socache_dbm.so
LoadModule socache_memcache_module modules/mod_socache_memcache.so
LoadModule socache_shmcb_module modules/mod_socache_shmcb.so
LoadModule status_module modules/mod_status.so
LoadModule substitute_module modules/mod_substitute.so
LoadModule suexec_module modules/mod_suexec.so
LoadModule unique_id_module modules/mod_unique_id.so
LoadModule unixd_module modules/mod_unixd.so
LoadModule userdir_module modules/mod_userdir.so
LoadModule version_module modules/mod_version.so
LoadModule vhost_alias_module modules/mod_vhost_alias.so

Also I am seeing dav, lua, mpm proxy, systemd and cgi in /etc/httpd/conf.modules.d so I am assuming those ones are loaded by default as well.

What to enable/disable and keep Apache running with PHP-FPM?

Solution

It really depends on exactly what you are doing and what configuration directives you are using.

If you want to start with an absolute minimal configuration and then build up from there, there is an example on the Apache httpd wiki here: https://cwiki.apache.org/confluence/display/HTTPD/Minimal+Config (original archive)

Then you could add mod_proxy, mod_proxy_ajp and whatever other modules you need.

Alternatively you could just remove all the ones you think you do not need either one by one or in groups. If you run apachectl configtest each time you modify your configuration, the output will tell you if you are using a directive for a module you are no longer loading.