Apache webserver reads its configuration files every time it's started. The configuration files are in plain text format, and Apache will need to restart every time there are changes in the configuration file for the changes to take effect.
Apache's primary configuration file location is set during compilation and is set differently between distributions. The configuration is usually split into multiple files for ease of management and separation of concern. It will then be called from the main configuration file using Include and IncludeOptional directives.
You can always check the location of the primary configuration file by running the Apache binary for your distribution with the -V option and then looking for the SERVER_CONFIG_FILE value.
$ apachectl -V
Server version: Apache/2.4.41 (Unix)
Server built: Nov 9 2019 07:53:54
Server's Module Magic Number: 20120211:88
Server loaded: APR 1.5.2, APR-UTIL 1.5.4
Compiled using: APR 1.5.2, APR-UTIL 1.5.4
Architecture: 64-bit
Server MPM: prefork
threaded: no
forked: yes (variable process count)
Server compiled with....
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
-D APR_USE_FLOCK_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D DYNAMIC_MODULE_LIMIT=256
-D HTTPD_ROOT="/usr"
-D SUEXEC_BIN="/usr/bin/suexec"
-D DEFAULT_PIDLOG="/private/var/run/httpd.pid"
-D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="/private/etc/apache2/mime.types"
-D SERVER_CONFIG_FILE="/private/etc/apache2/httpd.conf"
Combine the output for both HTTPD_ROOT and SERVER_CONFIG_FILE If the output doesn't provide an absolute full path of the configuration file.
Default Apache configuration location
The location of Apache's main configuration file is different for most distributions, and they are also split differently. The following table lists how the configuration file is managed for different distributions:
| Option | Debian, Ubuntu | openSUSE and SLES | Fedora Core, CentOS, RHEL | macOS | homebrew | xampp |
|---|---|---|---|---|---|---|
| Base directory | /etc/apache2/ | /etc/apache2/ | /etc/httpd/ | /private/etc/apache2/ | /usr/local/etc/httpd/ | {installation directory}/apache/conf/ |
| Main configuration | apache2.conf | httpd.conf | conf/httpd.conf | httpd.conf | httpd.conf | httpd.conf |
| ServerRoot | apache2.conf | n/a | conf/httpd.conf | httpd.conf | httpd.conf | httpd.conf |
| DocumentRoot | sites-enabled/*.conf | default-server.conf | conf/httpd.conf | httpd.conf | httpd.conf | httpd.conf, extra/httpd-ssl.conf |
| VirtualHost | sites-enabled/*.conf | vhosts.d/*.conf | conf/httpd.conf | httpd.conf, other/*.conf | httpd.conf | httpd.conf, extra/httpd-ssl.conf |
| LoadModule | mods-enabled/*.load | loadmodule.conf | conf.modules.d/*.conf | httpd.conf, extra/*.conf | httpd.conf | httpd.conf, extra/*.conf |
| Log | apache2.conf, sites-enabled/*.conf | httpd.conf, vhosts.d/*.conf | conf/httpd.conf | httpd.conf | httpd.conf | httpd.conf |
| User / Group | apache2.conf, envvars | uid.conf | conf/httpd.conf | httpd.conf | httpd.conf | httpd.conf |
Path for files and directories are relative to the Base directory if it doesn't start with a /; e.g. conf/httpd.conf for CentOS's main configuration file translates to /etc/httpd/conf/httpd.conf.
Default Apache configuration value
Apart from using a different location for the main configuration file, different distributions also use different values for Apache configuration options.
The table below lists some of the default configuration values for Apache on different distributions.
| Option | Debian, Ubuntu | openSUSE and SLES | Fedora Core, CentOS, RHEL | macOS | homebrew | xampp |
|---|---|---|---|---|---|---|
| ServerRoot | /etc/apache2/ | n/a | /etc/httpd | /usr/ | /usr/local/opt/httpd/ | {installation directory}/apache/ |
| DocumentRoot | /var/www/html/ | /srv/www/ | /var/www/html | /Library/WebServer/Documents/ | /usr/local/var/www/ | {installation directory}/htdocs/ |
| Module Location | /usr/lib/apache2/modules/ | /usr/lib64/apache2-prefork/ | modules/ | libexec/apache2/ | lib/httpd/modules/ | modules/ |
| Access / Error log | /var/log/apache2 | /var/log/apache2/ | logs/ | /private/var/log/apache2/ | /usr/local/var/log/httpd/ | logs/ |
| User | www-data | wwwrun | apache | _www | _www | daemon |
| Group | www-data | www | apache | _www | _www | daemon |
| Binary name | apache2 | httpd | httpd | httpd | httpd | httpd |
Path for files and directories are relative to the Base directory if it doesn't start with a /; e.g. modules/ for CentOS's module directory translates to /etc/httpd/modules/.
Absolute paths which start with /, such as Ubuntu's module location, are based on the root directory.
Mohd Shakir Zakaria is a skilled cloud architect with a background in development, entrepreneurship, and open-source advocacy. As the founder of Simplified Guide, he helps others understand the complexities of computing, making tech concepts accessible to all.
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