httpd.service(8)

1HTTPD.SERVICE(8)              httpd systemd units             HTTPD.SERVICE(8)
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NAME

6       httpd.service, httpd@.service, httpd.socket, httpd-init.service - httpd
7       unit files for systemd
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SYNOPSIS

10       /usr/lib/systemd/system/httpd.service,
11       /usr/lib/systemd/system/httpd@.service,
12       /usr/lib/systemd/system/httpd-init.service,
13       /usr/lib/systemd/system/httpd.socket
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DESCRIPTION

16       This manual page describes the systemd unit files used to integrate the
17       httpd daemon with systemd. Two main unit files are available:
18       httpd.service allows the httpd daemon to be run as a system service,
19       and httpd.socket allows httpd to be started via socket-based
20       activation. Most systems will use httpd.service.
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22       The apachectl command has been modified to invoke systemctl for most
23       uses, so for example, running apachectl start is equivalent to running
24       systemctl start httpd.service. This ensures that the running httpd
25       daemon is tracked and managed by systemd. In contrast, running httpd
26       directly from a root shell will start the service outside of systemd;
27       in this case, default security restrictions described below (including,
28       but not limited to, SELinux) will not be enforced.
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30   Changing default behaviour
31       To change the default behaviour of the httpd service, an over-ride file
32       should be created, rather than changing
33       /usr/lib/systemd/system/httpd.service directly, since such changes
34       would be lost over package upgrades. Running systemctl edit
35       httpd.service or systemctl edit httpd.socket as root will create a
36       drop-in file (in the former case, in
37       /etc/systemd/system/httpd.service.d) which over-rides the system
38       defaults.
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40       For example, to set the LD_LIBRARY_PATH environment variable for the
41       daemon, run systemctl edit httpd.service and enter:
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43           [Service]
44           Environment=LD_LIBRARY_PATH=/opt/vendor/lib
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46   Starting the service at boot time
47       The httpd.service and httpd.socket units are disabled by default. To
48       start the httpd service at boot time, run: systemctl enable
49       httpd.service. In the default configuration, the httpd daemon will
50       accept connections on port 80 (and, if mod_ssl is installed, TLS
51       connections on port 443) for any configured IPv4 or IPv6 address.
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53       If httpd is configured to depend on any specific IP address (for
54       example, with a "Listen" directive) which may only become available
55       during start-up, or if httpd depends on other services (such as a
56       database daemon), the service must be configured to ensure correct
57       start-up ordering.
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59       For example, to ensure httpd is only running after all configured
60       network interfaces are configured, create a drop-in file (as described
61       above) with the following section:
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63           [Unit]
64           After=network-online.target
65           Wants=network-online.target
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67       See https://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/
68       for more information on start-up ordering with systemd.
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70   SSL/TLS certificate generation
71       The httpd-init.service unit is provided with the mod_ssl package. This
72       oneshot unit automatically creates a TLS server certificate and key
73       (using a generated self-signed CA certificate and key) for testing
74       purposes before httpd is started. To inhibit certificate generation,
75       use systemctl mask httpd-init.service after installing mod_ssl, and
76       adjust the mod_ssl configuration to use an appropriate certificate and
77       key.
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79   Reloading and stopping the service
80       When running systemctl reload httpd.service, a graceful restart is
81       used, which sends a signal to the httpd parent process to reload the
82       configuration and re-open log files. Any children with open connections
83       at the time of reload will terminate only once they have completed
84       serving requests. This prevents users of the server seeing errors (or
85       potentially losing data) due to the reload, but means some there is
86       some delay before any configuration changes take effect for all users.
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88       Similarly, a graceful stop is used when systemctl stop httpd.service is
89       run, which terminates the server only once active connections have been
90       processed.
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92       To "ungracefully" stop the server without waiting for requests to
93       complete, use systemctl kill --kill-who=main httpd; similarly to
94       "ungracefully" reload the configuration, use systemctl kill
95       --kill-who=main --signal=HUP httpd.
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97   Automated service restarts
98       System packages (including the httpd package itself) may restart the
99       httpd service automatically after packages are upgraded, installed, or
100       removed. This is done using the systemctl reload httpd.service, which
101       produces a graceful restart by default as described above.
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103       To suppress automatic reloads entirely, create the file
104       /etc/sysconfig/httpd-disable-posttrans.
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106   Changing the default MPM (Multi-Processing Module)
107       httpd offers a choice of multi-processing modules (MPMs), which can be
108       configured in /etc/httpd/conf.modules.d/00-mpm.conf. See httpd.conf(5)
109       for more information on changing the MPM.
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111   systemd integration and mod_systemd
112       The httpd service uses the notify systemd service type. The mod_systemd
113       module must be loaded (as in the default configuration) for this to
114       work correctly - the service will fail if this module is not loaded.
115       mod_systemd also makes worker and request statistics available when
116       running systemctl status httpd. See systemd.exec(5) for more
117       information on systemd service types.
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119   Security and SELinux
120       The default SELinux policy restricts the httpd service in various ways.
121       For example, the default policy limits the ports to which httpd can
122       bind (using the Listen directive), which parts of the filesystem can be
123       accessed, and whether outgoing TCP connections are possible. Many of
124       these restrictions can be relaxed or adjusted by using semanage to
125       change booleans or other types. See httpd_selinux(8) for more
126       information.
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128       The httpd service enables PrivateTmp by default. The /tmp and /var/tmp
129       directories available within the httpd process (and CGI scripts, etc)
130       are not shared by other processes. See systemd.exec(5) for more
131       information.
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133   Socket activation
134       Socket activation (see systemd.socket(5) for more information) can be
135       used with httpd by enabling the httpd.socket unit. The httpd listener
136       configuration must exactly match the ListenStream options configured
137       for the httpd.socket unit. The default httpd.socket has a
138       ListenStream=80 and, if mod_ssl is installed, ListenStream=443 by a
139       drop-in file. If additional Listen directives are added to the httpd
140       configuration, corresponding ListenStream options should be added via
141       drop-in files, for example via systemctl edit httpd.socket.
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143       If using socket activation with httpd, only one listener on any given
144       TCP port is supported; a configuration with both "Listen 127.0.0.1:80"
145       and "Listen 192.168.1.2:80" will not work.
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147   Instantiated services
148       The httpd@.service unit is an instantiated template service. An
149       instance of this unit will be started using the configuration file
150       /etc/httpd/conf/INSTANCE.conf, where INSTANCE is replaced with the
151       instance name. For example, systemctl start httpd@foobar.service will
152       start httpd using the configuration file /etc/httpd/conf/foobar.conf.
153       The HTTPD_INSTANCE environment variable is set to the instance name by
154       the unit and is available for use within the configuration file.
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156       To allow multiple instances of httpd to run simultaneously, a number of
157       configuration directives must be changed, such as PidFile and
158       DefaultRuntimeDir to pick non-conflicting paths, and Listen to choose
159       different ports. The example configuration file
160       /usr/share/doc/httpd/instance.conf demonstrates how to make such
161       changes using HTTPD_INSTANCE variable.
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163       It can be useful to configure instances of httpd@.service to reload
164       when httpd.service is reloaded; for example, logrotate will reload only
165       httpd.service when logs are rotated. If this behaviour is required,
166       create a drop-in file for the instance as follows:
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168           [Unit]
169           ReloadPropagatedFrom=httpd.service
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171       As with normal units, drop-in files for instances can be created using
172       systemctl edit, e.g.  systemctl edit httpd@foobar.service.
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FILES

175       /usr/lib/systemd/system/httpd.service,
176       /usr/lib/systemd/system/httpd.socket,
177       /usr/lib/systemd/system/httpd@.service,
178       /etc/systemd/systemd/httpd.service.d
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AUTHOR

185       Joe Orton <jorton@redhat.com>
186           Author
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190httpd                             05/02/2019                  HTTPD.SERVICE(8)

NAME

SYNOPSIS

DESCRIPTION

FILES

SEE ALSO

AUTHOR