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diff --git a/httpd.service.xml b/httpd.service.xml new file mode 100644 index 0000000..9524045 --- /dev/null +++ b/httpd.service.xml @@ -0,0 +1,180 @@ +<?xml version='1.0' encoding='utf-8'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ + +]> + +<refentry> + <refentryinfo> + <title>httpd systemd units</title> + <productname>httpd</productname> + <author><contrib>Author</contrib><surname>Orton</surname><firstname>Joe</firstname><email>jorton@redhat.com</email></author> + </refentryinfo> + + <refmeta> + <refentrytitle>httpd.service</refentrytitle> + <manvolnum>5</manvolnum> + </refmeta> + + <refnamediv> + <refname>httpd.service</refname> + <refname>httpd.socket</refname> + <refpurpose>httpd unit files for systemd</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para> + <filename>/usr/lib/systemd/system/httpd.service</filename>, + <filename>/usr/lib/systemd/system/httpd.socket</filename> + </para> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para>This manual page describes the <command>systemd</command> + unit files used to integrate the <command>httpd</command> daemon + with <command>systemd</command>. Two unit files are available: + <command>httpd.service</command> allows the + <command>httpd</command> daemon to be run as a system service, and + <command>httpd.socket</command> allows httpd to be started via + socket-based activation. Most systems will use + <command>httpd.service</command>.</para> + + <refsect2> + <title>Changing default behaviour</title> + + <para>To change the default behaviour of the httpd service, an + <emphasis>over-ride</emphasis> file should be created, rather + than changing + <filename>/usr/lib/systemd/system/httpd.service</filename> + directly, since such changes would be lost over package + upgrades. Running <command>systemctl edit + httpd.service</command> or <command>systemctl edit + httpd.socket</command> as root will create a drop-in file in + <filename>/etc/systemd/system/httpd.service.d</filename> which + over-rides the system defaults.</para> + + <para>For example, to set the <literal>LD_LIBRARY_PATH</literal> + environment variable for the daemon, run <command>systemctl edit + httpd.service</command> and enter: + + <programlisting>[Service] +Environment=LD_LIBRARY_PATH=/opt/vendor/lib</programlisting></para> + + </refsect2> + + <refsect2> + <title>Starting the service at boot time</title> + + <para>The httpd.service and httpd.socket units are + <emphasis>disabled</emphasis> by default. To start the httpd + service at boot time, run: <command>systemctl enable + httpd.service</command>. In the default configuration, the + httpd daemon will accept connections on port 80 (and, if mod_ssl + is installed, TLS connections on port 443) for any configured + IPv4 or IPv6 address.</para> + + <para>If httpd is configured to depend on any specific IP + address (for example, with a "Listen" directive), which may only + become available during startup, or if httpd depends on other + services (such as a database daemon), the service + <emphasis>must</emphasis> be configured to ensure correct + startup ordering.</para> + + <para>For example, to ensure httpd is only running after all + configured network interfaces are configured, create a drop-in + file (as described above) with the following: + + <programlisting>[Unit] +After=network-online.target +Wants=network-online.target</programlisting> + + See <ulink + url="https://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/"/> + for more information on startup ordering with systemd.</para> + + </refsect2> + + <refsect2> + <title>Reloading and stopping the service</title> + + <para>When running <command>systemctl reload + httpd.service</command>, a "<emphasis>graceful</emphasis>" + restart is used, which sends a signal to the httpd parent + process to reload the configuration and re-open log files. Any + children with open connections at the time of reload will + terminate only once they have completed serving requests. This + prevents users of the server seeing errors (or potentially + losing data) due to the reload, but means some there is some + delay before any configuration changes take effect for all + users.</para> + + <para>Similarly, a "<emphasis>graceful stop</emphasis>" is used + when <command>systemctl stop httpd.service</command> is run, + which terminates the server only once active connections have + been processed.</para> + + </refsect2> + + <refsect2> + <title>systemd integration and mod_systemd</title> + + <para>httpd.service uses the "<option>notify</option>" systemd + service type. The <literal>mod_systemd</literal> module must be + loaded (as in the default configuration) for this to work + correctly - the service will fail if this module is not + loaded. <literal>mod_systemd</literal> also makes worker and + request statistics available when running <command>systemctl status + httpd</command>. See + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for more information on systemd service types.</para> + </refsect2> + + <refsect2> + <title>Security and SELinux</title> + + <para>The default SELinux policy restricts the httpd service in + various ways. The ports to which httpd can bind (using the + <literal>Listen</literal> directive), which parts of the + filesystem can be accessed, whether outgoing TCP connections are + possible, are limited by default, for example. Many of these + restrictions can be lifted using SELinux booleans and port + types. See + <citerefentry><refentrytitle>httpd_selinux</refentrytitle><manvolnum>8</manvolnum></citerefentry> + for more information.</para> + + <para>The httpd service enables <emphasis>PrivateTmp</emphasis> + by default. The <filename>/tmp</filename> and + <filename>/var/tmp</filename> directories available within the + httpd process (and CGI scripts, etc) are not shared by other + processes. See + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for more information.</para> + + </refsect2> + + </refsect1> + + <refsect1> + <title>Files</title> + + <para><filename>/usr/lib/systemd/system/httpd.service</filename>, + <filename>/usr/lib/systemd/system/httpd.socket</filename>, + <filename>/etc/systemd/systemd/httpd.service.d</filename></para> + </refsect1> + + <refsect1> + <title>See also</title> + + <para> + <citerefentry><refentrytitle>httpd</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>httpd_selinux</refentrytitle><manvolnum>8</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |