Base Service Commands
This article describes how to manage services by using systemd.
Introduction
Many modern Linux® operating systems available at Rackspace, such as Centos® 7 and later and Ubuntu® 16.04,
adopted systemd as a system manager. So you might want to know the ins and outs of how to use it to manage your applications.
Use systemctl
systemctlWhen you use systemd to manage applications, you use the command systemctl. The following sections
describe several of this command's functions.
Start and stop services
Use the command systemctl start application.service to start the application and the command systemctl stop application.service to stop the application. If you don't know if a service is running, you can use the
command systemctl status application.service to check the status, as shown in the following example:
[root@localhost ~]# systemctl status httpd.service
httpd.service - The Apache HTTP Server
Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled; vendor preset: disabled)
Active: inactive (dead)
Docs: man:httpd(8)
man:apachectl(8)[root@localhost ~]# ~# systemctl status apache2.service
○ apache2.service - The Apache HTTP Server
Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
Active: inactive (dead) since Wed 2026-07-22 19:32:44 IST; 2s ago
Docs: https://httpd.apache.org/docs/2.4/
Process: 1750 ExecStop=/usr/sbin/apachectl graceful-stop (code=exited, status=0/SUCCESS)
Main PID: 1481 (code=exited, status=0/SUCCESS)
CPU: 81ms[root@localhost ~]# systemctl start httpd.service OR [root@localhost ~]# systemctl enable --now httpd.service[root@localhost ~]# systemctl start apache2.service OR
[root@localhost ~]# systemctl enable --now apache2.service
Synchronizing state of apache2.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install enable apache2
[root@localhost ~]# systemctl status httpd.service
httpd.service - The Apache HTTP Server
Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled; vendor preset: disabled)
Active: active (running) since Sun 2020-05-24 01:30:02 UTC; 1s ago
Docs: man:httpd(8)
man:apachectl(8)
Main PID: 16117 (httpd)
Status: "Processing requests..."
CGroup: /system.slice/httpd.service
├─16117 /usr/sbin/httpd -DFOREGROUND
├─16118 /usr/sbin/httpd -DFOREGROUND
├─16119 /usr/sbin/httpd -DFOREGROUND
├─16120 /usr/sbin/httpd -DFOREGROUND
├─16121 /usr/sbin/httpd -DFOREGROUND
└─16122 /usr/sbin/httpd -DFOREGROUND
May 24 01:30:02 localhost.localdomain systemd[1]: Starting The Apache HTTP Server...
May 24 01:30:02 localhost.localdomain httpd[16117]: AH00558: httpd: Could not reliably determine
the server's fully qualified domain name, using localhost.localdomain. Set the 'ServerName'
directive globally to suppress this message
May 24 01:30:02 localhost.localdomain systemd[1]: Started The Apache HTTP Server.
[root@localhost ~]#[root@localhost ~]# systemctl status apache2.service
● apache2.service - The Apache HTTP Server
Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
Active: active (running) since Wed 2026-07-22 19:34:28 IST; 36s ago
Docs: https://httpd.apache.org/docs/2.4/
Process: 2021 ExecStart=/usr/sbin/apachectl start (code=exited, status=0/SUCCESS)
Main PID: 2025 (apache2)
Tasks: 55 (limit: 18848)
Memory: 5.7M
CPU: 30ms
CGroup: /system.slice/apache2.service
├─2025 /usr/sbin/apache2 -k start
├─2026 /usr/sbin/apache2 -k start
└─2027 /usr/sbin/apache2 -k start
Jul 22 19:34:28 AAD-70TSYB4 systemd[1]: Starting The Apache HTTP Server...
Jul 22 19:34:28 AAD-70TSYB4 systemd[1]: Started The Apache HTTP Server.
[root@localhost ~]#Restart or reload services
Restarting and reloading a service are two separate things with systemd.
When you run the command systemctl restart application.service, the specified service restarts. If the service is in a stopped state, it starts.
When you run the command systemctl reload application.service, the configuration of the specified service reloads. For example, if you make any changes to an Apache® virtual host (vhost) and you want those changes to go live without stopping Apache, you reload the service. The new configurations take place without interrupting the service.
Enable and disable services
If you want a specific service to start when the server is booted up, run the command systemctl enable application.service. If you want to make sure a service does not start when the server boots up, run the command systemctl disable application.service.
:~# systemctl -h
systemctl [OPTIONS...] COMMAND ...
Query or send control commands to the system manager.
Unit Commands:
list-units [PATTERN...] List units currently in memory
list-sockets [PATTERN...] List socket units currently in memory,
ordered by address
list-timers [PATTERN...] List timer units currently in memory,
ordered by next elapse
is-active PATTERN... Check whether units are active
is-failed PATTERN... Check whether units are failed
status [PATTERN...|PID...] Show runtime status of one or more units
show [PATTERN...|JOB...] Show properties of one or more
units/jobs or the manager
cat PATTERN... Show files and drop-ins of specified units
help PATTERN...|PID... Show manual for one or more units
list-dependencies [UNIT...] Recursively show units which are required
or wanted by the units or by which those
units are required or wanted
start UNIT... Start (activate) one or more units
stop UNIT... Stop (deactivate) one or more units
reload UNIT... Reload one or more units
restart UNIT... Start or restart one or more units
try-restart UNIT... Restart one or more units if active
reload-or-restart UNIT... Reload one or more units if possible,
otherwise start or restart
try-reload-or-restart UNIT... If active, reload one or more units,
if supported, otherwise restart
isolate UNIT Start one unit and stop all others
kill UNIT... Send signal to processes of a unit
clean UNIT... Clean runtime, cache, state, logs or
configuration of unit
freeze PATTERN... Freeze execution of unit processes
thaw PATTERN... Resume execution of a frozen unit
set-property UNIT PROPERTY=VALUE... Sets one or more properties of a unit
bind UNIT PATH [PATH] Bind-mount a path from the host into a
unit's namespace
mount-image UNIT PATH [PATH [OPTS]] Mount an image from the host into a
unit's namespace
service-log-level SERVICE [LEVEL] Get/set logging threshold for service
service-log-target SERVICE [TARGET] Get/set logging target for service
reset-failed [PATTERN...] Reset failed state for all, one, or more
units
Unit File Commands:
list-unit-files [PATTERN...] List installed unit files
enable [UNIT...|PATH...] Enable one or more unit files
disable UNIT... Disable one or more unit files
reenable UNIT... Reenable one or more unit files
preset UNIT... Enable/disable one or more unit files
based on preset configuration
preset-all Enable/disable all unit files based on
preset configuration
is-enabled UNIT... Check whether unit files are enabled
mask UNIT... Mask one or more units
unmask UNIT... Unmask one or more units
link PATH... Link one or more units files into
~]# systemctl -h
systemctl [OPTIONS...] COMMAND ...
Query or send control commands to the system manager.
Unit Commands:
list-units [PATTERN...] List units currently in memory
list-automounts [PATTERN...] List automount units currently in memory,
ordered by path
list-sockets [PATTERN...] List socket units currently in memory,
ordered by address
list-timers [PATTERN...] List timer units currently in memory,
ordered by next elapse
is-active PATTERN... Check whether units are active
is-failed PATTERN... Check whether units are failed
status [PATTERN...|PID...] Show runtime status of one or more units
show [PATTERN...|JOB...] Show properties of one or more
units/jobs or the manager
cat PATTERN... Show files and drop-ins of specified units
help PATTERN...|PID... Show manual for one or more units
list-dependencies [UNIT...] Recursively show units which are required
or wanted by the units or by which those
units are required or wanted
start UNIT... Start (activate) one or more units
stop UNIT... Stop (deactivate) one or more units
reload UNIT... Reload one or more units
restart UNIT... Start or restart one or more units
try-restart UNIT... Restart one or more units if active
reload-or-restart UNIT... Reload one or more units if possible,
otherwise start or restart
try-reload-or-restart UNIT... If active, reload one or more units,
if supported, otherwise restart
isolate UNIT Start one unit and stop all others
kill UNIT... Send signal to processes of a unit
clean UNIT... Clean runtime, cache, state, logs or
configuration of unit
freeze PATTERN... Freeze execution of unit processes
thaw PATTERN... Resume execution of a frozen unit
set-property UNIT PROPERTY=VALUE... Sets one or more properties of a unit
bind UNIT PATH [PATH] Bind-mount a path from the host into a
unit's namespace
mount-image UNIT PATH [PATH [OPTS]] Mount an image from the host into a
unit's namespace
service-log-level SERVICE [LEVEL] Get/set logging threshold for service
service-log-target SERVICE [TARGET] Get/set logging target for service
reset-failed [PATTERN...] Reset failed state for all, one, or more
units
Unit File Commands:
list-unit-files [PATTERN...] List installed unit files
enable [UNIT...|PATH...] Enable one or more unit files
disable UNIT... Disable one or more unit files
reenable UNIT... Reenable one or more unit files
preset UNIT... Enable/disable one or more unit files
based on preset configuration
preset-all Enable/disable all unit files based on
preset configuration
is-enabled UNIT... Check whether unit files are enabled
mask UNIT... Mask one or more units
Updated about 9 hours ago
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