use systemctl edit to modify units

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Christopher Engelhard 2020-08-05 18:44:28 +02:00 committed by lcts
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[#modifying-existing-systemd-services]
= Modifying existing systemd services
This example shows how to modify an existing service. The files for service modification are stored in a directory within `/etc/systemd/system`. This directory is named after the service. For example, this procedure modifies the `httpd` service.
This example shows how to modify an existing service. Service modification are stored within `/etc/systemd/system`, in a single file or in a subdirectory named after the service. For example, this procedure modifies the `httpd` service.
[discrete]
== Prerequisites
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[discrete]
== Procedure
. Create a directory for the service modification in the following format: `[SERVICE NAME].service.d`. For example, the directory for the `httpd.service` modification is `httpd.service.d`:
. _Systemd_ services can be modified using the `systemctl edit` command.
+
----
# mkdir /etc/systemd/system/httpd.service.d/
# systemctl edit httpd.service
----
. Create a configuration file within this directory:
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----
# vi /etc/systemd/system/httpd.service.d/custom.conf
----
This creates an override file `/etc/systemd/system/httpd.service.d/override.conf` and opens it in your text editor. Anything you put into this file will be *added* to the existing service file.
. Add your custom configuration. For example:
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Restart=always
RestartSec=30
----
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To replace an option that can be set multiple times, it must cleared first, otherwise the override file will add the option a second time.
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----
[Service]
ExecStart=
ExecStart=<new command>
----
. Save the file.
. Save the file. _Systemd_ automatically loads the new service configuration.
. Restart the `httpd` service:
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# systemctl restart httpd
----
To completely replace (instead of just add to/modify) an existing service file, use `systemctl edit --full`, e.g. `systemctl edit --full httpd.service`. This will create `/etc/systemctl/system/httpd.service`, which will be used instead of the existing service file.
[discrete]
== Related Information