How to redirect output of systemd service to a fil

Question

I am trying to redirect output of a systemd service to a file but it doesn't seem to work:

[Unit]
Description=customprocess
After=network.target

[Service]
Type=forking
ExecStart=/usr/local/bin/binary1 agent -config-dir /etc/sample.d/server
StandardOutput=/var/log1.log
StandardError=/var/log2.log
Restart=always

[Install]
WantedBy=multi-user.target

Please correct my approach.

Answer 1

I would suggest adding stdout and stderr file in systemd service file itself.

Referring : https://www.freedesktop.org/software/systemd/man/systemd.exec.html#StandardOutput=

As you have configured it should not like:

StandardOutput=/home/user/log1.log
StandardError=/home/user/log2.log

It should be:

StandardOutput=file:/home/user/log1.log
StandardError=file:/home/user/log2.log

This works when you don't want to restart the service again and again.

This will create a new file and does not append to the existing file.

Use Instead:

StandardOutput=append:/home/user/log1.log
StandardError=append:/home/user/log2.log

NOTE: Make sure you create the directory already. I guess it does not support to create a directory.

Answer 2

You possibly get this error:

Failed to parse output specifier, ignoring: /var/log1.log

From the systemd.exec(5) man page:

StandardOutput=

Controls where file descriptor 1 (STDOUT) of the executed processes is connected to. Takes one of inherit, null, tty, journal, syslog, kmsg, journal+console, syslog+console, kmsg+console or socket.

The systemd.exec(5) man page explains other options related to logging. See also the systemd.service(5) and systemd.unit(5) man pages.

Or maybe you can try things like this (all on one line):

ExecStart=/bin/sh -c '/usr/local/bin/binary1 agent -config-dir /etc/sample.d/server 2>&1 > /var/log.log' 

Answer 3

Short answer:

StandardOutput=file:/var/log1.log
StandardError=file:/var/log2.log

If you don't want the files to be cleared every time the service is run, use append instead:

StandardOutput=append:/var/log1.log
StandardError=append:/var/log2.log

Answer 4

If you have a newer distro with a newer systemd (systemd version 236 or newer), you can set the values of StandardOutput or StandardError to file:YOUR_ABSPATH_FILENAME.

---

Long story:

In newer versions of systemd there is a relatively new option (the github request is from 2016 ish and the enhancement is merged/closed 2017 ish) where you can set the values of StandardOutput or StandardError to file:YOUR_ABSPATH_FILENAME. The file:path option is documented in the most recent systemd.exec man page.

This new feature is relatively new and so is not available for older distros like centos-7 (or any centos before that).

Answer 5

If for a some reason can't use rsyslog, this will do: ExecStart=/bin/bash -ce "exec /usr/local/bin/binary1 agent -config-dir /etc/sample.d/server >> /var/log/agent.log 2>&1"

Answer 6

We are using Centos7, spring boot application with systemd. I was running java as below. and setting StandardOutput to file was not working for me.

ExecStart=/bin/java -jar xxx.jar  -Xmx512-Xms32M

Below workaround solution working without setting StandardOutput. running java through sh as below.

ExecStart=/bin/sh -c 'exec /bin/java -jar xxx.jar -Xmx512M -Xms32M >> /data/logs/xxx.log 2>&1'