How to use system.d service with SDKMan

Question

I am trying to install Sonatype Nexus 3 as a service via system.d and it fails due to INSTALL4J_JAVA_HOME not being set (or at least, so claims systemctl). I use SDKMan! (http://sdkman.io) to manage my Java installation. I am following the Sonatype directions at https://help.sonatype.com/repomanager3/installation/run-as-a-service .

I can run it as the user specified in run_as_user in a bash shell with no difficulties.

How do I make the java home environment variable provided by SDKman visible to system.d?

Answer 1

TL:DR; to resolve, add an Environment section to the system.d service file:

[Service]
Environment="INSTALL4J_JAVA_HOME=/home/nexus/.sdkman/candidates/java/current/"

Long-form answer:

As of this writing, the Sonatype documents say to use the following file as your /etc/systemd/system/nexus.service file, which works great if you installed java to your service user via the system distribution (ensuring your distro's java home is managed by the system). That doesn't work to resolve my question:

[Unit]
Description=nexus service
After=network.target

[Service]
Type=forking
LimitNOFILE=65536
ExecStart=/opt/nexus/bin/nexus start
ExecStop=/opt/nexus/bin/nexus stop
User=nexus
Restart=on-abort
TimeoutSec=600

[Install]
WantedBy=multi-user.target

To resolve, you must add the Environment variable to the system.d service file (with your_user replaced by the user you are running nexus as, and /opt/nexus being replaced by your nexus install location):

[Unit]
Description=nexus service
After=network.target

[Service]
Environment="INSTALL4J_JAVA_HOME=/home/your_user/.sdkman/candidates/java/current/"
Type=forking
LimitNOFILE=65536
ExecStart=/opt/nexus/bin/nexus start
ExecStop=/opt/nexus/bin/nexus stop
User=your_user
Restart=on-abort
TimeoutSec=600

[Install]
WantedBy=multi-user.target