Tuning Minion

Minion’s resource requirements scale with its workload. When assigned to locations with more nodes, interfaces, and services, the default settings may be insufficient.

Tuning Java heap memory

Edit the file /etc/sysconfig/minion (RHEL) or /etc/default/minion (Debian)

Uncomment and modify the values for the JAVA_MIN_MEM and JAVA_MAX_MEM variables

# minimum amount of memory for the Karaf container to allocate
export JAVA_MIN_MEM=512M

# maximum amount of memory for the Karaf container to allocate
export JAVA_MAX_MEM=4096M

If Minion is running when this change is made, it must be restarted to take effect.
```
systemctl restart minion
```

Tuning file descriptor limits

Edit the minion unit file:
```
systemctl edit minion
```
In the area dictated by the comments in the editor, add:
```
LimitNOFILE=100000
```
the value 100000 is used as an example only.
Edit /etc/sysconfig/minion (RHEL) or /etc/default/minion (Debian)
Uncomment and modify the values for the MAX_FD variable:
```
# maximum number of file descriptors to allocate
export MAX_FD=100000
```
the value 100000 is used as an example only.

Confirm the unit file reflects the changes:

# systemctl daemon-reload
# systemctl cat minion
[Unit]
Description=The OpenNMS Minion distributed client.
Requires=network.target network-online.target
After=network.target network-online.target

[Service]
User=minion
EnvironmentFile=-/opt/minion/etc/minion

PIDFile=/opt/minion/data/log/minion.pid
Type=forking

ExecStart=/opt/minion/bin/minion start
ExecStop=/opt/minion/bin/minion stop

AmbientCapabilities=CAP_NET_RAW CAP_NET_BIND_SERVICE

[Install]
WantedBy=multi-user.target

# /etc/systemd/system/minion.service.d/override.conf
LimitNOFILE=100000

If the minion is running when this change is made, it must be restarted to take effect.
```
systemctl restart minion
```

Adjusting the minion log level

In many situations it can be beneficial to change the log level to be more or less verbose. Follow these steps to change it.

Edit $MINION_HOME/etc/org.ops4j.pax.logging.cfg

$MINION_HOME is /opt/minion on RHEL, and /etc/minion on Debian.

Find and modify the logger.opennms section

# OPENNMS: Display all INFO logs for OpenNMS code
log4j2.logger.opennms.name = org.opennms
log4j2.logger.opennms.level = DEBUG

No restart is required to change the log level.