Increase Open File Limit Tomcat CentOS 7

1. check PID

systemctl status tomcat

2. Check max open file

cat /proc/<PID>/limits

3. create config file

mkdir -p /etc/systemd/system/tomcat.service.d/
vim /etc/systemd/system/tomcat.service.d/limits.conf
[Service]
LimitNOFILE=8192

4. reload and restart service

systemctl daemon-reload
systemctl restart tomcat