free server monitoring tool for Java based application

Question

I have applied couple of options like Nagios [which lead to problem after installation]-- Apache went irresponsive with lots of segmentation faults

child pid 32507 exit signal Segmentation fault (11) yes we can change the MPM nature to override but I am afraid of getting into another problem to overcome this.

what I need to monitor is:

1. is server up [pings are not allowed in my server DC], so i cannot trace by applying ping from another server to the monitoring server. what other option we can have?

2. Apache httpd and Tomcat working fine

3. MySQL db is working fine

4. Resource utilization [CPU, Memory] of above mentioned processes

Alerts like send email to admins.

what is industry best practice to Monitor the application servers.

Answer 1

is server up [pings are not allowed in my server DC], so i cannot trace by applying ping from another server to the monitoring server. what other option we can have?

That's unfortunate, because checking from the outside is the best option to be sure. If your server is down, no tool on your server can report you about it.

Apache httpd and Tomcat working fine

MySQL db is working fine

Monit is a good tool for this. It can alert you if a service is down or restart it.

Resource utilization [CPU, Memory] of above mentioned processes

Monit can also alert you about high cpu or memory utilization, low disk space, or other metrics.

If you want a live view, you can try netdata. It's very pretty and comprehensive, but not persistent (and least not out-of-the-box), so after a crash/reboot you wouldn't have any data.

For persistent data, you could use collectl (and colplot to plot the data).

I'm sure there are lots of other tools out there, but these have worked well for us.