Why is xinetd crashing in Red Hat Enterprise Linux 5?
Environment
- Red Hat Enterprise Linux 5
Issue
- Why is xinetd crashing in Red Hat Enterprise Linux 5?
- excessive incoming connections in xinetd
xinetd[5100]: Deactivating service nrpe due to excessive incoming connections. Restarting in 10 seconds.
xinetd[5100]: FAIL: nrpe connections per second from=16.24.1.9
xinetd[5100]: *** glibc detected *** xinetd: realloc(): invalid next size: 0x00002aaaaacf5e20 ***
- We were having a lot of problems today and after several troubleshooting steps we found that the xinetd process was hung. Is there any way to tell what caused xinetd to hang? Can you tell us why this happened?
Resolution
-
Increase the
per_sourceconnection limit for the nrpe sevice in/etc/xinetd.d/nrpe:service nrpe { ... server = /usr/local/nagios/bin/nrpe ... only_from = 127.0.0.1 16.24.1.9 16.24.2.9 per_source = 130 } -
You may also need to increase the
cps(maximum number of connections per second) setting in/etc/xinetd.conf.
Root Cause
By default, the xinetd service is configured to only allow 50 connections per second with a 10 second pause if this limit is reached. Also, it only accept 10 simultaneous connections from the same IP address, as shown in /etc/xinetd.conf:
cps = 50 10
per_source = 10
Red Hat does not ship or support the NRPE software.
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