Today I installed Varnish on a pretty standard system (CentOS + WHM) and the service wouldn't start. The system log (/var/log/messages) contained the following:
Oct 7 04:15:46 server varnishd[20836]: Child (20846) Panic message: Assert error in WRK_BgThread(), cache_pool.c line 582:#012 Condition((pthread_create(thr, ((void *)0), wrk_bgthread, bt)) == 0) not true.#012errno = 11 (Resource temporarily unavailable)#012thread = (cache-main)#012ident = Linux,2.6.32-358.2.1.el6.x86_64,x86_64,-sfile,-smalloc,-hcritbit,no_waiter#012
The settings for number of processes and file descriptors in /etc/security/limits.{conf,d} were correct and it still didn't start. The problem turned out to be with stack size - I have no idea why this is happening in just this one system and works with every other centos, but the solution was as following:
1. Patch /etc/init.d/varnish adding a new ulimit call in start()
# Stack size
ulimit -s unlimited
2. Increase system limits in /etc/security/limits.conf accordingly
varnish stack soft unlimited varnish stack hard unlimited
3. Restart Varnish
After successfully running Varnish this way, be sure to change the stack limit back to a reasonable size! Unlimited is not a very wise setting, but helps debugging the problem. Now Varnish and Joomla could happily work together.
