[libvirt-users] qemu: qemu_thread_create: Resource temporarily unavailable

[llilulu]

Hi:
My libvirt is 3.4.0 and qemu is 2.9.0, My host has a big memory(128G), I run many guest on my host(80 guests), when I batch stop and start guests, some guest will crash, the qemu log is "qemu: qemu_thread_create: Resource temporarily unavailable". I search qemu code, I find qemu_thread_create just like pthread_create function. I search on internet, someone say that is a bug of qemu.Because my host run many guest ,so I cann't ensure whether qemu bug or my host load heavy cause my guest crash. Can someone tell me what reason cause the promble? and what can I do avoid the promble?
Thanks

[Daniel P. Berrangé]

Post by llilulu
My libvirt is 3.4.0 and qemu is 2.9.0, My host has a big memory(128G),
I run many guest on my host(80 guests), when I batch stop and start guests,
some guest will crash, the qemu log is "qemu: qemu_thread_create: Resource
temporarily unavailable". I search qemu code, I find qemu_thread_create
just like pthread_create function. I search on internet, someone say
that is a bug of qemu.Because my host run many guest ,so I cann't ensure
whether qemu bug or my host load heavy cause my guest crash. Can someone
tell me what reason cause the promble? and what can I do avoid the promble?

It isn't a QEMU bug - it is the kernel telling you that you have hit the max
process limit.

80 guests is honestly not a very large value though, so I'm surprised it
would hit a max process limit. Unless perhaps you're using RBD storage
as that creates an insanely huge number (100+) of threads sometimes.

Check /proc/$PID/limits for one of the guests that it successfully
running and it will tell you current "Max processes" limit. Then
in /etc/libvirt/qemu.conf try setting max_processes to a larger value
and restart libvirtd.


Regards,
Daniel