On Thu, May 25, 2017 at 06:51:40PM +0800, dw wrote:

在 2017年05月25日 18:37, Daniel P. Berrange 写道:

On Thu, May 25, 2017 at 06:20:51PM +0800, dw wrote:

Hi:

     I'm trying to connect with libvirtd with virsh from a remote PC,but only
can establish 1000 connections.

     If try more connections,prompt:

     "error: failed to connect to the hypervisor
     error: Failed to open file '/etc/libvirt/libvirt.conf': Too many open
files"

     I tried in another PC,also get the same prompt.

     Anybody know why?

There's a limit of 1024 open file handles by default on Linux. You would
have to raise that limit in /etc/security/limits.d/ for your user.

In /etc/security/limits.d/,there is only 20-nproc.conf.

You can create any files you want in that sub-directory - they just
use the same syntax as limits.conf. It means that if RPM upgrades
limits.conf it doesn't interfere with your changes in limits.d/custom.conf

I modified /etc/security/limits.conf,what I added is:

        "*       soft nofile 81920
        *       hard nofile 81920"

I also modified /etc/pam.d/login,that I added is:

    "session required        pam_limits.so"

I don't think that's needed - its already activated via
pam.d/system-auth which is included from login.

The output of "ulimit -a" is:

    core file size          (blocks, -c) 0
    data seg size           (kbytes, -d) unlimited
    scheduling priority             (-e) 0
    file size               (blocks, -f) unlimited
    pending signals                 (-i) 385898
    max locked memory       (kbytes, -l) 64
    max memory size         (kbytes, -m) unlimited
    open files                      (-n) 81920
    pipe size            (512 bytes, -p) 8
    POSIX message queues     (bytes, -q) 819200
    real-time priority              (-r) 0
    stack size              (kbytes, -s) 8192
    cpu time               (seconds, -t) unlimited
    max user processes              (-u) 385898
    virtual memory          (kbytes, -v) unlimited
    file locks                      (-x) unlimited


What I did is right?

That at least shows the new limit is active

Regards,
Daniel

I restored  /etc/security/limits.conf and /etc/pam.d/login.

And added file /etc/security/limits.d/21-nofile.conf, the content is

 *       soft    nofile      10240
 *       hard    nofile      10240"

The output of "ulimit -a" now is:

core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 385898
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 10240
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited   
max user processes              (-u) 385898
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

The related config of /etc/libvirt/libvirtd.conf is:

max_clients = 5000
max_queued_clients = 2000
min_workers = 200
max_workers = 2000
max_requests = 5000
max_client_requests = 2000

error: failed to connect to the hypervisor
error: Failed to open file '/etc/libvirt/libvirt.conf': Too many open files