Re: Nested KVM issue

[Boris Derzhavets <bderzhavets@xxxxxxxxxxx>]

Sorry,

How you trigger the problem ?

B.

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From: centos-virt-bounces@xxxxxxxxxx <centos-virt-bounces@xxxxxxxxxx> on behalf of Laurentiu Soica <laurentiu@xxxxxxxx>
Sent: Tuesday, August 16, 2016 3:28 AM
To: Discussion about the virtualization on CentOS
Subject: Re: Nested KVM issue

 

Hello,

The issue reproduced again and it doesn't look like a swap problem. Some details:

on the baremetal, from top:

top - 08:08:52 up 5 days, 16:43,  3 users,  load average: 36.19, 36.05, 36.05

Tasks: 493 total,   1 running, 492 sleeping,   0 stopped,   0 zombie

%Cpu(s):  3.5 us, 87.9 sy,  0.0 ni,  8.6 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st

KiB Mem : 12357451+total, 14296000 free, 65634428 used, 43644088 buff/cache

KiB Swap:  4194300 total,  4073868 free,   120432 used. 56953888 avail Mem

19158 qemu      20   0  0.098t 0.041t  10476 S  3650 35.6  13048:24 qemu-kvm

The compute node has 36 CPUs and the usage is now 100%. There are more than 50 GB of memory still available on the baremetal. The swap is barely used, 120 MB.

On compute node, from top:

top - 05:11:58 up 1 day, 15:08,  2 users,  load average: 40.46, 40.49, 40.74

%Cpu(s): 99.1 us,  0.7 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.1 si,  0.1 st

KiB Mem : 10296246+total, 78079936 free, 23671360 used,  1211160 buff/cache

KiB Swap:        0 total,        0 free,        0 used. 78939968 avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND

 6032 qemu      20   0 10.601g 1.272g  12964 S 400.0  1.3 588:40.39 qemu-kvm

 5673 qemu      20   0 10.602g 1.006g  13020 S 399.7  1.0   1161:47 qemu-kvm

 5998 qemu      20   0 10.601g 1.192g  13028 S 367.9  1.2   1544:30 qemu-kvm

 5951 qemu      20   0 10.601g 1.246g  13020 S 348.3  1.3   1547:38 qemu-kvm

 5750 qemu      20   0 10.599g 990136  13060 S 339.1  1.0   1152:25 qemu-kvm

 5752 qemu      20   0 10.598g 1.426g  13040 S 313.9  1.5 663:13.65 qemu-kvm

....

There are more than 70 GB of memory available on the compute node. All VMs are using 100% their CPUs and they are not accessible anymore.

Laurentiu 

În dum., 14 aug. 2016 la 21:44, Boris Derzhavets <bderzhavets@xxxxxxxxxxx> a scris:

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From: centos-virt-bounces@xxxxxxxxxx <centos-virt-bounces@xxxxxxxxxx> on behalf of Laurentiu Soica <laurentiu@xxxxxxxx>
Sent: Sunday, August 14, 2016 10:17 AM
To: Discussion about the virtualization on CentOS
Subject: Re: Nested KVM issue

 

More details on the subject:

I suppose it is a nested KVM issue because it raised after I enabled the nested KVM feature. Without it, anyway, the second level VMs are unusable in terms of performance.

I am using CentOS 7 with:

kernel: 3.10.0-327.22.2.el7.x86_64

qemu-kvm:1.5.3-105.el7_2.4

libvirt:1.2.17-13.el7_2.5

on both the baremetal and the compute VM.

Please, post

1) # virsh dumpxml  VM-L1  ( where on L1 level you expect nested KVM to appear)
2) Login into VM-L1 and run :-
    # lsmod | grep kvm
3) I need outputs from VM-L1 ( in case it is Compute Node )

# cat /etc/nova/nova.conf | grep virt_type
# cat /etc/nova/nova.conf | grep  cpu_mode

Boris.


  

The only workaround now is to shutdown the compute VM and start it back from baremetal with virsh start.

A simple restart of the compute node doesn't help. It looks like the qemu-kvm process corresponding to the compute VM is the problem.

Laurentiu

În dum., 14 aug. 2016 la 00:19, Laurentiu Soica <laurentiu@xxxxxxxx> a scris:

Hello,

I have an OpenStack setup in virtual environment on CentOS 7.

The baremetal has nested KVM enabled and 1 compute node as a VM.

Inside the compute node I have multiple VMs running.

After about every 3 days the VMs get inaccessible and the compute node reports high CPU usage. The qemu-kvm process for each VM inside the compute node reports full CPU usage.

Please help me with some hints to debug this issue.

Thanks,

Laurentiu

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