[CentOS-virt] Nested KVM issue

Laurentiu Soica laurentiu at soica.ro
Wed Aug 17 08:56:00 UTC 2016 

Enabled the logging on both compute and baremetal. Nothing strange in logs:

on baremetal :
Wed Aug 17 11:51:01 EEST 2016: committed 62310764 free 58501808
Wed Aug 17 11:51:01 EEST 2016: 87025667 < 123574516 and free > 24714903,
stop ksm

on compute:
Wed Aug 17 08:52:52 UTC 2016: committed 24547132 free 76730936
Wed Aug 17 08:52:52 UTC 2016: 45139624 < 102962460 and free > 20592492,
stop ksm

and the compute node is again at 100% CPU utilization.



În mar., 16 aug. 2016 la 15:26, Boris Derzhavets <bderzhavets at hotmail.com>
a scris:

> I would enable ksmtuned logging ,if it has been done verify logs
>
>
> ------------------------------
> *From:* centos-virt-bounces at centos.org <centos-virt-bounces at centos.org>
> on behalf of Laurentiu Soica <laurentiu at soica.ro>
> *Sent:* Tuesday, August 16, 2016 7:16 AM
>
> *To:* Discussion about the virtualization on CentOS
> *Subject:* Re: [CentOS-virt] Nested KVM issue
> Yes. It is on both baremetal and compute node.
>
> În mar., 16 aug. 2016 la 13:37, Boris Derzhavets <bderzhavets at hotmail.com>
> a scris:
>
>> Is  KSM enabled on your Compute Nodes ( presuming CentOS 7.2 on bare
>> metal ) ?
>>
>>
>> ------------------------------
>> *From:* centos-virt-bounces at centos.org <centos-virt-bounces at centos.org>
>> on behalf of Laurentiu Soica <laurentiu at soica.ro>
>> *Sent:* Tuesday, August 16, 2016 5:25 AM
>>
>> *To:* Discussion about the virtualization on CentOS
>> *Subject:* Re: [CentOS-virt] Nested KVM issue
>> Running the compute node for several days simply triggers it.
>>
>> În mar., 16 aug. 2016 la 12:12, Boris Derzhavets <bderzhavets at hotmail.com>
>> a scris:
>>
>>> Sorry,
>>>
>>> How you trigger the problem ?
>>>
>>> B.
>>>
>>>
>>> ------------------------------
>>> *From:* centos-virt-bounces at centos.org <centos-virt-bounces at centos.org>
>>> on behalf of Laurentiu Soica <laurentiu at soica.ro>
>>> *Sent:* Tuesday, August 16, 2016 3:28 AM
>>>
>>> *To:* Discussion about the virtualization on CentOS
>>> *Subject:* Re: [CentOS-virt] 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 at hotmail.com> a scris:
>>>
>>>>
>>>>
>>>>
>>>> ------------------------------
>>>> *From:* centos-virt-bounces at centos.org <centos-virt-bounces at centos.org>
>>>> on behalf of Laurentiu Soica <laurentiu at soica.ro>
>>>> *Sent:* Sunday, August 14, 2016 10:17 AM
>>>> *To:* Discussion about the virtualization on CentOS
>>>> *Subject:* Re: [CentOS-virt] 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 at soica.ro> 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
>>>>>
>>>> _______________________________________________
>>>> CentOS-virt mailing list
>>>> CentOS-virt at centos.org
>>>> https://lists.centos.org/mailman/listinfo/centos-virt
>>>>
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>>>
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