Default Comment by Bridge ** Attachment added: "New dmesg output captured Aug 23" https://bugs.launchpad.net/bugs/1717224/+attachment/5006612/+files/dmesg_082317
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to procps in Ubuntu. https://bugs.launchpad.net/bugs/1717224 Title: virsh start of virtual guest domain fails with internal error due to low default aio-max-nr sysctl value Status in Ubuntu on IBM z Systems: In Progress Status in kvm package in Ubuntu: Confirmed Status in linux package in Ubuntu: In Progress Status in procps package in Ubuntu: New Status in kvm source package in Xenial: New Status in linux source package in Xenial: In Progress Status in procps source package in Xenial: New Status in kvm source package in Zesty: New Status in linux source package in Zesty: In Progress Status in procps source package in Zesty: New Status in kvm source package in Artful: Confirmed Status in linux source package in Artful: In Progress Status in procps source package in Artful: New Bug description: Starting virtual guests via on Ubuntu 16.04.2 LTS installed with its KVM hypervisor on an IBM Z14 system LPAR fails on the 18th guest with the following error: root@zm93k8:/rawimages/ubu1604qcow2# virsh start zs93kag70038 error: Failed to start domain zs93kag70038 error: internal error: process exited while connecting to monitor: 2017-07-26T01:48:26.352534Z qemu-kvm: -drive file=/guestimages/data1/zs93kag70038.qcow2,format=qcow2,if=none,id=drive-virtio-disk0,cache=none,aio=native: Could not open backing file: Could not set AIO state: Inappropriate ioctl for device The previous 17 guests started fine: root@zm93k8# virsh start zs93kag70020 Domain zs93kag70020 started root@zm93k8# virsh start zs93kag70021 Domain zs93kag70021 started . . root@zm93k8:/rawimages/ubu1604qcow2# virsh start zs93kag70036 Domain zs93kag70036 started We ended up fixing the issue by adding the following line to /etc/sysctl.conf : fs.aio-max-nr = 4194304 ... then, reload the sysctl config file: root@zm93k8:/etc# sysctl -p /etc/sysctl.conf fs.aio-max-nr = 4194304 Now, we're able to start more guests... root@zm93k8:/etc# virsh start zs93kag70036 Domain zs93kag70036 started The default value was originally set to 65535: root@zm93k8:/rawimages/ubu1604qcow2# cat /proc/sys/fs/aio-max-nr 65536 Note, we chose the 4194304 value, because this is what our KVM on System Z hypervisor ships as its default value. Eg. on our zKVM system: [root@zs93ka ~]# cat /proc/sys/fs/aio-max-nr 4194304 ubuntu@zm93k8:/etc$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 16.04.2 LTS Release: 16.04 Codename: xenial ubuntu@zm93k8:/etc$ ubuntu@zm93k8:/etc$ dpkg -s qemu-kvm |grep Version Version: 1:2.5+dfsg-5ubuntu10.8 Is something already documented for Ubuntu KVM users warning them about the low default value, and some guidance as to how to select an appropriate value? Also, would you consider increasing the default aio-max-nr value to something much higher, to accommodate significantly more virtual guests? Thanks! ---uname output--- ubuntu@zm93k8:/etc$ uname -a Linux zm93k8 4.4.0-62-generic #83-Ubuntu SMP Wed Jan 18 14:12:54 UTC 2017 s390x s390x s390x GNU/Linux Machine Type = z14 ---Debugger--- A debugger is not configured ---Steps to Reproduce--- See Problem Description. The problem was happening a week ago, so this may not reflect that activity. This file was collected on Aug 7, one week after we were hitting the problem. If I need to reproduce the problem and get fresh data, please let me know. /var/log/messages doesn't exist on this system, so I provided syslog output instead. All data have been collected too late after the problem was observed over a week ago. If you need me to reproduce the problem and get new data, please let me know. That's not a problem. Also, we would have to make special arrangements for login access to these systems. I'm happy to run traces and data collection for you as needed. If that's not sufficient, then we'll explore log in access for you. Thanks... - Scott G. I was able to successfully recreate the problem and captured / attached new debug docs. Recreate procedure: # Started out with no virtual guests running. ubuntu@zm93k8:/home/scottg$ virsh list Id Name State ---------------------------------------------------- # Set fs.aio-max-nr back to original Ubuntu "out of the box" value in /etc/sysctl.conf ubuntu@zm93k8:~$ tail -1 /etc/sysctl.conf fs.aio-max-nr = 65536 ## sysctl -a shows: fs.aio-max-nr = 4194304 ## Reload sysctl. ubuntu@zm93k8:~$ sudo sysctl -p /etc/sysctl.conf fs.aio-max-nr = 65536 ubuntu@zm93k8:~$ ubuntu@zm93k8:~$ sudo sysctl -a |grep fs.aio-max-nr fs.aio-max-nr = 65536 ubuntu@zm93k8:~$ cat /proc/sys/fs/aio-max-nr 65536 # Attempt to start more than 17 qcow2 virtual guests on the Ubuntu host. Fails on the 18th XML. Script used to start guests.. ubuntu@zm93k8:/home/scottg$ date;./start_privs.sh Wed Aug 23 13:21:25 EDT 2017 virsh start zs93kag70015 Domain zs93kag70015 started Started zs93kag70015 succesfully ... virsh start zs93kag70020 Domain zs93kag70020 started Started zs93kag70020 succesfully ... virsh start zs93kag70021 Domain zs93kag70021 started Started zs93kag70021 succesfully ... virsh start zs93kag70022 Domain zs93kag70022 started Started zs93kag70022 succesfully ... virsh start zs93kag70023 Domain zs93kag70023 started Started zs93kag70023 succesfully ... virsh start zs93kag70024 Domain zs93kag70024 started Started zs93kag70024 succesfully ... virsh start zs93kag70025 Domain zs93kag70025 started Started zs93kag70025 succesfully ... virsh start zs93kag70026 Domain zs93kag70026 started Started zs93kag70026 succesfully ... virsh start zs93kag70027 Domain zs93kag70027 started Started zs93kag70027 succesfully ... virsh start zs93kag70028 Domain zs93kag70028 started Started zs93kag70028 succesfully ... virsh start zs93kag70029 Domain zs93kag70029 started Started zs93kag70029 succesfully ... virsh start zs93kag70030 Domain zs93kag70030 started Started zs93kag70030 succesfully ... virsh start zs93kag70031 Domain zs93kag70031 started Started zs93kag70031 succesfully ... virsh start zs93kag70032 Domain zs93kag70032 started Started zs93kag70032 succesfully ... virsh start zs93kag70033 Domain zs93kag70033 started Started zs93kag70033 succesfully ... virsh start zs93kag70034 Domain zs93kag70034 started Started zs93kag70034 succesfully ... virsh start zs93kag70035 Domain zs93kag70035 started Started zs93kag70035 succesfully ... virsh start zs93kag70036 error: Failed to start domain zs93kag70036 error: internal error: process exited while connecting to monitor: 2017-08-23T17:21:47.131809Z qemu-kvm: -drive file=/guestimages/data1/zs93kag70036.qcow2,format=qcow2,if=none,id=drive-virtio-disk0,cache=none,aio=native: Could not open backing file: Could not set AIO state: Inappropriate ioctl for device Exiting script ... start zs93kag70036 failed ubuntu@zm93k8:/home/scottg$ # Show that there are only 17 running guests. ubuntu@zm93k8:/home/scottg$ virsh list |grep run |wc -l 17 ubuntu@zm93k8:/home/scottg$ virsh list Id Name State ---------------------------------------------------- 25 zs93kag70015 running 26 zs93kag70020 running 27 zs93kag70021 running 28 zs93kag70022 running 29 zs93kag70023 running 30 zs93kag70024 running 31 zs93kag70025 running 32 zs93kag70026 running 33 zs93kag70027 running 34 zs93kag70028 running 35 zs93kag70029 running 36 zs93kag70030 running 37 zs93kag70031 running 38 zs93kag70032 running 39 zs93kag70033 running 40 zs93kag70034 running 41 zs93kag70035 running # For fun, try starting zs93kag70036 again manually. ubuntu@zm93k8:/home/scottg$ date;virsh start zs93kag70036 Wed Aug 23 13:27:28 EDT 2017 error: Failed to start domain zs93kag70036 error: internal error: process exited while connecting to monitor: 2017-08-23T17:27:30.031782Z qemu-kvm: -drive file=/guestimages/data1/zs93kag70036.qcow2,format=qcow2,if=none,id=drive-virtio-disk0,cache=none,aio=native: Could not open backing file: Could not set AIO state: Inappropriate ioctl for device # Show the XML (they're all basically the same)... ubuntu@zm93k8:/home/scottg$ cat zs93kag70036.xml <domain type='kvm'> <name>zs93kag70036</name> <memory unit='MiB'>4096</memory> <currentMemory unit='MiB'>2048</currentMemory> <vcpu placement='static'>2</vcpu> <os> <type arch='s390x' machine='s390-ccw-virtio'>hvm</type> </os> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>preserve</on_crash> <devices> <emulator>/usr/bin/qemu-kvm</emulator> <disk type='file' device='disk'> <driver name ='qemu' type='qcow2' cache='none' io='native'/> <source file='/guestimages/data1/zs93kag70036.qcow2'/> <target dev='vda' bus='virtio'/> <address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0000'/> <boot order='1'/> </disk> <interface type='network'> <source network='privnet1'/> <model type='virtio'/> <mac address='52:54:00:70:d0:36'/> <address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0001'/> </interface> <!-- <disk type='block' device='disk'> <driver name ='qemu' type='raw' cache='none'/> <source dev='/dev/disk/by-id/dm-uuid-mpath-36005076802810e5540000000000006e4'/> <target dev='vde' bus='virtio'/> <address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0005'/> <readonly/> </disk> --> <disk type='file' device='disk'> <driver name ='qemu' type='raw' cache='none' io='native'/> <source file='/guestimages/data1/zs93kag70036.prm'/> <target dev='vdf' bus='virtio'/> <address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0006'/> </disk> <disk type='file' device='cdrom'> <driver name='qemu' type='raw'/> <source file='/guestimages/data1/zs93kag70036.iso'/> <target dev='sda' bus='scsi'/> <readonly/> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </disk> <controller type='usb' index='0' model='none'/> <memballoon model='none'/> <console type='pty'> <target type='sclp' port='0'/> </console> </devices> </domain> This condition is very easy to replicate. However, we may be losing this system in the next day or two, so please let me know ASAP if you need any more data. Thank you... - Scott G. == Comment: #11 - Viktor Mihajlovski <mihaj...@de.ibm.com> - 2017-09-14 In order to support many KVM guests it is advisable to raise the aio-max-nr as suggested in the problem description, see also http://kvmonz.blogspot.co.uk/p/blog-page_7.html. I would also suggest that the system default setting is increased. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1717224/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
