[openstack-nova] Attached volume is not available in the VM

Aleksander Wojtal aleksander.wojtal at tietoevry.com
Thu Jul 29 12:51:26 UTC 2021


Hi Lee

Let me clarify the steps, I might have mislead you. The reboot of the compute is done before issuing the server add volume command.
Steps:
1. Create VM
2. Create volume
3. Reboot compute on which is the VM
4. About 1 min later issue "openstack server add volume" command
5. Observe volume being attached in DB but not in Libvirt.

Pozdrawiam / Best regards, 

Aleksander Wojtal, Junior Software Engineer 
TietoEvry, BU Telco Cloud Infra & Applications

-----Original Message-----
From: Lee Yarwood <lyarwood at redhat.com> 
Sent: Tuesday, July 27, 2021 10:25 PM
To: Aleksander Wojtal <aleksander.wojtal at tietoevry.com>
Cc: openstack-discuss at lists.openstack.org; Balázs Gibizer <balazs.gibizer at ericsson.com>; Piotr Mossakowski <Piotr.Mossakowski at tietoevry.com>
Subject: Re: [openstack-nova] Attached volume is not available in the VM

On 26-07-21 08:14:46, Aleksander Wojtal wrote:
> Hello,
> 
> During our testing we perform reboot of compute during volume attached task. Result is as follows.

I was about to ask for more details when I saw this initial line. This is almost expected if you restart n-cpu while it's servicing a request like attaching a volume.

The compute service isn't able to pick these tasks back up again and complete them once it restarts. That said given the `in-use` volume state below we should've basically completed the attach before the host reboot so I don't understand why it didn't show up in the instance.
 
> Volume is marked as attached to VM (also in DB) ceeinfra at lcm1:~> 
> openstack volume list
> +--------------------------------------+-----------------------------------------------------------------------------+-----------+------+--------------------------------------------------------------------------------------------------------------+
> | ID                                   | Name                                                                        | Status    | Size | Attached to                                                                                                  |
> +--------------------------------------+-----------------------------------------------------------------------------+-----------+------+--------------------------------------------------------------------------------------------------------------+
> | c52d406c-5587-445d-9da1-436ffbbe3541 | vol_neXt-488                                                                | available |   10 |                                                                                                              |
> | f3e45efc-35eb-4f95-8e71-f50b5cb69028 | RebootOfComputeHostWhilePerformingVolumeOperations-Volume-0618_19_45_12_669 | in-use    |   20 | Attached to neXt-377_VM1--RebootOfComputeHostWhilePerformingVolumeOperations--0618_19_44_16_775 on /dev/vdb  |
> | 1bd81392-e2c9-4725-93c8-baa484924f21 | vol_neXt-488                                                                | available |   10 |                                                                                                              |
> | 919db17c-0729-409c-bf59-74539edcea47 | vol_neXt-488                                                                | available |   10 |                                                                                                              |
> +--------------------------------------+-----------------------------------------------------------------------------+-----------+------+--------------------------------------------------------------------------------------------------------------+
> 
> From VM perspective too.
> ceeinfra at lcm1:~> openstack server show 
> neXt-377_VM1--RebootOfComputeHostWhilePerformingVolumeOperations--0618
> _19_44_16_775
> +-------------------------------------+-------------------------------------------------------------------------------------+
> | Field                               | Value                                                                               |
> +-------------------------------------+-------------------------------------------------------------------------------------+
> | OS-DCF:diskConfig                   | MANUAL                                                                              |
> | OS-EXT-AZ:availability_zone         | nova                                                                                |
> | OS-EXT-SRV-ATTR:host                | compute-0-11.k2.ericsson.se                                                         |
> | OS-EXT-SRV-ATTR:hypervisor_hostname | compute-0-11.k2.ericsson.se                                                         |
> | OS-EXT-SRV-ATTR:instance_name       | instance-00001edc                                                                   |
> | OS-EXT-STS:power_state              | Running                                                                             |
> | OS-EXT-STS:task_state               | None                                                                                |
> | OS-EXT-STS:vm_state                 | active                                                                              |
> | OS-SRV-USG:launched_at              | 2021-06-18T14:14:58.000000                                                          |
> | OS-SRV-USG:terminated_at            | None                                                                                |
> | accessIPv4                          |                                                                                     |
> | accessIPv6                          |                                                                                     |
> | addresses                           | NovaController-Network-0618_19_44_16_852=10.0.0.5                                   |
> | config_drive                        | True                                                                                |
> | created                             | 2021-06-18T14:14:19Z                                                                |
> | flavor                              | m1.small (2)                                                                        |
> | hostId                              | 5078bfd4fabd8b2e7c9f4554b3ac08d536ceebb5f393db4d38c8ff60                            |
> | id                                  | 95ed49ed-b3f8-46ae-80a0-544b939c50b7                                                |
> | image                               | JCAT_Common_CirrOS_i386 (b71f3fbd-59f1-4c29-a296-5065fe0406f7)                      |
> | key_name                            | None                                                                                |
> | name                                | neXt-377_VM1--RebootOfComputeHostWhilePerformingVolumeOperations--0618_19_44_16_775 |
> | progress                            | 0                                                                                   |
> | project_id                          | b63725c8ebaf43ebabbed497f41eb71c                                                    |
> | properties                          | ha-policy='managed-on-host'                                                         |
> | scheduler_hints                     | {}                                                                                  |
> | security_groups                     | name='default'                                                                      |
> | status                              | ACTIVE                                                                              |
> | updated                             | 2021-06-18T14:22:07Z                                                                |
> | user_id                             | f490f07b813748698e56ca7641d46a72                                                    |
> | volumes_attached                    | id='f3e45efc-35eb-4f95-8e71-f50b5cb69028'                                           |
> +-------------------------------------+-------------------------------------------------------------------------------------+

What about `openstack server volume list 95ed49ed-b3f8-46ae-80a0-544b939c50b7`?

Did you restart the instance as I assuming a hard reboot would resolve the issue here.

> From Libvirt perspective, volume is not attached to VM
> 
> compute-0-11:/var/log # virsh dumpxml instance-00001edc <domain 
> type='kvm' id='1'>
>   <name>instance-00001edc</name>
>   <uuid>95ed49ed-b3f8-46ae-80a0-544b939c50b7</uuid>
> (...)
>   <devices>
>     <emulator>/usr/bin/qemu-system-x86_64</emulator>
>     <disk type='file' device='disk'>
>       <driver name='qemu' type='qcow2' cache='directsync'/>
>       <source file='/var/lib/nova/instances/95ed49ed-b3f8-46ae-80a0-544b939c50b7/disk' index='2'/>
>       <backingStore type='file' index='3'>
>         <format type='raw'/>
>         <source file='/var/lib/nova/instances/_base/af82cd8216adb002916bb9e422a3fbb637022ec6'/>
>         <backingStore/>
>       </backingStore>
>       <target dev='vda' bus='virtio'/>
>       <alias name='virtio-disk0'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
>     </disk>
>     <disk type='file' device='cdrom'>
>       <driver name='qemu' type='raw' cache='directsync'/>
>       <source file='/var/lib/nova/instances/95ed49ed-b3f8-46ae-80a0-544b939c50b7/disk.config' index='1'/>
>       <backingStore/>
>       <target dev='hdd' bus='ide'/>
>       <readonly/>
>       <alias name='ide0-1-1'/>
>       <address type='drive' controller='0' bus='1' target='0' unit='1'/>
>     </disk>
>     <controller type='usb' index='0' model='piix3-uhci'>
> (...)
> </domain>

It's easier to use `virsh domblklist 95ed49ed-b3f8-46ae-80a0-544b939c50b7` to list the attached disks FWIW.
 
> System does not provide any indication of the problem. There should be some kind of indication to user that volume attachment was not completed.

Yeah there's no real way for n-cpu to handle this, the event log for the action isn't going to be complete but there's no state machine for volume attachments that we can rely on here.

Would you mind opening a bug with the above and the following event details for the attach request:

$ openstack server event list 95ed49ed-b3f8-46ae-80a0-544b939c50b7

$ openstack server event show 95ed49ed-b3f8-46ae-80a0-544b939c50b7
$volume-attach-request-id

https://docs.openstack.org/api-guide/compute/faults.html

Cheers,

-- 
Lee Yarwood                 A5D1 9385 88CB 7E5F BE64  6618 BCA6 6E33 F672 2D76


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