[Qemu-devel] qemu live migration error from 2.0 to 2.1

[Qemu-devel] qemu live migration error from 2.0 to 2.1

[William Dauchy]

Hello,

For a qemu live migration from 2.0 to 2.1 I'm getting:

qemu-system-x86_64: Length mismatch: /rom@etc/acpi/tables: 3000 in != 20000
qemu-system-x86_64: Unknown ramblock "/table-loader", cannot accept migration
qemu-system-x86_64: Ack, bad migration stream!
qemu-system-x86_64: Illegal RAM offset f0e2d500f06000
qemu: warning: error while loading state for instance 0x0 of device 'ram'
qemu-system-x86_64: load of migration failed: Invalid argument

I was wondering if it was a bug or if I was supposed to do something
to avoid this error.
I saw the bug report for qemu1.7 but it's not my case.

Regards,
-- 
William

Re: [Qemu-devel] qemu live migration error from 2.0 to 2.1

[Dr. David Alan Gilbert]

(CC Paolo)

* William Dauchy (wdauchy@gmail.com) wrote:
> Hello,
> 
> For a qemu live migration from 2.0 to 2.1 I'm getting:
> 
> qemu-system-x86_64: Length mismatch: /rom@etc/acpi/tables: 3000 in != 20000
> qemu-system-x86_64: Unknown ramblock "/table-loader", cannot accept migration
> qemu-system-x86_64: Ack, bad migration stream!
> qemu-system-x86_64: Illegal RAM offset f0e2d500f06000
> qemu: warning: error while loading state for instance 0x0 of device 'ram'
> qemu-system-x86_64: load of migration failed: Invalid argument
> 
> I was wondering if it was a bug or if I was supposed to do something
> to avoid this error.

That should work.

> I saw the bug report for qemu1.7 but it's not my case.

Can you confirm this is on the final 2.1 release (there was a fix that
went in just around rc5).

What's your command line on both ends?

Dave
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [Qemu-devel] qemu live migration error from 2.0 to 2.1

[William Dauchy]

On Tue, Aug 5, 2014 at 8:57 PM, Dr. David Alan Gilbert
<dgilbert@redhat.com> wrote:
> Can you confirm this is on the final 2.1 release (there was a fix that
> went in just around rc5).

for the receiver, I'm using 2.1
# qemu-system-x86_64 --version
QEMU emulator version 2.1.0, Copyright (c) 2003-2008 Fabrice Bellar


for the sender side, here is the qmp result:

(QEMU) query-version
{   u'return': {   u'package': u'',
                   u'qemu': {   u'major': 2, u'micro': 50, u'minor': 0}}}

> What's your command line on both ends?

the receiver:

qemu-system-x86_64 -m 2048 -cpu host,level=9 -nodefconfig -nodefaults
-nographic -readconfig /var/lib/qemu/VM_A/config -pidfile
/var/lib/qemu/VM_A/pid -serial pty -D /var/lib/qemu/VM_A/log -d
unimp,guest_errors -incoming tcp:0:32768

/var/lib/qemu/VM_A/config:
[name]
  guest = "VM_A"
  process = "VM_A"

[chardev "compat_monitor0"]
  backend = "socket"
  path = "/var/lib/qemu/VM_A/sock"
  server = "on"
  wait = "off"

[device]
  driver = "virtio-balloon"

[rtc]
  base = "utc"

[mon "compat_monitor0"]
  mode = "control"
  chardev = "compat_monitor0"
  default = "on"

[machine]
  kernel = "/boot/bzImage"
  append = "root=/dev/sda console=ttyS0 ro"
  accel = "kvm"

[device]
  driver = "virtio-rng-pci"

[device "scsi0"]
  driver = "virtio-scsi-pci"
  hotplug = "on"

[...] vif config

[...] disk config

[smp-opts]
  cpus = "2"
  sockets = "1"
  cores = "1"
  threads = "1"
  maxcpus = "12"


the sender has the exact same command (without tcp receiver) and also
the same config; I'm just issuing a migrate command through qmp.

-- 
William

Re: [Qemu-devel] qemu live migration error from 2.0 to 2.1

[Markus Armbruster]

William Dauchy <wdauchy@gmail.com> writes:

> On Tue, Aug 5, 2014 at 8:57 PM, Dr. David Alan Gilbert
> <dgilbert@redhat.com> wrote:
>> Can you confirm this is on the final 2.1 release (there was a fix that
>> went in just around rc5).
>
> for the receiver, I'm using 2.1
> # qemu-system-x86_64 --version
> QEMU emulator version 2.1.0, Copyright (c) 2003-2008 Fabrice Bellar
>
>
> for the sender side, here is the qmp result:
>
> (QEMU) query-version
> {   u'return': {   u'package': u'',
>                    u'qemu': {   u'major': 2, u'micro': 50, u'minor': 0}}}
>
>> What's your command line on both ends?
>
> the receiver:
>
> qemu-system-x86_64 -m 2048 -cpu host,level=9 -nodefconfig -nodefaults
> -nographic -readconfig /var/lib/qemu/VM_A/config -pidfile
> /var/lib/qemu/VM_A/pid -serial pty -D /var/lib/qemu/VM_A/log -d
> unimp,guest_errors -incoming tcp:0:32768
>
> /var/lib/qemu/VM_A/config:
> [name]
>   guest = "VM_A"
>   process = "VM_A"
>
> [chardev "compat_monitor0"]
>   backend = "socket"
>   path = "/var/lib/qemu/VM_A/sock"
>   server = "on"
>   wait = "off"
>
> [device]
>   driver = "virtio-balloon"
>
> [rtc]
>   base = "utc"
>
> [mon "compat_monitor0"]
>   mode = "control"
>   chardev = "compat_monitor0"
>   default = "on"
>
> [machine]
>   kernel = "/boot/bzImage"
>   append = "root=/dev/sda console=ttyS0 ro"
>   accel = "kvm"
>
> [device]
>   driver = "virtio-rng-pci"
>
> [device "scsi0"]
>   driver = "virtio-scsi-pci"
>   hotplug = "on"
>
> [...] vif config
>
> [...] disk config
>
> [smp-opts]
>   cpus = "2"
>   sockets = "1"
>   cores = "1"
>   threads = "1"
>   maxcpus = "12"
>
>
> the sender has the exact same command (without tcp receiver) and also
> the same config; I'm just issuing a migrate command through qmp.

Looks like you're not specifying a machine type.

If that's the case, your source machine uses the old QEMU's default
machine type, probably pc-i440fx-2.0, and your destination machine uses
the new default, probably pc-i440fx-2.1.

Migration requires identical machine types on source and destination.
If they differ, migration may work anyway (this is the very lucky case),
fail outright (lucky case), or it may succeed, then make the guest
misbehave or blow up on the destination, possibly after some delay.

Please try with 'type = "pc-i440fx-2.0"' in your '[machine]' section.

Re: [Qemu-devel] qemu live migration error from 2.0 to 2.1

[Paolo Bonzini]

Il 05/08/2014 20:57, Dr. David Alan Gilbert ha scritto:
> (CC Paolo)
> 
> * William Dauchy (wdauchy@gmail.com) wrote:
>> Hello,
>>
>> For a qemu live migration from 2.0 to 2.1 I'm getting:
>>
>> qemu-system-x86_64: Length mismatch: /rom@etc/acpi/tables: 3000 in != 20000
>> qemu-system-x86_64: Unknown ramblock "/table-loader", cannot accept migration
>> qemu-system-x86_64: Ack, bad migration stream!
>> qemu-system-x86_64: Illegal RAM offset f0e2d500f06000
>> qemu: warning: error while loading state for instance 0x0 of device 'ram'
>> qemu-system-x86_64: load of migration failed: Invalid argument
>>
>> I was wondering if it was a bug or if I was supposed to do something
>> to avoid this error.
> 
> That should work.
> 
>> I saw the bug report for qemu1.7 but it's not my case.
> 
> Can you confirm this is on the final 2.1 release (there was a fix that
> went in just around rc5).
> 
> What's your command line on both ends?

I suspect he's using "-M pc" on both.  You must use "-M pc-i440fx-2.0"
on both if you're migrating from 2.0 to a different version.

Paolo

Re: [Qemu-devel] qemu live migration error from 2.0 to 2.1

[Paolo Bonzini]

Il 06/08/2014 08:16, Markus Armbruster ha scritto:
>> for the receiver, I'm using 2.1
>> # qemu-system-x86_64 --version
>> QEMU emulator version 2.1.0, Copyright (c) 2003-2008 Fabrice Bellar
>>
>>
>> for the sender side, here is the qmp result:
>>
>> (QEMU) query-version
>> {   u'return': {   u'package': u'',
>>                    u'qemu': {   u'major': 2, u'micro': 50, u'minor': 0}}}
>>

This is a development version between 2.0.0 and 2.0.0-rc1; it may have
bugs such as the one that was fixed in 2.0.0-rc5.

Migration from development versions is not supported.  You must either
upgrade to 2.1.0, or downgrade to the released 2.0.0 version.

Paolo

Re: [Qemu-devel] qemu live migration error from 2.0 to 2.1

[William Dauchy]

On Wed, Aug 6, 2014 at 9:47 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> I suspect he's using "-M pc" on both.

Is it the default value? because it's not the case in my command line.

> You must use "-M pc-i440fx-2.0"
> on both if you're migrating from 2.0 to a different version.

wow. I wasn't expecting such behavior; i.e migration between qemu
version does not seem trivial and it removes the benefits; better
using stop/start.
thanks for the info.

-- 
William

Re: [Qemu-devel] qemu live migration error from 2.0 to 2.1

[William Dauchy]

On Wed, Aug 6, 2014 at 9:49 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> This is a development version between 2.0.0 and 2.0.0-rc1; it may have
> bugs such as the one that was fixed in 2.0.0-rc5.

you mean 2.1.0-rc5

> Migration from development versions is not supported.  You must either
> upgrade to 2.1.0, or downgrade to the released 2.0.0 version.

in all case I would have the same issue with 2.0.0 version since the
fix has been pushed in 2.1.0-rc5

-- 
William

Re: [Qemu-devel] qemu live migration error from 2.0 to 2.1

[Dr. David Alan Gilbert]

* William Dauchy (wdauchy@gmail.com) wrote:
> On Wed, Aug 6, 2014 at 9:47 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
> > I suspect he's using "-M pc" on both.
> 
> Is it the default value? because it's not the case in my command line.
> 
> > You must use "-M pc-i440fx-2.0"
> > on both if you're migrating from 2.0 to a different version.
> 
> wow. I wasn't expecting such behavior; i.e migration between qemu
> version does not seem trivial and it removes the benefits; better
> using stop/start.
> thanks for the info.

The trick is to pick a -M value and stick with it; then you should be
able to keep migrating to newer QEMU versions easily (just don't
go with dev versions because things are often broken in them).

-M pc   is special, don't use that if you want to be able to migrate

Dave

--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [Qemu-devel] qemu live migration error from 2.0 to 2.1

[William Dauchy]

On Wed, Aug 6, 2014 at 11:17 AM, Dr. David Alan Gilbert
<dgilbert@redhat.com> wrote:
> The trick is to pick a -M value and stick with it; then you should be
> able to keep migrating to newer QEMU versions easily (just don't
> go with dev versions because things are often broken in them).

ok
for dev versions, I'm just cherry picking interesting fixes which are
not yet released in stable.

> -M pc   is special, don't use that if you want to be able to migrate

understood, I guess it's the default value
-- 
William