Xen users - Feb 2012 - Need technical support on Xen migration development

Dear everyone,

We are currently we are doing some research about Virtual Machine Migration, and
I was redirected here when asking the community manager for help.

What we know is that a VM running on Xen can be stored as *.chk, and that's
how VM migration is done by Xen. Also, IBM PowerVM has its way of storing a VM.
Our goal is to convert the *.chk file into the IBM PowerVM format, so the same
guest OS (e.g. Linux) can be migrated from x86 to Power servers.

Could anyone please give us some advice about the data structure of *.chk file,
or where to find more reference? Any suggestion would be highly appreciated.

Thanks a lot.


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2012/2/29 Sha <pichu@vip.sina.com>:
> Dear everyone,
>
> We are currently we are doing some research about Virtual Machine
Migration,
> and I was redirected here when asking the community manager for help.
>
> What we know is that a VM running on Xen can be stored as *.chk, and
that''s
> how VM migration is done by Xen. Also, IBM PowerVM has its way of storing a
> VM. Our goal is to convert the *.chk file into the IBM PowerVM format, so
> the same guest OS (e.g. Linux) can be migrated from x86 to Power servers.
>
> Could anyone please give us some advice about the data structure of *.chk
> file, or where to find more reference? Any suggestion would be highly
> appreciated.
Short version: You can''t.

Long version:
- xen runs on x86 (well, mostly on x86), while powerVM runs on Power
CPU architecture
- those two cpu architectures are binary incompatible
- For migration purpose, you need to install the new OS with the
correct arch, then migrate the config

-- 
Fajar

Dear Fajar,

Thank you for your reply.

However, I know that the PowerVM Lx86 from IBM can run x86 applications on Power
server, so is it technically possible for a VM migrating from Xen to PowerVM?

Thanks again.

Sha

----- Original Message -----
From: Fajar&nbsp;A.&nbsp;Nugraha&nbsp;<list@fajar.net>
To: Sha&nbsp;<pichu@vip.sina.com>
Subject:
Re:&nbsp;[Xen-users]&nbsp;Need&nbsp;technical&nbsp;support&nbsp;on&nbsp;Xen&nbsp;migration&nbsp;development
Date: 12-02-29 14:02:23

2012/2/29&nbsp;Sha&nbsp;<pichu@vip.sina.com>:
>&nbsp;Dear&nbsp;everyone,
>
>&nbsp;We&nbsp;are&nbsp;currently&nbsp;we&nbsp;are&nbsp;doing&nbsp;some&nbsp;research&nbsp;about&nbsp;Virtual&nbsp;Machine&nbsp;Migration,
>&nbsp;and&nbsp;I&nbsp;was&nbsp;redirected&nbsp;here&nbsp;when&nbsp;asking&nbsp;the&nbsp;community&nbsp;manager&nbsp;for&nbsp;help.
>
>&nbsp;What&nbsp;we&nbsp;know&nbsp;is&nbsp;that&nbsp;a&nbsp;VM&nbsp;running&nbsp;on&nbsp;Xen&nbsp;can&nbsp;be&nbsp;stored&nbsp;as&nbsp;*.chk,&nbsp;and&nbsp;that's
>&nbsp;how&nbsp;VM&nbsp;migration&nbsp;is&nbsp;done&nbsp;by&nbsp;Xen.&nbsp;Also,&nbsp;IBM&nbsp;PowerVM&nbsp;has&nbsp;its&nbsp;way&nbsp;of&nbsp;storing&nbsp;a
>&nbsp;VM.&nbsp;Our&nbsp;goal&nbsp;is&nbsp;to&nbsp;convert&nbsp;the&nbsp;*.chk&nbsp;file&nbsp;into&nbsp;the&nbsp;IBM&nbsp;PowerVM&nbsp;format,&nbsp;so
>&nbsp;the&nbsp;same&nbsp;guest&nbsp;OS&nbsp;(e.g.&nbsp;Linux)&nbsp;can&nbsp;be&nbsp;migrated&nbsp;from&nbsp;x86&nbsp;to&nbsp;Power&nbsp;servers.
>
>&nbsp;Could&nbsp;anyone&nbsp;please&nbsp;give&nbsp;us&nbsp;some&nbsp;advice&nbsp;about&nbsp;the&nbsp;data&nbsp;structure&nbsp;of&nbsp;*.chk
>&nbsp;file,&nbsp;or&nbsp;where&nbsp;to&nbsp;find&nbsp;more&nbsp;reference?&nbsp;Any&nbsp;suggestion&nbsp;would&nbsp;be&nbsp;highly
>&nbsp;appreciated.


Short&nbsp;version:&nbsp;You&nbsp;can't.



Long&nbsp;version:

-&nbsp;xen&nbsp;runs&nbsp;on&nbsp;x86&nbsp;(well,&nbsp;mostly&nbsp;on&nbsp;x86),&nbsp;while&nbsp;powerVM&nbsp;runs&nbsp;on&nbsp;Power

CPU&nbsp;architecture

-&nbsp;those&nbsp;two&nbsp;cpu&nbsp;architectures&nbsp;are&nbsp;binary&nbsp;incompatible

-&nbsp;For&nbsp;migration&nbsp;purpose,&nbsp;you&nbsp;need&nbsp;to&nbsp;install&nbsp;the&nbsp;new&nbsp;OS&nbsp;with&nbsp;the

correct&nbsp;arch,&nbsp;then&nbsp;migrate&nbsp;the&nbsp;config



--&nbsp;

Fajar



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2012/2/29 Sha <pichu@vip.sina.com>:
> Dear Fajar,
>
> Thank you for your reply.
>
> However, I know that the PowerVM Lx86 from IBM can run x86 applications on
> Power server, so is it technically possible for a VM migrating from Xen to
> PowerVM?
I''d suggest against any form of emulation. Your performance will
suffer.

If you insist to do it anyway:
- contact your IBM representative. You HAVE one, right? IMHO there''s
no point in having a high-end systems like power or sparc without a
good support contract. They might have some shiny P2V/V2V tool that
you can use.
- learn how Lx86 works.

For most virtualization products, you usually only need the disk image
(e.g. for xen, vmware, qemu/kvm, etc) or the files (e.g. solaris
containers, lxc, openvz). To do offline migration, simply copy what''s
needed, adjust the config, and you SHOULD be good. No need for
vendor-specific migration tool

For example, if you use new-enough linux distro (e.g. ubuntu oneiric),
migrating from xen <-> vmware is as simple as booting a rescue
environment (e.g. sysrescuecd) and using "dd" to copy the disk IMAGE.
Migrating from xen <-> lxc on the other hand requires copying the
FILES, adjusting some configs, and running some scripts.

-- 
Fajar
>
> Thanks again.
>
> Sha
>
>
> ----- Original Message -----
> From: Fajar A. Nugraha <list@fajar.net>
> To: Sha <pichu@vip.sina.com>
> Subject:
Re: [Xen-users] Need technical support on Xen migration development
> Date: 12-02-29 14:02:23
>
> 2012/2/29 Sha <pichu@vip.sina.com>:
>> Dear everyone,
>>
>> We are currently we are doing some research about Virtual Machine Migration,
>> and I was redirected here when asking the community manager for help.
>>
>> What we know is that a VM running on Xen can be stored as *.chk, and that''s
>> how VM migration is done by Xen. Also, IBM PowerVM has its way of storing a
>> VM. Our goal is to convert the *.chk file into the IBM PowerVM format, so
>> the same guest OS (e.g. Linux) can be migrated from x86 to Power servers.
>>
>> Could anyone please give us some advice about the data structure of *.chk
>> file, or where to find more reference? Any suggestion would be highly
>> appreciated.
>
> Short version: You can''t.
>
> Long version:
> - xen runs on x86 (well, mostly on x86), while powerVM runs on Power
> CPU architecture
> - those two cpu architectures are binary incompatible
> - For migration purpose, you need to install the new OS with the
> correct arch, then migrate the config
>
> --
> Fajar

On Wed, Feb 29, 2012 at 1:22 PM, Fajar A. Nugraha <list@fajar.net>
wrote:
> 2012/2/29 Sha <pichu@vip.sina.com>:
>> However, I know that the PowerVM Lx86 from IBM can run x86 applications
on
>> Power server, so is it technically possible for a VM migrating from Xen
to
>> PowerVM?
> For example, if you use new-enough linux distro (e.g. ubuntu oneiric),
> migrating from xen <-> vmware is as simple as booting a rescue
> environment (e.g. sysrescuecd) and using "dd" to copy the disk
IMAGE.
> Migrating from xen <-> lxc on the other hand requires copying the
> FILES, adjusting some configs, and running some scripts.
After reading the documentation, it looks very similar to what
qemu-i386 would do. It allows you to run a single APPLICATION. Which
means if your application depends on external programs that is
normally part of the OS (e.g. cron) to run, I highly doubt it would
work.

-- 
Fajar

Thanks again for your comments. I have also been reading many docs, and it seems
that PowerVM Lx86 is indeed a pratical way to run x86 app on Power server, but
the main chanllenge might be how to resume the running state of a suspended app
in migration. I'm looking into that.

----- Original Message -----
From: Fajar&nbsp;A.&nbsp;Nugraha&nbsp;<list@fajar.net>
To: Sha&nbsp;<pichu@vip.sina.com>
Subject:
Re:&nbsp;[Xen-users]&nbsp;Need&nbsp;technical&nbsp;support&nbsp;on&nbsp;Xen&nbsp;migration&nbsp;development
Date: 12-02-29 16:07:34

On&nbsp;Wed,&nbsp;Feb&nbsp;29,&nbsp;2012&nbsp;at&nbsp;1:22&nbsp;PM,&nbsp;Fajar&nbsp;A.&nbsp;Nugraha&nbsp;<list@fajar.net>&nbsp;wrote:
>&nbsp;2012/2/29&nbsp;Sha&nbsp;<pichu@vip.sina.com>:

>>&nbsp;However,&nbsp;I&nbsp;know&nbsp;that&nbsp;the&nbsp;PowerVM&nbsp;Lx86&nbsp;from&nbsp;IBM&nbsp;can&nbsp;run&nbsp;x86&nbsp;applications&nbsp;on
>>&nbsp;Power&nbsp;server,&nbsp;so&nbsp;is&nbsp;it&nbsp;technically&nbsp;possible&nbsp;for&nbsp;a&nbsp;VM&nbsp;migrating&nbsp;from&nbsp;Xen&nbsp;to
>>&nbsp;PowerVM?



>&nbsp;For&nbsp;example,&nbsp;if&nbsp;you&nbsp;use&nbsp;new-enough&nbsp;linux&nbsp;distro&nbsp;(e.g.&nbsp;ubuntu&nbsp;oneiric),
>&nbsp;migrating&nbsp;from&nbsp;xen&nbsp;<->&nbsp;vmware&nbsp;is&nbsp;as&nbsp;simple&nbsp;as&nbsp;booting&nbsp;a&nbsp;rescue
>&nbsp;environment&nbsp;(e.g.&nbsp;sysrescuecd)&nbsp;and&nbsp;using&nbsp;"dd"&nbsp;to&nbsp;copy&nbsp;the&nbsp;disk&nbsp;IMAGE.
>&nbsp;Migrating&nbsp;from&nbsp;xen&nbsp;<->&nbsp;lxc&nbsp;on&nbsp;the&nbsp;other&nbsp;hand&nbsp;requires&nbsp;copying&nbsp;the
>&nbsp;FILES,&nbsp;adjusting&nbsp;some&nbsp;configs,&nbsp;and&nbsp;running&nbsp;some&nbsp;scripts.


After&nbsp;reading&nbsp;the&nbsp;documentation,&nbsp;it&nbsp;looks&nbsp;very&nbsp;similar&nbsp;to&nbsp;what

qemu-i386&nbsp;would&nbsp;do.&nbsp;It&nbsp;allows&nbsp;you&nbsp;to&nbsp;run&nbsp;a&nbsp;single&nbsp;APPLICATION.&nbsp;Which

means&nbsp;if&nbsp;your&nbsp;application&nbsp;depends&nbsp;on&nbsp;external&nbsp;programs&nbsp;that&nbsp;is

normally&nbsp;part&nbsp;of&nbsp;the&nbsp;OS&nbsp;(e.g.&nbsp;cron)&nbsp;to&nbsp;run,&nbsp;I&nbsp;highly&nbsp;doubt&nbsp;it&nbsp;would

work.



--&nbsp;

Fajar



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2012/2/29 Sha <pichu@vip.sina.com>:
> Thanks again for your comments. I have also been reading many docs, and it
> seems that PowerVM Lx86 is indeed a pratical way to run x86 app on Power
> server, but the main chanllenge might be how to resume the running state of
> a suspended app in migration. I''m looking into that.
Do you REALLY need to suspend the application, instead of shutting it down?

It will be impossible. Moving the machine state requires identical
condition on both source and target. For example, when moving between
two Xen dom0s, the CPUs need to be the same (or at least same-enough),
that even live migrate between AMD <-> intel doesn''t always work.

You want to live-migrate between a full-virtualization/PV setup (that
can run full-blown OS, with their own kernel) to something that only
supports binary translation for running a single application. It''s
simply can''t work.

-- 
Fajar

Yes. Live-migrating suspended apps would be the ultimate goal, but it won't
be a bad idea to consider the shut-down plan as a preliminary target. In other
words, we are just trying to figure out the probability.

Please point it out in case I didn't express myself clearly.

----- Original Message -----
From: Fajar&nbsp;A.&nbsp;Nugraha&nbsp;<list@fajar.net>
To: Sha&nbsp;<pichu@vip.sina.com>
Subject:
Re:&nbsp;[Xen-users]&nbsp;Need&nbsp;technical&nbsp;support&nbsp;on&nbsp;Xen&nbsp;migration&nbsp;development
Date: 12-02-29 16:34:47

2012/2/29&nbsp;Sha&nbsp;<pichu@vip.sina.com>:
>&nbsp;Thanks&nbsp;again&nbsp;for&nbsp;your&nbsp;comments.&nbsp;I&nbsp;have&nbsp;also&nbsp;been&nbsp;reading&nbsp;many&nbsp;docs,&nbsp;and&nbsp;it
>&nbsp;seems&nbsp;that&nbsp;PowerVM&nbsp;Lx86&nbsp;is&nbsp;indeed&nbsp;a&nbsp;pratical&nbsp;way&nbsp;to&nbsp;run&nbsp;x86&nbsp;app&nbsp;on&nbsp;Power
>&nbsp;server,&nbsp;but&nbsp;the&nbsp;main&nbsp;chanllenge&nbsp;might&nbsp;be&nbsp;how&nbsp;to&nbsp;resume&nbsp;the&nbsp;running&nbsp;state&nbsp;of
>&nbsp;a&nbsp;suspended&nbsp;app&nbsp;in&nbsp;migration.&nbsp;I'm&nbsp;looking&nbsp;into&nbsp;that.


Do&nbsp;you&nbsp;REALLY&nbsp;need&nbsp;to&nbsp;suspend&nbsp;the&nbsp;application,&nbsp;instead&nbsp;of&nbsp;shutting&nbsp;it&nbsp;down?



It&nbsp;will&nbsp;be&nbsp;impossible.&nbsp;Moving&nbsp;the&nbsp;machine&nbsp;state&nbsp;requires&nbsp;identical

condition&nbsp;on&nbsp;both&nbsp;source&nbsp;and&nbsp;target.&nbsp;For&nbsp;example,&nbsp;when&nbsp;moving&nbsp;between

two&nbsp;Xen&nbsp;dom0s,&nbsp;the&nbsp;CPUs&nbsp;need&nbsp;to&nbsp;be&nbsp;the&nbsp;same&nbsp;(or&nbsp;at&nbsp;least&nbsp;same-enough),

that&nbsp;even&nbsp;live&nbsp;migrate&nbsp;between&nbsp;AMD&nbsp;<->&nbsp;intel&nbsp;doesn't&nbsp;always&nbsp;work.



You&nbsp;want&nbsp;to&nbsp;live-migrate&nbsp;between&nbsp;a&nbsp;full-virtualization/PV&nbsp;setup&nbsp;(that

can&nbsp;run&nbsp;full-blown&nbsp;OS,&nbsp;with&nbsp;their&nbsp;own&nbsp;kernel)&nbsp;to&nbsp;something&nbsp;that&nbsp;only

supports&nbsp;binary&nbsp;translation&nbsp;for&nbsp;running&nbsp;a&nbsp;single&nbsp;application.&nbsp;It's

simply&nbsp;can't&nbsp;work.



--&nbsp;

Fajar


								

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