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Re: [Xen-devel] Re: FT for XCP

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rshriram at cs

Sep 28, 2011, 9:08 AM

Views: 425
Re: [Xen-devel] Re: FT for XCP

On Mon, Sep 26, 2011 at 8:58 AM, R J <torushikeshj [at] gmail> wrote:

> Hello Mike,
> Thank you for suggestion. I would love to incorporate remus in xapi if
> thats possible.

Great. That would be certainly welcome. [I am not a fan of ocaml ;)]

Remus as its inbuilt logic of detecting checkpoint failure and taking
> decisions accordingly.
> I think there is remus support for xen 3.4
What matters is the toolstack.
a. I am not sure if the xe toolstack uses libxenguest (tools/libxc) and
if it does, then it should have the basic remus support already.

b. I am also not sure if it is recent enough to include all the remus bug
fixes that went in over the last 6 months.

What do you suggest as my next step ?
Most of the remus code is python based and completely self contained. It
just needs
the domU's info (disk paths & vifs) as an s-expression. There is only one
api call to
Xend- to obtain the domU's s-expression.

1. A quick and dirty way would be to change this single api call to xapi
and obtain the s-expression, then you should have Remus running.

2. Another approach would be to re-write the toolstack code in ocaml - which
be easy. But make sure that ocaml can make netlink api calls.


> Regards,
> Rushikesh
> On Mon, Sep 26, 2011 at 12:38 PM, Mike McClurg <mike.mcclurg [at] citrix>wrote:
>> On 09/25/2011 09:11 PM, R J wrote:
>> Hello List,
>> I have a proposal and wont mind to implement my self but need a helping
>> hand to start on.
>> I want to implement the aggressive FT feature in XCP. The best way I could
>> imagine is the use of feature *Live Migration*
>> Steps
>> 1. Enable the FT of a particular VM using xe commands and adding as a
>> param to that VM e.g. xe vm-param-set FT=true uuid=XYZ
>> 2. If the FT = true detected by xenstore then xapi will initiate a live
>> migrate of that VM to any of available host.
>> 3. A parallel "network ping"/"xapi heartbit" from/to that host could be
>> initialized for each FT VM.
>> 4. Live migrate will run forever until its disabled by FT = false or one
>> of the host is down. e.g. the process will loop at 99.99% migration state
>> 5. If there is a packet drop of x packets the VM Migrate procedure will
>> mark the VM Migration as Complete and will switch the devices forcefully.
>> -- this could result in some data loss but I dont have any alternative to
>> this.
>> -- The specific x packets can be set by XCP but we cant rely for default
>> XCP Errors
>> 6. If there is a successful migration due to host down then we will again
>> start from step2
>> Above steps I have assumed to my knowledge, we can discuss the problems in
>> it.
>> Apologies if I'm being too naive.
>> Regards,
>> Rushikesh
>> This sounds like Remus (http://nss.cs.ubc.ca/remus/). Are you proposing
>> to implement Remus support in xapi?
>> Mike
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Subject User Time
Re: [Xen-devel] Re: FT for XCP rshriram at cs Sep 28, 2011, 9:08 AM
    Re: [Xen-devel] Re: FT for XCP torushikeshj at gmail Oct 8, 2011, 12:46 PM
    Re: [Xen-devel] Re: FT for XCP pasik at iki Oct 9, 2011, 8:10 AM

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