On 04/21/2011 10:32 AM, Daniel P. Berrange wrote:
> Migration just seems togo from bad to worse. We already had to
s/togo/to go/
>
> This patch attempts to introduce a version 3 that uses the
> improved 5 step sequence
>
> * Src: Begin
> - Generate XML to pass to dst
> - Generate optional cookie to pass to dst
>
> * Dst: Prepare
> - Get ready to accept incoming VM
> - Generate optional cookie to pass to src
>
> * Src: Perform
> - Start migration and wait for send completion
> - Generate optional cookie to pass to dst
>
> * Dst: Finish
> - Wait for recv completion and check status
> - Kill off VM if failed, resume if success
> - Generate optional cookie to pass to src
>
> * Src: Confirm
> - Kill off VM if success, resume if failed
I think we've covered that this is a reasonable idiom in other threads.
At least, I can't think of anything else to add.
>
> The API is designed to allow both input and output cookies
> in all methods where applicable. This lets us pass around
> arbitrary extra driver specific data between src & dst during
> migration. Combined with the extra 'Begin' method this lets
> us pass lease information from source to dst at the start of
> migration
>
> Moving the killing of the source VM out of Perform and
> into Confirm, means we can now recover if the dst host
> can't successfully Finish receiving migration data.
I think this also opens the gate to allowing the destination side
gracefully abort the receive job, although I'm not sure if your patch
series got to that point, yet.
> + * Src: Begin
> + * - Generate XML to pass to dst
> + * - Generate optional cookie to pass to dst
> + *
> + * Dst: Prepare
> + * - Get ready to accept incoming VM
> + * - Generate optional cookie to pass to src
> + *
> + * Src: Perform
> + * - Start migration and wait for send completion
> + * - Generate optional cookie to pass to dst
> + *
> + * Dst: Finish
> + * - Wait for recv completion and check status
> + * - Kill off VM if failed, resume if success
> + * - Generate optional cookie to pass to src
> + *
> + * Src: Confirm
> + * - Kill off VM if success, resume if failed
> + *
> + */
>
> +/*
> + * Not for public use. This function is part of the internal
> + * implementation of migration in the remote case.
> + */
> +char *
> +virDomainMigrateBegin3(virDomainPtr domain,
> + char **cookieout,
> + int *cookieoutlen,
> + unsigned long flags,
> + const char *dname,
> + unsigned long bandwidth)
> +{
> + virConnectPtr conn;
> +
> + VIR_DOMAIN_DEBUG(domain, "cookieout=%p, cookieoutlen=%p, "
> + "flags=%lu, dname=%s, bandwidth=%lu",
> + cookieout, cookieoutlen, flags,
> + NULLSTR(dname), bandwidth);
> +
> + virResetLastError();
> +
> + if (!VIR_IS_CONNECTED_DOMAIN (domain)) {
I noticed spacing is funny here [s/DOMAIN (/DOMAIN(/]. Didn't look
closely for it elsewhere.
> +++ b/src/libvirt_private.syms
> @@ -547,6 +547,12 @@ virDomainMigratePerform;
> virDomainMigratePrepare2;
> virDomainMigratePrepare;
> virDomainMigratePrepareTunnel;
> +virDomainMigrateBegin3;
> +virDomainMigratePrepare3;
> +virDomainMigratePrepareTunnel3;
> +virDomainMigratePerform3;
> +virDomainMigrateFinish3;
> +virDomainMigrateConfirm3;
For consistency, sort these lines alphabetically amongst the other
functions.
You missed stubs for src/libxl/libxl_driver.c.
ACK with those nits fixed.
--
Eric Blake eblake@xxxxxxxxxx +1-801-349-2682
Libvirt virtualization library http://libvirt.org
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