Re: [libvirt] [PATCH] Add documentation about migration.
On Wed, Oct 26, 2011 at 12:46:42PM -0600, Eric Blake wrote:
On 10/24/2011 07:50 AM, Daniel P. Berrange wrote:
>From: "Daniel P. Berrange"<berrange(a)redhat.com>
>
>This adds a page documenting many aspects of migration:
>
> - The types of migration (managed direct, p2p, unmanaged direct)
> - Data transports (native, tunnelled)
> - Migration URIs
> - Config file handling
> - Example scenarios
Sounds very useful. The graphics generally look reasonable.
>
>diff --git a/docs/migration.html.in b/docs/migration.html.in
>index ee72b00..4a16162 100644
>--- a/docs/migration.html.in
>+++ b/docs/migration.html.in
I don't have this file in libvirt.git. Did you forget a
pre-requisite patch, or fail to squash two patches into one? It's
making it hard to review. I created a dummy version, if only to
test all the subsidiary pages.
Urgh, yes I meant to squash 2 patches together but forgot :-(
>+ very large RAM sizes, which dirty memory pages quickly. On
the deployment side, tunnelled
>+ transports do not require any extra network configuration over and above
what's already
>+ required for general libvirtd<a href="remote.html">remote
access</a>, and there is only
>+ need for a single port to be open on the firewall.
Also, should we mention "migration to file" (aka virsh
save), or is
that pushing the boundaries of what this page was intended to cover?
No, I consider that out of scope. This is just for cross-host
migration
>+<h3><a id="flowpeer2peer">Managed peer to
peer migration</a></h3>
>+
>+<p>
>+ With<em>peer to peer</em> migration, the libvirt client process
only
>+ talks to the libvirtd daemon on the source host. The libvirtd daemon
>+ will then connect to the destination host libvirtd and controls the
s/host libvirtd and/host libvirtd, which/
No, because that implies the dest host will control migration. Even my original
text was ambiguous in this respect, so I rewrote this block.
>+ will continue uninterrupted until completion.
>+</p>
>+
>+<p>
>+<img class="diagram" src="migration-managed-p2p.png"
alt="Migration peer-to-peer">
This image is wrong. It shows the client talking to the
destination, when in reality, the client only talks to the source,
and the source talks to the destination. That is, your diagram
looks identical to migration-managed-direct.png, although I don't
think you intended it to be that way.
Yep, saved over the top of the file :-(
Daniel
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