On 7/13/20 3:42 PM, Daniel Henrique Barboza wrote:
On 7/13/20 10:20 AM, Michal Privoznik wrote:
On 7/13/20 11:49 AM, Daniel Henrique Barboza wrote:
This document describes briefly how Libvirt migration internals
works, complementing the info available in migration.html.in.
Signed-off-by: Daniel Henrique Barboza <danielhb413@xxxxxxxxx>
---
docs/kbase/migrationinternals.rst | 174 ++++++++++++++++++++++++++++++
1 file changed, 174 insertions(+)
create mode 100644 docs/kbase/migrationinternals.rst
diff --git a/docs/kbase/migrationinternals.rst
b/docs/kbase/migrationinternals.rst
new file mode 100644
index 0000000000..869ee99bd7
--- /dev/null
+++ b/docs/kbase/migrationinternals.rst
@@ -0,0 +1,174 @@
+===========================
+Libvirt migration internals
+===========================
+
+.. contents::
+
+Migration is a multi-step operation with at least two distinct actors,
+the source and the destination libvirtd daemons, and a lot of failure
+points. This document describes the basic migration workflow in the
+code level, as a way to complement `the base migration docs
<migration.html>`_
+and help developers to get up to speed quicker with the code.
+
+In this document, unless stated otherwise, these conventions are
followed:
+
+* 'user' refers to any entity that initiates a migration, regardless
of being
+ an human using 'virsh' or a program consuming the Libvirt API;
+
+* 'source' refers to the source host of the migration, where the
guest currently
+ exists;
+
+* 'destination' refers to the destination host of the migration. As of
+ Libvirt 6.5.0 local migration isn't supported, thus source and
destination
+ refers to different hosts;
Is this right? What commit is reponsible for this change?
I guess my wording here is unclear. What I wanted to say is that, at
least up to the
current release we're at now (6.5.0), localhost migration (i.e. source
and destination
is the same host) isn't supported. I wanted to mention it this way
because there's always
the chance that Libvirt comes around and implements it.
If you want a commit id, the error message warning about localhost
migration appeared
first here:
commit 8654175c5b0c3db9e5f70907f102f0f900355d28
Author: Daniel P. Berrange <berrange@xxxxxxxxxx>
Date: Mon Jan 24 18:06:16 2011 +0000
Yeah, I was more interested whether we merged recently a patch that
explicitly forbids same host migration. Speaking of which, to some
extent we support same host migration (see v6.2.0-rc1~282) if both
libvirts live in separate containers (and effectively think they run on
different hosts).
Can you post a diff that I can squash in before merging?
Michal
