From: "Michael S. Tsirkin" <mst@redhat.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>,
"Eduardo Habkost" <ehabkost@redhat.com>,
"Juan Quintela" <quintela@redhat.com>,
"Jason Wang" <jasowang@redhat.com>,
qemu-devel@nongnu.org, "Paolo Bonzini" <pbonzini@redhat.com>
Subject: Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest
Date: Thu, 3 Dec 2020 07:11:17 -0500 [thread overview]
Message-ID: <20201203070339-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20201203114341.GB2919@work-vm>
On Thu, Dec 03, 2020 at 11:43:41AM +0000, Dr. David Alan Gilbert wrote:
> Another way to solve this would be to remove the unplugging from the
> migration layer and leave it as a problem for the management layer to do
> the unplug.
Daniel described the problem with modular management tools which expect
pausing or slowing down guest to cause migration to converge.
Point is, it actually *will* make it converge but only if you
pause it after unplug.
As it is, these tools fundamentally can not handle failover
requiring guest cooperation. Moving code between layers won't help.
Introducing failure modes as this patch does won't help either
especially since Daniel wrote there are countless tools like this.
We just break them all but have no resources to fix them,
this does not help at all.
We can just leave the situation as is.
Or if we do want to be nice to these tools, how about we
unpause the guest until unplug, then pause it again?
This actually addresses the problem instead of
shifting the blame, does it not?
--
MST
next prev parent reply other threads:[~2020-12-03 12:12 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 8:37 [PATCH v2 00/27] Virtio net failover fixes Juan Quintela
2020-11-18 8:37 ` [PATCH v2 01/27] migration: Network Failover can't work with a paused guest Juan Quintela
2020-11-25 12:05 ` Dr. David Alan Gilbert
2020-12-02 10:13 ` Michael S. Tsirkin
2020-12-02 10:27 ` Daniel P. Berrangé
2020-12-02 10:31 ` Michael S. Tsirkin
2020-12-02 10:33 ` Michael S. Tsirkin
2020-12-02 10:51 ` Juan Quintela
2020-12-02 10:55 ` Daniel P. Berrangé
2020-12-02 11:19 ` Michael S. Tsirkin
2020-12-02 11:26 ` Daniel P. Berrangé
2020-12-02 11:37 ` Michael S. Tsirkin
2020-12-02 12:01 ` Daniel P. Berrangé
2020-12-03 11:21 ` Michael S. Tsirkin
2020-12-03 11:32 ` Daniel P. Berrangé
2020-12-03 11:40 ` Michael S. Tsirkin
2020-12-03 11:43 ` Dr. David Alan Gilbert
2020-12-03 12:02 ` Michael S. Tsirkin
2020-12-03 12:04 ` Dr. David Alan Gilbert
2020-12-03 12:11 ` Michael S. Tsirkin [this message]
2020-12-03 12:16 ` Daniel P. Berrangé
2020-12-08 18:48 ` Michael S. Tsirkin
2020-12-03 11:45 ` Daniel P. Berrangé
2020-12-03 12:01 ` Michael S. Tsirkin
2020-12-03 12:06 ` Daniel P. Berrangé
2020-12-03 12:13 ` Michael S. Tsirkin
2020-12-08 18:32 ` Michael S. Tsirkin
2020-12-02 10:34 ` Daniel P. Berrangé
2020-11-18 8:37 ` [PATCH v2 02/27] failover: fix indentantion Juan Quintela
2020-11-18 8:37 ` [PATCH v2 03/27] failover: Use always atomics for primary_should_be_hidden Juan Quintela
2020-11-18 8:37 ` [PATCH v2 04/27] failover: primary bus is only used once, and where it is set Juan Quintela
2020-11-18 8:37 ` [PATCH v2 05/27] failover: Remove unused parameter Juan Quintela
2020-11-18 8:37 ` [PATCH v2 06/27] failover: Remove external partially_hotplugged property Juan Quintela
2020-11-18 8:37 ` [PATCH v2 07/27] failover: qdev_device_add() returns err or dev set Juan Quintela
2020-11-18 8:37 ` [PATCH v2 08/27] failover: Rename bool to failover_primary_hidden Juan Quintela
2020-11-18 8:37 ` [PATCH v2 09/27] failover: g_strcmp0() knows how to handle NULL Juan Quintela
2020-11-18 8:37 ` [PATCH v2 10/27] failover: Remove primary_device_opts Juan Quintela
2020-11-18 8:37 ` [PATCH v2 11/27] failover: remove standby_id variable Juan Quintela
2020-11-18 8:37 ` [PATCH v2 12/27] failover: Remove primary_device_dict Juan Quintela
2020-11-18 8:37 ` [PATCH v2 13/27] failover: Remove memory leak Juan Quintela
2020-11-18 8:37 ` [PATCH v2 14/27] failover: simplify virtio_net_find_primary() Juan Quintela
2020-11-18 8:37 ` [PATCH v2 15/27] failover: should_be_hidden() should take a bool Juan Quintela
2020-11-18 8:37 ` [PATCH v2 16/27] failover: Rename function to hide_device() Juan Quintela
2020-11-18 8:37 ` [PATCH v2 17/27] failover: virtio_net_connect_failover_devices() does nothing Juan Quintela
2020-11-18 8:37 ` [PATCH v2 18/27] failover: Rename to failover_find_primary_device() Juan Quintela
2020-11-18 8:37 ` [PATCH v2 19/27] failover: simplify qdev_device_add() failover case Juan Quintela
2020-11-18 8:37 ` [PATCH v2 20/27] failover: simplify qdev_device_add() Juan Quintela
2020-11-18 8:37 ` [PATCH v2 21/27] failover: make sure that id always exist Juan Quintela
2020-11-18 8:37 ` [PATCH v2 22/27] failover: remove failover_find_primary_device() error parameter Juan Quintela
2020-11-18 8:37 ` [PATCH v2 23/27] failover: split failover_find_primary_device_id() Juan Quintela
2020-11-18 8:37 ` [PATCH v2 24/27] failover: We don't need to cache primary_device_id anymore Juan Quintela
2020-11-18 8:37 ` [PATCH v2 25/27] failover: Caller of this two functions already have primary_dev Juan Quintela
2020-11-18 8:37 ` [PATCH v2 26/27] failover: simplify failover_unplug_primary Juan Quintela
2020-11-18 8:37 ` [PATCH v2 27/27] failover: Remove primary_dev member Juan Quintela
2020-11-18 8:53 ` [PATCH v2 00/27] Virtio net failover fixes Michael S. Tsirkin
2020-12-02 10:16 ` Juan Quintela
2020-12-02 10:30 ` Michael S. Tsirkin
2020-12-02 9:55 ` Michael S. Tsirkin
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