From: Thomas Lamprecht <t.lamprecht@proxmox.com>
To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>,
Fiona Ebner <f.ebner@proxmox.com>
Subject: [pve-devel] applied: [RFC qemu-server] migration: nbd export: switch away from deprecated QMP command
Date: Mon, 16 Jan 2023 14:02:35 +0100 [thread overview]
Message-ID: <b5f969fe-d2ab-3f24-5386-8bd6c042b0dd@proxmox.com> (raw)
In-Reply-To: <20221202125452.54621-1-f.ebner@proxmox.com>
Am 02/12/2022 um 13:54 schrieb Fiona Ebner:
> The 'nbd-server-add' QMP command has been deprecated since QEMU 5.2 in
> favor of a more general 'block-export-add'.
>
> When using 'nbd-server-add', QEMU internally converts the parameters
> and calls blk_exp_add() which is also used by 'block-export-add'. It
> does one more thing, namely calling nbd_export_set_on_eject_blk() to
> auto-remove the export from the server when the backing drive goes
> away. But that behavior is not needed in our case, stopping the NBD
> server removes the exports anyways.
>
> It was checked with a debugger that the parameters to blk_exp_add()
> are still the same after this change. Well, the block node names are
> autogenerated and not consistent across invocations.
>
> The alternative to using 'query-block' would be specifying a
> predictable 'node-name' for our '-drive' commandline. It's not that
> difficult for this use case, but in general one needs to be careful
> (e.g. it can't be specified for an empty CD drive, but would need to
> be set when inserting a CD later). Querying the actual 'node-name'
> seemed a bit more future-proof.
>
> Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
> ---
>
> RFC, because I'm not sure which approach is better.
for now this works out fine, we can always switch to persistent node-names
if it shows to has some relevant advantage.
>
> PVE/QemuServer.pm | 17 ++++++++++++++++-
> test/MigrationTest/QmMock.pm | 4 +++-
> 2 files changed, 19 insertions(+), 2 deletions(-)
>
>
applied, thanks!
prev parent reply other threads:[~2023-01-16 13:03 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-02 12:54 [pve-devel] " Fiona Ebner
2022-12-16 11:52 ` Thomas Lamprecht
2022-12-16 12:03 ` Fiona Ebner
2023-01-16 13:02 ` Thomas Lamprecht [this message]
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