From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CEC8BC71136 for ; Mon, 16 Jun 2025 09:57:18 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uR6Wv-0006UY-Qe; Mon, 16 Jun 2025 05:53:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uR6WT-0006CH-NS for qemu-devel@nongnu.org; Mon, 16 Jun 2025 05:53:06 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uR6WQ-0002St-JY for qemu-devel@nongnu.org; Mon, 16 Jun 2025 05:53:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1750067577; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cFZ3XfaJHHBYyrUjidgVSFS7BuCjSPvE2KeY0wm4Ah0=; b=bn1gGGSWeEW943ffa8DBgx25WL7qt84ug0oxy7jmqh5q1Q071uncsR/QF4tCOeIXgJzJQw JRKr/T5pdBDDNjhQ6ej35xhpfr1ZVl+LA7aa7HH7B71b0USZbP3yWJzeP63CnwRsL+65K/ upOq/s+UmhBZiuDrzgkCBXAETxZrOH4= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-369-S6WROfhNNYeSFMAsKBxOkw-1; Mon, 16 Jun 2025 05:52:53 -0400 X-MC-Unique: S6WROfhNNYeSFMAsKBxOkw-1 X-Mimecast-MFC-AGG-ID: S6WROfhNNYeSFMAsKBxOkw_1750067573 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 822E919560B0; Mon, 16 Jun 2025 09:52:52 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.53]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B2A10180045C; Mon, 16 Jun 2025 09:52:48 +0000 (UTC) Date: Mon, 16 Jun 2025 10:52:44 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Ilya Dryomov Cc: Fiona Ebner , qemu-block@nongnu.org, qemu-devel@nongnu.org, armbru@redhat.com, eblake@redhat.com, hreitz@redhat.com, kwolf@redhat.com, pl@dlhnet.de Subject: Re: [PATCH 1/2] block/rbd: support selected key-value-pairs via QAPI Message-ID: References: <20250515112908.383693-1-f.ebner@proxmox.com> <20250515112908.383693-2-f.ebner@proxmox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Jun 16, 2025 at 11:25:54AM +0200, Ilya Dryomov wrote: > On Thu, May 15, 2025 at 1:29 PM Fiona Ebner wrote: > > > > Currently, most Ceph configuration options are not exposed via QAPI. > > While it is possible to specify a dedicated Ceph configuration file, > > specialized options are often only required for a selection of images > > on the RBD storage, not all of them. To avoid the need to generate a > > dedicated Ceph configuration file for each image (or for each required > > combination of options), support a selection of key-value pairs via > > QAPI. > > > > Initially, this is just 'rbd_cache_policy'. For example, this is > > useful with small images used as a pflash for EFI variables. Setting > > the 'rbd_cache_policy' to 'writeback' yields a substantial improvement > > there [0]. > > > > The function qemu_rbd_extract_key_value_pairs() was copied/adapted > > from the existing qemu_rbd_extract_encryption_create_options(). > > > > [0]: https://bugzilla.proxmox.com/show_bug.cgi?id=3329#c9 > > > > Signed-off-by: Fiona Ebner snip > > ## > > # @BlockdevOptionsRbd: > > # > > @@ -4327,6 +4360,9 @@ > > # authentication. This maps to Ceph configuration option "key". > > # (Since 3.0) > > # > > +# @key-value-pairs: Key-value pairs for additional Ceph configuraton. > > +# (Since 10.1) > > +# > > # @server: Monitor host address and port. This maps to the "mon_host" > > # Ceph option. > > # > > @@ -4342,6 +4378,7 @@ > > '*user': 'str', > > '*auth-client-required': ['RbdAuthMode'], > > '*key-secret': 'str', > > + '*key-value-pairs' : 'RbdKeyValuePairs', > > To side-step all of the above, have you considered implementing > a straightforward passthrough to Ceph instead? Something like > > '*key-value-pairs': ['RbdKeyValuePair'] > > where RbdKeyValuePair is just a pair arbitrary strings (and > key-value-pairs is thus an optional list of those). rados_conf_set() > would be called just the same but the user would be able to override > any Ceph option they wish, not just a few that we thought of here. Passing through arbitrary key/value pairs as strings is essentially abdicating our design responsibility in QAPI. enums would no longer be introspectable. Integers / booleans would require abnormal formatting by clients. API stability / deprecation promises can no longer be made. and more besides. Given that limitation, if we did go the string pairs route, I would expect it to be marked as "unstable" in the QAPI schema, so apps have a suitable warning NOT to rely on this. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|