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[170.10.129.124]) by mx.google.com with ESMTPS id e5-20020a05620a208500b0078ee4539615si28071169qka.90.2024.04.30.02.55.46 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Apr 2024 02:55:46 -0700 (PDT) Received-SPF: pass (google.com: domain of berrange@redhat.com designates 170.10.129.124 as permitted sender) client-ip=170.10.129.124; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=fwE81C0f; spf=pass (google.com: domain of berrange@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=berrange@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1714470945; 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:in-reply-to:in-reply-to: references:references; bh=0W/IXaYxqHRtZC4KnnJtCdf+TXWLaEz5NbLVH4JP+kE=; b=fwE81C0fAwPfhL782+EUvwd6nCtGQk6lhwfusSphez3YPjPa2c7PywgzKP6UAp/TOq3wTQ 9x4MZ2KkEkt340NMoGzfiqNfmfYSqgGGDtH7KP5HSXmpNzgRx0zcIR+2ijOLYcyCLHOvZe XGnUacU/5oJYiNFMOihcqUiorugKb5U= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-455-sLhIWVSVMVyl_LnQM-YW1w-1; Tue, 30 Apr 2024 05:55:42 -0400 X-MC-Unique: sLhIWVSVMVyl_LnQM-YW1w-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9EB363806738; Tue, 30 Apr 2024 09:55:41 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.59]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F119151BF; Tue, 30 Apr 2024 09:55:39 +0000 (UTC) Date: Tue, 30 Apr 2024 10:55:38 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Thomas Huth Cc: qemu-devel@nongnu.org, Peter Maydell , devel@lists.libvirt.org, Alex =?utf-8?Q?Benn=C3=A9e?= , Laurent Vivier , qemu-s390x@nongnu.org, qemu-arm@nongnu.org, qemu-ppc@nongnu.org, Peter Xu , Fabiano Rosas Subject: Re: [PATCH] docs/about: Automatically deprecate versioned machine types older than 6 years Message-ID: Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20240430064529.411699-1-thuth@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240430064529.411699-1-thuth@redhat.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 X-TUID: i/BqGXl9KloJ On Tue, Apr 30, 2024 at 08:45:29AM +0200, Thomas Huth wrote: > Old machine types often have bugs or work-arounds that affect our > possibilities to move forward with the QEMU code base (see for example > https://gitlab.com/qemu-project/qemu/-/issues/2213 for a bug that likely > cannot be fixed without breaking live migration with old machine types, > or https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg04516.html or > commit ea985d235b86). So instead of going through the process of manually > deprecating old machine types again and again, let's rather add an entry > that can stay, which declares that machine types older than 6 years are > considered as deprecated automatically. Six years should be sufficient to > support the release cycles of most Linux distributions. Reading this again, I think we're mixing two concepts here. With this 6 year cut off, we're declaring the actual *removal* date, not the deprecation date. A deprecation is something that happens prior to removal normally, to give people a warning of /future/ removal, as a suggestion that they stop using it. If we never set the 'deprecation_reason' on a machine type, then unless someone reads this doc, they'll never realize they are on a deprecated machine. When it comes to machine types, I see deprecation as a way to tell people they should not deploy a /new/ VM on a machine type, only use it for back compat (incoming migration / restore from saved image) with existing deployed VMs. If we delete a machine on the 6 year anniversary, then users don't want to be deploying /new/ VMs using that on the 5 year anniversary as it only gives a 1 year upgrade window. So how long far back do we consider it reasonable for a user to deploy a /new/ VM on an old machine type ? 1 year, 2 years, 3 years ? How about picking the half way point ? 3 years ? ie, set deprecation_reason for any machine that is 3 years old, but declare that our deprecation cycle lasts for 3 years, instead of the normal 1 year, when applied to machine types. This would give a strong hint that users should get off the old machine type, several years before its finally deleted. > Signed-off-by: Thomas Huth > --- > docs/about/deprecated.rst | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst > index 6d595de3b6..fe69e2d44c 100644 > --- a/docs/about/deprecated.rst > +++ b/docs/about/deprecated.rst > @@ -220,6 +220,17 @@ is a chance the code will bitrot without anyone noticing. > System emulator machines > ------------------------ > > +Versioned machine types older than 6 years > +'''''''''''''''''''''''''''''''''''''''''' > + > +Starting with the release of QEMU 10.0, versioned machine types older than > +6 years will automatically be considered as deprecated and might be due to > +removal without furthor notice. For example, this affects machine types like > +pc-i440fx-X.Y, pc-q35-X.Y, pseries-X.Y, s390-ccw-virtio-X.Y or virt-X.Y where > +X is the major number and Y is the minor number of the old QEMU version. > +If you are still using machine types from QEMU versions older than 6 years, > +please update your setting to use a newer versioned machine type instead. > + > Arm ``virt`` machine ``dtb-kaslr-seed`` property (since 7.1) > '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' > > -- > 2.44.0 > 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 :|