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[170.10.129.124]) by mx.google.com with ESMTPS id h18-20020ac85e12000000b0043c5d50a7dbsi1365614qtx.780.2024.04.30.09.54.29 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Apr 2024 09:54:29 -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=fBdL9Jdy; 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=1714496069; 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=lCyskhAIpRLBQGrfOTVqz2y+o19Ke66o+fFMq5zx9yA=; b=fBdL9JdySXXAp5nC8nM8/jpb+nH5eRL1FVhX0wOi+bicvvTfhQONmlZ8nJ55fDgmv68rnP Ut7zHgupyuSbEu4sW9CBBFP3+14+tFw1eOmyeDe2lgUCwxgO7sO24MYqSjTX8lVQ+axsd9 V3e4ene7Nbc5Apyfmab8xesyB1liVog= 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-417-gorT3wfaNfqapfGCHOp6Og-1; Tue, 30 Apr 2024 12:54:26 -0400 X-MC-Unique: gorT3wfaNfqapfGCHOp6Og-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (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 6DE2929AC013; Tue, 30 Apr 2024 16:54:25 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.59]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6F5F240C5C2; Tue, 30 Apr 2024 16:54:23 +0000 (UTC) Date: Tue, 30 Apr 2024 17:54:21 +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> <05cab8d3-bda0-4452-92d7-061f4719eba7@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <05cab8d3-bda0-4452-92d7-061f4719eba7@redhat.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 X-TUID: 62zEL3f+684F On Tue, Apr 30, 2024 at 12:29:14PM +0200, Thomas Huth wrote: > On 30/04/2024 11.55, Daniel P. Berrangé wrote: > > 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. > > Sounds like a good idea, too! Since I have to drop this patch here anyway, > could you maybe write such a new patch? (or do you want me to try to > formulate this?) Yes, I'll send something for discussion soon. 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 :|