[pve-devel] [PATCH docs 19/19] qm: machine version: document support in PVE

[Fiona Ebner]

Elaborate on new QEMU machine version removal policy and how PVE will
support machine versions. Make sure to also mention the years, so that
users immediately have a good idea for how long it will be.

Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
---
 qm.adoc | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/qm.adoc b/qm.adoc
index 94fdd4e..695013c 100644
--- a/qm.adoc
+++ b/qm.adoc
@@ -173,6 +173,32 @@ This means that after a fresh start, the newest machine version supported by the
 QEMU binary is used (e.g. the newest machine version QEMU 8.1 supports is
 version 8.1 for each machine type).
 
+Starting with QEMU 10.1, machine versions will be removed from upstream QEMU
+after 6 years. In {pve}, major releases happen approximately every 2 years, so a
+major {pve} release will support machine versions from approximately two
+previous major {pve} releases, more details below.
+
+There will be an early informational message if a machine version is used that
+is going to be dropped at some point during the next major {pve} release life
+cycle. Before upgrading to a new major {pve} release, you should update all
+those machine versions to ensure that the guests can still be used throughout
+that release.
+
+The following table shows the expected baselines of supported machine versions
+for the current and upcoming major {pve} releases (best guesses):
+
+[width="100%",cols=">s,>,>s,2*>",options="header"]
+|===============================================================================================
+| {pve} | active development | supported baseline | dropped during life cycle | last QEMU binary
+|     8 |          2023-2025 |                2.4 |             2.3 and older |              9.2
+|     9 |          2025-2027 |                6.0 |             5.2 and older |             11.2
+|    10 |          2027-2029 |                8.0 |             7.2 and older |             13.2
+|===============================================================================================
+
+NOTE: Support for {pve} releases is longer than active development, but no new
+QEMU binary versions will be added after active development, just backports and
+fixes for existing binary versions.
+
 [[qm_machine_update]]
 
 Update to a Newer Machine Version
-- 
2.39.5