[PATCH manager 4/5] ceph: add require_min_compat_client upgrade check

[Kefu Chai <k.chai@proxmox.com>]

Notice if require_min_compat_client is unset or older than the current
backend default, with a reminder to run 'ceph features' first to check
connected clients. Bumping the flag unlocks commands that use newer
on-map features such as pg-upmap-primary and the read-balancer;
enabling any of those features afterwards will exclude older clients.

The check is notice-only. Admins need to decide on a case-by-case
basis whether it is safe to bump.

See
https://docs.ceph.com/en/latest/rados/operations/require-min-compat-client/

Signed-off-by: Kefu Chai <k.chai@proxmox.com>
---
 PVE/Ceph/UpgradeCheck.pm | 49 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/PVE/Ceph/UpgradeCheck.pm b/PVE/Ceph/UpgradeCheck.pm
index 5c454fd1..09418df3 100644
--- a/PVE/Ceph/UpgradeCheck.pm
+++ b/PVE/Ceph/UpgradeCheck.pm
@@ -52,6 +52,7 @@ sub run_checks {
     push @messages, $health_msgs->@*;
 
     push @messages, check_require_osd_release($supported_release)->@*;
+    push @messages, check_require_min_compat_client($supported_release)->@*;
 
     my ($version_msgs, $noout_wanted) = check_versions($supported_release, $upgraded);
     push @messages, $version_msgs->@*;
@@ -394,4 +395,52 @@ sub check_require_osd_release {
     return \@out;
 }
 
+sub check_require_min_compat_client {
+    my ($supported_release) = @_;
+
+    my @out;
+
+    my $osdmap = eval { PVE::Ceph::Tools::get_osd_dump() };
+    if ($@ || !$osdmap) {
+        my $err = $@ || 'empty osd dump';
+        push @out, { level => 'warn', msg => "could not query osd dump: $err" };
+        return \@out;
+    }
+
+    my $current = $osdmap->{require_min_compat_client} // '';
+    my $expected_codename = PVE::Ceph::Releases::get_codename_for_major_release($supported_release)
+        // PVE::Ceph::Releases::get_default_ceph_release_codename();
+
+    if (!$current) {
+        push @out,
+            {
+                level => 'notice',
+                msg => "require_min_compat_client is unset. Check connected clients with"
+                . " 'ceph features', then 'ceph osd set-require-min-compat-client <release>'"
+                . " to unlock features like pg-upmap-primary and the read-balancer."
+                . " Enabling any of those features afterwards will exclude older clients.",
+            };
+        return \@out;
+    }
+
+    my $expected_release = release_number($expected_codename);
+    my $current_release = release_number($current);
+
+    if (!defined($current_release) || $current_release < $expected_release) {
+        push @out,
+            {
+                level => 'notice',
+                msg => "require_min_compat_client is '$current' (< '$expected_codename')."
+                . " If 'ceph features' shows no clients older than '$expected_codename',"
+                . " 'ceph osd set-require-min-compat-client $expected_codename' unlocks"
+                . " features like pg-upmap-primary and the read-balancer."
+                . " Enabling any of those features afterwards will exclude older clients.",
+            };
+    } else {
+        push @out, { level => 'pass', msg => "require_min_compat_client is at '$current'." };
+    }
+
+    return \@out;
+}
+
 1;
-- 
2.47.3