[PATCH pve-ha-manager 12/15] manager: log changes to crs settings

[Dominik Rusovac <d.rusovac@proxmox.com>]

Especially with the addition of weights, it is important to be able to
trace how the load balancer is configured.

Signed-off-by: Dominik Rusovac <d.rusovac@proxmox.com>
---
 src/PVE/HA/Manager.pm | 89 +++++++++++++++++++++++++++++++++----------
 1 file changed, 68 insertions(+), 21 deletions(-)

diff --git a/src/PVE/HA/Manager.pm b/src/PVE/HA/Manager.pm
index c6818e2..4d0114c 100644
--- a/src/PVE/HA/Manager.pm
+++ b/src/PVE/HA/Manager.pm
@@ -99,6 +99,20 @@ sub new {
     return $self;
 }
 
+sub update_and_log_change {
+    my ($self, $curr, $next, $msg) = @_;
+
+    my $haenv = $self->{haenv};
+
+    if (defined($$curr) && $$curr ne $next) {
+        $haenv->log('info', "$msg from '$$curr' to '$next'");
+    }
+
+    $$curr = $next;
+
+    return;
+}
+
 sub update_crs_scheduler_mode {
     my ($self) = @_;
 
@@ -106,37 +120,70 @@ sub update_crs_scheduler_mode {
     my $dc_cfg = $haenv->get_datacenter_settings();
     my $crs_cfg = $dc_cfg->{crs} // {};
 
-    $self->{crs}->{rebalance_on_request_start} = !!$crs_cfg->{'ha-rebalance-on-start'};
-    $self->{crs}->{auto_rebalance}->{enable} = !!$crs_cfg->{'ha-auto-rebalance'};
+    my $log_prefix = "crs settings:";
+
+    $self->update_and_log_change(
+        \$self->{crs}->{rebalance_on_request_start},
+        !!$crs_cfg->{'ha-rebalance-on-start'},
+        "$log_prefix 'ha-rebalance-on-start' changed",
+    );
+
+    my $auto_rebalance = $self->{crs}->{auto_rebalance};
+
+    $self->update_and_log_change(
+        \$auto_rebalance->{enable},
+        !!$crs_cfg->{'ha-auto-rebalance'},
+        "$log_prefix 'ha-auto-rebalance' changed",
+    );
+
     # configured as percent for UI/config consistency, scaled to [0, 1] to match the
     # internal imbalance value that the comparison gates against.
-    $self->{crs}->{auto_rebalance}->{threshold} =
-        ($crs_cfg->{'ha-auto-rebalance-threshold'} // 30) / 100.0;
-    $self->{crs}->{auto_rebalance}->{method} = $crs_cfg->{'ha-auto-rebalance-method'}
-        // 'bruteforce';
-    $self->{crs}->{auto_rebalance}->{hold_duration} = $crs_cfg->{'ha-auto-rebalance-hold-duration'}
-        // 3;
-    $self->{crs}->{auto_rebalance}->{margin} =
-        ($crs_cfg->{'ha-auto-rebalance-margin'} // 10) / 100.0;
+    $self->update_and_log_change(
+        \$auto_rebalance->{threshold},
+        ($crs_cfg->{'ha-auto-rebalance-threshold'} // 30) / 100.0,
+        "$log_prefix 'ha-auto-rebalance-threshold' changed",
+    );
+    $self->update_and_log_change(
+        \$auto_rebalance->{method},
+        $crs_cfg->{'ha-auto-rebalance-method'} // 'bruteforce',
+        "$log_prefix 'ha-auto-rebalance-method' changed",
+    );
+    $self->update_and_log_change(
+        \$auto_rebalance->{hold_duration},
+        $crs_cfg->{'ha-auto-rebalance-hold-duration'} // 3,
+        "$log_prefix 'ha-auto-rebalance-hold-duration' changed",
+    );
+    $self->update_and_log_change(
+        \$auto_rebalance->{margin},
+        ($crs_cfg->{'ha-auto-rebalance-margin'} // 10) / 100.0,
+        "$log_prefix 'ha-auto-rebalance-margin' changed",
+    );
 
     my $default_weight = 1;
-    $self->{crs}->{auto_rebalance}->{cpu_weight} = $crs_cfg->{'ha-auto-rebalance-cpu-weight'} // $default_weight;
+    $self->update_and_log_change(
+        \$auto_rebalance->{cpu_weight},
+        $crs_cfg->{'ha-auto-rebalance-cpu-weight'} // $default_weight,
+        "$log_prefix 'ha-auto-rebalance-cpu-weight' changed",
+    );
     # by default TOPSIS weights mem higher than cpu
-    $default_weight = 5 if ($self->{crs}->{auto_rebalance}->{method} eq 'topsis');
-    $self->{crs}->{auto_rebalance}->{mem_weight} = $crs_cfg->{'ha-auto-rebalance-mem-weight'} // $default_weight;
+    $default_weight = 5 if ($auto_rebalance->{method} eq 'topsis');
+    $self->update_and_log_change(
+        \$auto_rebalance->{mem_weight},
+        $crs_cfg->{'ha-auto-rebalance-mem-weight'} // $default_weight,
+        "$log_prefix 'ha-auto-rebalance-mem-weight' changed",
+    );
 
-    my $old_mode = $self->{crs}->{scheduler};
+    my $old_mode = \$self->{crs}->{scheduler};
     my $new_mode = $crs_cfg->{ha} || 'basic';
 
-    if (!defined($old_mode)) {
+    if (!defined($$old_mode)) {
         $haenv->log('info', "using scheduler mode '$new_mode'") if $new_mode ne 'basic';
-    } elsif ($new_mode eq $old_mode) {
-        return; # nothing to do
-    } else {
-        $haenv->log('info', "switching scheduler mode from '$old_mode' to '$new_mode'");
     }
-
-    $self->{crs}->{scheduler} = $new_mode;
+    $self->update_and_log_change(
+        $old_mode,
+        $new_mode,
+        "$log_prefix scheduler mode changed"
+    );
 
     return;
 }
-- 
2.47.3