Use reflect.DeepEqual for CoreDNS config comparison

Since k0s uses a PDB for CoreDNS, the simple double equals equality
check wasn't appropriate to check if the CoreDNS configuration has
changed. The struct now contains a pointer which is always different for
newly constructed structs.

This caused a useless manifest regeneration every ten seconds.

Fixes: c802ffd ("Add a PodDisruptionBudget for CoreDNS")
Signed-off-by: Tom Wieczorek <[email protected]>

pkg/component/controller/coredns.go

@@ -22,6 +22,7 @@ import (
 	"math"
 	"path"
 	"path/filepath"
+	"reflect"
 	"time"
 
 	"github.com/k0sproject/k0s/pkg/component/manager"
@@ -429,7 +430,7 @@ func (c *CoreDNS) Reconcile(ctx context.Context, clusterConfig *v1beta1.ClusterC
 	if err != nil {
 		return fmt.Errorf("error calculating coredns configs: %v. will retry", err)
 	}
-	if cfg == c.previousConfig {
+	if reflect.DeepEqual(c.previousConfig, cfg) {
 		c.log.Infof("current cfg matches existing, not gonna do anything")
 		return nil
 	}