feat: Add support for controlplane rollout if ServerConfig has change…

…d, mirroring the approach used by kubeadm

Signed-off-by: Richard Draycott <[email protected]>

pkg/machinefilters/machine_filters.go

@@ -17,6 +17,9 @@ limitations under the License.
 package machinefilters
 
 import (
+	"encoding/json"
+	"reflect"
+
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
 	"sigs.k8s.io/cluster-api/util/collections"
@@ -83,6 +86,54 @@ func MatchesKubernetesVersion(kubernetesVersion string) Func {
 // MatchesKThreesBootstrapConfig checks if machine's KThreesConfigSpec is equivalent with KCP's KThreesConfigSpec.
 func MatchesKThreesBootstrapConfig(machineConfigs map[string]*bootstrapv1.KThreesConfig, kcp *controlplanev1.KThreesControlPlane) Func {
 	return func(machine *clusterv1.Machine) bool {
+		if machine == nil {
+			return false
+		}
+
+		// Check if KCP and machine KThreesServerConfig matches, if not return
+		if !matchKThreesServerConfig(kcp, machine) {
+			return false
+		}
+
+		bootstrapRef := machine.Spec.Bootstrap.ConfigRef
+		if bootstrapRef == nil {
+			// Missing bootstrap reference should not be considered as unmatching.
+			// This is a safety precaution to avoid selecting machines that are broken, which in the future should be remediated separately.
+			return true
+		}
+
 		return true
 	}
 }
+
+// matchKThreesServerConfig verifies if KCP and machine ClusterConfiguration matches.
+// NOTE: Machines that have KThreesServerConfigurationAnnotation will have to match with KCP KThreesServerConfig.
+// If the annotation is not present (machine is either old or adopted), we won't roll out on any possible changes
+// made in KCP's KThreesServerConfig given that we don't have enough information to make a decision.
+// Users should use KCP.Spec.RolloutAfter field to force a rollout in this case.
+func matchKThreesServerConfig(kcp *controlplanev1.KThreesControlPlane, machine *clusterv1.Machine) bool {
+	kThreesServerConfigStr, ok := machine.GetAnnotations()[controlplanev1.KThreesServerConfigurationAnnotation]
+	if !ok {
+		// We don't have enough information to make a decision; don't' trigger a roll out.
+		return true
+	}
+
+	kThreesServerConfig := &bootstrapv1.KThreesServerConfig{}
+
+	// ClusterConfiguration annotation is not correct, only solution is to rollout.
+	// The call to json.Unmarshal has to take a pointer to the pointer struct defined above,
+	// otherwise we won't be able to handle a nil ClusterConfiguration (that is serialized into "null").
+	if err := json.Unmarshal([]byte(kThreesServerConfigStr), &kThreesServerConfig); err != nil {
+		return false
+	}
+
+	// If any of the compared values are nil, treat them the same as an empty KThreesServerConfig.
+	if kThreesServerConfig == nil {
+		kThreesServerConfig = &bootstrapv1.KThreesServerConfig{}
+	}
+
+	kcpLocalKThreesServerConfig := kcp.Spec.KThreesConfigSpec.ServerConfig
+
+	// Compare and return.
+	return reflect.DeepEqual(kThreesServerConfig, kcpLocalKThreesServerConfig)
+}