diff --git a/internal/controller/reconcile_kubernetes_test.go b/internal/controller/reconcile_kubernetes_test.go
new file mode 100644
index 0000000..df1e803
--- /dev/null
+++ b/internal/controller/reconcile_kubernetes_test.go
@@ -0,0 +1,235 @@
+package controller
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	lifecyclev1alpha1 "github.com/suse-edge/upgrade-controller/api/v1alpha1"
+
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+)
+
+func TestIsKubernetesUpgraded(t *testing.T) {
+	const kubernetesVersion = "v1.30.3+k3s1"
+
+	nodeLabels := map[string]string{
+		"node-x": "z",
+	}
+
+	tests := []struct {
+		name            string
+		nodes           *corev1.NodeList
+		selector        labels.Selector
+		expectedUpgrade bool
+	}{
+		{
+			name: "All matching nodes upgraded",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.30.3+k3s1"}},
+					},
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.30.3+k3s1"}},
+					},
+					{
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.28.12+k3s1"}},
+					},
+				},
+			},
+			selector:        labels.SelectorFromSet(nodeLabels),
+			expectedUpgrade: true,
+		},
+		{
+			name: "Unschedulable matching node",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: true},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.30.3+k3s1"}},
+					},
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.30.3+k3s1"}},
+					},
+					{
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.28.12+k3s1"}},
+					},
+				},
+			},
+			selector:        labels.SelectorFromSet(nodeLabels),
+			expectedUpgrade: false,
+		},
+		{
+			name: "Not ready matching node",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionFalse}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.30.3+k3s1"}},
+					},
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.30.3+k3s1"}},
+					},
+					{
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.28.12+k3s1"}},
+					},
+				},
+			},
+			selector:        labels.SelectorFromSet(nodeLabels),
+			expectedUpgrade: false,
+		},
+		{
+			name: "Matching node on older Kubernetes version",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.28.12+k3s1"}},
+					},
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.30.3+k3s1"}},
+					},
+					{
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{KubeletVersion: "v1.28.12+k3s1"}},
+					},
+				},
+			},
+			selector:        labels.SelectorFromSet(nodeLabels),
+			expectedUpgrade: false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			assert.Equal(t, test.expectedUpgrade, isKubernetesUpgraded(test.nodes, test.selector, kubernetesVersion))
+		})
+	}
+}
+
+func TestControlPlaneOnlyCluster(t *testing.T) {
+	assert.True(t, controlPlaneOnlyCluster(&corev1.NodeList{
+		Items: []corev1.Node{
+			{ObjectMeta: metav1.ObjectMeta{Labels: map[string]string{"node-role.kubernetes.io/control-plane": "true"}}},
+			{ObjectMeta: metav1.ObjectMeta{Labels: map[string]string{"node-role.kubernetes.io/control-plane": "true"}}},
+		},
+	}))
+
+	assert.False(t, controlPlaneOnlyCluster(&corev1.NodeList{
+		Items: []corev1.Node{
+			{ObjectMeta: metav1.ObjectMeta{Labels: map[string]string{"node-role.kubernetes.io/control-plane": "true"}}},
+			{ObjectMeta: metav1.ObjectMeta{Labels: map[string]string{"node-role.kubernetes.io/control-plane": "false"}}},
+		},
+	}))
+
+	assert.False(t, controlPlaneOnlyCluster(&corev1.NodeList{
+		Items: []corev1.Node{
+			{ObjectMeta: metav1.ObjectMeta{Labels: map[string]string{"node-role.kubernetes.io/control-plane": "true"}}},
+			{ObjectMeta: metav1.ObjectMeta{Labels: map[string]string{}}},
+		},
+	}))
+
+	assert.False(t, controlPlaneOnlyCluster(&corev1.NodeList{
+		Items: []corev1.Node{
+			{ObjectMeta: metav1.ObjectMeta{Labels: map[string]string{}}},
+		},
+	}))
+}
+
+func TestTargetKubernetesVersion(t *testing.T) {
+	kubernetes := &lifecyclev1alpha1.Kubernetes{
+		K3S: lifecyclev1alpha1.KubernetesDistribution{
+			Version: "v1.30.3+k3s1",
+		},
+		RKE2: lifecyclev1alpha1.KubernetesDistribution{
+			Version: "v1.30.3+rke2r1",
+		},
+	}
+
+	tests := []struct {
+		name            string
+		nodes           *corev1.NodeList
+		expectedVersion string
+		expectedError   string
+	}{
+		{
+			name:          "Empty node list",
+			nodes:         &corev1.NodeList{},
+			expectedError: "unable to determine current kubernetes version due to empty node list",
+		},
+		{
+			name: "Unsupported Kubernetes version",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{{Status: corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{KubeletVersion: "v1.30.3"}}}},
+			},
+			expectedError: "upgrading from kubernetes version v1.30.3 is not supported",
+		},
+		{
+			name: "Target k3s version",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{{Status: corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{KubeletVersion: "v1.28.12+k3s1"}}}},
+			},
+			expectedVersion: "v1.30.3+k3s1",
+		},
+		{
+			name: "Target RKE2 version",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{{Status: corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{KubeletVersion: "v1.28.12+rke2r1"}}}},
+			},
+			expectedVersion: "v1.30.3+rke2r1",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			version, err := targetKubernetesVersion(test.nodes, kubernetes)
+			if test.expectedError != "" {
+				require.Error(t, err)
+				assert.EqualError(t, err, test.expectedError)
+				assert.Empty(t, version)
+			} else {
+				require.NoError(t, err)
+				assert.Equal(t, test.expectedVersion, version)
+			}
+		})
+	}
+}
diff --git a/internal/controller/reconcile_os.go b/internal/controller/reconcile_os.go
index b94c0ce..b196297 100644
--- a/internal/controller/reconcile_os.go
+++ b/internal/controller/reconcile_os.go
@@ -129,7 +129,7 @@ func validateOSArch(nodeList *corev1.NodeList, supportedArchs []lifecyclev1alpha
 	for _, node := range nodeList.Items {
 		nodeArch := node.Status.NodeInfo.Architecture
 		if _, ok := supportedArchMap[nodeArch]; !ok {
-			return fmt.Errorf("unsuported arch '%s' for '%s' node. Supported archs: %s", nodeArch, node.Name, supportedArchs)
+			return fmt.Errorf("unsupported arch '%s' for '%s' node. Supported archs: %s", nodeArch, node.Name, supportedArchs)
 		}
 	}
 
diff --git a/internal/controller/reconcile_os_test.go b/internal/controller/reconcile_os_test.go
new file mode 100644
index 0000000..0f6db3b
--- /dev/null
+++ b/internal/controller/reconcile_os_test.go
@@ -0,0 +1,220 @@
+package controller
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	lifecyclev1alpha1 "github.com/suse-edge/upgrade-controller/api/v1alpha1"
+
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+)
+
+func TestValidateOSArch(t *testing.T) {
+	validArchs := []lifecyclev1alpha1.Arch{
+		"x86_64",
+		"aarch64",
+	}
+
+	nodes := &corev1.NodeList{
+		Items: []corev1.Node{
+			{
+				ObjectMeta: metav1.ObjectMeta{Name: "node1"},
+				Status:     corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{Architecture: "arm64"}},
+			},
+			{
+				ObjectMeta: metav1.ObjectMeta{Name: "node2"},
+				Status:     corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{Architecture: "aarch64"}},
+			},
+			{
+				ObjectMeta: metav1.ObjectMeta{Name: "node3"},
+				Status:     corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{Architecture: "amd64"}},
+			},
+			{
+				ObjectMeta: metav1.ObjectMeta{Name: "node4"},
+				Status:     corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{Architecture: "x86_64"}},
+			},
+		}}
+
+	assert.NoError(t, validateOSArch(nodes, validArchs))
+}
+
+func TestValidateOSArch_InvalidArch(t *testing.T) {
+	archs := []lifecyclev1alpha1.Arch{
+		"x86_64",
+		"risc-v",
+	}
+
+	assert.PanicsWithValue(t, "unknown arch: risc-v", func() {
+		_ = validateOSArch(nil, archs)
+	})
+}
+
+func TestValidateOSArch_UnsupportedNode(t *testing.T) {
+	validArchs := []lifecyclev1alpha1.Arch{
+		"x86_64",
+		"aarch64",
+	}
+
+	nodes := &corev1.NodeList{
+		Items: []corev1.Node{
+			{
+				ObjectMeta: metav1.ObjectMeta{Name: "node1"},
+				Status:     corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{Architecture: "arm64"}},
+			},
+			{
+				ObjectMeta: metav1.ObjectMeta{Name: "node2"},
+				Status:     corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{Architecture: "aarch64"}},
+			},
+			{
+				ObjectMeta: metav1.ObjectMeta{Name: "node3"},
+				Status:     corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{Architecture: "amd64"}},
+			},
+			{
+				ObjectMeta: metav1.ObjectMeta{Name: "node4"},
+				Status:     corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{Architecture: "x86_64"}},
+			},
+			{
+				ObjectMeta: metav1.ObjectMeta{Name: "node5"},
+				Status:     corev1.NodeStatus{NodeInfo: corev1.NodeSystemInfo{Architecture: "risc-v"}},
+			},
+		}}
+
+	assert.EqualError(t, validateOSArch(nodes, validArchs),
+		"unsupported arch 'risc-v' for 'node5' node. Supported archs: [x86_64 aarch64]")
+}
+
+func TestIsOSUpgraded(t *testing.T) {
+	const osPrettyName = "SUSE Linux Micro 6.0"
+
+	nodeLabels := map[string]string{
+		"node-x": "z",
+	}
+
+	tests := []struct {
+		name            string
+		nodes           *corev1.NodeList
+		selector        labels.Selector
+		expectedUpgrade bool
+	}{
+		{
+			name: "All matching nodes upgraded",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Micro 6.0"}},
+					},
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Micro 6.0"}},
+					},
+					{
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Enterprise Micro 5.5"}},
+					},
+				},
+			},
+			selector:        labels.SelectorFromSet(nodeLabels),
+			expectedUpgrade: true,
+		},
+		{
+			name: "Unschedulable matching node",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: true},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Micro 6.0"}},
+					},
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Micro 6.0"}},
+					},
+					{
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Enterprise Micro 5.5"}},
+					},
+				},
+			},
+			selector:        labels.SelectorFromSet(nodeLabels),
+			expectedUpgrade: false,
+		},
+		{
+			name: "Not ready matching node",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionFalse}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Micro 6.0"}},
+					},
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Micro 6.0"}},
+					},
+					{
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Enterprise Micro 5.5"}},
+					},
+				},
+			},
+			selector:        labels.SelectorFromSet(nodeLabels),
+			expectedUpgrade: false,
+		},
+		{
+			name: "Matching node on older OS",
+			nodes: &corev1.NodeList{
+				Items: []corev1.Node{
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Micro Micro 5.5"}},
+					},
+					{
+						ObjectMeta: metav1.ObjectMeta{Labels: nodeLabels},
+						Spec:       corev1.NodeSpec{Unschedulable: false},
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Micro 6.0"}},
+					},
+					{
+						Status: corev1.NodeStatus{
+							Conditions: []corev1.NodeCondition{{Type: corev1.NodeReady, Status: corev1.ConditionTrue}},
+							NodeInfo:   corev1.NodeSystemInfo{OSImage: "SUSE Linux Enterprise Micro 5.5"}},
+					},
+				},
+			},
+			selector:        labels.SelectorFromSet(nodeLabels),
+			expectedUpgrade: false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			assert.Equal(t, test.expectedUpgrade, isOSUpgraded(test.nodes, test.selector, osPrettyName))
+		})
+	}
+}
diff --git a/internal/upgrade/os_test.go b/internal/upgrade/os_test.go
index b1e7959..a39fc91 100644
--- a/internal/upgrade/os_test.go
+++ b/internal/upgrade/os_test.go
@@ -80,13 +80,13 @@ func TestOSControlPlanePlan(t *testing.T) {
 
 	upgradeContainer := upgradePlan.Spec.Upgrade
 	require.NotNil(t, upgradeContainer)
-	assert.Equal(t, "registry.suse.com/bci/bci-base:15.5", upgradeContainer.Image)
+	assert.Equal(t, "registry.suse.com/bci/bci-base:15.6", upgradeContainer.Image)
 	assert.Equal(t, []string{"chroot", "/host"}, upgradeContainer.Command)
 	assert.Equal(t, []string{"sh", "/run/system-upgrade/secrets/some-secret/os-upgrade.sh"}, upgradeContainer.Args)
 
 	assert.Equal(t, "3.1.0", upgradePlan.Spec.Version)
 	assert.EqualValues(t, 1, upgradePlan.Spec.Concurrency)
-	assert.EqualValues(t, 3600, upgradePlan.Spec.JobActiveDeadlineSecs)
+	assert.EqualValues(t, 43200, upgradePlan.Spec.JobActiveDeadlineSecs)
 	assert.True(t, upgradePlan.Spec.Cordon)
 
 	assert.Equal(t, "system-upgrade-controller", upgradePlan.Spec.ServiceAccountName)
@@ -149,13 +149,13 @@ func TestOSWorkerPlan(t *testing.T) {
 
 	upgradeContainer := upgradePlan.Spec.Upgrade
 	require.NotNil(t, upgradeContainer)
-	assert.Equal(t, "registry.suse.com/bci/bci-base:15.5", upgradeContainer.Image)
+	assert.Equal(t, "registry.suse.com/bci/bci-base:15.6", upgradeContainer.Image)
 	assert.Equal(t, []string{"chroot", "/host"}, upgradeContainer.Command)
 	assert.Equal(t, []string{"sh", "/run/system-upgrade/secrets/some-secret/os-upgrade.sh"}, upgradeContainer.Args)
 
 	assert.Equal(t, "3.1.0", upgradePlan.Spec.Version)
 	assert.EqualValues(t, 2, upgradePlan.Spec.Concurrency)
-	assert.EqualValues(t, 3600, upgradePlan.Spec.JobActiveDeadlineSecs)
+	assert.EqualValues(t, 43200, upgradePlan.Spec.JobActiveDeadlineSecs)
 	assert.True(t, upgradePlan.Spec.Cordon)
 
 	assert.Equal(t, "system-upgrade-controller", upgradePlan.Spec.ServiceAccountName)