introduce cordon (#1231)

* introduce cordon

* clean import

* force one by one

tests/E2E.Tests/KubectlTests.cs

@@ -0,0 +1,32 @@
+using k8s.kubectl.beta;
+using System.Linq;
+using Xunit;
+
+namespace k8s.E2E;
+
+[Collection(nameof(Onebyone))]
+public class KubectlTests
+{
+    [MinikubeFact]
+    public void CordonTest()
+    {
+        var client = MinikubeTests.CreateClient();
+
+        var node = client.CoreV1.ListNode().Items.First();
+        var nodeName = node.Metadata.Name;
+
+        var kubectl = new Kubectl(client);
+
+        // cordon
+        kubectl.Cordon(nodeName);
+
+        // check node status
+        var cordonNode = client.CoreV1.ReadNode(nodeName);
+        Assert.True(cordonNode.Spec.Unschedulable);
+
+        // uncordon
+        kubectl.Uncordon(nodeName);
+        cordonNode = client.CoreV1.ReadNode(nodeName);
+        Assert.True(cordonNode.Spec.Unschedulable == null || cordonNode.Spec.Unschedulable == false);
+    }
+}