Support single control plane cluster.

Raise exception if no control planes are specified in the inventory.

documentation/Troubleshooting.md

@@ -4,7 +4,7 @@ This section provides troubleshooting information for Kubemarine and Kubernetes
   - [KME0001: Unexpected exception](#kme0001-unexpected-exception)
   - [KME0002: Remote group exception](#kme0002-remote-group-exception)
     - [Command did not complete within a number of seconds](#command-did-not-complete-within-a-number-of-seconds)
-  - [KME0004: There are no workers defined in the cluster scheme](#kme0004-there-are-no-workers-defined-in-the-cluster-scheme)
+  - [KME0004: There are no control planes defined in the cluster scheme](#kme0004-there-are-no-control-planes-defined-in-the-cluster-scheme)
   - [KME0005: {hostnames} are not sudoers](#kme0005-hostnames-are-not-sudoers)
 - [Troubleshooting Tools](#troubleshooting-tools)
   - [etcdctl Script](#etcdctl-script)
@@ -168,18 +168,18 @@ frozen stage of the procedure. It will be useful to check the cluster with
 [IAAS checker](Kubecheck.md#iaas-procedure) to detect problems with network connectivity.
 
 
-## KME0004: There are no workers defined in the cluster scheme
+## KME0004: There are no control planes defined in the cluster scheme
 
 ```
 FAILURE!
-KME0004: There are no workers defined in the cluster scheme
+KME0004: There are no control planes defined in the cluster scheme
 ```
 
-An error related with the absence of any worker role in the inventory file. The error occurs before
+An error related with the absence of any control plane role in the inventory file. The error occurs before
 the payload is executed on the cluster.
 
-To fix it, you need to either specify new nodes with the `worker` role, or add the `worker` role to 
-the existing control-planes nodes.
+To fix it, you need to either specify new nodes with the `control-plane` role, or add the `control-plane` role to 
+the existing worker nodes.
 
 An example of specifying different nodes with separate `control-plane` and `worker` roles is as follows.
 

kubemarine/core/errors.py

@@ -33,7 +33,7 @@ def get_kme_dictionary() -> dict:
             "name": "Remote group exception\n{reason}"
         },
         "KME0004": {
-            "name": "There are no workers defined in the cluster scheme"
+            "name": "There are no control planes defined in the cluster scheme"
         },
         "KME0005": {
             "name": "{hostnames} are not sudoers"

kubemarine/core/resources.py

@@ -431,6 +431,7 @@ def enrichment_functions(self) -> List[c.EnrichmentFunction]:
             kubemarine.core.defaults.apply_connection_defaults,
             kubemarine.core.defaults.calculate_nodegroups,
             kubemarine.core.defaults.remove_service_roles,
+            kubemarine.kubernetes.verify_roles,
             # Enrichment of inventory for LIGHT stage should be finished at this step.
 
             # Should be just after compilation, but currently not necessary for LIGHT stage.

kubemarine/kubernetes/__init__.py

@@ -106,6 +106,12 @@ def enrich_reconfigure_inventory(cluster: KubernetesCluster) -> None:
         default_merger.merge(cluster.inventory.setdefault('services', {}), utils.deepcopy_yaml(kubeadm_sections))
 
 
+@enrichment(EnrichmentStage.ALL)
+def verify_roles(cluster: KubernetesCluster) -> None:
+    if cluster.make_group_from_roles(['control-plane']).is_empty():
+        raise KME("KME0004")
+
+
 @enrichment(EnrichmentStage.FULL)
 def enrich_inventory(cluster: KubernetesCluster) -> None:
     inventory = cluster.inventory
@@ -136,8 +142,6 @@ def enrich_inventory(cluster: KubernetesCluster) -> None:
         if name not in certsans:
             certsans.append(name)
 
-    any_worker_found = False
-
     # validating node labels and configuring additional labels
     for node in inventory["nodes"]:
         if "control-plane" not in node["roles"] and "worker" not in node["roles"]:
@@ -150,8 +154,6 @@ def enrich_inventory(cluster: KubernetesCluster) -> None:
             continue
 
         if "worker" in node["roles"]:
-            any_worker_found = True
-
             if "labels" not in node:
                 node["labels"] = {}
             node["labels"]["node-role.kubernetes.io/worker"] = "worker"
@@ -175,9 +177,6 @@ def enrich_inventory(cluster: KubernetesCluster) -> None:
                 if control_plane_item != 'kubelet' and ('control-plane' not in node['roles']):
                     raise Exception(ERROR_CONTROL_PLANE_PATCH_NOT_CONTROL_PLANE_NODE % control_plane_item)
 
-    if not any_worker_found:
-        raise KME("KME0004")
-
     # check ignorePreflightErrors value and add mandatory errors from defaults.yaml if they're absent
     default_preflight_errors = static.DEFAULTS["services"]["kubeadm_flags"]["ignorePreflightErrors"].split(",")
     preflight_errors = inventory["services"]["kubeadm_flags"]["ignorePreflightErrors"].split(",")
@@ -851,7 +850,7 @@ def verify_upgrade_versions(cluster: KubernetesCluster) -> None:
     first_control_plane = cluster.nodes['control-plane'].get_first_member()
     upgrade_version = get_kubernetes_version(cluster.inventory)
 
-    k8s_nodes_group = cluster.nodes["worker"].include_group(cluster.nodes['control-plane'])
+    k8s_nodes_group = cluster.make_group_from_roles(['control-plane', 'worker'])
     for node in k8s_nodes_group.get_ordered_members_list():
         cluster.log.debug(f"Verifying current k8s version for node {node.get_node_name()}")
         result = first_control_plane.sudo("kubectl get nodes "

test/unit/test_defaults.py

@@ -242,6 +242,22 @@ def test_controlplain_skip_vrrp_ips_assigned_to_removed_balancer(self):
         self.assertEqual(inventory['control_plain']['internal'], inventory['vrrp_ips'][1]['ip'])
         self.assertEqual(inventory['control_plain']['external'], inventory['vrrp_ips'][1]['floating_ip'])
 
+    def test_single_control_plane(self):
+        inventory = demo.generate_inventory(master=['node-1'], worker=['node-1'], balancer=0)
+        inventory['nodes'][0]['roles'].remove('worker')
+        cluster = demo.new_cluster(inventory)
+        self.assertTrue(cluster.make_group_from_roles(['worker']).is_empty())
+
+    def test_error_no_control_planes_balancers(self):
+        inventory = demo.generate_inventory(master=0, worker=1, balancer=0)
+        with test_utils.assert_raises_kme(self, 'KME0004'):
+            demo.new_cluster(inventory)
+
+    def test_error_no_control_planes(self):
+        inventory = demo.generate_inventory(master=0, worker=1, balancer=1)
+        with test_utils.assert_raises_kme(self, 'KME0004'):
+            demo.new_cluster(inventory)
+
 
 class PrimitiveValuesAsString(unittest.TestCase):
     def test_default_enrichment(self):

test/unit/test_inventory.py

@@ -25,16 +25,20 @@
 class TestInventoryValidation(unittest.TestCase):
 
     def test_labels_check(self):
-        inventory = demo.generate_inventory(master=0, balancer=1, worker=0)
-        inventory["nodes"][0]["labels"] = {"should": "fail"}
+        inventory = demo.generate_inventory(master=1, balancer=1, worker=0)
+        for node in inventory['nodes']:
+            if 'balancer' in node['roles']:
+                node["labels"] = {"should": "fail"}
         with self.assertRaises(Exception) as context:
             demo.new_cluster(inventory)
 
         self.assertIn("Only 'worker' or 'control-plane' nodes can have labels", str(context.exception))
 
     def test_taints_check(self):
-        inventory = demo.generate_inventory(master=0, balancer=1, worker=0)
-        inventory["nodes"][0]["taints"] = ["should fail"]
+        inventory = demo.generate_inventory(master=1, balancer=1, worker=0)
+        for node in inventory['nodes']:
+            if 'balancer' in node['roles']:
+                node["taints"] = ["should fail"]
         with self.assertRaises(Exception) as context:
             demo.new_cluster(inventory)