Add args to namespaces context to specify custom ns

samples/scenario/contexts/namespaces.json

@@ -19,6 +19,27 @@
           "with_serviceaccount": true
         }
       }
+    },
+    {
+      "title": "Run a single workload with create/read/delete pod",
+      "scenario": {
+        "Kubernetes.create_and_delete_pod": {
+          "image": "kubernetes/pause"
+        }
+      },
+      "runner": {
+        "constant": {
+          "concurrency": 2,
+          "times": 10
+        }
+      },
+      "contexts": {
+        "namespaces": {
+          "namespaces": [
+            "default"
+          ]
+        }
+      }
     }
   ]
-}
+}

samples/scenario/contexts/namespaces.yaml

@@ -13,3 +13,15 @@ subtasks:
     namespaces:
       count: 4
       with_serviceaccount: true
+- title: Run a single workload with create/read/delete pod
+  scenario:
+    Kubernetes.create_and_delete_pod:
+      image: kubernetes/pause
+  runner:
+    constant:
+      concurrency: 2
+      times: 10
+  contexts:
+    namespaces:
+      namespaces:
+      - default

tests/unit/tasks/contexts/test_namespaces.py

@@ -132,3 +132,20 @@ def test_create_several_namespaces_with_sa_and_round_choice(self):
         self.assertEqual(3, self.client.create_namespace.call_count)
         self.assertEqual(3, self.client.create_serviceaccount.call_count)
         self.assertEqual(3, self.client.create_secret.call_count)
+
+    def test_namespaces_context_specify_namespaces(self):
+        old_config = copy.deepcopy(self.ctx.config)
+        old_config.update({
+            "namespaces": ["default", "non-default"],
+            "namespace_choice_method": "round_robin"
+        })
+        self.ctx.config = old_config
+        self.ctx.setup()
+
+        self.assertEqual(["default", "non-default"],
+                         self.ctx.context["kubernetes"]["namespaces"])
+        self.assertEqual(
+            "round_robin",
+            self.ctx.context["kubernetes"]["namespace_choice_method"]
+        )
+        self.assertFalse(self.ctx.context["kubernetes"]["serviceaccounts"])

xrally_kubernetes/tasks/contexts/namespaces.py

@@ -23,19 +23,39 @@ class NamespaceContext(common_context.BaseKubernetesContext):
 
     CONFIG_SCHEMA = {
         "type": "object",
-        "additionalProperties": False,
-        "properties": {
-            "count": {
-                "type": "integer",
-                "minimum": 1
+        "oneOf": [
+            {
+                "description": "Create number of namespaces in kubernetes env",
+                "properties": {
+                    "count": {
+                        "type": "integer",
+                        "minimum": 1
+                    },
+                    "with_serviceaccount": {
+                        "type": "boolean"
+                    },
+                    "namespace_choice_method": {
+                        "enum": ["random", "round_robin"]
+                    }
+                },
+                "required": ["count"],
+                "additionalProperties": False
             },
-            "with_serviceaccount": {
-                "type": "boolean"
+            {
+                "description": "Select from specified namespaces, which "
+                               "already exists in kubernetes env",
+                "properties": {
+                    "namespaces": {
+                        "type": "array"
+                    },
+                    "namespace_choice_method": {
+                        "enum": ["random", "round_robin"]
+                    }
+                },
+                "required": ["namespaces"],
+                "additionalProperties": False
             },
-            "namespace_choice_method": {
-                "enum": ["random", "round_robin"]
-            }
-        }
+        ]
     }
 
     DEFAULT_CONFIG = {"namespace_choice_method": "random"}
@@ -47,13 +67,19 @@ def setup(self):
         })
 
         self.context["kubernetes"].setdefault("namespaces", [])
-        for _ in range(self.config.get("count")):
-            name = self.client.create_namespace(status_wait=False)
-            self.context["kubernetes"]["namespaces"].append(name)
-            if self.config.get("with_serviceaccount"):
-                self.client.create_serviceaccount(name, namespace=name)
-                self.client.create_secret(name, namespace=name)
+        if self.config.get("count"):
+            for _ in range(self.config.get("count")):
+                name = self.client.create_namespace(status_wait=False)
+                self.context["kubernetes"]["namespaces"].append(name)
+                if self.config.get("with_serviceaccount"):
+                    self.client.create_serviceaccount(name, namespace=name)
+                    self.client.create_secret(name, namespace=name)
+        else:
+            self.context["kubernetes"]["namespaces"].extend(
+                self.config.get("namespaces")
+            )
 
     def cleanup(self):
-        for name in self.context["kubernetes"].get("namespaces"):
-            self.client.delete_namespace(name)
+        if self.config.get("count"):
+            for name in self.context["kubernetes"].get("namespaces"):
+                self.client.delete_namespace(name)