OpenShift/k8s Provider: Basic Support for k8s nodeSelectors

This adds support to specify node selectors on Pod node labels.
They are used by the k8s scheduler to place a Pod on specific nodes with
corresponding labels.
This allows to place a build node/Pod on k8s nodes with certain
capabilities (e.g. storage types, number of CPU cores, etc.)

Change-Id: Ic00a84181c8ef66189e4259ef6434dc62b81c3c6

doc/source/configuration.rst

@@ -1423,6 +1423,14 @@ Selecting the kubernetes driver adds the following options to the
 
                The value of the environment variable passed to the Pod.
 
+         .. attr:: node-selector
+            :type: dict
+
+            Only used by the
+            :value:`providers.[kubernetes].pools.labels.type.pod` label type;
+            A map of key-value pairs to ensure the Kubernetes scheduler
+            places the Pod on a node with specific node labels.
+
 
 Openshift Driver
 ----------------
@@ -1594,6 +1602,14 @@ Selecting the openshift driver adds the following options to the
 
             The value of the environment variable passed to the Pod.
 
+      .. attr:: node-selector
+         :type: dict
+
+         Only used by the
+         :value:`providers.[openshift].labels.type.pod` label type;
+         A map of key-value pairs to ensure the OpenShift scheduler
+         places the Pod on a node with specific node labels.
+
 
 Openshift Pods Driver
 ---------------------
@@ -1724,6 +1740,12 @@ Selecting the openshift pods driver adds the following options to the
 
             The value of the environment variable passed to the Pod.
 
+      .. attr:: node-selector
+         :type: dict
+
+         A map of key-value pairs to ensure the OpenShift scheduler
+         places the Pod on a node with specific node labels.
+
 
 AWS EC2 Driver
 --------------

nodepool/driver/kubernetes/config.py

@@ -31,7 +31,8 @@ class KubernetesLabel(ConfigValue):
                     other.image == self.image and
                     other.cpu == self.cpu and
                     other.memory == self.memory and
-                    other.env == self.env)
+                    other.env == self.env and
+                    other.node_selector == self.node_selector)
         return False
 
     def __repr__(self):
@@ -63,6 +64,7 @@ class KubernetesPool(ConfigPool):
             pl.cpu = label.get('cpu')
             pl.memory = label.get('memory')
             pl.env = label.get('env', [])
+            pl.node_selector = label.get('node-selector')
             pl.pool = self
             self.labels[pl.name] = pl
             full_config.labels[label['name']].pools.append(self)
@@ -113,6 +115,7 @@ class KubernetesProviderConfig(ProviderConfig):
             'cpu': int,
             'memory': int,
             'env': [env_var],
+            'node-selector': dict,
         }
 
         pool = ConfigPool.getCommonSchemaDict()

nodepool/driver/kubernetes/provider.py

@@ -274,7 +274,7 @@ class KubernetesProvider(Provider, QuotaSupport):
         return resource
 
     def createPod(self, node, pool, label):
-        spec_body = {
+        container_body = {
             'name': label.name,
             'image': label.image,
             'imagePullPolicy': label.image_pull,
@@ -285,22 +285,27 @@ class KubernetesProvider(Provider, QuotaSupport):
         }
 
         if label.cpu or label.memory:
-            spec_body['resources'] = {}
+            container_body['resources'] = {}
             for rtype in ('requests', 'limits'):
                 rbody = {}
                 if label.cpu:
                     rbody['cpu'] = int(label.cpu)
                 if label.memory:
                     rbody['memory'] = '%dMi' % int(label.memory)
-                spec_body['resources'][rtype] = rbody
+                container_body['resources'][rtype] = rbody
+
+        spec_body = {
+            'containers': [container_body]
+        }
+
+        if label.node_selector:
+            spec_body['nodeSelector'] = label.node_selector
 
         pod_body = {
             'apiVersion': 'v1',
             'kind': 'Pod',
             'metadata': {'name': label.name},
-            'spec': {
+            'spec': spec_body,
-                'containers': [spec_body],
-            },
             'restartPolicy': 'Never',
         }
 

nodepool/driver/openshift/config.py

@@ -32,7 +32,8 @@ class OpenshiftLabel(ConfigValue):
                     other.cpu == self.cpu and
                     other.memory == self.memory and
                     other.python_path == self.python_path and
-                    other.env == self.env)
+                    other.env == self.env and
+                    other.node_selector == self.node_selector)
         return False
 
     def __repr__(self):
@@ -64,6 +65,7 @@ class OpenshiftPool(ConfigPool):
             pl.memory = label.get('memory')
             pl.python_path = label.get('python-path', 'auto')
             pl.env = label.get('env', [])
+            pl.node_selector = label.get('node-selector')
             pl.pool = self
             self.labels[pl.name] = pl
             full_config.labels[label['name']].pools.append(self)
@@ -115,6 +117,7 @@ class OpenshiftProviderConfig(ProviderConfig):
             'memory': int,
             'python-path': str,
             'env': [env_var],
+            'node-selector': dict,
         }
 
         pool = ConfigPool.getCommonSchemaDict()

nodepool/driver/openshift/provider.py

@@ -204,7 +204,7 @@ class OpenshiftProvider(Provider):
 
     def createPod(self, project, pod_name, label):
         self.log.debug("%s: creating pod in project %s" % (pod_name, project))
-        spec_body = {
+        container_body = {
             'name': label.name,
             'image': label.image,
             'imagePullPolicy': label.image_pull,
@@ -214,23 +214,30 @@ class OpenshiftProvider(Provider):
             'env': label.env,
         }
         if label.cpu or label.memory:
-            spec_body['resources'] = {}
+            container_body['resources'] = {}
             for rtype in ('requests', 'limits'):
                 rbody = {}
                 if label.cpu:
                     rbody['cpu'] = int(label.cpu)
                 if label.memory:
                     rbody['memory'] = '%dMi' % int(label.memory)
-                spec_body['resources'][rtype] = rbody
+                container_body['resources'][rtype] = rbody
+
+        spec_body = {
+            'containers': [container_body]
+        }
+
+        if label.node_selector:
+            spec_body['nodeSelector'] = label.node_selector
+
         pod_body = {
             'apiVersion': 'v1',
             'kind': 'Pod',
             'metadata': {'name': pod_name},
-            'spec': {
+            'spec': spec_body,
-                'containers': [spec_body],
-            },
             'restartPolicy': 'Never',
         }
+
         self.k8s_client.create_namespaced_pod(project, pod_body)
 
     def waitForPod(self, project, pod_name):

nodepool/driver/openshiftpods/config.py

@@ -57,6 +57,7 @@ class OpenshiftPodsProviderConfig(OpenshiftProviderConfig):
             'memory': int,
             'python-path': str,
             'env': [env_var],
+            'node-selector': dict
         }
 
         pool = ConfigPool.getCommonSchemaDict()

nodepool/tests/fixtures/config_validate/good.yaml

@@ -143,6 +143,8 @@ providers:
                 value: hello
               - name: BAR
                 value: world
+            node-selector:
+              storageType: ssd
 
   - name: openshift
     driver: openshift
@@ -163,6 +165,8 @@ providers:
                 value: hello
               - name: BAR
                 value: world
+            node-selector:
+              storageType: ssd
 
   - name: ec2-us-east-2
     driver: aws

releasenotes/notes/k8s-provider-node-selector-6a16173ac11af61e.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Basic support for specifying k8s/OpenShift `nodeSelectors` on Pod node
+    labels. This allows to schedule a Pod on k8s nodes with specific labels,
+    e.g., having certain capabilities.