Remove pseudo distributed toggle

- The same functionality can be achieved by using the
  node-scheduler.include-coordinator property. Removing
  the pseudo distributed toggle simplifies setup.

Author: Anton Petrov

README.md

@@ -57,7 +57,7 @@ $ ambari-server restart
 
 ## Supported topologies
 
-The following two screens will allow you to assign the Presto processes among the nodes in your cluster.
+The following two screens will allow you to assign the Presto processes among the nodes in your cluster. Unfortunately, once you pick a topology for Presto and finish the installation process it is impossible to tweak the topology.
 
 Presto is composed of a coordinator and worker processes. The same code runs all nodes because the same Presto server RPM is installed for both workers and coordinator. It is the configuration on each node that determines how a particular node will behave. Presto can run in pseudo-distributed mode, where a single Presto process on one node acts as both coordinator and worker, or in distributed mode, where the Presto coordinator runs on one node and the Presto workers run on other nodes.
 
@@ -67,7 +67,7 @@ The client component of Presto is the `presto-cli` executable JAR. You should pl
 
 ### Pseudo-distributed
 
-Pick a node for the Presto coordinator and *do not assign any Presto workers*. On the configuration screen that follows, you must also enable pseudo-distributed mode by clicking the toggle. If you assign Presto workers to nodes and enable the pseudo-distributed toggle, the installation will fail.
+Pick a node for the Presto coordinator and *do not assign any Presto workers*. On the configuration screen that follows, you must also enable `node-scheduler.include-coordinator` by clicking the toggle.
 
 ### Distributed
 

configuration/config.properties.xml

@@ -113,29 +113,4 @@
   </property>
 -->
 
-  <property>
-    <name>pseudo.distributed.enabled</name>
-    <value>false</value>
-    <description>
-      Run Presto in pseudo-distributed mode. Coordinator and worker run in
-      a single process on a single node. If this option is selected the only
-      component that needs to be assigned to a node is the coordinator.
-    </description>
-    <display-name>Pseudo Distributed Mode</display-name>
-    <value-attributes>
-      <type>value-list</type>
-      <entries>
-        <entry>
-          <value>true</value>
-          <label>Enabled</label>
-        </entry>
-        <entry>
-          <value>false</value>
-          <label>Disabled</label>
-        </entry>
-      </entries>
-      <selection-cardinality>1</selection-cardinality>
-    </value-attributes>
-  </property>
-
 </configuration>

package/scripts/presto_coordinator.py

@@ -68,24 +68,11 @@ def configure(self, env):
             for key, value in config_properties.iteritems():
                 if key == 'query.queue-config-file' and value.strip() == '':
                     continue
-                # Ignore as it's not an actual config property, just
-                # the user visible equivalent to node-scheduler.include-coordinator
-                if key == 'pseudo.distributed.enabled' or key == 'node-scheduler.include-coordinator':
-                    continue
                 if key in memory_configs:
                     value += 'GB'
                 f.write(key_val_template.format(key, value))
             f.write(key_val_template.format('coordinator', 'true'))
             f.write(key_val_template.format('discovery-server.enabled', 'true'))
-            if (config_properties['pseudo.distributed.enabled'] and
-                'presto_worker_hosts' in host_info.keys()):
-                raise RuntimeError('You cannot specify worker nodes in pseudo distributed mode')
-            elif config_properties['pseudo.distributed.enabled']:
-                f.write(key_val_template.format(
-                    'node-scheduler.include-coordinator', 'true'))
-            else:
-                f.write(key_val_template.format('node-scheduler.include-coordinator',
-                    str(config_properties['node-scheduler.include-coordinator'])))
 
         create_connectors(node_properties, connectors_to_add)
         delete_connectors(node_properties, connectors_to_delete)

package/scripts/presto_worker.py

@@ -58,8 +58,6 @@ def configure(self, env):
             for key, value in config_properties.iteritems():
                 if key == 'query.queue-config-file' and value.strip() == '':
                     continue
-                if key == 'pseudo.distributed.enabled':
-                    continue
                 if key in memory_configs:
                     value += 'GB'
                 f.write(key_val_template.format(key, value))

tests/test_coordinator.py

@@ -28,16 +28,9 @@
 
 class TestCoordinator(unittest.TestCase):
 
-    dummy_config_properties = {'pseudo.distributed.enabled': False,
-                               'query.queue-config-file': '',
+    dummy_config_properties = {'query.queue-config-file': '',
                                'http-server.http.port': '8081',
-                               'node-scheduler.include-coordinator': True}
-
-    pseudo_distributed_config_properties = {'pseudo.distributed.enabled': True,
-                                            'node-scheduler.include-coordinator': False}
-
-    minimal_config_properties = {'pseudo.distributed.enabled': False,
-                                 'node-scheduler.include-coordinator': False}
+                               'node-scheduler.include-coordinator': 'true'}
 
     for memory_config in memory_configs:
         dummy_config_properties[memory_config] = '123'
@@ -114,7 +107,7 @@ def test_start_smoketests_presto(
         assert smoketest_presto_mock.called
 
     @patch('package.scripts.presto_coordinator.create_connectors')
-    @patch('package.scripts.params.config_properties', new=minimal_config_properties)
+    @patch('package.scripts.params.config_properties', new={})
     def test_assert_constant_properties(self, create_connectors_mock):
         config = collect_config_vars_written_out(self.mock_env, Coordinator())
 
@@ -132,32 +125,19 @@ def test_configure_ignore_empty_queue_config_file(self, create_connectors_mock):
 
     @patch('package.scripts.params.host_info', new={'presto_coordinator_hosts': ['master']})
     @patch('package.scripts.presto_coordinator.create_connectors')
-    @patch('package.scripts.params.config_properties', new=pseudo_distributed_config_properties)
+    @patch('package.scripts.params.config_properties', new=dummy_config_properties)
     def test_configure_pseudo_distributed(self, create_connectors_mock):
         config = collect_config_vars_written_out(self.mock_env, Coordinator())
 
         assert 'node-scheduler.include-coordinator=true\n' in config
 
-    @patch('package.scripts.presto_coordinator.create_connectors')
-    @patch('package.scripts.params.config_properties', new=dummy_config_properties)
-    def test_user_set_coordinator_as_worker(self, create_connectors_mock):
-        config = collect_config_vars_written_out(self.mock_env, Coordinator())
-
-        assert 'node-scheduler.include-coordinator=True\n' in config
-
     @patch('package.scripts.presto_coordinator.create_connectors')
     @patch('package.scripts.params.config_properties', new=dummy_config_properties)
     def test_memory_settings_have_units(self, create_connectos_mock):
         config = collect_config_vars_written_out(self.mock_env, Coordinator())
 
         assert_memory_configs_properly_formatted(config)
 
-    @patch('package.scripts.presto_coordinator.create_connectors')
-    @patch('package.scripts.params.host_info', new={'presto_worker_hosts': ['slave1']})
-    @patch('package.scripts.params.config_properties', new=pseudo_distributed_config_properties)
-    def test_pseudo_distributed_topology_enforced(self, create_connectors_mock):
-        TestCase.assertRaises(self, RuntimeError, collect_config_vars_written_out, self.mock_env, Coordinator())
-
 def assert_memory_configs_properly_formatted(configs_to_test):
     import re
     from package.scripts.params import memory_configs

themes/theme.json

@@ -130,10 +130,6 @@
           "config": "config.properties/discovery.uri",
           "subsection-name": "subsection-general-config"
         },
-        {
-          "config": "config.properties/pseudo.distributed.enabled",
-          "subsection-name": "subsection-general-config"
-        },
         {
           "config": "jvm.config/jvm.config",
           "subsection-name": "subsection-jvm-config"
@@ -211,12 +207,6 @@
           "type": "text-area"
         }
       },
-      {
-        "config": "config.properties/pseudo.distributed.enabled",
-        "widget": {
-          "type": "toggle"
-        }
-      },
       {
         "config": "jvm.config/jvm.config",
         "widget": {