Add config for disabling creation of PING type HMs

PING is a trap. There is no real-world scenario where PING is the option
that makes the most sense, but people are familiar with it, and it seems
"simple", so they pick it. This needs to stop. Empower operators to
disable this!

Change-Id: Ifa80b7a5973361c13f2e6611789aa9798325ece0

etc/octavia.conf

@@ -40,6 +40,9 @@
 # Enable/disable ability for users to create TLS Terminated listeners
 # allow_tls_terminated_listeners = True
 
+# Enable/disable ability for users to create PING type Health Monitors
+# allow_ping_health_monitors = True
+
 [database]
 # This line MUST be changed to actually run the plugin.
 # Example:

octavia/api/v2/controllers/health_monitor.py

@@ -151,6 +151,12 @@ class HealthMonitorController(base.BaseController):
         """Creates a health monitor on a pool."""
         context = pecan.request.context.get('octavia_context')
         health_monitor = health_monitor_.healthmonitor
+
+        if (not CONF.api_settings.allow_ping_health_monitors and
+                health_monitor.type == constants.HEALTH_MONITOR_PING):
+            raise exceptions.DisabledOption(
+                option='type', value=constants.HEALTH_MONITOR_PING)
+
         pool = self._get_db_pool(context.session, health_monitor.pool_id)
         health_monitor.project_id = pool.project_id
 

octavia/common/config.py

@@ -100,6 +100,8 @@ api_opts = [
                 help=_("Expose the v2 API?")),
     cfg.BoolOpt('allow_tls_terminated_listeners', default=True,
                 help=_("Allow users to create TLS Terminated listeners?")),
+    cfg.BoolOpt('allow_ping_health_monitors', default=True,
+                help=_("Allow users to create PING type Health Monitors?")),
 ]
 
 # Options only used by the amphora agent

octavia/tests/functional/api/v2/test_health_monitor.py

@@ -740,6 +740,21 @@ class TestHealthMonitor(base.BaseAPITest):
             lb_id=self.lb_id, listener_id=self.listener_id,
             pool_id=self.pool_id)
 
+    def test_create_ping_when_ping_disabled(self):
+        self.conf = self.useFixture(oslo_fixture.Config(cfg.CONF))
+        self.conf.config(group='api_settings',
+                         allow_ping_health_monitors=False)
+        req_dict = {'pool_id': self.pool_id,
+                    'type': constants.HEALTH_MONITOR_PING,
+                    'delay': 1,
+                    'timeout': 1,
+                    'max_retries_down': 1,
+                    'max_retries': 1}
+        self.post(self.HMS_PATH, self._build_body(req_dict), status=400)
+        self.assert_correct_status(
+            lb_id=self.lb_id, listener_id=self.listener_id,
+            pool_id=self.pool_id)
+
     def test_create_with_bad_handler(self):
         self.handler_mock().health_monitor.create.side_effect = Exception()
         api_hm = self.create_health_monitor(

releasenotes/notes/allow-operators-to-disable-ping-healthchecks-42fd8c3b88edaf35.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    Cloud deployers can set `api_settings.allow_ping_health_monitors = False`
+    in `octavia.conf` to disable the ability to create PING health monitors.