Add a new config to configure the host of the scheduler health check …

…server (apache#35616)

* Add a new config to configure the host of the scheduler healthcheck server

* Add a test

airflow/config_templates/config.yml

@@ -2142,6 +2142,14 @@ scheduler:
       type: boolean
       example: ~
       default: "False"
+    scheduler_health_check_server_host:
+      description: |
+        When you start a scheduler, airflow starts a tiny web server
+        subprocess to serve a health check on this host
+      version_added: 2.8.0
+      type: string
+      example: ~
+      default: "0.0.0.0"
     scheduler_health_check_server_port:
       description: |
         When you start a scheduler, airflow starts a tiny web server

airflow/utils/scheduler_health.py

@@ -57,8 +57,10 @@ def do_GET(self):
 
 
 def serve_health_check():
+    """Start a http server to serve scheduler health check."""
+    health_check_host = conf.get("scheduler", "SCHEDULER_HEALTH_CHECK_SERVER_HOST")
     health_check_port = conf.getint("scheduler", "SCHEDULER_HEALTH_CHECK_SERVER_PORT")
-    httpd = HTTPServer(("0.0.0.0", health_check_port), HealthServer)
+    httpd = HTTPServer((health_check_host, health_check_port), HealthServer)
     httpd.serve_forever()
 
 

tests/cli/commands/test_scheduler_command.py

@@ -141,6 +141,22 @@ def test_disable_scheduler_health(
         with pytest.raises(AssertionError):
             mock_process.assert_has_calls([mock.call(target=serve_health_check)])
 
+    @mock.patch("airflow.utils.scheduler_health.HTTPServer")
+    def test_scheduler_health_host(
+        self,
+        http_server_mock,
+    ):
+        health_check_host = "192.168.0.0"
+        health_check_port = 1111
+        with conf_vars(
+            {
+                ("scheduler", "SCHEDULER_HEALTH_CHECK_SERVER_HOST"): health_check_host,
+                ("scheduler", "SCHEDULER_HEALTH_CHECK_SERVER_PORT"): str(health_check_port),
+            }
+        ):
+            serve_health_check()
+        assert http_server_mock.call_args.args[0] == (health_check_host, health_check_port)
+
     @mock.patch("airflow.cli.commands.scheduler_command.SchedulerJobRunner")
     @mock.patch("airflow.cli.commands.scheduler_command.Process")
     @mock.patch("airflow.cli.commands.scheduler_command.run_job", side_effect=Exception("run_job failed"))