Improvements to health checks

- Adds a warning endpoint for warning-only checks
- Changes the default for the disk space check to 1%, instead of 10%
- Removes instance services from the overall health check endpoint

endpoints/web.py

@@ -257,7 +257,6 @@ def privacy():
   return index('')
 
 
-# TODO(jschorr): Remove this mirrored endpoint once we migrate ELB.
 @web.route('/health', methods=['GET'])
 @web.route('/health/instance', methods=['GET'])
 @process_auth_or_cookie
@@ -270,7 +269,6 @@ def instance_health():
   return response
 
 
-# TODO(jschorr): Remove this mirrored endpoint once we migrate pingdom.
 @web.route('/status', methods=['GET'])
 @web.route('/health/endtoend', methods=['GET'])
 @process_auth_or_cookie
@@ -283,6 +281,17 @@ def endtoend_health():
   return response
 
 
+@web.route('/health/warning', methods=['GET'])
+@process_auth_or_cookie
+@no_cache
+def warning_health():
+  checker = get_healthchecker(app, config_provider, instance_keys)
+  (data, status_code) = checker.check_warning()
+  response = jsonify(dict(data=data, status_code=status_code))
+  response.status_code = status_code
+  return response
+
+
 @web.route('/health/dbrevision', methods=['GET'])
 @route_show_if(features.BILLING) # Since this is only used in production.
 @process_auth_or_cookie