Allow enable/disable of Prometheus endpoints

Since these are unauthenticated, it might be the case that an
administrator wishes to completely disable these metrics endpoints.
Provide that option via pvc.conf through pvc-ansible's existing
enable_prometheus_exporters option and the new enable_prometheus
configuration flag.

Defaults to "yes" to provide all functionality unless explicitly
disabled, as the author assumes that the PVC API is secured in other
ways as well and that metric information is not completely sensitive.

api-daemon/pvcapid/flaskapi.py

@@ -629,8 +629,9 @@ class API_Metrics(Resource):
         Return the current PVC cluster status in Prometheus-compatible metrics format and
         the Ceph cluster metrics as one document.
 
-        Endpoint is unauthenticated to allow metrics exfiltration without having to deal
+        Endpoint is UNAUTHENTICATED to allow metrics exfiltration without having to deal
-        with the Prometheus compatibility later.
+        with Prometheus compatibility (only basic auth support). Ensure this API endpoint
+        is only opened to trusted networks that cannot abuse the data provided!
         ---
         tags:
           - root
@@ -657,7 +658,8 @@ class API_Metrics(Resource):
         return response
 
 
-api.add_resource(API_Metrics, "/metrics")
+if config["enable_prometheus"]:
+    api.add_resource(API_Metrics, "/metrics")
 
 
 # /metrics/health
@@ -666,8 +668,9 @@ class API_Metrics_Health(Resource):
         """
         Return the current PVC cluster health status in Prometheus-compatible metrics format
 
-        Endpoint is unauthenticated to allow metrics exfiltration without having to deal
+        Endpoint is UNAUTHENTICATED to allow metrics exfiltration without having to deal
-        with the Prometheus compatibility later.
+        with Prometheus compatibility (only basic auth support). Ensure this API endpoint
+        is only opened to trusted networks that cannot abuse the data provided!
         ---
         tags:
           - root
@@ -691,7 +694,8 @@ class API_Metrics_Health(Resource):
         return response
 
 
-api.add_resource(API_Metrics_Health, "/metrics/health")
+if config["enable_prometheus"]:
+    api.add_resource(API_Metrics_Health, "/metrics/health")
 
 
 # /metrics/resource
@@ -700,8 +704,9 @@ class API_Metrics_Resource(Resource):
         """
         Return the current PVC cluster resource utilizations in Prometheus-compatible metrics format
 
-        Endpoint is unauthenticated to allow metrics exfiltration without having to deal
+        Endpoint is UNAUTHENTICATED to allow metrics exfiltration without having to deal
-        with the Prometheus compatibility later.
+        with Prometheus compatibility (only basic auth support). Ensure this API endpoint
+        is only opened to trusted networks that cannot abuse the data provided!
         ---
         tags:
           - root
@@ -725,7 +730,8 @@ class API_Metrics_Resource(Resource):
         return response
 
 
-api.add_resource(API_Metrics_Resource, "/metrics/resource")
+if config["enable_prometheus"]:
+    api.add_resource(API_Metrics_Resource, "/metrics/resource")
 
 
 # /metrics/ceph
@@ -736,6 +742,10 @@ class API_Metrics_Ceph(Resource):
 
         Proxies a metrics request to the current active MGR, since this is dynamic
         and can't be controlled by PVC easily.
+
+        Endpoint is UNAUTHENTICATED to allow metrics exfiltration without having to deal
+        with Prometheus compatibility (only basic auth support). Ensure this API endpoint
+        is only opened to trusted networks that cannot abuse the data provided!
         ---
         tags:
           - root
@@ -759,7 +769,8 @@ class API_Metrics_Ceph(Resource):
         return response
 
 
-api.add_resource(API_Metrics_Ceph, "/metrics/ceph")
+if config["enable_prometheus"]:
+    api.add_resource(API_Metrics_Ceph, "/metrics/ceph")
 
 
 # /metrics/zookeeper
@@ -770,6 +781,10 @@ class API_Metrics_Zookeeper(Resource):
 
         Proxies a metrics request to the current primary node, since all coordinators
         run an active Zookeeper instance and we want one central location.
+
+        Endpoint is UNAUTHENTICATED to allow metrics exfiltration without having to deal
+        with Prometheus compatibility (only basic auth support). Ensure this API endpoint
+        is only opened to trusted networks that cannot abuse the data provided!
         ---
         tags:
           - root
@@ -793,7 +808,8 @@ class API_Metrics_Zookeeper(Resource):
         return response
 
 
-api.add_resource(API_Metrics_Zookeeper, "/metrics/zookeeper")
+if config["enable_prometheus"]:
+    api.add_resource(API_Metrics_Zookeeper, "/metrics/zookeeper")
 
 
 # /faults

daemon-common/config.py

@@ -176,6 +176,7 @@ def get_parsed_configuration(config_file):
             "enable_storage": o_subsystem.get("enable_storage", True),
             "enable_worker": o_subsystem.get("enable_worker", True),
             "enable_api": o_subsystem.get("enable_api", True),
+            "enable_prometheus": o_subsystem.get("enable_prometheus", True),
         }
         config = {**config, **config_subsystem}
 

pvc.sample.conf

@@ -44,6 +44,9 @@ subsystem:
     # Enable or disable the API client, if installed, when node is Primary
     enable_api: yes
 
+    # Enable or disable the Prometheus metrics endpoints in the API; if disabled, these return 404
+    enable_prometheus: yes
+
 # Cluster configuration
 cluster: