chore: add built-in Prometheus support

CHANGELOG.md

@@ -10,6 +10,7 @@ All notable changes to this project will be documented in this file.
   - Use `--file-log-max-files` (or `FILE_LOG_MAX_FILES`) to limit the number of log files kept.
   - Use `--file-log-rotation-period` (or `FILE_LOG_ROTATION_PERIOD`) to configure the frequency of rotation.
   - Use `--console-log-format` (or `CONSOLE_LOG_FORMAT`) to set the format to `plain` (default) or `json`.
+- Add built-in Prometheus support and expose metrics on `/metrics` path of `native-metrics` port ([#955]).
 
 ### Changed
 
@@ -45,6 +46,7 @@ All notable changes to this project will be documented in this file.
 [#942]: https://github.com/stackabletech/zookeeper-operator/pull/942
 [#946]: https://github.com/stackabletech/zookeeper-operator/pull/946
 [#950]: https://github.com/stackabletech/zookeeper-operator/pull/950
+[#955]: https://github.com/stackabletech/zookeeper-operator/pull/955
 
 ## [25.3.0] - 2025-03-21
 

docs/modules/zookeeper/pages/usage_guide/monitoring.adoc

@@ -2,4 +2,23 @@
 :description: The managed ZooKeeper instances are automatically configured to export Prometheus metrics.
 
 The managed ZooKeeper instances are automatically configured to export Prometheus metrics.
-See xref:operators:monitoring.adoc[] for more details.
+See xref:operators:monitoring.adoc[window=_blank] for more details.
+
+Depending on the SDP version, different ZooKeeper monitoring systems are used to produce metrics. Currently, JMX in combination with JMX Exporter
+is used, but will be removed in a later release. Starting with SDP 25.7 the built-in Prometheus support of ZooKeeper is also added.
+The naming of the metrics differs between the two systems.
+
+== Metrics
+
+Starting with SDP 25.7 ZooKeeper is configured to export metrics using the built-in Prometheus provider. More on the Prometheus provider in
+the https://zookeeper.apache.org/doc/current/zookeeperMonitor.html[ZooKeeper Monitor Guide,window=_blank].
+
+The configuration is located in the `zoo.cfg`:
+
+[source,properties]
+----
+metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider
+metricsProvider.httpPort=7000
+----
+
+The metrics can be accessed by calling the `/metrics` endpoint on the specified port.

rust/operator-binary/src/crd/mod.rs

@@ -48,6 +48,8 @@ pub const ZOOKEEPER_PROPERTIES_FILE: &str = "zoo.cfg";
 pub const JVM_SECURITY_PROPERTIES_FILE: &str = "security.properties";
 
 pub const METRICS_PORT: u16 = 9505;
+pub const METRICS_PROVIDER_HTTP_PORT_KEY: &str = "metricsProvider.httpPort";
+pub const METRICS_PROVIDER_HTTP_PORT: u16 = 7000;
 
 pub const STACKABLE_DATA_DIR: &str = "/stackable/data";
 pub const STACKABLE_CONFIG_DIR: &str = "/stackable/config";
@@ -468,6 +470,16 @@ impl Configuration for v1alpha1::ZookeeperConfigFragment {
                 v1alpha1::ZookeeperConfig::DATA_DIR.to_string(),
                 Some(STACKABLE_DATA_DIR.to_string()),
             );
+            result.insert(
+                "metricsProvider.className".to_string(),
+                Some(
+                    "org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider".to_string(),
+                ),
+            );
+            result.insert(
+                METRICS_PROVIDER_HTTP_PORT_KEY.to_string(),
+                Some(METRICS_PROVIDER_HTTP_PORT.to_string()),
+            );
         }
 
         Ok(result)

rust/operator-binary/src/zk_controller.rs

@@ -72,8 +72,9 @@ use crate::{
     config::jvm::{construct_non_heap_jvm_args, construct_zk_server_heap_env},
     crd::{
         DOCKER_IMAGE_BASE_NAME, JVM_SECURITY_PROPERTIES_FILE, MAX_PREPARE_LOG_FILE_SIZE,
-        MAX_ZK_LOG_FILES_SIZE, STACKABLE_CONFIG_DIR, STACKABLE_DATA_DIR, STACKABLE_LOG_CONFIG_DIR,
-        STACKABLE_LOG_DIR, STACKABLE_RW_CONFIG_DIR, ZOOKEEPER_PROPERTIES_FILE, ZookeeperRole,
+        MAX_ZK_LOG_FILES_SIZE, METRICS_PROVIDER_HTTP_PORT, METRICS_PROVIDER_HTTP_PORT_KEY,
+        STACKABLE_CONFIG_DIR, STACKABLE_DATA_DIR, STACKABLE_LOG_CONFIG_DIR, STACKABLE_LOG_DIR,
+        STACKABLE_RW_CONFIG_DIR, ZOOKEEPER_PROPERTIES_FILE, ZookeeperRole,
         security::{self, ZookeeperSecurity},
         v1alpha1,
     },
@@ -415,6 +416,7 @@ pub async fn reconcile_zk(
             &rolegroup,
             &resolved_product_image,
             &zookeeper_security,
+            rolegroup_config,
         )?;
         let rg_configmap = build_server_rolegroup_config_map(
             zk,
@@ -675,6 +677,7 @@ fn build_server_rolegroup_service(
     rolegroup: &RoleGroupRef<v1alpha1::ZookeeperCluster>,
     resolved_product_image: &ResolvedProductImage,
     zookeeper_security: &ZookeeperSecurity,
+    rolegroup_config: &HashMap<PropertyNameKind, BTreeMap<String, String>>,
 ) -> Result<Service> {
     let prometheus_label =
         Label::try_from(("prometheus.io/scrape", "true")).context(BuildLabelSnafu)?;
@@ -716,6 +719,12 @@ fn build_server_rolegroup_service(
                 protocol: Some("TCP".to_string()),
                 ..ServicePort::default()
             },
+            ServicePort {
+                name: Some("native-metrics".to_string()),
+                port: metrics_port_from_rolegroup_config(rolegroup_config).into(),
+                protocol: Some("TCP".to_string()),
+                ..ServicePort::default()
+            },
         ]),
         selector: Some(service_selector_labels.into()),
         publish_not_ready_addresses: Some(true),
@@ -898,6 +907,10 @@ fn build_server_rolegroup_statefulset(
         .add_container_port("zk-leader", 2888)
         .add_container_port("zk-election", 3888)
         .add_container_port("metrics", 9505)
+        .add_container_port(
+            "native-metrics",
+            metrics_port_from_rolegroup_config(server_config).into(),
+        )
         .add_volume_mount("data", STACKABLE_DATA_DIR)
         .context(AddVolumeMountSnafu)?
         .add_volume_mount("config", STACKABLE_CONFIG_DIR)
@@ -1063,6 +1076,27 @@ fn build_server_rolegroup_statefulset(
     })
 }
 
+fn metrics_port_from_rolegroup_config(
+    rolegroup_config: &HashMap<PropertyNameKind, BTreeMap<String, String>>,
+) -> u16 {
+    let metrics_port = rolegroup_config
+        .get(&PropertyNameKind::File(
+            ZOOKEEPER_PROPERTIES_FILE.to_string(),
+        ))
+        .expect("{ZOOKEEPER_PROPERTIES_FILE} is present")
+        .get(METRICS_PROVIDER_HTTP_PORT_KEY)
+        .expect("{METRICS_PROVIDER_HTTP_PORT_KEY} is set");
+
+    match u16::from_str(metrics_port) {
+        Ok(port) => port,
+        Err(err) => {
+            tracing::error!("{err}");
+            tracing::info!("Defaulting to using {METRICS_PROVIDER_HTTP_PORT} as metrics port.");
+            METRICS_PROVIDER_HTTP_PORT
+        }
+    }
+}
+
 pub fn error_policy(
     _obj: Arc<DeserializeGuard<v1alpha1::ZookeeperCluster>>,
     error: &Error,

tests/templates/kuttl/smoke/test_zookeeper.py

@@ -3,6 +3,7 @@
 import requests
 import time
 import sys
+
 sys.tracebacklimit = 0
 
 
@@ -37,17 +38,29 @@ def check_ruok(hosts):
         url = host + ":8080/commands/" + cmd_ruok
         response = try_get(url).json()
 
-        if "command" in response and response["command"] == cmd_ruok \
-                and "error" in response and response["error"] is None:
+        if (
+            "command" in response
+            and response["command"] == cmd_ruok
+            and "error" in response
+            and response["error"] is None
+        ):
             continue
         else:
-            print("Error[" + cmd_ruok + "] for [" + url + "]: received " + str(
-                response) + " - expected {'command': 'ruok', 'error': None} ")
+            print(
+                "Error["
+                + cmd_ruok
+                + "] for ["
+                + url
+                + "]: received "
+                + str(response)
+                + " - expected {'command': 'ruok', 'error': None} "
+            )
             exit(-1)
 
 
 def check_monitoring(hosts):
     for host in hosts:
+        # test for the jmx exporter metrics
         url = host + ":9505"
         response = try_get(url)
 
@@ -57,16 +70,46 @@ def check_monitoring(hosts):
             print("Error for [" + url + "]: could not access monitoring")
             exit(-1)
 
+        # test for the native metrics
+        url = host + ":7000/metrics"
+        response = try_get(url)
+
+        if response.ok:
+            # arbitrary metric was chosen to test if metrics are present in the response
+            if "quorum_size" in response.text:
+                continue
+            else:
+                print("Error for [" + url + "]: missing metrics")
+                exit(-1)
+            continue
+        else:
+            print("Error for [" + url + "]: could not access monitoring")
+            exit(-1)
+
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     all_args = argparse.ArgumentParser(description="Test ZooKeeper.")
-    all_args.add_argument("-n", "--namespace", help="The namespace to run in", required=True)
+    all_args.add_argument(
+        "-n", "--namespace", help="The namespace to run in", required=True
+    )
     args = vars(all_args.parse_args())
     namespace = args["namespace"]
 
-    host_primary_0 = "http://test-zk-server-primary-0.test-zk-server-primary." + namespace + ".svc.cluster.local"
-    host_primary_1 = "http://test-zk-server-primary-1.test-zk-server-primary." + namespace + ".svc.cluster.local"
-    host_secondary = "http://test-zk-server-secondary-0.test-zk-server-secondary." + namespace + ".svc.cluster.local"
+    host_primary_0 = (
+        "http://test-zk-server-primary-0.test-zk-server-primary."
+        + namespace
+        + ".svc.cluster.local"
+    )
+    host_primary_1 = (
+        "http://test-zk-server-primary-1.test-zk-server-primary."
+        + namespace
+        + ".svc.cluster.local"
+    )
+    host_secondary = (
+        "http://test-zk-server-secondary-0.test-zk-server-secondary."
+        + namespace
+        + ".svc.cluster.local"
+    )
 
     hosts = [host_primary_0, host_primary_1, host_secondary]