Add Prometheus Zookeeper exporter

roles/pvc/handlers/main.yml

@@ -4,6 +4,11 @@
     name: zookeeper
     state: restarted
 
+- name: restart prometheus-zookeeper
+  service:
+    name: prometheus-zookeeper-exporter
+    state: restarted
+
 - name: restart libvirtd
   service:
     name: libvirtd

roles/pvc/tasks/zookeeper/main.yml

@@ -21,6 +21,26 @@
     - zoo.cfg
   notify: restart zookeeper
 
+- name: install Prometheus zookeeper exporter if enabled
+  apt:
+    name:
+      - prometheus-zookeeper-exporter
+  register: apt_res
+  retries: 5
+  until: apt_res is success
+  when: enable_prometheus_exporters is defined and enable_prometheus_exporters
+
+- name: install Prometheus zookeeper exporter config if enabled
+  template:
+    src: patroni/prometheus.env.j2
+    dest: /etc/default/prometheus-zookeeper-exporter
+    owner: prometheus
+    group: prometheus
+    mode: 0640
+  notify:
+    - restart prometheus-zookeeper
+  when: enable_prometheus_exporters is defined and enable_prometheus_exporters
+
 - name: install daily vacuum script
   template:
     src: zookeeper/zookeeper-vacuum.j2

roles/pvc/templates/zookeeper/prometheus.j2

@@ -0,0 +1,5 @@
+# Zookeeper Prometheus exporter arguments
+# {{ ansible_managed }}
+
+# Set the zk-hosts to our cluster local IP address as this is where Zookeeper listens
+ARGS="-zk-hosts='{% for node in pvc_nodes if node.hostname == this_node %}{{ node.cluster_ip }}{% endfor %}:2181'"

roles/pvc/templates/zookeeper/zoo.cfg.j2

@@ -19,11 +19,14 @@ maxClientCnxns=200
 autopurge.snapRetainCount=3
 autopurge.purgeInterval=1
 
-# Enable Prometheus metrics (someday, but not today under Debian 12 or less)
+# Enable internal Prometheus metrics (someday, but not today under Debian 12 or less)
 #metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider
 #metricsProvider.httpPort=9181
 #metricsProvider.exportJvmInfo=true
 
+# Enable all 4LW commands; need MNTR for external Prometheus metrics
+4lw.commands.whitelist=*
+
 # Listen on port 2181 on the cluster IP
 clientPort=2181
 clientPortAddress={% for node in pvc_nodes if node.hostname == this_node %}{{ node.cluster_ip }}{% endfor %}