Enable Prometheus metrics in Zookeeper too

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

@@ -19,6 +19,10 @@ maxClientCnxns=200
 autopurge.snapRetainCount=3
 autopurge.purgeInterval=1
 
+# Enable Prometheus metrics
+metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider
+metricsProvider.httpPort=9181
+
 # 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 %}