Healthcheck check

Dockerfile

@@ -41,4 +41,13 @@ RUN yum install -y openssl findutils && yum clean all && mkdir -p "${ZOOKEEPER_D
    	&& chmod -R ag+w "${ZOOKEEPER_LOG4J_DIR}" "${ZOOKEEPER_LOG_DIR}" "${ZOOKEEPER_CONFIG_DIR}" "$ZOOKEEPER_DATA_DIR" "/opt"
 
 CMD ["/opt/caas/bin/run"]
+
+# Polling period  : 5 seconds
+# Timeout period  :10 seconds (if the polling does not return within this time, treat as a failed poll)
+# Start-up period : 2 minutes (during which failures are not counted as failures)
+# Retry period    : 8 minutes (after which container is deemed unhealthy)
+# All settings can be overriden at run-time in Docker/Docker Compose. 
+HEALTHCHECK --start-period=120s --interval=5s --timeout=10s --retries=96 \
+    CMD /usr/bin/zookeeper-shell localhost:2181 ls / || exit 1
+
 USER 1001
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