CODEWITHSUNDEEP
hazelcastnetflix-eureka
Prajesh
Prajesh

Reputation: 151

Hazelcast Eureka Cloud Discovery Plugin not working

We have implemented Hazelcast as an embedded cache in our Spring Boot app, and need a way using which Hazelcast members within a "cluster group" can discover each other dynamically so that we dont have to provide possible IP address/port where Hazelcast might be running.

We came across this hazelcast plugin on github: https://github.com/hazelcast/hazelcast-eureka which seems to provide the same feature using Eureka as discovery/registration tool.

As mentioned in this github documentation, hazelcast-eureka-one library is included within our boot app classpath, we also disabled TCP-IP & multicast discovery and added below discovery strategy in hazelcast.xml:

            <discovery-strategies>
                <discovery-strategy class="com.hazelcast.eureka.one.EurekaOneDiscoveryStrategy" enabled="true">
                    <properties>
                       <property name="self-registration">true</property>
                       <property name="namespace">hazelcast</property>
                    </properties>
                </discovery-strategy>
            </discovery-strategies>

Our application also provides configured EurekaClient, which is what we are autowiring and inject into this plugin implementation:

*

Config hazelcastConfig = new FileSystemXmlConfig(hazelcastConfigFilePath);
**EurekaOneDiscoveryStrategyFactory.setEurekaClient(eurekaClient);**
hazelcastInstance = Hazelcast.newHazelcastInstance(hazelcastConfig);

*

Problem: We are able to start 2 instances of our spring boot app on same machine and we notice that each app is starting hazelcast instance embedded on separate port (5701, 5702). But it doesnt seem to recognize each other running within a cluster, this is what we see in app logs when 2nd instance is starting:

Members [1] {

    Member [10.41.70.143]:5702 - 7c42eb24-3fa0-45cb-9394-17175cc92b9c this

}

17-12-13 12:22:44.480 WARN [main] c.h.i.Node.log(LoggingServiceImpl.java:168) - [10.41.70.143]:5702 [domain-services] [3.8.2] Config seed port is 5701 and cluster size is 1. Some of the ports seem occupied!

which seem to indicate that both hazelcast instances are running independently and doesnt recognize other running instance in a cluster/group.

Also, immediately after restart we see this exception thrown frequently on both the nodes:

*

java.lang.ClassCastException: com.hazelcast.nio.tcp.MemberWriteHandler cannot be cast to com.hazelcast.nio.ascii.TextWriteHandler
    at com.hazelcast.nio.ascii.TextReadHandler.<init>(TextReadHandler.java:109) ~[hazelcast-3.8.2.jar:3.8.2]
    at com.hazelcast.nio.tcp.SocketReaderInitializerImpl.init(SocketReaderInitializerImpl.java:89) ~[hazelcast-3.8.2.jar:3.8.2]

*

which seem to indicate there is Incompatibility between hazelcast library in the classpath?

Upvotes: 1

Views: 600

Answers (1)

noctarius
noctarius

Reputation: 6104

It seems like your Eureka service returns the wrong ports. Hazelcast tries to connect to 8080 and other ports in the same range, whereas Hazelcast uses 5701. Not exactly sure why this happens but it feels like you requesting the wrong service name from Eureka which ends up returning the HTTP (Tomcat?!) ports instead of the separate Hazelcast service that should be registered.

Upvotes: 0

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