Latency for sharing data while using Hazelcast on Virtual Machine

A few days back we found out one old app which was running on multiple nodes while having in-memory cache usage. So, as a result, there was a case when the request came to the first node and the second node didn't get that data, and the app wasn't functioning properly. 

So, as always first thing which we considered to use Redis. However, we don't have ready to use the Redis cluster and we started looking for other solutions in a market. Finally, I saw there is a Hazelcast which allows sharing data between nodes even without having the Hazelcast cluster. Of course, it is working when you are running in the same network. So, nodes should be able to multicast and make a proper cluster.

Of course, I was happy with a solution while checking locally it was working like magic, everything was fine for testing in a laptop with multiple running instances. But, when I pushed my changed to TEST environment headache started :) When I pushed the data to a node it was able to sync with other nodes. However, when I shutdown one node and return it back Hazelcast wasn't able to join that node to cluster (not shared the data with that node) at least 2-3 minutes. So, I was experimenting with multiple configs to achieve it.

NO LUCK... I decided to ask my question in a StackOverflow because wasn't able to find anything useful while googling. And before publishing my question StackOverflow suggested me to check some posts, while checking them one by one I found a question in a Hazelcast's git page. One guy was asking why they are using "224.2.2.3" as a default Multicast Group. So, he said he is running in a VM and having similar problem as mine. He mentioned when he changes the default group to "224.0.0.1" it works for him. So, I decided to give a try and it worked :D

So, if somebody has a similar problem, please change the multicast default group as below and retry:

Config config = Config.load().setClusterName(CLUSTER_NAME);
config.getNetworkConfig().getJoin().getMulticastConfig().setMulticastGroup("224.0.0.1");
hazelcastInstance = Hazelcast.newHazelcastInstance(config);