How do you programmatically configure hazelcast for the multicast discovery mechanism?

java configuration multicast hazelcast
DaveFar picture DaveFar · Dec 4, 2013 · Viewed 37.3k times · Source

How do you programmatically configure hazelcast for the multicast discovery mechanism?

Details:

The documentation only supplies an example for TCP/IP and is out-of-date: it uses Config.setPort(), which no longer exists.

My configuration looks like this, but discovery does not work (i.e. I get the output "Members: 1":

Config cfg = new Config();                  
NetworkConfig network = cfg.getNetworkConfig();
network.setPort(PORT_NUMBER);

JoinConfig join = network.getJoin();
join.getTcpIpConfig().setEnabled(false);
join.getAwsConfig().setEnabled(false);
join.getMulticastConfig().setEnabled(true);

join.getMulticastConfig().setMulticastGroup(MULTICAST_ADDRESS);
join.getMulticastConfig().setMulticastPort(PORT_NUMBER);
join.getMulticastConfig().setMulticastTimeoutSeconds(200);

HazelcastInstance instance = Hazelcast.newHazelcastInstance(cfg);
System.out.println("Members: "+hazelInst.getCluster().getMembers().size());

Update 1, taking asimarslan's answer into account

If I fumbled with the MulticastTimeout, I either get "Members: 1" or

Dec 05, 2013 8:50:42 PM com.hazelcast.nio.ReadHandler WARNING: [192.168.0.9]:4446 [dev] hz._hzInstance_1_dev.IO.thread-in-0 Closing socket to endpoint Address[192.168.0.7]:4446, Cause:java.io.EOFException: Remote socket closed! Dec 05, 2013 8:57:24 PM com.hazelcast.instance.Node SEVERE: [192.168.0.9]:4446 [dev] Could not join cluster, shutting down! com.hazelcast.core.HazelcastException: Failed to join in 300 seconds!

Update 2, taking pveentjer's answer about using tcp/ip into account

If I change the configuration to the following, I still only get 1 member:

Config cfg = new Config();                  
NetworkConfig network = cfg.getNetworkConfig();
network.setPort(PORT_NUMBER);

JoinConfig join = network.getJoin();

join.getMulticastConfig().setEnabled(false);
join.getTcpIpConfig().addMember("192.168.0.1").addMember("192.168.0.2").
addMember("192.168.0.3").addMember("192.168.0.4").
addMember("192.168.0.5").addMember("192.168.0.6").
addMember("192.168.0.7").addMember("192.168.0.8").
addMember("192.168.0.9").addMember("192.168.0.10").
addMember("192.168.0.11").setRequiredMember(null).setEnabled(true);

//this sets the allowed connections to the cluster? necessary for multicast, too?
network.getInterfaces().setEnabled(true).addInterface("192.168.0.*");

HazelcastInstance instance = Hazelcast.newHazelcastInstance(cfg);
System.out.println("debug: joined via "+join+" with "+hazelInst.getCluster()
.getMembers().size()+" members.");

More precisely, this run produces the output

debug: joined via JoinConfig{multicastConfig=MulticastConfig [enabled=false, multicastGroup=224.2.2.3, multicastPort=54327, multicastTimeToLive=32, multicastTimeoutSeconds=2, trustedInterfaces=[]], tcpIpConfig=TcpIpConfig [enabled=true, connectionTimeoutSeconds=5, members=[192.168.0.1, 192.168.0.2, 192.168.0.3, 192.168.0.4, 192.168.0.5, 192.168.0.6, 192.168.0.7, 192.168.0.8, 192.168.0.9, 192.168.0.10, 192.168.0.11], requiredMember=null], awsConfig=AwsConfig{enabled=false, region='us-east-1', securityGroupName='null', tagKey='null', tagValue='null', hostHeader='ec2.amazonaws.com', connectionTimeoutSeconds=5}} with 1 members.

My non-hazelcast-implementation is using UDP multicasts and works fine. So can a firewall really be the problem?

Update 3, taking pveentjer's answer about checking the network into account

Since I do not have permissions for iptables or to install iperf, I am using com.hazelcast.examples.TestApp to check whether my network is working, as described in Getting Started With Hazelcast in Chapter 2, Section "Showing Off Straight Away":

I call java -cp hazelcast-3.1.2.jar com.hazelcast.examples.TestApp on 192.168.0.1 and get the output 

...Dec 10, 2013 11:31:21 PM com.hazelcast.instance.DefaultAddressPicker
INFO: Prefer IPv4 stack is true.
Dec 10, 2013 11:31:21 PM com.hazelcast.instance.DefaultAddressPicker
INFO: Picked Address[192.168.0.1]:5701, using socket ServerSocket[addr=/0:0:0:0:0:0:0:0,localport=5701], bind any local is true
Dec 10, 2013 11:31:22 PM com.hazelcast.system
INFO: [192.168.0.1]:5701 [dev] Hazelcast Community Edition 3.1.2 (20131120) starting at Address[192.168.0.1]:5701
Dec 10, 2013 11:31:22 PM com.hazelcast.system
INFO: [192.168.0.1]:5701 [dev] Copyright (C) 2008-2013 Hazelcast.com
Dec 10, 2013 11:31:22 PM com.hazelcast.instance.Node
INFO: [192.168.0.1]:5701 [dev] Creating MulticastJoiner
Dec 10, 2013 11:31:22 PM com.hazelcast.core.LifecycleService
INFO: [192.168.0.1]:5701 [dev] Address[192.168.0.1]:5701 is STARTING
Dec 10, 2013 11:31:24 PM com.hazelcast.cluster.MulticastJoiner
INFO: [192.168.0.1]:5701 [dev] 

Members [1] {
    Member [192.168.0.1]:5701 this
}

Dec 10, 2013 11:31:24 PM com.hazelcast.core.LifecycleService
INFO: [192.168.0.1]:5701 [dev] Address[192.168.0.1]:5701 is STARTED

I then call java -cp hazelcast-3.1.2.jar com.hazelcast.examples.TestApp on 192.168.0.2 and get the output 

...Dec 10, 2013 9:50:22 PM com.hazelcast.instance.DefaultAddressPicker
INFO: Prefer IPv4 stack is true.
Dec 10, 2013 9:50:22 PM com.hazelcast.instance.DefaultAddressPicker
INFO: Picked Address[192.168.0.2]:5701, using socket ServerSocket[addr=/0:0:0:0:0:0:0:0,localport=5701], bind any local is true
Dec 10, 2013 9:50:23 PM com.hazelcast.system
INFO: [192.168.0.2]:5701 [dev] Hazelcast Community Edition 3.1.2 (20131120) starting at Address[192.168.0.2]:5701
Dec 10, 2013 9:50:23 PM com.hazelcast.system
INFO: [192.168.0.2]:5701 [dev] Copyright (C) 2008-2013 Hazelcast.com
Dec 10, 2013 9:50:23 PM com.hazelcast.instance.Node
INFO: [192.168.0.2]:5701 [dev] Creating MulticastJoiner
Dec 10, 2013 9:50:23 PM com.hazelcast.core.LifecycleService
INFO: [192.168.0.2]:5701 [dev] Address[192.168.0.2]:5701 is STARTING
Dec 10, 2013 9:50:23 PM com.hazelcast.nio.SocketConnector
INFO: [192.168.0.2]:5701 [dev] Connecting to /192.168.0.1:5701, timeout: 0, bind-any: true
Dec 10, 2013 9:50:23 PM com.hazelcast.nio.TcpIpConnectionManager
INFO: [192.168.0.2]:5701 [dev] 38476 accepted socket connection from /192.168.0.1:5701
Dec 10, 2013 9:50:28 PM com.hazelcast.cluster.ClusterService
INFO: [192.168.0.2]:5701 [dev] 

Members [2] {
    Member [192.168.0.1]:5701
    Member [192.168.0.2]:5701 this
}

Dec 10, 2013 9:50:30 PM com.hazelcast.core.LifecycleService
INFO: [192.168.0.2]:5701 [dev] Address[192.168.0.2]:5701 is STARTED

So multicast discovery is generally working on my cluster, right? Is 5701 also the port for discovery? Is 38476 in the last output an ID or a port?

Joining still does not work for my own code with programmatical configuration :(

Update 4, taking pveentjer's answer about using the default configuration into account

The modified TestApp gives the output 

joinConfig{multicastConfig=MulticastConfig [enabled=true, multicastGroup=224.2.2.3, 
multicastPort=54327, multicastTimeToLive=32, multicastTimeoutSeconds=2, 
trustedInterfaces=[]], tcpIpConfig=TcpIpConfig [enabled=false, 
connectionTimeoutSeconds=5, members=[], requiredMember=null], 
awsConfig=AwsConfig{enabled=false, region='us-east-1', securityGroupName='null', 
tagKey='null', tagValue='null', hostHeader='ec2.amazonaws.com', connectionTimeoutSeconds=5}}

and does detect other members after a couple of seconds (after each instance once lists only itself as a member if all are started at the same time), whereas

myProgram gives the output 

joined via JoinConfig{multicastConfig=MulticastConfig [enabled=true, multicastGroup=224.2.2.3, multicastPort=54327, multica\
stTimeToLive=32, multicastTimeoutSeconds=2, trustedInterfaces=[]], tcpIpConfig=TcpIpConfig [enabled=false, connectionTimeoutSecond\
s=5, members=[], requiredMember=null], awsConfig=AwsConfig{enabled=false, region='us-east-1', securityGroupName='null', tagKey='nu\
ll', tagValue='null', hostHeader='ec2.amazonaws.com', connectionTimeoutSeconds=5}} with 1 members.

and does not detect members within its runtime of about 1 minute (I am counting the members about every 5 seconds).

BUT if at least one instance of TestApp runs concurrently on the cluster, all TestApp instances and all myProgram instances are detected and my program works fine. In case I start TestApp once and then myProgram twice in parallel, TestApp gives the following output:

java -cp ~/CaseStudy/jtorx-1.10.0-beta8/lib/hazelcast-3.1.2.jar:. TestApp
Dec 12, 2013 12:02:15 PM com.hazelcast.instance.DefaultAddressPicker
INFO: Prefer IPv4 stack is true.
Dec 12, 2013 12:02:15 PM com.hazelcast.instance.DefaultAddressPicker
INFO: Picked Address[192.168.180.240]:5701, using socket ServerSocket[addr=/0:0:0:0:0:0:0:0,localport=5701], bind any local is true
Dec 12, 2013 12:02:15 PM com.hazelcast.system
INFO: [192.168.180.240]:5701 [dev] Hazelcast Community Edition 3.1.2 (20131120) starting at Address[192.168.180.240]:5701
Dec 12, 2013 12:02:15 PM com.hazelcast.system
INFO: [192.168.180.240]:5701 [dev] Copyright (C) 2008-2013 Hazelcast.com
Dec 12, 2013 12:02:15 PM com.hazelcast.instance.Node
INFO: [192.168.180.240]:5701 [dev] Creating MulticastJoiner
Dec 12, 2013 12:02:15 PM com.hazelcast.core.LifecycleService
INFO: [192.168.180.240]:5701 [dev] Address[192.168.180.240]:5701 is STARTING
Dec 12, 2013 12:02:21 PM com.hazelcast.cluster.MulticastJoiner
INFO: [192.168.180.240]:5701 [dev] 


Members [1] {
    Member [192.168.180.240]:5701 this
}

Dec 12, 2013 12:02:22 PM com.hazelcast.core.LifecycleService
INFO: [192.168.180.240]:5701 [dev] Address[192.168.180.240]:5701 is STARTED
Dec 12, 2013 12:02:22 PM com.hazelcast.management.ManagementCenterService
INFO: [192.168.180.240]:5701 [dev] Hazelcast will connect to Management Center on address: http://localhost:8080/mancenter-3.1.2/
Join: JoinConfig{multicastConfig=MulticastConfig [enabled=true, multicastGroup=224.2.2.3, multicastPort=54327, multicastTimeToLive=32, multicastTimeoutSeconds=2, trustedInterfaces=[]], tcpIpConfig=TcpIpConfig [enabled=false, connectionTimeoutSeconds=5, members=[], requiredMember=null], awsConfig=AwsConfig{enabled=false, region='us-east-1', securityGroupName='null', tagKey='null', tagValue='null', hostHeader='ec2.amazonaws.com', connectionTimeoutSeconds=5}}
Dec 12, 2013 12:02:22 PM com.hazelcast.partition.PartitionService
INFO: [192.168.180.240]:5701 [dev] Initializing cluster partition table first arrangement...
hazelcast[default] > Dec 12, 2013 12:03:27 PM com.hazelcast.nio.SocketAcceptor
INFO: [192.168.180.240]:5701 [dev] Accepting socket connection from /192.168.0.8:38764
Dec 12, 2013 12:03:27 PM com.hazelcast.nio.TcpIpConnectionManager
INFO: [192.168.180.240]:5701 [dev] 5701 accepted socket connection from /192.168.0.8:38764
Dec 12, 2013 12:03:27 PM com.hazelcast.nio.SocketAcceptor
INFO: [192.168.180.240]:5701 [dev] Accepting socket connection from /192.168.0.7:54436
Dec 12, 2013 12:03:27 PM com.hazelcast.nio.TcpIpConnectionManager
INFO: [192.168.180.240]:5701 [dev] 5701 accepted socket connection from /192.168.0.7:54436
Dec 12, 2013 12:03:32 PM com.hazelcast.partition.PartitionService
INFO: [192.168.180.240]:5701 [dev] Re-partitioning cluster data... Migration queue size: 181
Dec 12, 2013 12:03:32 PM com.hazelcast.cluster.ClusterService
INFO: [192.168.180.240]:5701 [dev] 

Members [3] {
    Member [192.168.180.240]:5701 this
    Member [192.168.0.8]:5701
    Member [192.168.0.7]:5701
}

Dec 12, 2013 12:03:43 PM com.hazelcast.partition.PartitionService
INFO: [192.168.180.240]:5701 [dev] Re-partitioning cluster data... Migration queue size: 181
Dec 12, 2013 12:03:45 PM com.hazelcast.partition.PartitionService
INFO: [192.168.180.240]:5701 [dev] All migration tasks has been completed, queues are empty.
Dec 12, 2013 12:03:46 PM com.hazelcast.nio.TcpIpConnection
INFO: [192.168.180.240]:5701 [dev] Connection [Address[192.168.0.8]:5701] lost. Reason: Socket explicitly closed
Dec 12, 2013 12:03:46 PM com.hazelcast.cluster.ClusterService
INFO: [192.168.180.240]:5701 [dev] Removing Member [192.168.0.8]:5701
Dec 12, 2013 12:03:46 PM com.hazelcast.cluster.ClusterService
INFO: [192.168.180.240]:5701 [dev] 

Members [2] {
    Member [192.168.180.240]:5701 this
    Member [192.168.0.7]:5701
}

Dec 12, 2013 12:03:48 PM com.hazelcast.partition.PartitionService
INFO: [192.168.180.240]:5701 [dev] Partition balance is ok, no need to re-partition cluster data... 
Dec 12, 2013 12:03:48 PM com.hazelcast.nio.TcpIpConnection
INFO: [192.168.180.240]:5701 [dev] Connection [Address[192.168.0.7]:5701] lost. Reason: Socket explicitly closed
Dec 12, 2013 12:03:48 PM com.hazelcast.cluster.ClusterService
INFO: [192.168.180.240]:5701 [dev] Removing Member [192.168.0.7]:5701
Dec 12, 2013 12:03:48 PM com.hazelcast.cluster.ClusterService
INFO: [192.168.180.240]:5701 [dev] 

Members [1] {
    Member [192.168.180.240]:5701 this
}

Dec 12, 2013 12:03:48 PM com.hazelcast.partition.PartitionService
INFO: [192.168.180.240]:5701 [dev] Partition balance is ok, no need to re-partition cluster data...

The only difference I see in TestApp's configuration is 

config.getManagementCenterConfig().setEnabled(true);
        config.getManagementCenterConfig().setUrl("http://localhost:8080/mancenter-"+version);

for(int k=1;k<= LOAD_EXECUTORS_COUNT;k++){
    config.addExecutorConfig(new ExecutorConfig("e"+k).setPoolSize(k));
}

so I added it in a desperate attempt into myProgram, too. But it does not solve the problem - still each instance only detects itself as member during the whole run.

Update about how long myProgram runs

Could it be that the program is not running long enough (as pveentjer put it)?

My experiments seem to confirm this: If the time t between Hazelcast.newHazelcastInstance(cfg); and initializing cleanUp() (i.e. no longer communicating via hazelcast and no longer checking the number of members) is

  • less than 30 seconds, no communication and members: 1
  • more than 30 seconds: all members are found and communication happens (which weirdly seems to be happening for much longer than t - 30 seconds).

Is 30 seconds a realistic time span that a hazelcast cluster needs, or is there something strange going on? Here is a log from 4 myPrograms running concurrently (looking for hazelcast-members overlaps 30 seconds for instance 1 and instance 3):

instance 1: 2013-12-19T12:39:16.553+0100 LOG 0 (START) engine started 
looking for members between 2013-12-19T12:39:21.973+0100 and 2013-12-19T12:40:27.863+0100  
2013-12-19T12:40:28.205+0100 LOG 35 (Torx-Explorer) Model  SymToSim is about to\  exit

instance 2: 2013-12-19T12:39:16.592+0100 LOG 0 (START) engine started 
looking for members between 2013-12-19T12:39:22.192+0100 and 2013-12-19T12:39:28.429+0100 
2013-12-19T12:39:28.711+0100 LOG 52 (Torx-Explorer) Model  SymToSim is about to\  exit

instance 3: 2013-12-19T12:39:16.593+0100 LOG 0 (START) engine started 
looking for members between 2013-12-19T12:39:22.145+0100 and 2013-12-19T12:39:52.425+0100  
2013-12-19T12:39:52.639+0100 LOG 54 (Torx-Explorer) Model  SymToSim is about to\  exit

INSTANCE 4: 2013-12-19T12:39:16.885+0100 LOG 0 (START) engine started 
looking for members between 2013-12-19T12:39:21.478+0100 and 2013-12-19T12:39:35.980+0100  
2013-12-19T12:39:36.024+0100 LOG 34 (Torx-Explorer) Model  SymToSim is about to\  exit

How do I best start my actual distributed algorithm only after enough members are present in the hazelcast cluster? Can I set hazelcast.initial.min.cluster.size programmatically? https://groups.google.com/forum/#!topic/hazelcast/sa-lmpEDa6A sounds like this would block Hazelcast.newHazelcastInstance(cfg); until the initial.min.cluster.size is reached. Correct? How synchronously (within which time span) will the different instances unblock?

Answer

pveentjer picture pveentjer · Dec 21, 2013

The problem appearently is that the cluster starts (and stops) and doesn't wait till enough members are in the cluster. You can set the hazelcast.initial.min.cluster.size property, to prevent this from happening.

You Can set 'hazelcast.initial.min.cluster.size' programmatically using: 

Config config = new Config(); 
config.setProperty("hazelcast.initial.min.cluster.size","3");

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