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This is a cluster manager implementation for Vert.x that uses Infinispan.

This implementation is packaged inside:

<dependency>
  <groupId>io.vertx</groupId>
  <artifactId>vertx-infinispan</artifactId>
  <version>3.4.1</version>
</dependency>

In Vert.x a cluster manager is used for various functions including:

  • Discovery and group membership of Vert.x nodes in a cluster

  • Maintaining cluster wide topic subscriber lists (so we know which nodes are interested in which event bus addresses)

  • Distributed Map support

  • Distributed Locks

  • Distributed Counters

Cluster managers do not handle the event bus inter-node transport, this is done directly by Vert.x with TCP connections.

Using this cluster manager

If you are using Vert.x from the command line, the jar corresponding to this cluster manager (it will be named vertx-infinispan-3.4.1.jar should be in the lib directory of the Vert.x installation.

If you want clustering with this cluster manager in your Vert.x Maven or Gradle project then just add a dependency to the artifact: io.vertx:vertx-infinispan:3.4.1 in your project.

If the jar is on your classpath as above then Vert.x will automatically detect this and use it as the cluster manager. Please make sure you don’t have any other cluster managers on your classpath or Vert.x might choose the wrong one.

You can also specify the cluster manager programmatically if you are embedding Vert.x by specifying it on the options when you are creating your Vert.x instance, for example:

ClusterManager mgr = new InfinispanClusterManager();

VertxOptions options = new VertxOptions().setClusterManager(mgr);

Vertx.clusteredVertx(options, res -> {
  if (res.succeeded()) {
    Vertx vertx = res.result();
  } else {
    // failed!
  }
});

Configuring this cluster manager

Usually the cluster manager is configured by two files packaged inside the jar:

If you want to override one or both of them, place a file with the same name on your classpath and it will be used instead. If you want to embed your custom file in a fat jar, it must be located at the root of the fat jar. If it’s an external file, the directory containing the file must be added to the classpath. For example, if you are using the launcher class from Vert.x, the classpath enhancement can be done as follows:

# If the infinispan.xml is in the current directory:
java -jar ... -cp . -cluster
vertx run MyVerticle -cp . -cluster

# If the infinispan.xml is in the conf directory
java -jar ... -cp conf -cluster

Another way to override the infinispan.xml configuration is by providing the system property vertx.infinispan.config with a location:

# Use a cluster configuration located in an external file
java -Dvertx.infinispan.config=./config/my-infinispan.xml -jar ... -cluster

# Or use a custom configuration from the classpath
java -Dvertx.infinispan.config=my/package/config/my-infinispan.xml -jar ... -cluster

The cluster manager will search for the file in classpath first, and fallback to the filesystem.

The vertx.infinispan.config system property, when present, overrides any infinispan.xml on the classpath.

The xml files are Infinispan and JGroups configuration files and are described in detail in the documentation on the Infinispan and JGroups web-sites.

You can also specify configuration programmatically if embedding:

ClusterManager mgr = new InfinispanClusterManager("custom-infinispan.xml");

VertxOptions options = new VertxOptions().setClusterManager(mgr);

Vertx.clusteredVertx(options, res -> {
  if (res.succeeded()) {
    Vertx vertx = res.result();
  } else {
    // failed!
  }
});

JGroups supports several different transports including multicast and TCP. The default configuration uses multicast for discovery so you must have multicast enabled on your network for this to work.

For full documentation on how to configure the transport differently or use a different transport please consult the JGroups documentation.

Using an existing Infinispan Cache Manager

You can pass an existing DefaultCacheManager in the cluster manager to reuse an existing cache manager:

ClusterManager mgr = new InfinispanClusterManager(cacheManager);
VertxOptions options = new VertxOptions().setClusterManager(mgr);
Vertx.clusteredVertx(options, res -> {
  if (res.succeeded()) {
    Vertx vertx = res.result();
  } else {
    // failed!
  }
});

In this case, vert.x is not the cache manager owner and so do not shut it down on close.

Notice that the custom Infinispan instance need to be configured with:

<cache-container default-cache="__vertx.distributed.cache">

  <replicated-cache name="__vertx.subs">
    <expiration interval="-1"/>
  </replicated-cache>

  <replicated-cache name="__vertx.haInfo">
    <expiration interval="-1"/>
  </replicated-cache>

  <distributed-cache name="__vertx.distributed.cache">
    <expiration interval="-1"/>
  </distributed-cache>

</cache-container>

Configuring for Openshift 3

In order to run a Vert.x cluster on Openshift 3, a few configuration and dependencies changes are needed.

First, add the JGroups KUBE_PING protocol JAR to the stack.

<dependency>
  <groupId>org.jgroups.kubernetes</groupId>
  <artifactId>kubernetes</artifactId>
  <version>0.9.0</version>
  <exclusions>
    <exclusion>                                          (1)
      <artifactId>undertow-core</artifactId>
      <groupId>io.undertow</groupId>
    </exclusion>
  </exclusions>
</dependency>
  1. avoid extra dependencies, KUBE_PING works fine with the JDK’s Http server

Then override the default JGroups config so that KUBE_PING becomes the discovery protocol.

<config xmlns="urn:org:jgroups"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="urn:org:jgroups http://www.jgroups.org/schema/JGroups-3.6.xsd">

  <TCP bind_addr="${jgroups.tcp.address:match-interface:eth.*}"
       bind_port="${jgroups.tcp.port:7800}"
       enable_diagnostics="false"
       thread_naming_pattern="pl"
       send_buf_size="640k"
       sock_conn_timeout="300"
       bundler_type="transfer-queue"

       thread_pool.min_threads="${jgroups.thread_pool.min_threads:2}"
       thread_pool.max_threads="${jgroups.thread_pool.max_threads:30}"
       thread_pool.keep_alive_time="60000"
       thread_pool.queue_enabled="false"

       internal_thread_pool.min_threads="${jgroups.internal_thread_pool.min_threads:5}"
       internal_thread_pool.max_threads="${jgroups.internal_thread_pool.max_threads:20}"
       internal_thread_pool.keep_alive_time="60000"
       internal_thread_pool.queue_enabled="true"
       internal_thread_pool.queue_max_size="500"

       oob_thread_pool.min_threads="${jgroups.oob_thread_pool.min_threads:20}"
       oob_thread_pool.max_threads="${jgroups.oob_thread_pool.max_threads:200}"
       oob_thread_pool.keep_alive_time="60000"
       oob_thread_pool.queue_enabled="false"
  />
  <kubernetes.KUBE_PING
  />
  <MERGE3 min_interval="10000"
*           max_interval="30000"
*   />
  <FD_SOCK/>
  <FD_ALL timeout="60000"
*           interval="15000"
*           timeout_check_interval="5000"
*   />
  <VERIFY_SUSPECT timeout="5000"/>
  <pbcast.NAKACK2 use_mcast_xmit="false"
                  xmit_interval="1000"
                  xmit_table_num_rows="50"
                  xmit_table_msgs_per_row="1024"
                  xmit_table_max_compaction_time="30000"
                  max_msg_batch_size="100"
                  resend_last_seqno="true"
  />
  <UNICAST3 xmit_interval="500"
*             xmit_table_num_rows="50"
*             xmit_table_msgs_per_row="1024"
*             xmit_table_max_compaction_time="30000"
*             max_msg_batch_size="100"
*             conn_expiry_timeout="0"
*   />
  <pbcast.STABLE stability_delay="500"
                 desired_avg_gossip="5000"
                 max_bytes="1M"
  />
  <pbcast.GMS print_local_addr="false"
              join_timeout="${jgroups.join_timeout:5000}"
  />
  <MFC max_credits="2m"
*        min_threshold="0.40"
*   />
  <FRAG3/>
</config>

KUBE_PING listens to requests on port 8888 by default, so make sure to declare it when building the container image.

EXPOSE 8888

Also, set the project namespace as the scope for discovery.

ENV OPENSHIFT_KUBE_PING_NAMESPACE my-openshift3-project

Then, force usage of IPv4 in the JVM with a system property.

-Djava.net.preferIPv4Stack=true

Eventually, the setup needs a service account.

oc policy add-role-to-user view system:serviceaccount:$(oc project -q):default -n $(oc project -q)

Further configuration details are available in the Kubernetes discovery protocol for JGroups README.

Configuring for Docker Compose

Make sure to start the Java Virtual Machines with those system properties:

-Djava.net.preferIPv4Stack=true -Djgroups.tcp.address=NON_LOOPBACK

This will make JGroups pick the interface of the virtual private network created by Docker.

Trouble shooting clustering

If the default multicast discovery configuration is not working here are some common causes:

Multicast not enabled on the machine.

It is quite common in particular on OSX machines for multicast to be disabled by default. Please google for information on how to enable this.

Using wrong network interface

If you have more than one network interface on your machine (and this can also be the case if you are running VPN software on your machine), then JGroups may be using the wrong one.

To tell JGroups to use a specific interface you can provide the IP address of the interface in the bind_addr element of the configuration. For example:

<TCP bind_addr="192.168.1.20"
     ...
     />
<MPING bind_addr="192.168.1.20"
     ...
     />

Alternatively, if you want to stick with the bundled jgroups.xml file, you can set the jgroups.tcp.address system property:

-Djgroups.tcp.address=192.168.1.20

When running Vert.x is in clustered mode, you should also make sure that Vert.x knows about the correct interface. When running at the command line this is done by specifying the cluster-host option:

vertx run myverticle.js -cluster -cluster-host your-ip-address

Where your-ip-address is the same IP address you specified in the JGroups configuration.

If using Vert.x programmatically you can specify this using setClusterHost.

Using a VPN

This is a variation of the above case. VPN software often works by creating a virtual network interface which often doesn’t support multicast. If you have a VPN running and you do not specify the correct interface to use in both the JGroups configuration and to Vert.x then the VPN interface may be chosen instead of the correct interface.

So, if you have a VPN running you may have to configure both JGroups and Vert.x to use the correct interface as described in the previous section.

When multicast is not available

In some cases you may not be able to use multicast discovery as it might not be available in your environment. In that case you should configure another protocol, e.g. TCPPING to use TCP sockets, or S3_PING when running on Amazon EC2.

For more information on available JGroups discovery protocols and how to configure them please consult the JGroups documentation.

Problems with IPv6

If you have troubles configuring an IPv6 host, force the use of IPv4 with the java.net.preferIPv4Stack system property.

-Djava.net.preferIPv4Stack=true

Enabling logging

When trouble-shooting clustering issues with it’s often useful to get some logging output from Infinispan and JGroups to see if it’s forming a cluster properly. You can do this (when using the default JUL logging) by adding a file called vertx-default-jul-logging.properties on your classpath. This is a standard java.util.logging (JUL) configuration file. Inside it set:

org.infinispan.level=INFO
org.jgroups.level=INFO

and also

java.util.logging.ConsoleHandler.level=INFO
java.util.logging.FileHandler.level=INFO

Infinispan logging

Infinispan relies on JBoss logging. JBoss Logging is a logging bridge providing integration with numerous logging frameworks.

Add the logging JARs of you choice to the classpath and JBoss Logging will pick them up automatically.

If you have multiple logging backends on your classpath, you can force selection with the org.jboss.logging.provider system property. For exeample:

-Dorg.jboss.logging.provider=log4j2

See this JBoss Logging guide for more details.

JGroups logging

JGroups uses JDK logging by default. log4j and log4j2 are supported if the corresponding JARs are found on the classpath.

Please refer to the JGroups logging documentation if you need more details or want to implement your own logging backend implementation.