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Network Configuration

IPv4 vs IPv6

Ignite tries to support IPv4 and IPv6 but this can sometimes lead to issues where the cluster becomes detached. A possible solution — unless you require IPv6 — is to restrict Ignite to IPv4 by setting the -Djava.net.preferIPv4Stack=true JVM parameter.

Discovery

This section describes the network parameters of the default discovery mechanism, which uses the TCP/IP protocol to exahcange discovery messages and is implemented in the TcpDiscoverySpi class.

You can change the properties of the discovery mechanism as follows:

<bean class="org.apache.ignite.configuration.IgniteConfiguration">

    <property name="discoverySpi">
        <bean class="org.apache.ignite.spi.discovery.tcp.TcpDiscoverySpi">
            <property name="localPort" value="8300"/>
        </bean>
    </property>

</bean>
IgniteConfiguration cfg = new IgniteConfiguration();

TcpDiscoverySpi discoverySpi = new TcpDiscoverySpi().setLocalPort(8300);

cfg.setDiscoverySpi(discoverySpi);
Ignite ignite = Ignition.start(cfg);
This API is not presently available for C++. You can use XML configuration.

The following table describes some most important properties of TcpDiscoverySpi. You can find the complete list of properties in the TcpDiscoverySpi javadoc.

Property Description Default Value

localAddress

Local host IP address used for discovery.

By default, the node uses the first non-loopback address it finds. If there is no non-loopback address available, then java.net.InetAddress.getLocalHost() is used.

localPort

The port that the node binds to. If set to a non-default value, other cluster nodes must know this port to be able to discover the node.

47500

localPortRange

If the localPort is busy, the node attempts to bind to the next port (incremented by 1) and continues this process until it finds a free port. The localPortRange property defines the number of ports the node will try (starting from localPort).

100

reconnectCount

The number of times the node tries to (re)establish connection to another node.

10

networkTimeout

The maximum network timeout in milliseconds for network operations.

5000

socketTimeout

The socket operations timeout. This timeout is used to limit connection time and write-to-socket time.

5000

ackTimeout

The acknowledgement timeout for discovery messages. If an acknowledgement is not received within this timeout, the discovery SPI tries to resend the message.

5000

joinTimeout

The join timeout defines how much time the node waits to join a cluster. If a non-shared IP finder is used and the node fails to connect to any address from the IP finder, the node keeps trying to join within this timeout. If all addresses are unresponsive, an exception is thrown and the node terminates. 0 means waiting indefinitely.

0

statisticsPrintFrequency

Defines how often the node prints discovery statistics to the log. 0 indicates no printing. If the value is greater than 0, and quiet mode is disabled, then statistics is printed out at INFO level once every period.

0

Communication

After the nodes discover each other and the cluster is formed, the nodes exchange messages via the communication SPI. The messages represent distributed cluster operations, such as task execution, data modification operations, queries, etc. The default implementation of the communication SPI uses the TCP/IP protocol to exchange messages (TcpCommunicationSpi). This section describes the properties of TcpCommunicationSpi.

Each node opens a local communication port and address to which other nodes connect and send messages. At startup, the node tries to bind to the specified communication port (default is 47100). If the port is already used, the node increments the port number until it finds a free port. The number of attempts is defined by the localPortRange property (defaults to 100).

<bean class="org.apache.ignite.configuration.IgniteConfiguration">

    <property name="communicationSpi">
        <bean class="org.apache.ignite.spi.communication.tcp.TcpCommunicationSpi">
            <property name="localPort" value="4321"/>
        </bean>
    </property>

</bean>
TcpCommunicationSpi commSpi = new TcpCommunicationSpi();

// Set the local port.
commSpi.setLocalPort(4321);

IgniteConfiguration cfg = new IgniteConfiguration();
cfg.setCommunicationSpi(commSpi);

// Start the node.
Ignite ignite = Ignition.start(cfg);
 var cfg = new IgniteConfiguration
 {
     CommunicationSpi = new TcpCommunicationSpi
     {
         LocalPort = 1234
     }
 };
Ignition.Start(cfg);
This API is not presently available for C++. You can use XML configuration.

Below is a list of some important properties of TcpCommunicationSpi. You can find the list of all properties in the TcpCommunicationSpi javadoc.

Property Description Default Value

localAddress

The local address for the communication SPI to bind to.

localPort

The local port that the node uses for communication.

47100

localPortRange

The range of ports the nodes tries to bind to sequentially until it finds a free one.

100

tcpNoDelay

Sets the value for the TCP_NODELAY socket option. Each socket accepted or created will use the provided value.

The option should be set to true (default) to reduce request/response time during communication over TCP. In most cases we do not recommend changing this option.

true

idleConnectionTimeout

The maximum idle connection timeout (in milliseconds) after which the connection is closed.

600000

usePairedConnections

Whether dual socket connection between the nodes should be enforced. If set to true, two separate connections will be established between the communicating nodes: one for outgoing messages, and one for incoming messages. When set to false, a single TCP connection will be used for both directions. This flag is useful on some operating systems when messages take too long to be delivered.

false

directBuffer

A boolean flag that indicates whether to allocate NIO direct buffer instead of NIO heap allocation buffer. Although direct buffers perform better, in some cases (especially on Windows) they may cause JVM crashes. If that happens in your environment, set this property to false.

true

directSendBuffer

Whether to use NIO direct buffer instead of NIO heap allocation buffer when sending messages.

false

socketReceiveBuffer

Receive buffer size for sockets created or accepted by the communication SPI. If set to 0, the operating system’s default value is used.

0

socketSendBuffer

Send buffer size for sockets created or accepted by the communication SPI. If set to 0 the operating system’s default value is used.

0

Connection Timeouts

There are several properties that define connection timeouts:

Property Description Default Value

IgniteConfiguration.failureDetectionTimeout

A timeout for basic network operations for server nodes.

10000

IgniteConfiguration.clientFailureDetectionTimeout

A timeout for basic network operations for client nodes.

30000

You can set the failure detection timeout in the node configuration as shown in the example below. The default values allow the discovery SPI to work reliably on most on-premise and containerized deployments. However, in stable low-latency networks, you can set the parameter to ~200 milliseconds in order to detect and react to​ failures more quickly.

<bean class="org.apache.ignite.configuration.IgniteConfiguration">

    <property name="failureDetectionTimeout" value="5000"/>

    <property name="clientFailureDetectionTimeout" value="10000"/>

</bean>
IgniteConfiguration cfg = new IgniteConfiguration();

cfg.setFailureDetectionTimeout(5_000);

cfg.setClientFailureDetectionTimeout(10_000);
This API is not presently available for C++. You can use XML configuration.