Cluster APIs

❗️

This is a legacy Apache Ignite documentation

The new documentation is hosted here: https://ignite.apache.org/docs/latest/

• IgniteCluster
• ClusterNode
• Cluster Node Attributes
• Cluster Node Metrics
• Local Cluster Node

IgniteCluster

Cluster functionality is provided via the IgniteCluster interface. You can get an instance of IgniteCluster from Ignite as follows:

Ignite ignite = Ignition.ignite();

IgniteCluster cluster = ignite.cluster();

Through the IgniteCluster interface you can:

• Start and stop remote cluster nodes
• Get a list of all cluster members
• Create logical Cluster Groups

ClusterNode

The ClusterNode interface has a very concise API and deals only with the node as a logical network endpoint in the topology: its globally unique ID, the node metrics, its static attributes set by the user, and a few other parameters.

Cluster Node Attributes

All cluster nodes on startup automatically register all the environment and system properties as node attributes. However, users can choose to assign their own node attributes in the configuration:

<bean class="org.apache.ignite.IgniteConfiguration">
    ...
    <property name="userAttributes">
        <map>
            <entry key="ROLE" value="worker"/>
        </map>
    </property>
    ...
</bean>

The following example shows how to get the nodes where the "worker" attribute has been set.

ClusterGroup workers = ignite.cluster().forAttribute("ROLE", "worker");

Collection<ClusterNode> nodes = workers.nodes();

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All node attributes are available via the ClusterNode.attribute("propertyName") method.

Cluster Node Metrics

Ignite automatically collects metrics for all the nodes in the cluster. Metrics are collected in the background and are updated with every heartbeat message exchanged between the cluster nodes.

Node metrics are available via the ClusterMetrics interface which contains over 50 various metrics (note that the same metrics are available for Cluster Groups as well).

Here is an example of getting some metrics, including average CPU load and used heap, for the local node:

// Local Ignite node.
ClusterNode localNode = cluster.localNode();

// Node metrics.
ClusterMetrics metrics = localNode.metrics();

// Get some metric values.
double cpuLoad = metrics.getCurrentCpuLoad();
long usedHeap = metrics.getHeapMemoryUsed();
int numberOfCores = metrics.getTotalCpus();
int activeJobs = metrics.getCurrentActiveJobs();

Local Cluster Node

The local grid node is an instance of the ClusterNode representing this Ignite node.

Here is an example of how to get a local node:

ClusterNode localNode = ignite.cluster().localNode();