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GridGain 8.7.27 Release Notes

New Features

Java Thin Client Service API

Java thin clients can invoke GridGain Services that are deployed to the cluster from servers or thick clients.

Deploying Ignite service from a server node
public class FooService implements Service {
    // Service interface omitted
    public int addOne(int x) {
        return x + 1;

..."foo", new FooService());
Invoking Ignite service from a thin client (no code is shared)
public interface FooService {
    int addOne(int x);


FooService svc ="foo", FooService.class);
Java Thin Client Cluster API

Java thin client now has an API to inspect the Ignite cluster, control cluster state, enable or disable write-ahead logging, and restrict Compute or Service calls to custom cluster groups.

Inspecting the cluster
// Get client and server node count
ClientCluster cluster = client.cluster();

int clients = cluster.forClients().nodes().size();
int servers = cluster.forServers().nodes().size();

// List all nodes with start time and CPU count
Collection<ClusterNode> nodes = cluster.nodes();
for (ClusterNode node : nodes) {
    ClusterMetrics metrics = node.metrics();

            "Node " + +
            " started at " + metrics.getNodeStartTime() +
            ", CPUs: " + metrics.getTotalCpus());
Changing the cluster state
// Activate the cluster

// Enable WAL for Person cache
Invoking Compute and Services on a specific set of nodes
// Get server nodes with user attribute "foo" set to "bar"
ClientClusterGroup clusterGroup = client.cluster()
    .forAttribute("foo", "bar");

// Invoke "MyTask" compute task using only the nodes from the specified cluster group
client.compute(clusterGroup).execute("", null);

// Invoke "my-service" service method using only the nodes from the specified cluster group"my-service", MyService.class).fooBar();
.NET Thin Client Service API

GridGain.NET thin clients can invoke services that are deployed to the cluster from servers or thick clients. Services can be deployed from .NET or Java code.

Deploying GridGain service from a server node
public class FooService : IService {
    // Service interface omitted
    public int AddOne(int x) => x + 1;


ignite.GetServices().DeployNodeSingleton("foo", new FooService());
Invoking GridGain service from a thin client (no code is shared)
public interface IFooService {
    int AddOne(int x);


IFooService svc = client.GetServices().GetServiceProxy<IFooService>("foo");

Improvements and Fixed Issues

Community Edition Changes



Fixed the issue when Ignite JDBC drivers return metadata with invalid information about actual capabilities



Added an ability to avoid opening of server TCP socket on client nodes.


Atomic Cache

Client nodes no longer require CacheInterceptor classes to be present locally if they don’t use the cache in question

Ultimate Edition Changes


Snapshots & PITR

Fixed an issue when a Point-in-Time Recovery could not be completed due to a loss of an unrelated WAL segment



Fixed an issue causing errors on upgrading from 8.5 <TBD>

Installation and Upgrade Information

See the Rolling Upgrades page for information about how to perform automated upgrades and for details about version compatibility.

Below is a list of versions that are compatible with the current version. You can rolling-upgrade from any of those. Compatibility with other versions is not guaranteed. If you are on a version that is not listed, contact GridGain for the information on upgrade options.

8.5.3, 8.5.5, 8.5.6, 8.5.7, 8.5.8, 8.5.8-p6, 8.5.9, 8.5.10, 8.5.11, 8.5.12, 8.5.13, 8.5.14, 8.5.15, 8.5.16, 8.5.17, 8.5.18, 8.5.19, 8.5.20, 8.5.22, 8.5.23, 8.5.24, 8.7.2, 8.7.2-p12, 8.7.2-p13, 8.7.3, 8.7.4, 8.7.5, 8.7.6, 8.7.7, 8.7.8, 8.7.9, 8.7.10, 8.7.11, 8.7.12, 8.7.13, 8.7.14, 8.7.15, 8.7.16, 8.7.17, 8.7.18, 8.7.19, 8.7.19-p1, 8.7.20, 8.7.21, 8.7.22, 8.7.23, 8.7.24, 8.7.25, 8.7.26

Known Limitations

Jetty configuration incompatibility in GridGain 8.7.21 and later

If you are upgrading from version 8.7.20 or earlier, you must take into account an incompatibility related to Jetty configuration, which was introduced in GridGain 8.7.21.

Your setup may be affected if:

  • You’re using the ignite-rest-http module (e.g. to connect to GridGain Web Console)

  • You have a custom Jetty configuration that enables SSL for REST

  • Your Jetty configuration uses the org.eclipse.jetty.util.ssl.SslContextFactory class

  • The keystore specified in the Jetty configuration contains both the CA certificate and the private certificate

In this case, after starting the new version, you’ll see an error similar to:

java.lang.IllegalStateException: KeyStores with multiple certificates are not supported on the base class
org.eclipse.jetty.util.ssl.SslContextFactory. (Use org.eclipse.jetty.util.ssl.SslContextFactory$Server
or org.eclipse.jetty.util.ssl.SslContextFactory$Client instead)

To workaround this issue, you need to alter the Jetty configuration to use org.eclipse.jetty.util.ssl.SslContextFactory$Server or org.eclipse.jetty.util.ssl.SslContextFactory$Client. For a configuration example, see Client Certificate Authentication.

Default rebalanceThreadPoolSize in GridGain 8.7.26 and later

In GridGain 8.7.26, the default value of the property IgniteConfiguration.rebalanceThreadPoolSize has changed from 1 to min(4, number of CPU / 4). It may cause a compatibility issue under the following conditions:

  • A Rolling Upgrade is being performed

  • The upgrade is performed from a version 8.5.7 or earlier for 8.5.x, or 8.7.3 or earlier for 8.7.x

  • The server nodes have at least 8 CPU cores

  • The nodes configuration don’t have the property IgniteConfiguration.rebalanceThreadPoolSize set (i.e. the default value is used)

In this case, you’ll see an error similar to

сlass org.apache.ignite.IgniteException: Rebalance configuration mismatch (fix configuration or set -DIGNITE_SKIP_CONFIGURATION_CONSISTENCY_CHECK=true system property).
Different values of such parameter may lead to rebalance process instability and hanging.  [rmtNodeId=5fc58fb7-209d-489a-8034-0127a81abed6, locRebalanceThreadPoolSize = 4, rmtRebalanceThreadPoolSize = 1]

To workaround this issue, you need to change the configuration of the server nodes to set rebalanceThreadPoolSize=1 so that it matches the old default. Example:

<bean class="org.apache.ignite.configuration.IgniteConfiguration">
    <property name="rebalanceThreadPoolSize" value="1"/>

    <!-- The rest of the configuration goes here -->

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