ClickHouse/tests/integration/test_dictionary_ddl_on_cluster/configs/config.d/clusters.xml

<yandex>
<remote_servers>
    <cluster>
        <shard>
            <internal_replication>true</internal_replication>
            <replica>
                <host>ch1</host>
                <port>9000</port>
            </replica>
            <replica>
                <host>ch2</host>
                <port>9000</port>
            </replica>
        </shard>
        <shard>
            <internal_replication>true</internal_replication>
            <replica>
                <host>ch3</host>
                <port>9000</port>
            </replica>
            <replica>
                <host>ch4</host>
                <port>9000</port>
            </replica>
        </shard>
    </cluster>
</remote_servers>
</yandex>