ClickHouse/tests/integration/test_alter_comment_on_cluster/configs/clusters.xml

<clickhouse>
<remote_servers>
    <cluster>
        <shard>
            <replica>
                <host>node_1</host>
                <port>9000</port>
            </replica>
            <replica>
                <host>node_2</host>
                <port>9000</port>
            </replica>
        </shard>
    </cluster>
</remote_servers>
</clickhouse>