@Override
    public List<ClickHouseNode> getFaultyNodes(ClickHouseNodeSelector selector, int groupSize) {
        lock.readLock().lock();
        try {
            return pickNodes(faultyNodes, selector, groupSize);
        } finally {
            lock.readLock().unlock();
        }
    }
Discovers nodes in the same cluster by querying against
{@code system.clusters} table.
clickhouse-client/src/main/java/com/clickhouse/client/ClickHouseNodes.java