**Describe the solution you'd like**

We already can run clickhouse-server without configured ZooKeeper (the tables will start in read-only mode)
and with configured ZooKeeper, if it starts to be inaccessible at runtime (the tables will be read-only until the session is re-established).

Let's also make it possible to start up when ZooKeeper is unavailable.

**Additional context**

If that will be very hard to implement, we can consider other options:
- lazy attaching of the tables after sever start-up;
- a maintenance mode when the tables are not attached at start-up and require manual ATTACH queries.
}
            else
            {
                auto metadata_drop_lock = zkutil::EphemeralNodeHolder::existing(drop_lock_path, *zookeeper);
                if (!removeTableNodesFromZooKeeper(zookeeper, zookeeper_path, metadata_drop_lock, log))
                {
                    
                    continue;
                }
            }
        }
        LOG_DEBUG(log, "Creating table {}", zookeeper_path);
        
        String metadata_str = ReplicatedMergeTreeTableMetadata(*this, metadata_snapshot).toString();
        Coordination::Requests ops;
        ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path, "", zkutil::CreateMode::Persistent));
        ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/metadata", metadata_str,
            zkutil::CreateMode::Persistent));
        ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/columns", metadata_snapshot->getColumns().toString(),
            zkutil::CreateMode::Persistent));
        ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/log", "",
            zkutil::CreateMode::Persistent));
        ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/blocks", "",
            zkutil::CreateMode::Persistent));
        ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/block_numbers", "",
            zkutil::CreateMode::Persistent));
        ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/nonincrement_block_numbers", "",
            zkutil::CreateMode::Persistent)); 
        ops.emplace_back(zkutil::makeCreateRequest(zookeeper_path + "/leader_election", "",
            zkutil::CreateMode::Persistent));