Scylla is a distributed database, which means that it operates on multiple nodes running independently.
When creating a Session you can specify a few known nodes to which the driver will try connecting:
# extern crate scylla;
# extern crate tokio;
use scylla::{Session, SessionBuilder};
use std::error::Error;
use std::time::Duration;
use std::net::{IpAddr, Ipv4Addr, SocketAddr};
#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
let uri = std::env::var("SCYLLA_URI")
.unwrap_or_else(|_| "127.0.0.1:9042".to_string());
let session: Session = SessionBuilder::new()
.known_node(uri)
.known_node("127.0.0.72:4321")
.known_node("localhost:8000")
.connection_timeout(Duration::from_secs(3))
.known_node_addr(SocketAddr::new(
IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)),
9000,
))
.build()
.await?;
Ok(())
}
After successfully connecting to some specified node the driver will fetch topology information about other nodes in this cluster and connect to them as well.