fix(relay): add SO_REUSEPORT flag to enable smooth restarts

CHANGELOG.md

@@ -26,6 +26,7 @@
 - Promote some `span.data` fields to the top level. ([#4298](https://github.com/getsentry/relay/pull/4298))
 - Remove metrics summaries. ([#4278](https://github.com/getsentry/relay/pull/4278), [#4279](https://github.com/getsentry/relay/pull/4279), [#4296](https://github.com/getsentry/relay/pull/4296))
 - Use async `redis` for `projectconfig`. ([#4284](https://github.com/getsentry/relay/pull/4284))
+- Set `SO_REUSEPORT` to enable smooth restarts. ([#4375](https://github.com/getsentry/relay/pull/4375))
 
 ## 24.11.1
 

relay-server/src/services/server/mod.rs

@@ -108,6 +108,8 @@ fn listen(config: &Config) -> Result<TcpListener, ServerError> {
         SocketAddr::V6(_) => TcpSocket::new_v6(),
     }?;
 
+    #[cfg(all(unix, not(target_os = "solaris"), not(target_os = "illumos")))]
+    socket.set_reuseport(true)?;
     socket.bind(addr)?;
     Ok(socket.listen(config.tcp_listen_backlog())?.into_std()?)
 }