Relay HA
- High Availability of Relay Server in one of the two below ways
- 2 or more Relay Servers read from the Source Data Sources.
- The Clients connect to Relay Server via a LB.
- Since the requests from clients are over HTTP one of the Relay Servers or both can be serving the request based on the configuration in the LB.
- When one Relay goes down the other can still handle the requests.
- Pros
- Simple Solution
- Cons and Issues
- There will be additional load on the Network as two Relays would be reading from the same Master.
- Relay Chaining with HA using Leader Follower model
- Relay Producer reads from another Relay. This Relay can act as normal Relay for Clients.
- Relays have both producer, Source Producer and Relay Producers, bit only one is active at a time.
- On Leader Relay the source producer is active. On follower relay the relay producer is active.
- Clients can read from either relay via a LB.
- Leader/Follower election is done via Helix Leader/Follower algorithm.
- In fact we can have total of N relays with k leaders and n-k followers.
- The clients can either read from each relay via a LB or act as spectators so that they know which relay is the leader and connect to that Relay.
- This approach has not yet been implemented.
