Forwarding in Ringpop

Ringpop provides intelligent request forwarding capabilities when nodes join, leave, or fail. This allows Ringpop-enabled applications to seamlessly handle cluster changes without service disruption.

Handling Node Changes

• When a new node joins the cluster, it is instantly added to the consistent hash ring
• The membership protocol lets it quickly discover all other nodes
• When a node fails, it is removed from the hash ring
• Its previously owned requests are forwarded to new owners

This happens automatically without application involvement.

Forwarding Logic

Normally, Ringpop routes requests directly to the owning node:

1. Request comes in
2. Key is hashed to find owner node
3. Request is routed to owner for handling

If the owner node fails, the request is automatically forwarded:

1. Request comes in
2. Owner node is unreachable
3. Request is forwarded to the next node in the hash ring
4. That node handles the request

This provides graceful degradation if nodes fail. Requests are seamlessly routed to other nodes.

Benefits

• New nodes are quickly utilized
• Failed nodes cause minimal disruption
• Requests are evenly load balanced across nodes
• No special logic needed in application code

The application sees a single consistent hash ring despite underlying cluster changes.

By handling cluster membership and request forwarding internally, Ringpop simplifies building resilient distributed applications.