Session Affinity

Hashes a request header to pin a user’s requests to one backend

Category: Practical
Task: Hashes a request header to pin a user’s requests to one backend

Prerequisites: The product runtime and any backend services referenced by this configuration.

This configuration comes from the selected release. The example has not been run here; external services are not bundled.

Download the source file.

# Session Affinity via Consistent Hashing
#
# Hashes a request header to pin a user's requests to one backend.
# Falls back to URI path when the header is absent. Adding or
# removing a backend re-hashes ~1/N of traffic.
#
# Usage:
#   cargo run -p praxis-proxy -- -c examples/configs/traffic-management/session-affinity.yaml
#   for i in $(seq 1 6); do
#     curl -H "X-User-Id: user-42" http://localhost:8080/
#   done

listeners:
  - name: default
    address: "127.0.0.1:8080"
    filter_chains:
      - main

filter_chains:
  - name: main
    filters:
      - filter: router
        routes:
          - path_prefix: "/"
            cluster: backend

      - filter: load_balancer
        clusters:
          - name: backend
            load_balancer_strategy:
              consistent_hash:
                header: "X-User-Id"   # omit to hash on URI path instead
            endpoints:
              - "127.0.0.1:3001"
              - "127.0.0.1:3002"
              - "127.0.0.1:3003"

insecure_options:
  allow_private_endpoints: true # example proxies to local backends