Hostname Upstream

Demonstrates using DNS hostnames instead of IP addresses for upstream endpoints

Category: Practical
Task: Route requests by hostname

Prerequisites: Praxis runtime; HTTP backends for the configured hostnames

Expected outcome: The request hostname selects the configured upstream.

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

Download the source file.

# Hostname Upstream Endpoints
#
# Demonstrates using DNS hostnames instead of IP addresses for
# upstream endpoints. The proxy resolves hostnames to IP addresses
# at connection time, preferring IPv4 when multiple records exist.
#
# Usage:
#   cargo run -p praxis-proxy -- -c examples/configs/traffic-management/hostname-upstream.yaml
#
#   curl http://localhost:8080/
#
# The request is forwarded to the backend resolved from the
# hostname endpoint. Because a hostname can be rebound between
# config load and connection time, a resolved private or reserved
# address is refused unless insecure_options.allow_private_upstreams
# is set - which this example needs, since "localhost" resolves to
# loopback.

listeners:
  - name: default
    address: "0.0.0.0:8080"
    filter_chains: [main]

filter_chains:
  - name: main
    filters:
      - filter: router
        routes:
          - path_prefix: "/"
            cluster: backend
      - filter: load_balancer
        clusters:
          - name: backend
            endpoints:
              - "localhost:9000"

insecure_options:
  allow_private_endpoints: true # example proxies to local backends
  allow_private_upstreams: true # "localhost" resolves to loopback at connection time