This example is using Envoy-Pilot xDS Server (https://github.com/tak2siva/Envoy-Pilot)

This docker compose setup contains:

- Envoy (port: 10000)
- App1 (port: 8123)
- App2 (port: 8126)

To start

docker-compose up

Config Version 1.0

Open consul on localhost:8500 and check the key xDS/app-cluster/adstest-cluster/CDS/config By default the cluster some_service will be pointing to app1:8123 with version 1.0

xDS/app-cluster/adstest-cluster/CDS/config

[
		{
			"name": "some_service",
			"connect_timeout": "0.25s",
			"type": "STRICT_DNS",
			"lb_policy": "ROUND_ROBIN",
			"hosts" : [ { "socket_address" : { "address" : "app1", "port_value" : 8123 }}]
		}
]

xDS/app-cluster/adstest-cluster/CDS/version

1.0

Verify that by

curl http://localhost:10000
this is app --ONE--

Config Version 2.0 (Dynamic Updates)

Now change the some_service hosts to point app2:8126 with version 2.0 (i.e)

xDS/app-cluster/adstest-cluster/CDS/config

[
		{
			"name": "some_service",
			"connect_timeout": "0.25s",
			"type": "STRICT_DNS",
			"lb_policy": "ROUND_ROBIN",
			"hosts" : [ { "socket_address" : { "address" : "app2", "port_value" : 8126 }}]
		}
]

xDS/app-cluster/adstest-cluster/CDS/version

2.0

Verify that by

curl http://localhost:10000
this is app --TWO--