Registering Multiple Same-Host Services - consul

Question

I am using the Consul API to register a local web-service running on various ports on my local machine. My end-goal is to be able to run multiple backends and load balance against them on different ports.
I am running a local Consul server of one node for development in a Vagrant VM. I have registered the first instance of my service:
{
"Node": {
"ID": "49d3be4b-5ee5-5f0f-e145-dcb1782e5b4b",
"Node": "localhost",
"Address": "127.0.0.1",
"Datacenter": "dc1",
"TaggedAddresses": {
"lan": "127.0.0.1",
"wan": "127.0.0.1"
},
"Meta": {
"consul-network-segment": ""
},
"CreateIndex": 5,
"ModifyIndex": 6
},
"Services": {
"consul": {
"ID": "consul",
"Service": "consul",
"Tags": [],
"Address": "",
"Port": 8300,
"EnableTagOverride": false,
"CreateIndex": 5,
"ModifyIndex": 5
},
"rusty": {
"ID": "rusty",
"Service": "rusty",
"Tags": [
"rusty",
"rust"
],
"Address": "127.0.0.1",
"Port": 8001,
"EnableTagOverride": false,
"CreateIndex": 247,
"ModifyIndex": 491
}
}
}
You can see my service, rusty, registered on port 8001. The strange thing is that when I register the same service on a different port, Consul supersedes port 8001 with the new service port.
Is there not a way to run multiple backends for a service on different ports on the same host?

Answer 1

Try to check that you are registering services with different IDs. For complete info see the parameters for /agent/service/register endpoint.
Here is an example with two rusty service instances with different IDs rusty1 and rusty2
{
"Node": {
"ID": "eff2fae3-6ee5-5de7-bf1a-c041992a1d6a",
"Node": "FB20160707",
"Address": "192.168.1.66",
"Datacenter": "dc1",
"TaggedAddresses": {
"lan": "192.168.1.66",
"wan": "192.168.1.66"
},
"Meta": {},
"CreateIndex": 5,
"ModifyIndex": 6
},
"Services": {
"consul": {
"ID": "consul",
"Service": "consul",
"Tags": [],
"Address": "",
"Port": 8300,
"EnableTagOverride": false,
"CreateIndex": 5,
"ModifyIndex": 5
},
"rusty1": {
"ID": "rusty1",
"Service": "rusty",
"Tags": [],
"Address": "10.10.10.10",
"Port": 8001,
"EnableTagOverride": false,
"CreateIndex": 16,
"ModifyIndex": 28
},
"rusty2": {
"ID": "rusty2",
"Service": "rusty",
"Tags": [],
"Address": "10.10.10.10",
"Port": 8002,
"EnableTagOverride": false,
"CreateIndex": 19,
"ModifyIndex": 29
}
}
}

Answer 2

As per my comment to #ruslan-sennov, if the services section looked like this (the ID for each instance of the rusty service is made unique by adding the port, but the name is kept as rusty):
"Services": {
"consul": {
"ID": "consul",
"Service": "consul",
"Tags": [],
"Address": "",
"Port": 8300,
"EnableTagOverride": false,
"CreateIndex": 5,
"ModifyIndex": 5
},
"rusty": {
"ID": "rusty:8001",
"Service": "rusty",
"Tags": [
"rusty",
"rust"
],
"Address": "127.0.0.1",
"Port": 8001,
"EnableTagOverride": false,
"CreateIndex": 247,
"ModifyIndex": 491
},
"rusty": {
"ID": "rusty:8002",
"Service": "rusty",
"Tags": [
"rusty",
"rust"
],
"Address": "127.0.0.1",
"Port": 8002,
"EnableTagOverride": false,
"CreateIndex": 247,
"ModifyIndex": 491
}
}
This then means you can query the rusty service with a SRV query and get detail on which ports are available:
dig #127.0.0.1 rusty.service.consul SRV
; <<>> DiG 9.11.3 <<>> rusty.service.consul SRV
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56091
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 52, AUTHORITY: 0, ADDITIONAL: 5
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;rusty.service.consul. IN SRV
;; ANSWER SECTION:
rusty.service.consul. 0 IN SRV 1 1 8001 FB20160707.node.dc1.consul.
rusty.service.consul. 0 IN SRV 1 1 8002 FB20160707.node.dc1.consul.
If you also change the names to be unique (rusty1 and rusty2 as suggested by Ruslan) you lose this querying ability.

Answer 3

I know this is late to answer this, but hope this would help someone.
As per Spring Cloud Consul docs, Add this to bootstrap.yml.
spring:
cloud:
consul:
discovery:
instanceId: ${spring.application.name}:${vcap.application.instance_id:${spring.application.instance_id:${random.value}}}