Two services with the same name but in different namespaces in k8s are mapped to a single service in consul

[ishustava]

consul-helm chart version: branch master
Deployed to AWS EKS

Issue

If I create two services with the same name but in different namespaces in k8s, consul registers them as two instances under the same name.

For example, I have an ngnix service in the default and foo namespaces.

Consul would then load balance between those two services if I use consul as DNS.

kubectl port-forward consul-consul-server-0 5000:8600 &

$ dig -p 5000 @127.0.0.1 +tcp nginx.service.consul

; <<>> DiG 9.10.6 <<>> -p 5000 @127.0.0.1 +tcp nginx.service.consul
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47981
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 3
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;nginx.service.consul.		IN	A

;; ANSWER SECTION:
nginx.service.consul.	0	IN	CNAME	ac0771705dcc411e997eb02853705779-27038583.us-east-2.elb.amazonaws.com.

;; ADDITIONAL SECTION:
nginx.service.consul.	0	IN	TXT	"external-source=kubernetes"
nginx.service.consul.	0	IN	TXT	"external-source=kubernetes"

;; Query time: 326 msec
;; SERVER: 127.0.0.1#5000(127.0.0.1)
;; WHEN: Mon Sep 23 10:38:13 PDT 2019
;; MSG SIZE  rcvd: 210


~:
$ dig -p 5000 @127.0.0.1 +tcp nginx.service.consul

; <<>> DiG 9.10.6 <<>> -p 5000 @127.0.0.1 +tcp nginx.service.consul
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2446
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 3
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;nginx.service.consul.		IN	A

;; ANSWER SECTION:
nginx.service.consul.	0	IN	CNAME	a3f17333edcaf11e997eb02853705779-1573697906.us-east-2.elb.amazonaws.com.

;; ADDITIONAL SECTION:
nginx.service.consul.	0	IN	TXT	"external-source=kubernetes"
nginx.service.consul.	0	IN	TXT	"external-source=kubernetes"

;; Query time: 315 msec
;; SERVER: 127.0.0.1#5000(127.0.0.1)
;; WHEN: Mon Sep 23 10:38:15 PDT 2019
;; MSG SIZE  rcvd: 212

Desired behavior

Sync should disambiguate between services deployed to different namespaces.

[filintod]

Yes this is true. I try to mitigate it by adding a tag for namespace so at least I can target it differently (kind of weird to put the namespace before the service name though) but don't see how this can get resolved as consul does not have a knowledge of namespaces unless it is added to consul code somehow.

[jasonliu747]

@lkysow Hey Luke, I think it really is a bug if consul officially supported k8s. The only workaround so far is by combining namespace and service name. Dose consul plan to take a look of this issue?

[lkysow]

Hi @jasonliu747 yes it's on our roadmap to fix this.