Implementing traffic distribution among micro-service deployments in Kubernetes without Ingress

DevOps Kubernetes
1

hey folks :wave: , hope you are having/had a great day :smile:
we have a use-case where our micro-service A in namespace X needs to talks micro-service B in namespace Y. Condition is that for each micro-service we have 3 deployments each, base, baseline and canary and traffic should be distributed among three deployments based on some weight. Can we achieve this without making use of Ingress ? attached is the high level architecture which we want to achieve.
Thanks

2

hello! Did you try using service FQDN

3

no, can you please help with one example?

4

It is like

service-1.namespace-1.svc.cluster.local

5

yeah that I am already using but if you see the diagram, there are 3 instances of the same application and load from application A should be equally distributed to application B’s (3 deployments)

6

Are you using service mesh?

7

but with traefik, we would have to create IngressRoute which will help with traffic splitting but then we’ll have to do DNS resolution outside of cluster, right?

8

application A → route 53 resolution → AWS ALB → traefik → k8s service → application B

9

please correct me I am wrong here :sweat_smile:

10

May be you can try service mesh istio

11

it will be a big change for our prod cluster :sweat_smile:

12

And you are also using HPA ?

13

but HPA will scale up/down the no of pods of a particular deployment. The reason why we are maintaining 3 versions of an application is one would be canary with 2% traffic, one would be baseline again with 2% traffic and last one would be having 96% traffic with HPA enabled

14

btw, can we create Ingress and pass k8s fqdn as host? something like

kind: IngressRoute
metadata:
  annotations:
    <http://kubernetes.io/ingress.class|kubernetes.io/ingress.class>: traefik-internal
  creationTimestamp: "2024-01-17T10:51:52Z"
  name: gcoms-test-int
  namespace: gcoms-test
  uid: 5c7a9a44-f237-4c03-972a-feeb73e26c5b
spec:
  routes:
  - kind: Rule
    match: Host(`wallet-test.wallet.svc.cluster.local`) && PathPrefix(`/`)
    middlewares:
    - name: headers-common
      namespace: traefik-v2-flux
    - name: headers-common-cache-control
      namespace: gcoms-test
    services:
    - kind: Service
      name: gcoms-test
      namespace: gcoms-test
      port: 80
      weight: 96
    - kind: Service
      name: gcoms-test-baseline
      namespace: gcoms-test
      port: 80
      weight: 2
    - kind: Service
      name: gcoms-test-canary
      namespace: gcoms-test
      port: 80
      weight: 2```
15

I have never tested IngressRoute Object. You are facing problem with ingress object?

16

nope, IngressRoute is fine, what I was trying to ask here was can we do something like

    match: Host(`wallet-test.wallet.svc.cluster.local`) && PathPrefix(`/`)```


?
here our host is k8s dns
17

I don’t think we can use service fqdn as it is not accessible outside the cluster

18

yeah that was my assumption as well :sweat_smile:

19

https://argo-rollouts.readthedocs.io/en/stable/

20

I think that using an Ingress (load-balancer) instead of the simple Service name for intra-cluster communication is sub-optimal but you cannot do without if you need canary-deployment.