Hashicorp Consul, Agent/Client access - kubernetes

Question

I am trying to do Consul setup via Kubernetes, helm chart, https://www.consul.io/docs/k8s/helm
Based on my pre-Kubernetes knowledge: services, using Consul access via Consul Agent, running on each host and listening on hosts IP
Now, I deployed via Helm chart to Kubernetes cluster. First misunderstanding the terminology, Consul Agent vs Client in this setup? I presume it is the same
Now, set up:
Helm chart config (Terraform fragment), nothing specific to Clients/Agent's and their service:
global:
name: "consul"
datacenter: "${var.consul_config.datacenter}"
server:
storage: "${var.consul_config.storage}"
connect: false
syncCatalog:
enabled: true
default: true
k8sAllowNamespaces: ['*']
k8sDenyNamespaces: [${join(",", var.consul_config.k8sDenyNamespaces)}]
Pods, client/agent ones are DaemonSet, not in host network mode
kubectl get pods
NAME READY STATUS RESTARTS AGE
consul-8l587 1/1 Running 0 11h
consul-cfd8z 1/1 Running 0 11h
consul-server-0 1/1 Running 0 11h
consul-server-1 1/1 Running 0 11h
consul-server-2 1/1 Running 0 11h
consul-sync-catalog-8b688ff9b-klqrv 1/1 Running 0 11h
consul-vrmtp 1/1 Running 0 11h
Services
kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
consul ExternalName <none> consul.service.consul <none> 11h
consul-dns ClusterIP 172.20.124.238 <none> 53/TCP,53/UDP 11h
consul-server ClusterIP None <none> 8500/TCP,8301/TCP,8301/UDP,8302/TCP,8302/UDP,8300/TCP,8600/TCP,8600/UDP 11h
consul-ui ClusterIP 172.20.131.29 <none> 80/TCP 11h
Question 1 Where is a service, to target Client (Agent) pods, but not Server's pods ? Did I miss it in helm chart?
My plan is, while I am not going to use Host (Kubernetes node) networking:
Find the Client/Agent service or make my own. So, it will be used by the Consul's user's. E.g., this service address I will specify for Consul template init pod of the Consul template. In the config consuming application
kubectl get pods --selector app=consul,component=client,release=consul
consul-8l587 1/1 Running 0 11h
consul-cfd8z 1/1 Running 0 11h
consul-vrmtp 1/1 Running 0 11h
Optional: will add a topologyKeys in to agent service, so each consumer will not cross host boundary
Question 2 Is it right approach? Or it is different for Consul Kubernetes deployments

Answer 1

You can use the Kubernetes downward API to inject the IP of host as an environment variable for your pod.
apiVersion: v1
kind: Pod
metadata:
name: consul-example
spec:
containers:
- name: example
image: 'consul:latest'
env:
- name: HOST_IP
valueFrom:
fieldRef:
fieldPath: status.hostIP
command:
- '/bin/sh'
- '-ec'
- |
export CONSUL_HTTP_ADDR="${HOST_IP}:8500"
consul kv put hello world
restartPolicy: Never
See https://www.consul.io/docs/k8s/installation/install#accessing-the-consul-http-api for more info.