I created a namespace and a pod in it like this:
# Create the namespace
kubectl create namespace one
# Create the pod (NOTE - Without a service)
kubectl run rest -n one --image nginx --labels app=rest --expose --port 80
I then created a second namespace and pod (that I'll use to reach the first one).
# Create the namespace
kubectl create namespace two
# Create the pod (NOTE - Without a service)
kubectl run call-rest -n two --image alpine -- sleep 3600
Then I grab the ip address of the first pod:
kubectl get pod rest -n one -o wide
# This gives me
# NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
# rest 1/1 Running 0 10m 192.168.0.142 k3d-dev-server-0 <none> <none>
I use that ip address to call it from the other pod.
# This uses the format that K8s creates for DNS
kubectl exec -it call-rest -n two -- wget -qO- --timeout=2 http://192-168-0-142.one.pod.cluster.local
The above just times out
wget: download timed out
command terminated with exit code 1
To verify, I checked the domain for the cluster and I have it correct:
# Run this inside the pod
kubectl exec -it call-rest -n two -- cat /etc/resolv.conf
# And it prints out:
#
# search two.svc.cluster.local svc.cluster.local cluster.local
# nameserver 10.43.0.10
# options ndots:5
The pods can reach each other if they're in the same namespace (but then I don't need to use the ip address).
Any idea how I can make them reach each other?
I'm using:
Turns out this is because I'm using Calico. With the default Flannel used in k3d, the above does work. However, in Calico it creates cluster-wide IP addresses for pods, not IPs within each namespace. So the following works:
kubectl exec -it call-rest -n two -- wget -qO- --timeout=2 http://192.168.0.142