Kube Proxy

Pod service setup

Switch context

kubectl config use-context k8s-c1-H

Create nginx yaml

kubectl run p2-pod --image=nginx:1.21.3-alpine $do > p2.yaml

Update p2.yaml namespace and container

metadata:
  namespace: project-hamster             # add
spec:
  containers:
  - image: nginx:1.21.3-alpine
    name: p2-pod
  - image: busybox:1.31                  # add
    name: c2                             # add
    command: ["sh", "-c", "sleep 1d"]    # add

Create pod

kubectl apply -f p2.yaml

Create service

kubectl -n project-hamster expose pod p2-pod --name p2-service --port 3000 --target-port 80

Confirm service endpoints

kubectl -n project-hamster get pod,svc,ep

Check kubeproxy is using iptables

k get node

ssh cluster1-controlplane1

# root@cluster1-controlplane1
$ crictl ps | grep kube-proxy
$ crictl logs <id>
# Output: Using iptables Proxier

Check created iptables rules by kube-proxy

ssh cluster1-controlplane1 iptables-save | grep p2-service >> /opt/course/p2/iptables.txt
ssh cluster1-node1 iptables-save | grep p2-service >> /opt/course/p2/iptables.txt
ssh cluster1-node2 iptables-save | grep p2-service >> /opt/course/p2/iptables.txt

Cleanup

Delete service

k -n project-hamster delete svc p2-service

iptables rules should be deleted

ssh cluster1-controlplane1 iptables-save | grep p2-service
ssh cluster1-node1 iptables-save | grep p2-service
ssh cluster1-node2 iptables-save | grep p2-service