• How to check the network range the nodes in the cluster are part of:
    • Use the ipcalc utility.
    • Firstly find the internal IP of the nodes from the Control Plane node with: ip a | grep eth0.
    • Use the ipcalc command to see the network details. An example is below: 
      root@controlplane:~> ipcalc -b 10.33.39.8
Address:   10.33.39.8           
Netmask:   255.255.255.0 = 24   
Wildcard:  0.0.0.255            
=>
Network:   10.33.39.0/24        
HostMin:   10.33.39.1           
HostMax:   10.33.39.254         
Broadcast: 10.33.39.255         
Hosts/Net: 254                   Class A, Private Internet
  • The answer in this case is Network: 10.33.39.0/24
  • How to check the range of IP addresses configured for pods in the cluster?
    • Network is configured with weave.
    • Check the weave pods with kubectl logs <weave-pod-name> weave -n kube-system.
    • Look for ipalloc-range.
    • Good command to use: kubectl logs weave-net-v28kc -n kube-system | grep ipalloc
  • Example output: 
    kubectl logs weave-net-v28kc -n kube-system | grep ipalloc
Defaulted container "weave" out of: weave, weave-npc, weave-init (init)
INFO: 2025/04/20 12:06:29.654624 Command line options: map[conn-limit:200 datapath:datapath db-prefix:/weavedb/weave-net docker-api: expect-npc:true http-addr:127.0.0.1:6784 ipalloc-init:consensus=0 ipalloc-range:10.244.0.0/16 metrics-addr:0.0.0.0:6782 name:52:4d:00:38:8e:f8 nickname:controlplane no-dns:true no-masq-local:true port:6783]
  • How to check the IP range configured for services within the cluster? 
    cat /etc/kubernetes/manifests/kube-apiserver.yaml   | grep cluster-ip-range
  • Example output: ``` cat /etc/kubernetes/manifests/kube-apiserver.yaml | grep cluster-ip-range
    • –service-cluster-ip-range=10.96.0.0/12 ```
  • How to check the amount of kube-proxy pods?
  • Run the following: 
    kubectl get pods -n kube-system
  • How to find the proxy that kube-proxy is configured to use?
    • Check the logs of the proxy pods.
    • Run this command: kubectl logs <kube-proxy-pod-name> -n kube-system
      • Example: kubectl logs kube-proxy-bcnwv -n kube-system
      • grep for the following:
        • userspace, firewalld, ipvs and iptables.
  • How does the Kubernetes cluster ensure that a kube-proxy pod runs on all nodes in the cluster?
    • Run kubectl get ds -n kube-system to check this

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