🚀 Hands-on Tutorial: Switching kube-proxy to IPVS Mode in Kubernetes
If you’re running Kubernetes at scale, switching from iptables mode to IPVS can dramatically improve performance and scalability. IPVS (IP Virtual Server) is a kernel-based load balancer that offers better traffic handling than iptables.
🔹 Why Switch to IPVS?
✅ Better Performance – Handles thousands of services efficiently.
✅ Advanced Load Balancing – Supports algorithms like Least Connections, Round Robin, etc.
✅ Faster Packet Processing – Uses the Linux kernel for direct packet forwarding.
Step 1: Check if IPVS Modules are Available
Before enabling IPVS mode, ensure your Linux system supports the required kernel modules.
Run the following command on each Kubernetes node:
lsmod | grep ip_vs
If no output appears, load the necessary modules manually:
modprobe ip_vs
modprobe ip_vs_rr
modprobe ip_vs_wrr
modprobe ip_vs_sh
Now verify again:
lsmod | grep ip_vs
To ensure modules persist after reboot, add them to /etc/modules-load.d/ipvs.conf:
echo -e "ip_vs\nip_vs_rr\nip_vs_wrr\nip_vs_sh" | sudo tee /etc/modules-load.d/ipvs.conf
Step 2: Install ipvsadm to Manage IPVS Rules
IPVS requires the ipvsadm tool to monitor and manage load-balancing rules. Install it using:
sudo apt install -y ipvsadm # For Debian/Ubuntu
sudo yum install -y ipvsadm # For CentOS/RHEL
Check if it’s installed correctly:
ipvsadm -Ln
If no output appears, it means no IPVS rules are currently set.
Step 3: Modify kube-proxy to Use IPVS Mode
Now, configure kube-proxy to use IPVS instead of iptables.
A. Edit the kube-proxy ConfigMap
kubectl edit cm kube-proxy -n kube-system
Find this section:
mode: "iptables"
Change it to:
mode: "ipvs"
Save and exit.
Step 4: Restart kube-proxy
For the changes to take effect, restart the kube-proxy pods:
kubectl delete pod -n kube-system -l k8s-app=kube-proxy
Verify if kube-proxy is now running in IPVS mode:
kubectl logs -n kube-system -l k8s-app=kube-proxy | grep "Using ipvs"
Step 5: Verify IPVS Mode is Active
Run the following command:
ipvsadm -Ln
If you see load-balancing rules listed, congratulations! 🎉 Your Kubernetes cluster is now using IPVS mode!
Step 6: Test Service Load Balancing in IPVS Mode
Deploy a test service:
apiVersion: v1
kind: Service
metadata:
name: my-test-service
spec:
selector:
app: my-test-app
ports:
- protocol: TCP
port: 80
targetPort: 80
type: ClusterIP
Apply the service:
kubectl apply -f my-service.yaml
Now, check the IPVS load balancing table again:
ipvsadm -Ln
You should see load-balancing rules pointing to your pod IPs instead of iptables rules.
🎯 Summary: Why Use IPVS Mode?
✔ More efficient packet handling than iptables
✔ Supports multiple load-balancing algorithms
✔ Faster rule updates for large clusters
✔ Scales better with thousands of services
🔥 Next Steps
✅ Test different IPVS scheduling algorithms (Least Connections, Round Robin, etc.).
✅ Tune IPVS settings for even better performance.
✅ Use kubectl get endpoints to check pod routing dynamically.
#Kubernetes, #kube-proxy, #IPVS, #Networking, #CloudComputing, #DevOps, #LoadBalancing, #K8sNetworking, #ContainerOrchestration
