Lesson 14: Benchmark Networking
Building a production-ready Kubernetes cluster from scratch / Configuring the Kubernetes Cluster
In this lesson, we will test and verify the high-availability configuration of your Kubernetes control plane. Ensuring that your control plane is resilient to node failures is critical for maintaining cluster stability and continuous operation. We will simulate node failures and observe the behavior of the control plane to confirm that the redundancy and load balancing setup is functioning correctly.
This is the 14th lesson of the guide Building a production-ready Kubernetes cluster from scratch. Make sure you have completed the previous lesson before continuing here. The full list of lessons in the guide can be found in the overview.
Verify connection and network speed between pods
To test the network speed between pods, you can use the iperf3 tool. This tool allows you to measure the network
bandwidth between two pods in your cluster.
To deploy the iperf3 server pod on every node at the same time, we can use a Kubernetes DaemonSet. Connect to one of
your nodes and create a file named iperf3-daemonset.yaml with the following content (e.g. using nano or vi):
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: iperf3
spec:
selector:
matchLabels:
app: iperf3
template:
metadata:
labels:
app: iperf3
spec:
containers:
- name: iperf3
image: networkstatic/iperf3
ports:
- containerPort: 5201
command: ['iperf3']
args: ['-s'] # Run in server mode
Apply the DaemonSet configuration to deploy the iperf3 server pods:
$ kubectl apply -f iperf3-daemonset.yaml
Get the list of pods to verify that the iperf3 server pods are running:
$ kubectl get pods -l app=iperf3 -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
iperf3-b7tp5 1/1 Running 0 5m45s 10.244.0.6 kubernetes-node-1 <none> <none>
iperf3-g4k2b 1/1 Running 0 5m45s 10.244.2.4 kubernetes-node-3 <none> <none>
iperf3-zztwd 1/1 Running 0 5m45s 10.244.1.5 kubernetes-node-2 <none> <none>
Create an interactive shell session in one of the iperf3 server pods to check the network speed:
$ kubectl exec -it iperf3-b7tp5 -- /bin/bash
Run the following command to test the network speed to one of the other iperf3 server pods:
root@iperf3-pgt7j:/# iperf3 -c 10.244.2.9
Connecting to host 10.244.2.9, port 5201
[ 5] local 10.244.0.9 port 48980 connected to 10.244.2.9 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 111 MBytes 933 Mbits/sec 0 3.87 MBytes
[ 5] 1.00-2.00 sec 109 MBytes 912 Mbits/sec 0 3.87 MBytes
[ 5] 2.00-3.00 sec 109 MBytes 912 Mbits/sec 0 3.87 MBytes
[ 5] 3.00-4.00 sec 108 MBytes 902 Mbits/sec 0 3.87 MBytes
[ 5] 4.00-5.00 sec 109 MBytes 912 Mbits/sec 0 3.87 MBytes
[ 5] 5.00-6.00 sec 108 MBytes 902 Mbits/sec 0 3.87 MBytes
[ 5] 6.00-7.00 sec 109 MBytes 912 Mbits/sec 0 3.87 MBytes
[ 5] 7.00-8.00 sec 109 MBytes 912 Mbits/sec 0 3.87 MBytes
[ 5] 8.00-9.00 sec 109 MBytes 912 Mbits/sec 0 3.87 MBytes
[ 5] 9.00-10.00 sec 108 MBytes 902 Mbits/sec 0 3.87 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 1.06 GBytes 911 Mbits/sec 0 sender
[ 5] 0.00-10.03 sec 1.06 GBytes 909 Mbits/sec receiver
iperf Done.
Cleanup the iperf3 server pods after you are done testing:
$ kubectl delete -f iperf3-daemonset.yaml
$ rm iperf3-daemonset.yaml
Lesson Conclusion
Congratulations! After successfully testing and verifying the high-availability setup of your control plane, your cluster is now resilient and capable of maintaining operation even during node failures You have completed this lesson and you can now continue with the next one.
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