Sometimes network connections on your Kubernetes cluster can be very slow, and you need to understand where there are bottlenecks.
Since IBM Cloud Kubernetes Service is a managed service, debugging the network can be very difficult. In this post, we will show you how to debug network performance on your own by using open source tools.
iPerf3 is an open source software used frequently to measure the maximum bandwidth allowed for a network interface. This is not installed by default in every container image, so in order to install, you will need to define a container image by yourself.
If you would like to use a predefined container image, you could use the iperf image from ClearLinux.
Once you have the container image, you have to deploy it into your IBM Cloud Kubernetes Service cluster. To do that, you can use a
As per DaemonSet definition, one replica for each node will be created.
Once the DaemonSet is ready, list all pods created:
The output should be something similar to this:
Then, select one pod as master (which will receive all the packets that are sent) and the others as clients.
Opening a terminal, run the following on the master pod:
Opening a separate terminal, run the following for each client pod:
The result should be something similar to the following:
This is just one way to debug network performances in a Kubernetes cluster.
If the output of iPerf tests return low bitrates, there is something misconfigured on the cluster, and you should immediately ask to IBM Cloud support to have a look.
Engage the support via the IBM Cloud Support Center.