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2 years ago

Kubernetes CNI loopback

Hi All,

There are soma "exam tips" in the cloud foundation website for the CKA exam, one is in regards to the types of clusters available. E.g.:

At the very end there is a list of the clusters that will be in the exam. Note that one of the clusters uses following different CNIs: calico, and loopback.

- Any idea please on how much of the peculiarities of each CNI type will be covered?
- What is the loopback CNI? I can't find much information about it.


Image of chadrm
2 years ago
The peculiarities of the CNI types were not covered when I took the exam.  The loopback CNI is automatically used by Kubernetes to do low-level networking (like for the Kubelet to talk to the containers local to the node) and Kubernetes will fail if it's not installed or running, but the error messages in the log are extremely helpful in this regard, and will let you know precisely what to do.  This is a rare situation, though, as it's one of the core components.
Image of aoldoni
2 years ago

Thanks very much!

Image of paulmiles01
2 years ago
I've just been going through the certification tips, and I'm confused about the cluster ik8s.

With a loopback cni - can you only build a cluster of 1 ?
Any idea what a 'base node' is ? Is this where the master also acts as a worker?

Thanks in advance

Image of
1 year ago
 @paulmiles01 , I think they refer as a provisioned base server, ready for you to install the worker components and join to the cluster.