Hello Everyone, Can anyone help me with below interview questions i faced - Ca . . .

Faizan Shaikh:
Hello Everyone,

Can anyone help me with below interview questions i faced

  • Can a Pod have multiple IP address assigned. Whether that Pod contains one or more containers.

  • How can we find who is the owner of a POD or a Deployment, so that we can reach to their Team.

  • If we add a Master node in cluster, how will the previous kublets know the location of this new Master node.

PavanKumar Rallabhandi:
I am not an expert as I just started reading the basic of Kubernetes and hence will try to answer two of them

PavanKumar Rallabhandi:

  1. POD can contain more than one container

PavanKumar Rallabhandi:
2. Kubectl describe POD <podname> should give that info and lot more

Vinod Kumar Nair:

  • Can a Pod have multiple IP addresses assigned -> No, IP addresses are Ephemeral for a pod but still 1 at a time…they come and go…resolved against a DNS entry.

Whether that Pod contains one or more containers -> Yes, multi-container pod…or a sidecar is one of the patterns

How can we find who is the owner of a POD or a Deployment, so that we can reach to their Team. -> This is tricky however can be identified by various factors…such as labels in pods & deployments or a LABEL instruction in a Dockerfile, if provided to identify the right team

If we add a Master node in cluster, how will the previous kublets know the location of this new Master node -> Not sure about this though we can join a new worker node to a cluster

hope it helps to you

Faizan Shaikh:
Thanks for the explanation :blush:

Raul Butuc:
@Faizan Shaikh your cluster should be divided into multiple namespaces. Each team has a namespace and all their deployments/pods/etc. will be found under their respective namespace.

1. A Pod in Kubernetes can have multiple IP addresses assigned to it, but it is less common in a single container pod.

By default, a Pod in Kubernetes is assigned a single IP address, which is shared by all the containers in the Pod. This IP address is used for communication within the cluster.

In case of multiple containers in a pod, each container can be assigned with its own IP address, this is called container-to-container communication, and it enables the containers to communicate with each other directly.

However, if you want to assign multiple IP addresses to a single container pod, you can use a feature called IP Aliases. IP Aliases allows you to assign multiple IP addresses to a single network interface on a pod, but it requires a specific network plugin that supports it, also this is not a common use case.

2. You can find the owner of a POD or Deployment in a Kubernetes cluster by looking at the metadata section of the resource’s configuration. The metadata section contains information about the resource, including information about the resource’s owner.

For a POD, you can use the kubectl describe pod command followed by the name of the POD you want to inspect. The output will include a section called Labels which will contain the information of the owner.

For a Deployment, you can use the kubectl describe deployment command followed by the name of the Deployment you want to inspect. The output will include a section called Labels which will contain the information of the owner.

If the owner information is not present in the Labels, you can look for Annotations section , it may contain the information of the owner.

Once you have the information of the owner, you can reach out to their team using the contact information provided in the owner information.

3. When a new Master node is added to a cluster, the existing Kubernetes nodes (also known as kublets) will not automatically know the location of the new Master. However, the administrator can update the cluster’s configuration to point the kublets to the new Master node, which will allow them to communicate with it and join the cluster. This can typically be done by updating the cluster’s kubeconfig file or by modifying the kublet’s configuration on each individual node.