Basic Networking

Question 1

Who has an IP-address in Kubernetes?

Answer 1

• each Node has its own address
• each pod has its own internal address

Question 2

How does a Pod receive his ip address?

Answer 2

• When Kubernetes is initially configured it creates an internal private network (i.e 10.244.0.0)
• all the pods are attached to it
• when multiple pods are created, each one gets his own ip from this network assigned (first: 10.244.0.2, second: 10.244.0.3)
• pods can communicate with each other through this ip, but not a good idea, since it can change

Question 3

What is the initial challange with Networking in Kubernetes?

Answer 3

Example scenario: two nodes (192.168.1.2 and .3) with each one pod (10.244.0.2)
When a Kubernetes Cluster is set up, it does not handle automatically the issue, that both pods have the same internal IP
- Kubernetes expects us to set up a networking solution that meets two criterias

Question 4

What criterias are expected from Kubernetes to be solved via a networking solution?

Answer 4

• all containers/pods can communicate with one another without Network address translation (NAT)
• all nodes can communicate with all containers and vice-versa without NAT

Question 5

Name a few possible networking solutions?

Answer 5

• Cisco
• cilium
• flannel
• NSX T

Depending on the Platform, the Kubernetes cluster is deployed on

Question 6

How does the networking work with multiple nodes in the cluster?

Answer 6

We use a custom networking to manage the network and assign different network addresses for each node in the network
- Creates a virtual network, where all nodes and pods are assigned their unique IP address