The document discusses Kubernetes networking. It covers how pods each have their own IP address and act like VMs. It also discusses how overlay networking plugins like Flannel can deliver packets to the correct nodes. Additionally, it explains how services in Kubernetes work using a cluster IP to load balance traffic across pods. Managing networking and services can involve manually configuring networks or using third party plugins to simplify configuration.

1. Insights on Kubernetes networking
Engineer AbdelRahman Adel
Prepared by

2. Better understanding of the picture

3. Easier bug Fixing

4. Cleaner Solution

5. Evolution of Services’ communication model

6. Strongly Coupled Services

7. Coupling to a Gateway

8. Resolving names instead

9. Update Gateway when scaling out service.
Update DNS when Gateways change.
Still need to manually:

10. Kubernetes Model
Pod is a collection of containers sharing the same network namespace.
Each pod has a unique IP.
Pods can be viewed more like a VM.
Pod is the atomic unit of work.

11. IP 1
IP 2
IP 3
IP 4
IP 5
IP 6
IP 7
IP 8
IP 9

12. IP 1
IP 2
IP 3
IP 4
IP 5
IP 6
IP 7
IP 8
IP 9
Destination: IP3
Destination: IP3
Destination: IP3
Destination: IP3
12
3
4

13. Kubernetes is responsible to deliver packet once arrived at the correct node.
BUT
Its your network’s responsibility to deliver it to the correct node

14. Manually Configure our network ?

15. IP 1
IP 2
IP 3
IP 4
IP 5
IP 6
IP 7
IP 8
IP 9
Virtual IP Real IP
IP1 Node1
IP2 Node1
IP3 Node1
IP4 Node2
IP5 Node2
IP6 Node2
IP7 Node3

16. Third Party Plugin
Overlay Network

17. Flannel Software Defined Network

18. IP 1
IP 2
IP 3
IP 4
IP 5
IP 6
IP 7
IP 8
IP 9
Destination: IP3
4
Destination: Node1
Destination: IP3
Destination: Node1
Destination: IP3
Destination: IP3
Destination: IP3
Flannel Flannel Flannel

19. Cluster on Public Cloud?
AWS VPC CNI for Kubernetes
Google Compute Engine (GCE)

20. Services

21. IP 1
IP 2
IP 3
IP 4
IP 5
IP 6
IP 7
IP 8
IP 9
MessageHubService Message_ClusterIP
Message_ClusterIP IP 2
IP 3
IP 4
Message_ClusterIP IP 2
IP 3
IP 4
Message_ClusterIP IP 2
IP 3
IP 4

22. IP 1
IP 2
IP 3
IP 4
IP 5
IP 6
IP 7
IP 8
IP 9
MessageHubService Message_ClusterIP
Message_ClusterIP IP 2
IP 3
IP 4
Message_ClusterIP IP 2
IP 3
IP 4
Message_ClusterIP IP 2
IP 3
IP 4

23. IP 1
IP 2
IP 3
IP 7
IP 8
IP 9
MessageHubService Message_ClusterIP
Message_ClusterIP IP 2
IP 3
IP 4
Message_ClusterIP IP 2
IP 3
IP 4

24. IP 1
IP 2
IP 3
IP 7
IP 8
IP 9
MessageHubService Message_ClusterIP
Message_ClusterIP IP 2
IP 3
IP 9
Message_ClusterIP IP 2
IP 3
IP 9

25. Thank you