⚡ Lightning Talk: Where Did All My IPs Go?

Conference: KubeCon + CloudNativeCon North America 2022

2022-10-25

Authors: Cynthia Thomas

Summary

The presentation discusses IP management challenges faced by Kubernetes cluster operators and the solutions introduced by the Kubernetes networking team to mitigate these challenges.

Kubernetes clusters require IP addressing for network communication between pods and agents on nodes.
Assigning large IP blocks for Kubernetes constructs can cause fragmentation problems within organizations and make it difficult to migrate workloads to new clusters.
The Kubernetes networking team has introduced solutions such as single stack IPv6 and IPv4 only support, dual stack IPv4 and IPv6 support, and multiple cluster ciders support for node ipam to address these challenges.
Upcoming solutions include multiple service ciders and reserving static and dynamic allocation for service IP ranges.
Best practices for Kubernetes IP management include starting with a smaller application allocation for IP address ciders and gradually building up, and moving towards IPv6.
The networking community is being asked for feedback on the possibility of mixed mode services.

When building Kubernetes clusters, assigning IP addresses can be a challenge due to the need for large IP blocks for Kubernetes constructs. This can cause fragmentation problems within organizations and make it difficult to migrate workloads to new clusters. To address these challenges, the Kubernetes networking team has introduced solutions such as single stack IPv6 and IPv4 only support, dual stack IPv4 and IPv6 support, and multiple cluster ciders support for node ipam. These solutions allow for more flexible IP management and make it easier to scale and grow workloads on Kubernetes clusters.

Abstract

Kubernetes cluster planning requires quite a few things to get started. What about IPs? Common IP management hurdles with Kubernetes clusters include IP assignments when building a cluster and challenges faced when deploying in a multi-faceted environment. Kubernetes Admins often need to use IP addressing handed out by Network Admins juggling other non-k8s workload IP assignments and IP exhaustion. In this talk, Cynthia will discuss new and existing KEPs that SIG-network has implemented to help mitigate IP challenges. Such features include discontiguous cluster CIDRs and the journey to IPv6. Cynthia will also discuss how the best practices for Kubernetes IP management are changing with these new capabilities to help scale and grow instead of rebuild.

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