Learn Kubernetes Basics

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Networking

Kubernetes supports the Container Network Interface (CNI). This is a network plugin architecture that allows you to use whatever Kubernetes-friendly SDN you want. Currently this means support for Flannel and Canal.

This page shows how the various network portions of a cluster work and how to configure them.

Before you begin

This page assumes you have a working Juju deployed cluster.

Note: Note that if you deploy a cluster via conjure-up or the CDK bundles, manually deploying CNI plugins is unnecessary.

The CNI charms are subordinates. These charms will require a principal charm that implements the kubernetes-cni interface in order to properly deploy.

Flannel

juju deploy flannel
juju add-relation flannel kubernetes-master
juju add-relation flannel kubernetes-worker
juju add-relation flannel etcd

Canal

juju deploy canal
juju add-relation canal kubernetes-master
juju add-relation canal kubernetes-worker
juju add-relation canal etcd

Configuration

iface The interface to configure the flannel or canal SDN binding. If this value is empty string or undefined the code will attempt to find the default network adapter similar to the following command:

$ route | grep default | head -n 1 | awk {'print $8'}

cidr The network range to configure the flannel or canal SDN to declare when establishing networking setup with etcd. Ensure this network range is not active on layers 2/3 you’re deploying to, as it will cause collisions and odd behavior if care is not taken when selecting a good CIDR range to assign to flannel. It’s also good practice to ensure you allot yourself a large enough IP range to support how large your cluster will potentially scale. Class A IP ranges with /24 are a good option.

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