kubernetes-the-hard-way/docs/11-pod-network-routes.md

Provisioning Pod Network Routes

Pods scheduled to a node receive an IP address from the node's Pod CIDR range. At this point pods can not communicate with other pods running on different nodes due to missing network routes.

In this lab you will create a route for each worker node that maps the node's Pod CIDR range to the node's internal IP address.

There are other ways to implement the Kubernetes networking model.

The Routing Table

In this section you will gather the information required to create routes in the kubernetes-the-hard-way VPC network.

Create the Azure route table

az network route-table create --resource-group kubernetes-the-hard-way --name kubernetes-the-hard-way-rt

Routes

Create network routes for each worker instance:

for i in 0 1 2; do
  az network route-table route create \
    --resource-group kubernetes-the-hard-way \
    --name kubernetes-the-hard-way-route-10-200-${i}-0-24 \
    --route-table-name kubernetes-the-hard-way-rt \
    --next-hop-type VirtualAppliance \
    --next-hop-ip-address 10.240.0.2${i} \
    --address-prefix 10.200.${i}.0/24
done

az network vnet subnet update \
  --resource-group kubernetes-the-hard-way \
  --vnet-name kubernetes-the-hard-way-vnet \
  --name kubernetes-the-hard-way-subnet \
  --route-table kubernetes-the-hard-way-rt

List the routes in the kubernetes-the-hard-way VPC network:

az network route-table route list --resource-group kubernetes-the-hard-way --route-table-name kubernetes-the-hard-way-rt -o table

output

AddressPrefix    Name                                         NextHopIpAddress    NextHopType       ProvisioningState    ResourceGroup
---------------  -------------------------------------------  ------------------  ----------------  -------------------  -----------------------
10.200.0.0/24    kubernetes-the-hard-way-route-10-200-0-0-24  10.240.0.20         VirtualAppliance  Succeeded            kubernetes-the-hard-way
10.200.1.0/24    kubernetes-the-hard-way-route-10-200-1-0-24  10.240.0.21         VirtualAppliance  Succeeded            kubernetes-the-hard-way
10.200.2.0/24    kubernetes-the-hard-way-route-10-200-2-0-24  10.240.0.22         VirtualAppliance  Succeeded            kubernetes-the-hard-way

Next: Deploying the DNS Cluster Add-on