Change virtual IP´s for CSE K8s services

The VMware Container Service extensions offers a nice integration of Kubernetes into the NSX Advanced Loadbalancer (formerly known as AVI LoadBalancer).

With the follwoing steps, you can create a demo nginx and expose it to the VMware Cloud director external network:

$ kubectl expose deplyoment nginx --type=LoadBalancer --port=80

You might have noticed that an internal virtual IP address within the 192.168.8.x range is assigned!

Loadbalancer virtual IP address

I was quite often asked, if and how you can change the IP address range!

Yes, it is possible to change the IP address range but some Kubernetes magic is needed!

Disclaimer: You are executing the steps described below on your own responsibility!

First of all, you have to backup the original config! If you do not backup your config, there is a high risk of destroying your K8s cluster!

We have to figure out which configmap needs to be backed up. Look out for ccm.

$ kubectl get configmaps -n kube-system
NAME                                      DATA   AGE
antrea-ca                                 1      27h
antrea-config-9c7h568bgf                  3      27h
cert-manager-cainjector-leader-election   0      26h
cert-manager-controller                   0      26h
coredns                                   1      27h
extension-apiserver-authentication        6      27h
kube-proxy                                2      27h
kube-root-ca.crt                          1      27h
kubeadm-config                            2      27h
kubelet-config-1.21                       1      27h
vcloud-ccm-configmap                      1      27h
vcloud-csi-configmap                      1      27h

You need to backup the vcloud-ccm-configmap!

$ kubectl get configmap vcloud-ccm-configmap -o yaml -n kube-system > ccm-configmap-backup.yaml

As a next and more important step, you have to backup the ccm deployment config.

Use kubectl to figure out which pod needs to be backed up. Typically the pod is deployed in the namespace kube-system. Look out for a pod containing vmware-cloud-director-ccm-*.

$ kubectl get pods -n kube-system
NAME                                         READY   STATUS    RESTARTS   AGE
antrea-agent-4t9wb                           2/2     Running   0          27h
antrea-agent-5dhz9                           2/2     Running   0          27h
antrea-agent-tfrqv                           2/2     Running   0          27h
antrea-controller-5456b989f5-fz45d           1/1     Running   0          27h
coredns-76c9c76db4-dz7sl                     1/1     Running   0          27h
coredns-76c9c76db4-tlggh                     1/1     Running   0          27h
csi-vcd-controllerplugin-0                   3/3     Running   0          27h
csi-vcd-nodeplugin-7w9k5                     2/2     Running   0          27h
csi-vcd-nodeplugin-bppmr                     2/2     Running   0          27h
etcd-mstr-7byg                               1/1     Running   0          27h
kube-apiserver-mstr-7byg                     1/1     Running   0          27h
kube-controller-manager-mstr-7byg            1/1     Running   0          27h
kube-proxy-5kk9j                             1/1     Running   0          27h
kube-proxy-psxlr                             1/1     Running   0          27h
kube-proxy-sh68t                             1/1     Running   0          27h
kube-scheduler-mstr-7byg                     1/1     Running   0          27h
vmware-cloud-director-ccm-669599b5b5-z572s   1/1     Running   0          27h
$ kubectl get pod vmware-cloud-director-ccm-669599b5b5-z572s -n kube-system -o yaml > ccm-deployment-backup.yaml

Copy the ccm-configmap-backup.yaml to antoher file like ccm-configmap-new.yaml. Open the ccm-configmap-new.yaml, you created before, in a text editor like vim. Change the startIP and endIP according to your needs!

apiVersion: v1
data:
  vcloud-ccm-config.yaml: |
    vcd:
      host: "https://vcd.berner.ws"
      org: "next-gen"
      vdc: "next-gen-ovdc"
      vAppName: ClusterAPI-MGMT
      network: "next-gen-int"
      vipSubnet: ""
    loadbalancer:
      oneArm:
        startIP: "192.168.8.2"
        endIP: "192.168.8.100"
      ports:
        http: 80
        https: 443
      certAlias: urn:vcloud:entity:cse:nativeCluster:58ae31cd-17b6-4702-bf79-7777b401eb32-cert
    clusterid: urn:vcloud:entity:cse:nativeCluster:58ae31cd-17b6-4702-bf79-7777b401eb32
immutable: true
kind: ConfigMap
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"v1","data":{"vcloud-ccm-config.yaml":"vcd:\n  host: \"https://vcd.berner.ws\"\n  org: \"next-gen\"\n  vdc: \"next-gen-ovdc\"\n  vAppName: ClusterAPI-MGMT\n  network: \"next-gen-int\"\n  vipSubnet: \"\"\nloadbalancer:\n  oneArm:\n    startIP: \"192.168.8.2\"\n    endIP: \"192.168.8.100\"\n  ports:\n    http: 80\n    https: 443\n  certAlias: urn:vcloud:entity:cse:nativeCluster:58ae31cd-17b6-4702-bf79-7777b401eb32-cert\nclusterid: urn:vcloud:entity:cse:nativeCluster:58ae31cd-17b6-4702-bf79-7777b401eb32\n"},"immutable":true,"kind":"ConfigMap","metadata":{"annotations":{},"name":"vcloud-ccm-configmap","namespace":"kube-system"}}
  creationTimestamp: "2022-01-27T09:46:18Z"
  name: vcloud-ccm-configmap
  namespace: kube-system
  resourceVersion: "440"
  uid: db3e8894-5060-44e2-b20f-1eda812f84a4

PLEASE DOUBLE_CHECK that you have backed up your original config before continuing!

After applying the config, the new virtual IP address range is used:

kubectl delete -f ccm-deployment-backup.yaml
kubectl delete -f ccm-configmap-backup.yaml
kubectl apply -f ccm-configmap-new.yaml
kubectl apply -f ccm-deployment-backup.yaml

 

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