## Introduction

The following guide shows how to setup an IPv6 only cluster at ungleich.

## Steps

- Boot Alpine
- Configure with cdist to get cri-o configured

## Control plane

Initialise with all components:

```
kubeadm init -service-cidr 2a0a:e5c0:13:aaa::/108 --pod-network-cidr 2a0a:e5c0:13:bbb::/64
```

We cannot yet skip kube-proxy, because calico does not support eBPF
for IPv6. Cilium supports IPv6 eBPF, but on the other hand does not
support automatic BGP peering. So the following **does not** work:

```
kubeadm init --skip-phases=addon/kube-proxy --service-cidr 2a0a:e5c0:13:aaa::/108 --pod-network-cidr 2a0a:e5c0:13:bbb::/64
```

## Alpine / kubelet hack

Due to some misconfiguration on alpine, **DURING** the **kubeadm
init** we need to modify the **generated**
/var/lib/kubelet/config.yaml to replace "cgroupDriver: systemd" with
"cgroupDriver: cgroupfs".

The same is necessary on the worker nodes, however that can be done
anytime before you plan to schedule containers on them, after the
**kubeadm join** request.

## Worker nodes

```
kubeadm join [2a0a:e5c0:13:0:225:b3ff:fe20:38cc]:6443 --token bw3x98.chp31kcgcd4b5fpf --discovery-token-ca-cert-hash sha256:...

```

## CNI/networking

```
kubectl apply -f calico.yaml
```

Warning: needs to be updated:

```
serviceaccount/calico-kube-controllers created
Warning: policy/v1beta1 PodDisruptionBudget is deprecated in v1.21+, unavailable in v1.25+; use policy/v1 PodDisruptionBudget
poddisruptionbudget.policy/calico-kube-controllers created
```

Checking pods:

```
[21:53] server47.place7:~/v3-calico# kubectl -n kube-system get pods
NAME                                       READY   STATUS              RESTARTS   AGE
calico-kube-controllers-6d8ccdbf46-4xzz9   0/1     Pending             0          60s
calico-node-5gkp9                          0/1     Init:0/3            0          60s
calico-node-8lct9                          0/1     Init:0/3            0          60s
calico-node-jmjhn                          0/1     Init:0/3            0          60s
calico-node-krnzr                          0/1     Init:ErrImagePull   0          60s
coredns-558bd4d5db-4rvrf                   0/1     Pending             0          3m40s
coredns-558bd4d5db-g9lbx                   0/1     Pending             0          3m40s
etcd-server47                              1/1     Running             0          3m56s
kube-apiserver-server47                    1/1     Running             0          3m55s
kube-controller-manager-server47           1/1     Running             0          3m56s
kube-scheduler-server47                    1/1     Running             0          3m55s
[21:54] server47.place7:~/v3-calico#
```

## Getting calicoctl

```
kubectl apply -f https://docs.projectcalico.org/manifests/calicoctl.yaml
```

And alias it:

```
alias calicoctl="kubectl exec -i -n kube-system calicoctl -- /calicoctl"
```

## Configuring BGP routing

```
calicoctl create -f - < bgp....yaml
```

## Setup a test deployment

Do *NOT* use https://k8s.io/examples/application/deployment.yaml. It
contains an outdated nginx container that has no IPv6 listener. You
will get results such as

```
[19:03] server47.place7:~/ungleich-k8s/v3-calico#  curl http://[2a0a:e5c0:13:bbb:176b:eaa6:6d47:1c41]
curl: (7) Failed to connect to 2a0a:e5c0:13:bbb:176b:eaa6:6d47:1c41 port 80: Connection refused
```

if you use that deployment. Instead use something on the line of the
included **nginx-test-deployment.yaml**:

```
kubectl appply -f nginx-test-deployment.yaml
```