# Kubernetes cluster manifests

## Introduction

This is the Kubernetes manifests of services running on k-space.ee domains.
The applications are listed on https://auth2.k-space.ee for authenticated users.


## Cluster access

General discussion is happening in the `#kube` Slack channel.

<details><summary>Bootstrapping access</summary>
For bootstrap access obtain `/etc/kubernetes/admin.conf` from one of the master
nodes and place it under `~/.kube/config` on your machine.

Once Passmower is working, OIDC access for others can be enabled with
running following on Kubernetes masters:

```bash
patch /etc/kubernetes/manifests/kube-apiserver.yaml - << EOF
@@ -23,6 +23,10 @@
     - --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt
     - --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
     - --etcd-servers=https://127.0.0.1:2379
+    - --oidc-issuer-url=https://auth2.k-space.ee/
+    - --oidc-client-id=kubelogin
+    - --oidc-username-claim=sub
+    - --oidc-groups-claim=groups
     - --kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt
     - --kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key
     - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
EOF
sudo systemctl daemon-reload
systemctl restart kubelet
```
</details>

The following can be used to talk to the Kubernetes cluster using OIDC credentials:

```bash
kubectl krew install oidc-login
mkdir -p ~/.kube
cat << EOF > ~/.kube/config
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: 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
    server: https://master.kube.k-space.ee:6443
  name: kubernetes
contexts:
- context:
    cluster: kubernetes
    user: oidc
  name: default
current-context: default
kind: Config
preferences: {}
users:
- name: oidc
  user:
    exec:
      apiVersion: client.authentication.k8s.io/v1beta1
      args:
      - oidc-login
      - get-token
      - --oidc-issuer-url=https://auth2.k-space.ee/
      - --oidc-client-id=oidc-gateway-kubelogin
      - --oidc-use-pkce
      - --oidc-extra-scope=profile,email,groups
      - --listen-address=127.0.0.1:27890
      command: kubectl
      env: null
      provideClusterInfo: false
EOF
```

For access control mapping see [cluster-role-bindings.yml](cluster-role-bindings.yml)

### systemd-resolved issues on access
```sh
Unable to connect to the server: dial tcp: lookup master.kube.k-space.ee on 127.0.0.53:53: no such host
```
```
Network → VPN → `IPv4` → Other nameservers (Muud nimeserverid): `172.21.0.1`
Network → VPN → `IPv6` → Other nameservers (Muud nimeserverid): `2001:bb8:4008:21::1`
Network → VPN → `IPv4` → Search domains (Otsingudomeenid): `kube.k-space.ee`
Network → VPN → `IPv6` → Search domains (Otsingudomeenid): `kube.k-space.ee`
```

# Technology mapping

Our self-hosted Kubernetes stack compared to AWS based deployments:

| Hipster startup   | Self-hosted hackerspace             | Purpose                                                             |
|-------------------|-------------------------------------|---------------------------------------------------------------------|
| AWS ALB           | Traefik                             | Reverse proxy also known as ingress controller in Kubernetes jargon |
| AWS AMP           | Prometheus Operator                 | Monitoring and alerting                                             |
| AWS CloudTrail    | ECK Operator                        | Log aggregation                                                     |
| AWS DocumentDB    | MongoDB Community Operator          | Highly available NoSQL database                                     |
| AWS EBS           | Longhorn                            | Block storage for arbitrary applications needing persistent storage |
| AWS EC2           | Proxmox                             | Virtualization layer                                                |
| AWS ECR           | Harbor                              | Docker registry                                                     |
| AWS EKS           | kubeadm                             | Provision Kubernetes master nodes                                   |
| AWS NLB           | MetalLB                             | L2/L3 level load balancing                                          |
| AWS RDS for MySQL | MySQL Operator                      | Provision highly available relational databases                     |
| AWS Route53       | Bind and RFC2136                    | DNS records and Let's Encrypt DNS validation                        |
| AWS S3            | Minio Operator                      | Highly available object storage                                     |
| AWS VPC           | Calico                              | Overlay network                                                     |
| Dex               | Passmower                           | ACL mapping and OIDC provider which integrates with GitHub/Samba    |
| GitHub Actions    | Drone                               | Build Docker images                                                 |
| GitHub            | Gitea                               | Source code management, issue tracking                              |
| GitHub OAuth2     | Samba (Active Directory compatible) | Source of truth for authentication and authorization                |
| Gmail             | Wildduck                            | E-mail                                                              |


External dependencies running as classic virtual machines:

- Bind as DNS server


## Adding applications

Deploy applications via [ArgoCD](https://argocd.k-space.ee)

We use Treafik with Passmower for Ingress.
Applications where possible and where applicable should use `Remote-User`
authentication. This prevents application exposure on public Internet.
Otherwise use OpenID Connect for authentication,
see Argo itself as an example how that is done.

See `camtiler/ingress.yml` for commented Ingress example.

Note that we do not use IngressRoute objects because they don't
support `external-dns` out of the box.
Do NOT add nginx annotations, we use Traefik.
Do NOT manually add DNS records, they are added by `external-dns`.
Do NOT manually create Certificate objects,
these should be handled by `tls:` section in Ingress.


## Cluster formation

Created Ubuntu 22.04 VM-s on Proxmox with local storage.
Added some ARM64 workers by using Ubuntu 22.04 server on Raspberry Pi.

After machines have booted up and you can reach them via SSH:

```
# Disable Ubuntu caching DNS resolver
systemctl disable systemd-resolved.service
systemctl stop systemd-resolved
rm -fv /etc/resolv.conf
cat > /etc/resolv.conf << EOF
nameserver 1.1.1.1
nameserver 8.8.8.8
EOF

# Disable multipathd as Longhorn handles that itself
systemctl mask multipathd snapd
systemctl disable --now multipathd snapd bluetooth ModemManager hciuart wpa_supplicant packagekit

# Permit root login
sed -i -e 's/PermitRootLogin no/PermitRootLogin without-password/' /etc/ssh/sshd_config
systemctl reload ssh
cat ~ubuntu/.ssh/authorized_keys > /root/.ssh/authorized_keys
userdel -f ubuntu
apt-get install -yqq linux-image-generic
apt-get remove -yq cloud-init linux-image-*-kvm
```

On master:

```
kubeadm init --token-ttl=120m --pod-network-cidr=10.244.0.0/16 --control-plane-endpoint "master.kube.k-space.ee:6443" --upload-certs --apiserver-cert-extra-sans master.kube.k-space.ee --node-name master1.kube.k-space.ee
```

For the `kubeadm join` command specify FQDN via `--node-name $(hostname -f)`.

Set AZ labels:

```
for j in $(seq 1 9); do
  for t in master mon worker storage; do
    kubectl label nodes ${t}${j}.kube.k-space.ee topology.kubernetes.io/zone=node${j}
  done
done
```

After forming the cluster add taints:

```bash
for j in $(seq 1 9); do
  kubectl label nodes worker${j}.kube.k-space.ee node-role.kubernetes.io/worker=''
done

for j in $(seq 1 4); do
  kubectl taint nodes mon${j}.kube.k-space.ee dedicated=monitoring:NoSchedule
  kubectl label nodes mon${j}.kube.k-space.ee dedicated=monitoring
done

for j in $(seq 1 4); do
  kubectl taint nodes storage${j}.kube.k-space.ee dedicated=storage:NoSchedule
  kubectl label nodes storage${j}.kube.k-space.ee dedicated=storage
done
```

For `arm64` nodes add suitable taint to prevent scheduling non-multiarch images on them:

```bash
kubectl taint nodes worker9.kube.k-space.ee arch=arm64:NoSchedule
```

For door controllers:

```
for j in ground front back; do
  kubectl taint nodes door-${j}.kube.k-space.ee dedicated=door:NoSchedule
  kubectl label nodes door-${j}.kube.k-space.ee dedicated=door
  kubectl taint nodes door-${j}.kube.k-space.ee arch=arm64:NoSchedule
done
```

To reduce wear on storage:

```
echo StandardOutput=null >> /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
systemctl daemon-reload
systemctl restart kubelet
```