Kubernetes cluster manifests

Introduction

This is the Kubernetes manifests of services running on k-space.ee domains:

• Authelia for authentication
• Drone.io for building Docker images
• Harbor for hosting Docker images
• ArgoCD for deploying Kubernetes manifests and Helm charts into the cluster
• camtiler for cameras
• Longhorn Dashboard for administering Longhorn storage
• Kubernetes Dashboard for read-only overview of the Kubernetes cluster
• Wildduck Webmail

Most endpoints are protected by OIDC autentication or Authelia SSO middleware.

Cluster access

General discussion is happening in the #kube Slack channel.

Bootstrapping access

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

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

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://auth.k-space.ee
+    - --oidc-client-id=kubelogin
+    - --oidc-username-claim=preferred_username
+    - --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

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

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://auth.k-space.ee
      - --oidc-client-id=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

systemd-resolved issues on access

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	Authelia	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:

• Samba as Authelia's source of truth
• Bind as DNS server

Adding applications

Deploy applications via ArgoCD

We use Treafik with Authelia 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 kspace-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

Create Ubuntu 20.04 VM-s on Proxmox with local storage.

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

# Enable required kernel modules
cat > /etc/modules << EOF
overlay
br_netfilter
EOF
cat /etc/modules | xargs -L 1 -t modprobe

# Finetune sysctl:
cat > /etc/sysctl.d/99-k8s.conf << EOF
net.ipv4.conf.all.accept_redirects  = 0
net.bridge.bridge-nf-call-iptables  = 1
net.ipv4.ip_forward                 = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF
sysctl --system

# 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
systemctl disable multipathd
systemctl stop multipathd

# Disable Snapcraft
systemctl mask snapd
systemctl disable snapd
systemctl stop snapd

# Permit root login
sed -i -e 's/PermitRootLogin no/PermitRootLogin without-password/' /etc/ssh/sshd_config
systemctl reload ssh
cat << EOF > /root/.ssh/authorized_keys
sk-ecdsa-sha2-nistp256@openssh.com AAAAInNrLWVjZHNhLXNoYTItbmlzdHAyNTZAb3BlbnNzaC5jb20AAAAIbmlzdHAyNTYAAABBBD4/e9SWYWYoNZMkkF+NirhbmHuUgjoCap42kAq0pLIXFwIqgVTCre03VPoChIwBClc8RspLKqr5W3j0fG8QwnQAAAAEc3NoOg== lauri@lauri-x13
EOF
userdel -f ubuntu
apt-get remove -yq cloud-init

Install packages, for Raspbian set OS=Debian_11

OS=xUbuntu_20.04
VERSION=1.23
cat <<EOF | sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable.list
deb https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/ /
EOF
cat <<EOF | sudo tee /etc/apt/sources.list.d/devel:kubic:libcontainers:stable:cri-o:$VERSION.list
deb http://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable:/cri-o:/$VERSION/$OS/ /
EOF

curl -L https://download.opensuse.org/repositories/devel:/kubic:/libcontainers:/stable/$OS/Release.key | sudo apt-key --keyring /etc/apt/trusted.gpg.d/libcontainers.gpg add -
curl -L https://download.opensuse.org/repositories/devel:kubic:libcontainers:stable:cri-o:$VERSION/$OS/Release.key | sudo apt-key --keyring /etc/apt/trusted.gpg.d/libcontainers-cri-o.gpg add -
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" > /etc/apt/sources.list.d/kubernetes.list

apt-get update
apt-get install -yqq apt-transport-https curl cri-o cri-o-runc kubelet=1.23.5-00 kubectl=1.23.5-00 kubeadm=1.23.5-00
sudo systemctl daemon-reload
sudo systemctl enable crio --now
apt-mark hold kubelet kubeadm kubectl
sed -i -e 's/unqualified-search-registries = .*/unqualified-search-registries = ["docker.io"]/' /etc/containers/registries.conf

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).

After forming the cluster add taints:

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 $(seq 1 3); do
  kubectl taint nodes mon${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

On Raspberry Pi you need to take additonal steps:

• Manually enable cgroups by appending cgroup_memory=1 cgroup_enable=memory to /boot/cmdline.txt,
• Disable swap with swapoff -a; apt-get purge -y dphys-swapfile
• For mounting Longhorn volumes on Rasbian install open-iscsi

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

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