Add Kubernetes

Kubernetes.md

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+# Setting up K3S/K8S from scratch 
+
+[[TOC]]
+
+## Requirements
+### Control plane node:
+- 2 or more cores
+- 1GB of RAM
+- 16GB of disk space
+### Worker node:
+- 1 or more cores
+- 512MB of RAM
+- 16GB of disk space
+
+# Node installation
+## K3S control plane node
+You need atleast 3 of these, for a micro cluster of 2-3 nodes you can only have one if you wish so.
+Be sure to store your token in a safe place as you will need it to connect additional nodes in the future.
+First node:
+```
+curl -sfL https://get.k3s.io | K3S_TOKEN="<Rand0mlyG3n3rat3dT0ken>" sh -s - server --cluster-init --disable servicelb --disable traefik 
+```
+
+Other nodes:
+```
+curl -sfL https://get.k3s.io | K3S_TOKEN="<Rand0mlyG3n3rat3dT0ken>" sh -s - server --server https://<ipofthefirstnode>:6443  --disable servicelb --disable traefik 
+```
+
+## K3S worker node
+```
+curl -sfL https://get.k3s.io | K3S_TOKEN="<Rand0mlyG3n3rat3dT0ken>" sh -s - agent --server https://<ipofthemasternode>:6443 ---disable servicelb --disable traefik 
+```
+
+you can check the state of the cluster by SSHing to any of the master nodes and running
+```
+kubectl get node
+```
+or you can install https://k9scli.io for fancy terminal UI(highly recommendded)
+
+# Network configuration
+## Installing MetalLB
+MetalLB hooks into your Kubernetes cluster, and provides a network load-balancer implementation. In short, it allows you to expose services via IP address. 
+```
+kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.14.4/config/manifests/metallb-native.yaml
+```
+
+### MetalLB IP pool 
+Create a new yaml file with the following content and be sure to customize your ip range:
+```
+apiVersion: metallb.io/v1beta1
+kind: IPAddressPool
+metadata:
+  name: first-pool
+  namespace: metallb-system
+spec:
+  addresses:
+  - 192.168.1.240-192.168.1.250
+```
+
+save and apply the IPAddressPool config
+```
+kubectl apply -f file.yaml
+```
+
+### IP pool advertising
+Create a file:
+```
+apiVersion: metallb.io/v1beta1
+kind: L2Advertisement
+metadata:
+  name: example
+  namespace: metallb-system
+```
+
+save and apply the L2Advertisement config
+```
+kubectl apply -f file.yaml
+```
+
+
+# Ingress nginx
+
+Ingress Nginx is a special nginx container setup that allows you to expose HTTP(s) apps from your kubernetes to the outside world via MetalLB ip address
+First clone the ingress repo from git:
+```
+git clone https://github.com/nginxinc/kubernetes-ingress.git
+cd kubernetes-ingress
+```
+Then apply these files:
+```
+kubectl apply -f deployments/common/ns-and-sa.yaml
+kubectl apply -f deployments/rbac/rbac.yaml
+kubectl apply -f examples/shared-examples/default-server-secret/default-server-secret.yaml
+kubectl apply -f deployments/common/nginx-config.yaml
+kubectl apply -f deployments/common/ingress-class.yaml
+kubectl apply -f config/crd/bases/k8s.nginx.org_virtualservers.yaml
+kubectl apply -f config/crd/bases/k8s.nginx.org_virtualserverroutes.yaml
+kubectl apply -f config/crd/bases/k8s.nginx.org_transportservers.yaml
+kubectl apply -f config/crd/bases/k8s.nginx.org_policies.yaml
+kubectl apply -f config/crd/bases/k8s.nginx.org_globalconfigurations.yaml
+kubectl apply -f deployments/daemon-set/nginx-ingress.yaml
+kubectl apply -f deployments/service/loadbalancer.yaml
+```
+
+# Longhorn
+
+Longhorn is a system that manages permanent storage inside your kubernetes cluster.
+On each storage node in your cluster you must install:
+
+```
+apt-get install open-iscsi nfs-common
+``` 
+
+before installing Longhorn itself
+```
+kubectl apply -f https://raw.githubusercontent.com/longhorn/longhorn/v1.6.1/deploy/longhorn.yaml
+```
+
+To make longhorn UI available trough ingress, create a file:
+
+```
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: longhorn-ingress
+  namespace: longhorn-system
+spec:
+  rules:
+  - http:
+      paths:
+      - pathType: Prefix
+        path: "/"
+        backend:
+          service:
+            name: longhorn-frontend
+            port:
+              number: 80
+```
+
+then apply it:
+```
+kubectl apply -f file.yml
+```