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Cheulong Sear
Cheulong Sear

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Expose the Kubernetes Load Balancer on Bare Metal using MetalLB

#homelab #kubernetes #devops #metallb

This article will show you how to install MetalLB in K8s and expose a load balancer in your network.
Please refer to the official doc for more detail.

Preparation

If you’re using kube-proxy in IPVS mode, since Kubernetes v1.14.2 you have to enable strict ARP mode.
run

kubectl get configmap kube-proxy -n kube-system -o yaml | \
sed -e "s/strictARP: false/strictARP: true/" | \
kubectl diff -f - -n kube-system
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if you see something like this

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then run

kubectl get configmap kube-proxy -n kube-system -o yaml | \
sed -e "s/strictARP: false/strictARP: true/" | \
kubectl apply -f - -n kube-system
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Installation with Helm 

helm repo add metallb https://metallb.github.io/metallb
helm install metallb metallb/metallb --create-namespace -n metallb-system
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L2 configuration

create metallb-config.yaml

apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  name: default-ip-pool
  namespace: metallb-system
spec:
  addresses:
  - 192.168.186.241-192.168.186.250
---
apiVersion: metallb.io/v1beta1
kind: L2Advertisement
metadata:
  name: default
  namespace: metallb-system
spec:
  ipAddressPools:
  - default-ip-pool
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run kubectl apply -f metallb-config.yaml
Note: ip range need to be inside 192.168.186.0/24 range

Check if it works

kubectl get ipaddresspools -n metallb-system
kubectl get l2advertisement -n metallb-system

Deploy nginx

run kubectl create deploy nginx --image nginx:latest

Expose nginx

using load balancer

run kubectl expose deploy nginx --port 80 --type LoadBalancer

cheulong-sear@cheulong-linux:~$ k get svc
NAME         TYPE           CLUSTER-IP      EXTERNAL-IP       PORT(S)        AGE
kubernetes   ClusterIP      10.96.0.1       <none>            443/TCP        16d
nginx        LoadBalancer   10.106.24.222   192.168.186.242   80:32454/TCP   69s
test-nginx   NodePort       10.99.173.211   <none>            80:32544/TCP   16d
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go to 192.168.186.242

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using Ingress Nginx

Install ingress nginx using helm

helm upgrade --install ingress-nginx ingress-nginx \
  --repo https://kubernetes.github.io/ingress-nginx \
  --namespace ingress-nginx --create-namespace
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Expose ClusterIp Service

run kubectl expose deploy nginx --port 80

create manifest to route to nginx service 

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: nginx-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx
  rules:
  - http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: nginx
            port:
              number: 8080
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kubectl apply ingress.yaml

kubectl -n ingress-nginx get svc ingress-nginx-controller

NAME                       TYPE           CLUSTER-IP    EXTERNAL-IP       PORT(S)                      AGE
ingress-nginx-controller   LoadBalancer   10.97.61.44   192.168.186.241   80:31540/TCP,443:32342/TCP   16m
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go to 192.168.186.242

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=== Done ===

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Leave a comment if you have any questions.

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