Reading this article will guide us on how to setup basic steps to expose a Kubernetes service. Example: Accessing an Nginx web server from a Multipass Ubuntu VMs using Kubernetes deployment and service.
Things we need:
Deployment
Below is where we deploy a simply nginx web server with 1 replica that runs on port 8080
cat << EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
labels:
app: nginx
spec:
replicas: 1
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.15.4
ports:
- containerPort: 80
EOF
Install MetalLB
The the commands below to install MetalLB. This is required for us to expose our service (access the nginx web server on our machine / not just inside the VMs (using Multipass))
Source: https://makeoptim.com/en/service-mesh/kubeadm-kubernetes-istio-setup#metallb
kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.6/manifests/namespace.yaml
kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.6/manifests/metallb.yaml
# On first install only
kubectl create secret generic -n metallb-system memberlist --from-literal=secretkey="$(openssl rand -base64 128)"
Get the IP addresses of your worker nodes.
kubectl get nodes -o wideBelow we got the node1 and node two IP’s (doesn’t matter if they are internal)
Now we need to set an IP range for each node. Node1 is 172.29.94.50-172.29.94.254 and Node2 is 172.29.91.50-172.29.91.254
Which means that our service can generate an IP between 172.29.94.50-172.29.94.254 and is 172.29.91.50-172.29.91.254
kubectl apply -f - <<EOF
apiVersion: v1
kind: ConfigMap
metadata:
namespace: metallb-system
name: config
data:
config: |
address-pools:
- name: default
protocol: layer2
addresses:
- 172.29.94.50-172.29.94.254
- 172.29.91.50-172.29.91.254
EOF
You can also edit the MetalLB config by running:
kubectl edit configmap -n metallb-systemExpose the service!
The code below shows that we selected the deployment nginx , we set the type to LoadBalancer and we name the service my-service
kubectl expose deployment nginx --type=LoadBalancer --name=my-service
Check the demo
Remember we are using Multipass to create our VMs, right? The goal here is to access the service inside and outside our Multipass servers.
Inside multipass
root@k8s-master:~# curl 172.29.94.50 -n 10
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>Outside multipass (Windows command prompt)
Google Chrome from my Windows 10 Machine
