After to to learn K8s basic theory, its time to apply the knowledge on practice! Let's install K3s inside my little home lab with Proxmox.

Requirements:

• 3 VMs with Ubuntu 22.04 LTS
• kubectl

The VMs were created from a template with Ubuntu 22.04 and cloud-init

For these example I used 1 node master and 2 nodes workers

1. K3s-master - IP 192.168.52.229
2. k3s-worker1 - IP 192.168.52.228
3. k3s-worker2 - IP 192.168.52.227

We need to change the IP from dynamic to static.

##Example

# This file is generated from information provided by the datasource.  Changes
# to it will not persist across an instance reboot.  To disable cloud-init's
# network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    version: 2
    renderer: networkd
    ethernets:
        eth0:
            addresses:
                - 192.168.52.228/24
            nameservers:
                addresses: [8.8.8.8, 8.8.4.4, 192.168.52.1]
            routes:
                - to: default
                  via: 192.168.52.1

Add the hostname of the VMS in the hosts file of each other.

echo -e "192.168.52.229 K3s-master" | sudo tee -a /etc/hosts
echo -e "192.168.52.228 K3s-worker1" | sudo tee -a /etc/hosts
echo -e "192.168.52.227 K3s-worker2" | sudo tee -a /etc/hosts

#master node
sudo hostnamectl set-hostname K3s-master

#worker node
sudo hostnamectl set-hostname k3s-worker1
sudo hostnamectl set-hostname k3s-worker2

Install K3s

Master node

Inside the Master node, we need to disable the load balancer for default (kippler-db), because for this lab we're going to install MetaLB as a LoadBalancer.

Also we must disable Traefik for use Nginx Ingress Controller as ingress service instead of Traefik.

curl -sfL https://get.k3s.io | INSTALL_K3S_EXEC="server --disable traefik --disable servicelb" sh -

Once the K3s installation is completed in master node, we need to obtain the token for install the worker nodes.

sudo cat /var/lib/rancher/k3s/server/node-token

Worker Node

With the token obtained from the "node-token" file, we must run the next command to add the worker nodes.

curl -sfL https://get.k3s.io | K3S_URL=https://ip_master_node:6443 K3S_TOKEN=<node-token> sh -

Connect your cluster remotely

Copy the k3s.yaml file content

#path k3s file
/etc/rancher/k3s/k3s.yaml

Create a config file on your local machine and copy the k3s file content inside.

touch $HOME/.kube/config

Open your config file and change the address IP from 127.0.0.1 to <your_server_ip>:6443

apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: <Secret>
    server: https://<your_server_ip>:6443
  name: default

Now you can use kubectl

$ kubectl get nodes
NAME          STATUS   ROLES                  AGE    VERSION
k3s-worker2   Ready    <none>                 178d   v1.27.4+k3s1
k3s-worker1   Ready    <none>                 178d   v1.27.4+k3s1
k3s-master    Ready    control-plane,master   178d   v1.27.4+k3s1

Install MetalLB

When we work with K8s implementations on the cloud (AWS EKS, Azure EKS or Google GKE) we can create in native form a Service type "Load Balancer", but in baremetal cluster plataforms we need to deploy this kind of service.
For this homelab we're going to deploy MetalLB as a LoadBalancer.

Requirements:

• A K8s Cluster
• Some IPV4 IP reserved for MetalLB
• Helm
• Kubectl

#1 - Add MetalLB respository to Helm
helm repo add metallb https://metallb.github.io/metallb

#2 - Update Helm repo
helm repo update

#3 - Create a MetalLB namespace
kubectl create namespace metallb

#4 - Install metalLB
helm install metallb metallb/metallb --namespace metallb

#5 - Confirm that the deploy was successful
kubectl -n metallb get pod

Configure the reserved an IP address pool with the Layer2 metod. I have a Mikrotik router where I reserve the ip range 192.168.52.30 - 192.168.52.80

# Metallb address pool
apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  name: cluster-pool
  namespace: metallb
spec:
  addresses:
  - 192.168.52.30-192.168.52.80

---
# L2 configuration
apiVersion: metallb.io/v1beta1
kind: L2Advertisement
metadata:
  name: metallb-homelab
  namespace: metallb
spec:
  ipAddressPools:
  - cluster-pool

Load Balancer test

To test te correct operation of the load balancer we are going to deploy Nginx

#Create deploy
kubectl create deploy nginx --image=nginx

#Expose the deploy as a LoadBalancer type
kubectl expose deploy nginx --port=80 --target-port=80 --type=LoadBalancer

#Verify
kubectl get svc nginx
NAME    TYPE           CLUSTER-IP     EXTERNAL-IP     PORT(S)        AGE
nginx   LoadBalancer   10.43.60.115   192.168.52.30   80:32676/TCP   5h19m

Using the curl command we can see the successful response

$ curl 192.168.52.30:80
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

This was a minimal guide about how to deploy a baremetal K8s cluster, on the next post we're going to install Nginx Ingress Controller to expose the services outside our network.

Hace unas semanas atrás rendí la primer Certificación de Azure AZ-900 Fundamentals. Me llevo aproximadamente 3 meses prepararme, el examen fue a través de Certiprof y es todo teoría, nada de ejercicios y abarca muchos servicios de Azure Cloud y aspectos fundamentales sobre cloud en general.

El examen podes rendirlo en inglés o español. Yo lo rendí en español por que me sentia mas comodo. Si o si es requisito contar con una Laptop con Windows o Mac OS, te instalan un agente que te toma la laptop para que solo puedas rendir el examen y no poder acceder a ningún otro recurso. https://certiport.pearsonvue.com/Support/Technical-requirements

Lo que tenemos que aprender para aprobar el examen:

• Entre 15 y 25% Conceptos de la Nube
• Entre 30 y 35% Servicios Principales (Core) de Azure
• Entre 25 y 30% Seguridad, Privacidad, Normatividad y Confianza
• Entre 20 y 25% Costos y Soporte

Se aprueba con 700 puntos de 1000 y el examen tiene entre 40 y 60 preguntas, el tipo de pregunta es multiple choice, múltiples respuestas y arrastrar (drag and drop).

Una vez que aprobas la certificacion es valida por 2 años.

Para prepararme empecé con la guia oficial de Microsoft Learn, son 3 rutas de aprendizaje.

• Descripción de los conceptos de la nube (3 módulos)
• Descripción de la arquitectura y los servicios de Azure(4 módulos)
• Descripción de la administración y la gobernanza de Azure(4 módulos)

Examen AZ-900: Microsoft Azure Fundamentals - Certifications

Examen AZ-900: Microsoft Azure Fundamentals

Microsoft Learnbipach

Recomiendo también los siguientes videos para afianzar conocimientos:

Es un video de 3 horas de freeCodeCamp que abarca todo lo requerido para afianzar conocimientos una vez que terminamos los módulos de Microsoft Learn

También está el curso de certificación Azure AZ-900 de John Savill's en Youtube, es muy intuitivo y también muy recomendado si queres afianzar conocimientos.

Después de esto tenes algunas paginas en donde podes realizar test para ver las preguntas a las que te vas a enfrentar:

La  evaluación de practica de Microsoft la podes realizar las veces que quieras:

Evaluación de práctica

Evaluación de práctica

Microsoft Learnbipach

En examtopics con preguntas para repasar:

Microsoft AZ-900 Certification with Actual Free Questions | ExamTopics

Conquer certification from Microsoft Microsoft Azure Fundamentals. ExamTopics offers free and accurate questions.

ExamTopics Logo

Con estos recursos creo que es más que suficiente para animarte a rendir.

This is Chicho's SysAdmin and DevOps Blog, a brand new site that's just getting started. Things will be up and running here shortly. I'm going to talk about Linux, devops and video games, enjoy it!!