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How to re-generate K8s SSL Certificates on MicroK8s

Issue

You might encounter the following error when you the IP addresses is changed on the host machine:

Unable to connect to the server: x509: certificate is valid for <internal IPs>, not <external IP>

Solution

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Adding Users with Role Policy in Argo CD

Step 1: Login to Argo CD

You can log in to Argo CD or bash into the Argo CD pod running in Kubernetes:

argocd login <ARGOCD_SERVER> --username admin --password <ADMIN_PASSWORD>

Step 2: Create a User

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Fixing K8s Node UnHealthy after Re-boot Issue

Issue:

Nodes in the Kubernetes cluster may remain in an "Unhealthy" state on the control plane/master node after they are restarted. This problem occurs because the nf_conntrack module, which is essential for network connection tracking, is not automatically loaded on reboot.

Solution:

To ensure nodes reconnect properly after a restart, you need to make sure the nf_conntrack module is loaded at boot on all workers nodes thought this command;

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Fixing Network Driver Issues on Ubuntu 20.04

If you encounter missing network drivers when installing Ubuntu on new machines, you might notice that network cards are listed as (UNCLAIMED) when you execute the command:

lshw -c network

This indicates that your device requires Hardware Enablement (HWE).

About Hardware Enablement (HWE)

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Cert Manager Setup for MicroK8s (v1.20.2)

Install cert-manager

sudo microk8s kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.20.2/cert-manager.yaml
sudo microk8s kubectl wait --for=condition=available deployment/cert-manager -n cert-manager --timeout=120s

Verify installation

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Allow Root User Access via SSH

1. Reset Ubuntu Root Password

Ensure you set a strong password:

sudo passwd root

2. Install OpenSSH Server and Client

Update the system and install both SSH components:

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Install Docker on Linux (Ubuntu)

To install Docker run the command:

curl -sSL https://get.docker.com/ | sudo sh

Check version if working correctly:

docker --version

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Install Kubernetes Cluster using Microk8s on Linux

STEP 1 (Update and Upgrade the System)

sudo apt update
sudo apt upgrade

STEP 2 (Install MicroK8s)

sudo snap install microk8s --classic

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Install MSSQL Server 2019 On Linux (Ubuntu)

This script can be used to install Microsoft sql server 2019 on Ubuntu 20.04 versions

# Password for the SA user (required)
MSSQL_SA_PASSWORD='<ENTER SA PASSWORD HERE>'
# Product ID of the version of SQL server you're installing
# Must be evaluation, developer, express, web, standard, enterprise, or your 25 digit product key
# Defaults to developer