the_information_nexus/tech_docs/edge-compute-k3s.md

Great! I’ll review and streamline the suggestions to ensure they are **useful**, **actionable**, and **necessary**, focusing on practical learning while setting up your system. Here’s a clean, highly focused version to guide your journey into learning the Linux CLI, bash, and shell scripting as you set up Rocky Linux for K3s and Python-based workloads:

---

### **1. Update and Secure the System**

Start by ensuring your system is updated and secure. This is essential to establish a solid foundation.

#### **System Updates**
```bash
sudo dnf update -y && sudo dnf upgrade -y
sudo reboot
```
- **Purpose**: Keep the system updated with the latest security patches and improvements.

#### **SELinux Configuration**
```bash
sestatus  # Check SELinux status
```
- **If not in enforcing mode**, edit the config:
```bash
sudo nano /etc/selinux/config
```
- Set `SELINUX=enforcing`, save, and reboot.
- **Purpose**: Enforce security at the kernel level by keeping SELinux enabled.

---

### **2. Install Essential System Tools**

Install basic tools for system management and development.

#### **Install Development Tools and Utilities**
```bash
sudo dnf groupinstall "Development Tools" -y
sudo dnf install wget curl vim nano net-tools git unzip -y
```
- **Purpose**: Install necessary utilities and compilers to manage and build software.

#### **Firewall Configuration**
```bash
sudo firewall-cmd --permanent --add-port=6443/tcp  # K3s API server port
sudo firewall-cmd --permanent --add-port=10250/tcp # Kubelet port
sudo firewall-cmd --reload
```
- **Purpose**: Allow required ports for K3s operations and secure the system by controlling network access.

---

### **3. Install Python and Set Up a Virtual Environment**

#### **Install Python 3 and Development Tools**
```bash
sudo dnf install python3 python3-pip python3-devel -y
python3 --version
pip3 --version
```
- **Purpose**: Install Python 3 and ensure it's set up for development.

#### **Set Up a Python Virtual Environment**
```bash
python3 -m venv ~/myenv
source ~/myenv/bin/activate
```
- **Purpose**: Create and activate a virtual environment to manage Python packages independently.

---

### **4. Install and Configure K3s**

#### **Install K3s**
```bash
curl -sfL https://get.k3s.io | sh -
sudo systemctl status k3s  # Check K3s status
```
- **Purpose**: Install K3s and ensure the service is running.

#### **Configure K3s CLI**
```bash
sudo ln -s /usr/local/bin/kubectl /usr/bin/kubectl
kubectl get nodes  # Verify the node is running
```
- **Purpose**: Set up kubectl to interact with your K3s cluster.

---

### **5. Learn Bash Scripting through Automation**

Now that the basics are in place, you can learn shell scripting by automating common tasks. This reinforces your CLI skills while building useful scripts.

#### **Automate System Updates**
Create a script to automate updates and log the process.

- **Script**: `update-system.sh`
```bash
#!/bin/bash
LOGFILE=~/update-log.txt
echo "Updating system..." | tee -a $LOGFILE
sudo dnf update -y | tee -a $LOGFILE
sudo dnf upgrade -y | tee -a $LOGFILE
echo "System updated on $(date)" | tee -a $LOGFILE
```
- **Purpose**: Automate the update process and learn about logging and automation.

#### **Automate Python Environment Setup**
- **Script**: `setup-python-env.sh`
```bash
#!/bin/bash
ENV_NAME=$1

if [ -z "$ENV_NAME" ]; then
    echo "Usage: $0 <env_name>"
    exit 1
fi

echo "Creating Python virtual environment '$ENV_NAME'..."
python3 -m venv ~/$ENV_NAME

echo "Activating virtual environment..."
source ~/$ENV_NAME/bin/activate

echo "Virtual environment '$ENV_NAME' created and activated."
```
- **Purpose**: Create a flexible script to automate Python environment setup, using arguments and learning bash conditionals.

#### **Automate K3s Installation and Configuration**
- **Script**: `install-k3s.sh`
```bash
#!/bin/bash

echo "Installing K3s..."
curl -sfL https://get.k3s.io | sh -

if systemctl status k3s | grep "active (running)" > /dev/null; then
    echo "K3s is installed and running!"
else
    echo "K3s installation failed."
fi

echo "Configuring firewall..."
sudo firewall-cmd --permanent --add-port=6443/tcp
sudo firewall-cmd --permanent --add-port=10250/tcp
sudo firewall-cmd --reload

echo "K3s and firewall configured successfully."
```
- **Purpose**: Automate the installation and configuration of K3s while practicing bash scripting with conditionals.

---

### **6. Monitor the System**

Create a script to monitor your system’s health. This teaches system commands and formatting output.

- **Script**: `monitor-resources.sh`
```bash
#!/bin/bash
echo "System Resource Usage"
echo "---------------------"
echo "Disk Usage:"
df -h
echo "Memory Usage:"
free -m
echo "CPU Load:"
uptime
```
- **Purpose**: Gather and display system metrics to monitor performance.

---

### **7. Learn Automation through Cron Jobs**

Use cron to automate tasks like system backups or updates.

#### **Example**: Schedule a Daily Backup of K3s Data
- **Script**: `backup-k3s.sh`
```bash
#!/bin/bash
BACKUP_DIR="/var/lib/rancher/k3s/server/db/backups"
BACKUP_FILE="k3s-backup-$(date +%Y-%m-%d-%H-%M-%S).db"

echo "Backing up K3s data..."
sudo cp $BACKUP_DIR/snapshot.db /backups/$BACKUP_FILE
echo "Backup completed: /backups/$BACKUP_FILE"
```

- **Automate with Cron**:
```bash
crontab -e
```
- Add the following line for daily backups at 2 am:
```bash
0 2 * * * /path/to/backup-k3s.sh
```
- **Purpose**: Learn how to schedule recurring tasks with cron and automate backups.

---

### **8. Secure the K3s Environment**

Focus on basic security configurations and policies as you learn.

#### **Create a Pod Security Policy**
Write a basic Pod Security Policy (PSP) for K3s to enforce non-root container execution.

- **Example YAML**:
```yaml
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
  name: restricted-psp
spec:
  privileged: false
  runAsUser:
    rule: MustRunAsNonRoot
```
- **Purpose**: Practice creating Kubernetes manifests and learn how to secure your environment.

---

### **Final Thoughts and Next Steps**

This clean, focused approach not only sets up your Rocky Linux system for K3s and Python-based workloads but also helps you gain **hands-on experience** with the Linux CLI, bash scripting, and automation through real-world tasks.

**What’s next?**
- Continuously refine your scripts and make them more robust.
- As you gain comfort, start incorporating more advanced Linux features (e.g., process management, networking).
- Work towards automating the entire K3s environment, including monitoring, logging, and alerting.

---

You're absolutely right! Let’s include a few actionable examples to introduce more **advanced Linux features**, such as process management and networking, while keeping the learning process gradual and practical.

---

### **1. Process Management: Monitor and Control Running Processes**

Understanding how to manage processes is fundamental in Linux. Let’s create a couple of bash scripts that help you monitor and control processes on your system.

#### **Example: Monitor Active Processes**
- **Script**: `monitor-processes.sh`
  ```bash
  #!/bin/bash
  echo "Monitoring System Processes"
  echo "---------------------------"
  
  echo "Top 10 CPU-consuming processes:"
  ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%cpu | head -n 10
  
  echo
  echo "Top 10 Memory-consuming processes:"
  ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%mem | head -n 10
  ```
  - **Learning Outcomes**:
    - Use `ps` to view processes and understand the options for filtering and sorting by CPU or memory usage.
    - Practice managing processes by identifying high-resource users.

#### **Example: Kill a Process by Name**
- **Script**: `kill-process.sh`
  ```bash
  #!/bin/bash

  if [ -z "$1" ]; then
      echo "Usage: $0 <process_name>"
      exit 1
  fi

  PROCESS_NAME=$1
  echo "Attempting to kill process: $PROCESS_NAME"
  
  pkill $PROCESS_NAME && echo "Process '$PROCESS_NAME' terminated."
  ```
  - **Learning Outcomes**:
    - Use `pkill` to terminate a process by name.
    - Understand how to handle input arguments in bash scripts.

---

### **2. Advanced Networking: Network Configuration and Monitoring**

Networking is key for edge compute workloads. Let’s dive into monitoring your network connections and controlling traffic with basic networking scripts.

#### **Example: Monitor Network Usage**
- **Script**: `monitor-network.sh`
  ```bash
  #!/bin/bash
  echo "Network Usage Report"
  echo "--------------------"

  echo "Current network interfaces:"
  ip link show
  
  echo "Network traffic summary:"
  ifconfig | grep -A 8 "eth0"
  
  echo
  echo "Routing table:"
  netstat -rn
  ```
  - **Learning Outcomes**:
    - Learn to use `ifconfig` and `ip` for network interface status.
    - Display routing information using `netstat`.

#### **Example: Block/Unblock IP Address Using Iptables**
- **Script**: `block-ip.sh`
  ```bash
  #!/bin/bash

  if [ -z "$1" ]; then
      echo "Usage: $0 <ip_address>"
      exit 1
  fi

  IP_ADDRESS=$1
  echo "Blocking IP: $IP_ADDRESS"
  
  sudo iptables -A INPUT -s $IP_ADDRESS -j DROP
  echo "IP address $IP_ADDRESS has been blocked."
  ```

- **Unblock Script**: `unblock-ip.sh`
  ```bash
  #!/bin/bash

  if [ -z "$1" ]; then
      echo "Usage: $0 <ip_address>"
      exit 1
  fi

  IP_ADDRESS=$1
  echo "Unblocking IP: $IP_ADDRESS"
  
  sudo iptables -D INPUT -s $IP_ADDRESS -j DROP
  echo "IP address $IP_ADDRESS has been unblocked."
  ```

  - **Learning Outcomes**:
    - Use `iptables` to block and unblock network traffic from specific IP addresses.
    - Learn basic network security by controlling traffic at the firewall level.

---

### **3. Automate Network Health Checks**

Automate network status checks by writing a script to ping external servers and display results. This is useful to test the connectivity from your edge devices.

#### **Example: Ping Multiple Servers**
- **Script**: `network-health.sh`
  ```bash
  #!/bin/bash
  SERVERS=("8.8.8.8" "1.1.1.1" "google.com" "example.com")
  
  echo "Pinging Servers..."
  
  for SERVER in "${SERVERS[@]}"; do
      echo "Pinging $SERVER:"
      ping -c 4 $SERVER
      echo "------------------------------------"
  done
  ```
  - **Learning Outcomes**:
    - Use arrays in bash to handle multiple items (servers).
    - Learn about network connectivity testing using `ping`.

---

### **4. Advanced Disk Usage and Resource Monitoring**

As edge workloads may have limited resources, disk usage monitoring becomes crucial. Let’s script resource checks for disk space, memory, and CPU usage.

#### **Example: Monitor Disk Space and Report Critical Usage**
- **Script**: `disk-usage-report.sh`
  ```bash
  #!/bin/bash
  THRESHOLD=80

  echo "Checking Disk Usage..."
  df -h | awk 'NR>1 {print $5 " " $1}' | while read output; do
    usep=$(echo $output | awk '{print $1}' | sed 's/%//')
    partition=$(echo $output | awk '{print $2}')
    if [ $usep -ge $THRESHOLD ]; then
      echo "CRITICAL: $partition is $usep% full."
    fi
  done
  ```

  - **Learning Outcomes**:
    - Use `df` to check disk usage.
    - Apply basic conditional logic to report when usage crosses a defined threshold (80%).

---

### **5. Advanced Automation with Cron Jobs**

After you’re comfortable with your scripts, you can automate more advanced monitoring and reporting using cron.

#### **Example: Automate Disk Monitoring**
- **Automate Disk Usage Check**:
  ```bash
  crontab -e
  ```
- Add this cron job to run the disk usage check script every day at 6 am:
  ```bash
  0 6 * * * /path/to/disk-usage-report.sh
  ```

  - **Learning Outcomes**:
    - Learn how to use cron for recurring tasks.
    - Automate your monitoring and alerts, reducing manual checks.

---

### **Conclusion**

This approach adds **actionable examples** to help you dive deeper into advanced Linux features such as process management, networking, and resource monitoring, all while integrating them into your current workflow. These tweaks provide you with hands-on practice in managing and automating system processes, monitoring network activity, and ensuring system health—all key skills for managing K3s and edge compute workloads effectively.

---

# Learning Roadmap for K3s, Edge Computing, and Advanced Networking

## Networking Basics
- **TCP/IP**
  - Understanding IP addressing
  - Subnetting and Routing
- **DNS**
  - DNS Resolution Process
  - Configuring DNS Servers
- **HTTP/S**
  - HTTP Request/Response Cycle
  - SSL/TLS and Secure Communication
- **Network Protocols and Architecture**
  - OSI and TCP/IP Models
  - Common Network Protocols (DHCP, SSH, FTP)

## Kubernetes Core Concepts
- **Kubernetes Architecture**
  - Master and Node Components
  - Control Plane and Worker Nodes
- **Pods, Deployments, Services**
  - Lifecycle of a Pod
  - Creating and Managing Deployments
  - Service Types and Load Balancing
- **Persistent Storage and Networking**
  - Volumes and Persistent Volumes
  - Storage Classes and Dynamic Provisioning
  - Kubernetes Networking Model

## K3s Specific Learning
- **Installation and Configuration**
  - Setting Up a K3s Cluster
  - Configuring K3s on Different Environments
- **Cluster Management**
  - Node Management
  - Backup and Restore Strategies
- **Resource Optimization**
  - Resource Limits and Requests
  - Autoscaling in K3s

## Edge Computing and IoT with K3s
- **K3s in Edge Scenarios**
  - Deployment Strategies for Edge Computing
  - Managing Low-Resource Environments
- **Integrating IoT Devices with Kubernetes**
  - Connecting IoT Devices to K3s
  - Security Considerations in IoT and Kubernetes

## Advanced Kubernetes Networking
- **Deep Dive into CNI (Container Network Interface)**
  - Understanding CNI Plugins
  - Custom Network Solutions in Kubernetes
- **Network Policies**
  - Implementing Network Policies
  - Securing Pod-to-Pod Communication
- **Service Meshes (Istio, Linkerd)**
  - Introduction to Istio and Linkerd
  - Traffic Management and Observability

## Hands-On and Practical Implementation
- **Setting up K3s Clusters**
  - Creating High-Availability Clusters
  - Disaster Recovery and Failover
- **Real-World Projects and Scenarios**
  - Implementing a CI/CD Pipeline with K3s
  - Deploying a Multi-Service Application