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.

---

Absolutely! Here are additional **CLI learning tips** to enhance your mastery of Linux and shell scripting. These tips are designed to help you deepen your understanding of the command line, make your work more efficient, and improve your problem-solving skills.

---

### **1. Master Command-Line Navigation**

- **Tip**: Practice basic navigation commands until they become second nature:
  - `cd`: Change directory.
  - `ls`: List directory contents.
  - `pwd`: Print current working directory.
  - `mkdir`/`rmdir`: Create and remove directories.
  
- **Try this**:
  - Create a directory structure, navigate through it, and practice moving and renaming files:
    ```bash
    mkdir -p ~/projects/k3s/python
    cd ~/projects/k3s
    mv python/ ~/projects/
    ```

### **2. Command History and Shortcuts**

- **Tip**: Use the **command history** to save time when repeating or modifying commands.
  - Use the `up` and `down` arrow keys to scroll through previously executed commands.
  - Use `!!` to re-run the last command or `!<number>` to run a specific command from history.
  - `Ctrl + r`: Search through command history interactively.

- **Try this**:
  - Run multiple commands and practice recalling them using `history` and `!<number>`.
    ```bash
    history
    !45  # Re-run command number 45
    ```

### **3. Tab Completion and Wildcards**

- **Tip**: Use **tab completion** to autocomplete file names, paths, and commands, which will make you faster and reduce errors.

- **Wildcards**: Use wildcards like `*` and `?` to work with multiple files or patterns:
  - `*.txt`: Match all files with `.txt` extension.
  - `file?.txt`: Match files with one-character differences (e.g., `file1.txt`, `file2.txt`).

- **Try this**:
  - Practice file matching and renaming using wildcards:
    ```bash
    mv *.log ~/logs/  # Move all .log files to logs directory
    ```

### **4. Learn to Use `man` and `help`**

- **Tip**: Whenever you’re unsure how a command works, use `man` (manual pages) or `--help`:
  - `man ls`: Get the manual for the `ls` command.
  - `ls --help`: Get a quick overview of the command options.

- **Try this**:
  - Explore the options of a new command you haven’t used before, like `find` or `tar`:
    ```bash
    man find
    ```

### **5. Chain Commands with Pipes and Redirection**

- **Tip**: Learn how to **chain commands** together to process data more effectively:
  - Use `|` (pipe) to send the output of one command as input to another.
    ```bash
    ps aux | grep python
    ```
  - Use `>` to redirect output to a file, and `>>` to append.
    ```bash
    df -h > disk-usage.txt  # Save disk usage output to a file
    ```

- **Try this**:
  - Combine pipes and redirection to filter and store information:
    ```bash
    ps aux | grep k3s > k3s-processes.txt
    ```

### **6. Automate Tasks with Aliases**

- **Tip**: Define **aliases** for frequently used commands to save time.
  - Open `~/.bashrc` and add your aliases:
    ```bash
    alias ll='ls -lah'
    alias upd='sudo dnf update -y && sudo dnf upgrade -y'
    ```
  - Reload the `.bashrc`:
    ```bash
    source ~/.bashrc
    ```

- **Try this**:
  - Define your own alias for frequently run commands or scripts, like K3s or Python management tasks.

### **7. Learn to Use `grep`, `awk`, and `sed`**

- **Tip**: Master text processing tools like `grep`, `awk`, and `sed` for searching and manipulating text output:
  - `grep`: Search for patterns in files or output.
    ```bash
    grep "error" /var/log/syslog
    ```
  - `awk`: Process and extract fields from structured data.
    ```bash
    awk '{print $1, $5}' /path/to/file
    ```
  - `sed`: Stream editor for text substitution.
    ```bash
    sed 's/error/success/g' file.txt  # Replace 'error' with 'success' in the file
    ```

- **Try this**:
  - Extract useful information from logs or system commands using `grep`:
    ```bash
    ps aux | grep k3s
    ```

### **8. Create More Complex Bash Scripts**

- **Tip**: Start combining loops, conditionals, and functions in your scripts to automate more complex tasks:
  - **For loops**: Iterate over a list of items.
    ```bash
    for file in *.txt; do
      echo "Processing $file"
    done
    ```
  - **If statements**: Add conditional logic.
    ```bash
    if [ -f /path/to/file ]; then
      echo "File exists"
    else
      echo "File not found"
    fi
    ```

- **Try this**:
  - Create a script that checks if a service is running and restarts it if necessary:
    ```bash
    #!/bin/bash
    if systemctl is-active --quiet k3s; then
      echo "K3s is running"
    else
      echo "K3s is not running, restarting..."
      sudo systemctl restart k3s
    fi
    ```

### **9. Explore `tmux` or `screen` for Multitasking**

- **Tip**: Use `tmux` or `screen` to manage multiple CLI sessions within a single terminal. This is especially useful when running long tasks or managing multiple remote connections.

- **Try this**:
  - Install and use `tmux`:
    ```bash
    sudo dnf install tmux
    tmux
    ```
  - Split the screen and run different tasks in separate panes.

### **10. Learn Networking Commands**

- **Tip**: Gain familiarity with networking-related commands to troubleshoot connectivity:
  - `ping`: Check connectivity to another host.
    ```bash
    ping 8.8.8.8
    ```
  - `traceroute`: See the path packets take to a destination.
    ```bash
    traceroute google.com
    ```
  - `netstat`: Check open network connections.
    ```bash
    netstat -tuln
    ```

- **Try this**:
  - Run `netstat` or `ss` to inspect which ports are open and which services are listening:
    ```bash
    netstat -tuln
    ```

### **11. Practice Permissions and Ownership**

- **Tip**: Understanding file permissions is critical for securing your system. Learn the basics of `chmod`, `chown`, and `chgrp`.
  - `chmod`: Change file permissions.
    ```bash
    chmod 755 script.sh
    ```
  - `chown`: Change file ownership.
    ```bash
    chown user:group file.txt
    ```

- **Try this**:
  - Modify file permissions on a script to make it executable only by you:
    ```bash
    chmod 700 myscript.sh
    ```

### **12. Learn Job Control: Background Jobs and Process Management**

- **Tip**: Use job control features to manage processes in the foreground and background:
  - Run a command in the background by appending `&`:
    ```bash
    long_process &  # Runs long_process in the background
    ```
  - Use `jobs` to list background jobs and `fg` to bring one to the foreground:
    ```bash
    jobs
    fg %1  # Bring job 1 to foreground
    ```

- **Try this**:
  - Start a long-running command in the background and monitor it using `jobs`.

---

### **Conclusion**

By incorporating these CLI learning tips, you’ll not only increase your proficiency with Linux commands but also develop more robust skills in automation, scripting, and problem-solving. As you continue setting up and managing your system, these techniques will help you work more efficiently and tackle increasingly complex tasks with confidence.

Make sure to practice these techniques daily and gradually incorporate them into your workflows. The more you explore the Linux command line, the more intuitive it will become.

---

# 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