Mukulwarude changes

2026/day-01/my-plan.md

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+**My 90 days DevOps and cloud learning plan **
+
+- **Current level:**
+  - I understand the basic the basic idea of DevOps (collaboration b/w devs and ops, automations, and I know that as DevOps it is my job to bring efficiency.
+
+- **My understanding:**
+  - As I attend TWS today's live session "DevOps is a mindset and a set of practices that focus on automations, reliability, and time efficiency in software delivery.
+
+- **Why I am learning DevOps:**
+  - So heres why I choose DevOps as the skill path the reason is when I got my first internship as web developer in 2023 I got interacted with the IT culturethen it won't take me so long to identify the most interesting and dependable jod in        the whole office which is DevOps but life has its own way to treat your ambition and then as I was familier with IT culture I gave interview for a QA role and get selected I work one whole year at this position and by doing this job it          brings me more closerto DevOps practices, then in 2025 August I started watching TWS one shot videos and finally when I have have a budget I immediately brought this amazing course.
+  - the simple reason why I choose DevOps as career path is, it was the only thing which excite me the most at very first time (and I am a huge beliver in love at first sight). I want to be the engineer who keeps system running, scalable, and       sane.
+
+- **Where I want to reach in 90 days:**
+  - By the end of the 90 days, I want to move from theory to hands-on confidence.
+  - **MY 3 clear goals:**
+    - Start earning in huge amount.
+    - Travel around the world by achiving the peak on remote role.
+    - Get settle in Singapore/Europe/Japan with my family and give a high level education to my lil bro and excelent environment to my Mom & Dad.
+
+- **Time Comitment and consistency plan:**
+  - Week Days: 1.5 - 2 hours.
+  - Weekends: 5 - 6 hours.
+  - Total: 16 - 18 hours a week.
+- **How I will stay consistent:**
+  - By maintaining the discipline rather than just being motivated.
+  - Be patient while learning.
+  - And as I said DevOps makes me excited I will never get bored.
+  - Focus hands-on practice, not just watch videos.
+
+- **Final Comitment:**
+  - This 90 days plan is not abou t perfection.
+  - It is about showing-up daily, and building fundamentals the right way.
+  - System over shortcuts.

2026/day-02/linux-architecture-notes.md

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+**Linux Architecture – Core Understanding for DevOps**
+
+Linux is not a tool you memorize.
+It is a system you learn to reason about under pressure.
+
+1. Big Picture: How Linux Actually Works
+
+Think of Linux as three layers, not one OS blob:
+
+[ User Applications ]
+        ↓
+[ User Space (Shell, Services, Tools) ]
+        ↓
+[ Kernel ]
+        ↓
+[ Hardware ]
+
+
+Rule of Linux:
+👉 Nothing touches hardware except the kernel
+
+Everything else negotiates.
+
+2. The Linux Kernel (The Authority)
+
+The kernel is responsible for control and fairness.
+
+What the Kernel Manages
+
+Process scheduling (who gets CPU, when)
+
+Memory management (RAM, swap)
+
+File systems (read/write permissions, caching)
+
+Networking (packets, ports, sockets)
+
+Device drivers (disk, NIC, keyboard)
+
+Key Insight
+
+User programs ask the kernel to do things using system calls.
+If the kernel says no, the program cannot proceed.
+
+This is why permissions, limits, and failures exist.
+
+3. User Space (Where You Live)
+
+User space contains:
+
+Shells (bash, zsh)
+
+Core utilities (ls, ps, grep)
+
+Services (nginx, docker)
+
+Your applications
+
+Why User Space Is Safe
+
+Crashes don’t kill the system
+
+Permissions are enforced
+
+Isolation enables multi-user systems
+
+If a service crashes, Linux survives. That’s not accidental. That’s design.
+
+4. systemd and init (The First Breath)
+What Happens at Boot
+
+Kernel loads into memory
+
+Kernel starts PID 1
+
+PID 1 = systemd
+
+systemd starts everything else
+
+Why systemd Matters
+
+Service lifecycle management
+
+Automatic restarts
+
+Dependency control
+
+Centralized logging
+
+If systemd dies, the system dies.
+That’s why PID 1 is sacred.
+
+5. Process Creation (How Programs Come Alive)
+Process Birth
+
+fork() → parent process duplicates itself
+
+exec() → child loads a new program
+
+Kernel assigns a PID
+
+Every process:
+
+Has a parent
+
+Consumes memory
+
+Competes for CPU
+
+Nothing is free.
+
+6. Process States (You Must Recognize These)
+State	Meaning
+R	Running on CPU
+S	Sleeping (waiting for event)
+D	Uninterruptible sleep (I/O wait)
+T	Stopped
+Z	Zombie (dead, not cleaned up)
+DevOps Insight
+
+Many D processes → disk or network issue
+
+Many Z processes → bad parent process
+
+High R → CPU saturation
+
+This is how incidents start.
+
+7. systemd in Practice (Real Control)
+Core Actions
+systemctl status nginx
+systemctl start nginx
+systemctl stop nginx
+systemctl restart nginx
+systemctl enable nginx
+
+
+systemd ensures:
+
+Services start after reboot
+
+Failed services restart
+
+Logs are traceable
+
+8. Logs: Where Truth Lives
+systemd Logging
+journalctl
+journalctl -u nginx
+journalctl -xe
+
+
+Logs explain why, not just what failed.
+
+No logs = blind debugging.
+
+9. 5 Commands Used Every Day
+Command	Why It Matters
+ps aux	See all processes
+top / htop	Resource monitoring
+systemctl	Service control
+journalctl	Logs
+kill	Stop broken processes
+
+These are not optional skills.
+
+10. Interactive Checks (Do These)
+
+Try this on your system:
+
+ps -p 1
+
+
+→ Confirm systemd is PID 1
+
+systemctl list-units --type=service
+
+
+→ See active services
+
+top
+
+
+→ Observe CPU ownership
+
+journalctl -b
+
+
+→ Read boot logs
+
+11. Why This Matters for DevOps
+
+Every DevOps failure eventually becomes:
+
+A stuck process
+
+A failed service
+
+A resource bottleneck
+
+A mismanaged restart
+
+Linux knowledge lets you:
+
+Diagnose instead of guessing
+
+Act instead of panic
+
+Fix instead of rebooting blindly
+
+This is the difference between an operator and an engineer.
+
+Final Mental Model
+
+Kernel = judge
+
+systemd = conductor
+
+Processes = workers
+
+Logs = history
+
+You = debugger
+
+Master this, and Docker, Kubernetes, and cloud systems stop being mysterious.
+
+Next logical continuation (no rush):
+
+Linux → Containers
+
+systemd → Kubernetes control loops
+
+Processes → Pods
+
+Same ideas. Bigger scale.