Day1

2026/day-01/learning-plan.md

@@ -0,0 +1,20 @@
+Current level: working professional with 10 years of exp
+3 clear goals for the next 90 days: learn, code and deploy
+3 core DevOps skills you want to build: Linux troubleshooting, CI/CD pipelines, Kubernetes debugging, Terraform implementation
+Allocate a weekly time budget: 3 hours per day on weekdays, almost 6 hours weekends
+
+What is your understanding of DevOps and Cloud Engineering?
+Ans: Devops is not tools it is a culture, which follow collaboration, automation and continuous processes.
+This culture defines continuous Integration, continuous delivery and continuous deployment.
+It means Code-->Build-->Test-->Release-->Deploy.
+And, in todays world every second company is following this culture.
+While, Cloud Engineering involves in designing, deploying and managing app on the cloud platform.
+
+Why you are starting learning DevOps & Cloud?
+Ans: To upskill and upgrade with the latest features which are getting adapted in the market.
+
+Where do you want to reach?
+Ans: I want to reach a stable position with good skills in DevOps and Cloud, along with financial stability and a responsible role.
+
+How you will stay consistent every single day?
+Ans:I will stay consistent by following a daily routine with adding devops, setting small goals, and staying disciplined every day.

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

@@ -0,0 +1,75 @@
+The core components of Linux (kernel, user space, init/systemd)
+  Ans: Kernel: It is the heart of the linux OS which is used to interact with hardware(CPU, Memory, devices).
+       user space: The space where user application and program works or run.
+       systemd: It is the very 1st process which starts once the linux boots, PID-1 or init process. It means system is the         process which is running in the background which is known as d
+
+How processes are created and managed?
+  Ans: 
+
+What systemd does and why it matters?
+  Ans: It is the first process started by the kernel (PID 1).
+  Responsibilities:
+    1. Bootstraps the system (starts services during boot)
+    2. Manages background services (daemons)
+    3. Handles logging, networking, and device management
+  Replaces older init systems like SysVinit.
+  Uses unit files to define and control services.
+
+useful folders
+/ - top most directory, base of the entire file system, every thing starts here
+/home - Contains user directories, Each user has their own folder - user
+/bin - Contains essential user commands (binaries) - basic commands
+/sbin - Contains system/admin commands - system commands
+/etc - Contains configuration files - configs
+/mnt - Used to temporarily mount filesystems
+/tmp - Used for temporary files - temporary 
+/usr - Contains user programs and utilities - applications
+/var - Variable data (changes frequently) - logs data
+/root - Home directory of root user
+/dev - Contains device files
+/proc - Shows process and system info (virtual filesystem)
+/boot - Contains bootloader & kernel files
+/lib - System libraries required by /bin and /sbin
+
+Various commands:
+1.echo - to print the output
+2.pwd - to check the current directory path
+3.cd - to get into the folder or directory
+4.cat - to check the content of the file
+5.ls - to list all the files and folder available(if used with -lrth for long list with reverse with sort and in human         readable)
+6.df -h - to check for the disk space usage in human readable form for entire filesystem
+7.du -sh - to check the disk space usage for particular folder or directory
+8.mkdir - to create the new folder or directory(if used with -p then it will check for the folder present and if not present then it    will create the folder)
+9.free -m - to check the memory utilization and free space
+10.vi/vim/nano - to write in to the file, it is an editor(i - to insret, :wq - to quit)
+11.grep - to search for the pattern or text inside the file
+12.top/htop - to monitor system process and resouce usage in realtime
+13.ps -ef - to display info about the current running process(e- show all processes on the system, f- detailed form)
+14.rm -rf - delete the file or folder in particular directory(r - recersively, f- forcefully, note donot use rm -rf / or rm -rf *)
+15.touch - to create an empty file
+16.head - to display from the start of the file for first 10 line(-n 2 to view the first 2 row)
+17.tail - to display from the end of the file for last 10 lines(-n 2 to view the last 2 rows)
+18.clear - to clear the terminal screen
+19.apt-get install - Install new package
+20.apt-get update - Update existing packages (safe)
+21.apt-get upgrade - Update + remove/replace obsolete packages
+22.ip -a - to check and manage n/w config(-a - show all n/w interface)
+23.telnet - to connect to a remote system or port
+24.ping - to check network connection b/w 2 system( -t - how many hops a packet can travel)
+25.dig - to Advanced details for DNS queries
+26.netstat -tunlp - Shows network connections and listening ports(-t → TCP, -u → UDP, -n → Numeric (no DNS lookup), -l → Listening       ports, -p → Process ID/program name)
+27.ss -tunlp - ss is preferred in newer systems, Shows network connections and listening ports(-t → TCP, -u → UDP, -n → Numeric (no       DNS lookup), -l → Listening ports, -p → Process ID/program name)
+28.nslookup - to Queries DNS to find IP address from domain
+29.curl - to transfer data / test web endpoints
+30.wget - to download files from internet
+31.hostname - to show or set system name
+32.uname -r - to check the kernel version
+33.kill - to kill the process(-9 - forcefully)
+34.nohup - to run the script in background
+35.wc -l - to have no. of lines in the file as count
+36.& - to run command in background
+37.| - to combine multiple commands
+38.&& - it is in operator
+
+Task:
+  create folder - mkdir -p yogesh; goto the folder - cd yogesh; create the file - touch yogesh.txt; write into the file - echo "hello   dosto!" > yogesh.txt; view the content in the file - cat yogesh.txt; edit the file - vim yogesh.txt; show again content of            yogesh.txt - cat yogesh.txt; to check first 10 rows then - head yogesh.txt; to check last 10 rows then - tail yogesh.txt

2026/day-03/linux-commands-cheatsheet

@@ -0,0 +1,49 @@
+Fav command: history, top, df -h, free -m, telnet, ps -auf
+
+File system:
+
+ls - to list all the files and folder available(if used with -lrth for long list with reverse with sort and in human readable)
+df -h - to check for the disk space usage in human readable form for entire filesystem
+du -sh - to check the disk space usage for particular folder or directory
+mkdir - to create the new folder or directory(if used with -p then it will check for the folder present and if not present then it    will create the folder)
+free -m - to check the memory utilization and free space
+ps -ef --sort=%mem%
+pwd - to check the path of current directory you are in
+cd - to change the directory
+touch - to create empty file
+cp - to copy from one folder to another folder
+mv - to move from one folder to another folder
+rm - to remove the file and directory
+cat - to view the file content
+less - to view the content via scrollable view
+tail - to view last 10 lines of the file
+head - to view 1st 10 lines of the file
+tar - to zip the file or directory
+ln - for hardlink, ln -s - for softlink
+
+Process management:
+
+top/htop - to monitor system process and resouce usage in realtime
+ps -ef - to display info about the current running process(e- show all processes on the system, f- detailed form)
+vmstat
+iostat
+bg %1 - send to background
+fg %1 - bring job to foreground
+pgrep - to search process by name
+nice -n - to start the process with priority
+renice -n - to change priority of running process
+systemctl restart/stop/start/status - to check statu/stop/start/restart the process
+uname -r - to check the kernel version
+
+Networking troubleshooting:
+
+ip -a - to check and manage n/w config(-a - show all n/w interface)
+telnet - to connect to a remote system or port
+ping - to check network connection b/w 2 system( -t - how many hops a packet can travel)
+dig - to Advanced details for DNS queries
+netstat -tunlp - Shows network connections and listening ports(-t → TCP, -u → UDP, -n → Numeric (no DNS lookup), -l → Listening       ports, -p → Process ID/program name)
+ss -tunlp - ss is preferred in newer systems, Shows network connections and listening ports(-t → TCP, -u → UDP, -n → Numeric (no       DNS lookup), -l → Listening ports, -p → Process ID/program name)
+nslookup - to Queries DNS to find IP address from domain
+curl - to transfer data / test web endpoints
+wget - to download files from internet
+hostname - to show or set system name

2026/day-04/linux-practice

@@ -0,0 +1,19 @@
+Check running processes
+Output:
+sandbox@playground:~$ ps -aux
+USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
+sandbox        1  0.1  0.0   4628  3708 pts/0    Ss+  15:36   0:00 /bin/bash
+sandbox       13  0.0  0.0   4628  3764 pts/1    Ss   15:36   0:00 /bin/bash
+sandbox       25  0.0  0.0   7064  1564 pts/1    R+   15:36   0:00 ps -aux
+sandbox@playground:~$ 
+
+Inspect one systemd service
+
+Capture a small troubleshooting flow
+
+
+Run and record output for at least 6 commands
+Include 2 process commands (ps, top, pgrep, etc.)
+Include 2 service commands (systemctl status, systemctl list-units, etc.)
+Include 2 log commands (journalctl -u <service>, tail -n 50, etc.)
+Pick one service on your system (example: ssh, cron, docker) and inspect it

2026/day-05/linux-troubleshooting-runbook

@@ -0,0 +1 @@
+