🌩️ Azure Session 1 – Cloud Computing Basics

Cloud Computing Basics

Target Audience: Beginners, DevOps Engineers, Middleware Administrators, AZ-900 & AZ-104 aspirants.

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☁️ What is Cloud Computing?

Cloud Computing is the delivery of computing services such as servers, storage, databases, networking and software over the internet instead of using physical hardware in your own data center.

• No need to buy physical servers
• Resources can be created in minutes
• Scalable and flexible
• Pay only for what you use

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☁️ Cloud Service Models

• IaaS (Infrastructure as a Service): Virtual servers, storage and networks.
  Use: Full control over OS and applications (Azure Virtual Machines).
• PaaS (Platform as a Service): Platform and runtime without managing servers.
  Use: Fast application deployment (Azure App Service, Azure SQL).
• SaaS (Software as a Service): Fully managed software.
  Use: Ready-to-use applications (Microsoft 365).

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☁️ Cloud Deployment Models

• Public Cloud: Shared cloud infrastructure.
  Use: Cost-effective and scalable. like AWS, Azure, GCP [Pay As you Go]
• Private Cloud: Dedicated infrastructure.
  Use: High security and compliance. like Azure Stack and AWS Outposts
• Hybrid Cloud: On-premise + cloud.
  Use: Enterprise flexibility.
• Multi-Cloud: Multiple cloud providers.
  Use: Avoid vendor lock-in. if one providers gets stuck others can be present

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⚡ Cloud Characteristics (NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY- NIST)

• On-Demand Self Service
• Broad Network Access
• Resource Pooling
• Rapid Elasticity
• Measured Service (Pay-as-you-go)

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🌍 User Location & Latency

Latency: Delay between request and response.
Use: Deploy applications near users for better performance.

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📊 Data Types in Cloud

• Structured Data: SQL databases
• Unstructured Data: Images, videos, logs
• Semi-Structured Data: JSON, XML

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🏛️ Compliance & Data Residency

Some industries require data to stay in specific countries due to legal rules.
Use: Banking, Finance, Healthcare, Government.

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🔐 Conditional Access

Controls access based on user identity, device and location.
Use: Block access from unknown or insecure devices.

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🏗️ Azure Resource Hierarchy

• Management Groups
• Subscriptions
• Resource Groups
• Resources

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🌐 Hub-and-Spoke Network Model

Central hub contains firewall and security services, while spokes host applications.
Use: Cost saving and centralized security.

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📊 Logs vs Metrics vs Alerts

• Logs: Event records
• Metrics: Performance values (CPU, memory)
• Alerts: Notifications when limits crossed

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☁️ Cloud Bursting

Extra workload moves to cloud when on-premise capacity is full.
Use: Payroll processing, exam systems.

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🏢 Business Continuity vs Disaster Recovery

• Business Continuity (BCP): Keep business running
• Disaster Recovery (DR): Recover systems after failure

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🧑‍💼 Identity & Access Management (IAM)

Manages users and their access to resources.
Use: Azure Active Directory, RBAC, MFA.

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📊 Subscription Limits & Quotas

Limits resources to prevent misuse and control cost.

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💰 Cloud Pricing Models

• Pay-as-you-go: Pay only for usage
• Reserved Instances: Discount for long-term usage
• Spot Instances: Low-cost unused capacity

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🌐 Cloud Networking

• VNet (Virtual Network): Private network for cloud resources.
  Use: Secure communication.
• Subnet: Smaller network inside VNet.
  Use: Separate web, app and database layers.
• NSG (Network Security Group): Firewall rules.
  Use: Allow or block traffic.
• Load Balancer: Distributes traffic.
  Use: High availability.
• VPN (Virtual Private Network): Secure tunnel to cloud.
  Use: Connect office to cloud.
• ExpressRoute: Private dedicated connection.
  Use: Faster enterprise connectivity.

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🚚 Cloud Migration – 6R Strategy

• Rehost (Lift and Shift):
  Move applications from on-premise to cloud without changing their design.
  Use: Fast migration when you want minimal changes and quick cloud adoption.


• Refactor:
  Modify application architecture to use cloud-native features like auto-scaling and managed databases.
  Use: Improve performance, scalability, and long-term cost efficiency.


• Replatform:
  Move applications to cloud with small optimizations but without full redesign.
  Use: Gain some cloud benefits while keeping application structure mostly same.


• Retire:
  Remove applications that are no longer needed or used.
  Use: Reduce cost and simplify IT environment by eliminating unused systems.


• Retain:
  Keep certain applications on-premise due to security, compliance, or technical reasons.
  Use: When apps cannot be moved to cloud immediately.


• Replace:
  Replace existing applications with cloud-based SaaS solutions.
  Use: Modernize systems using ready-made cloud software (example: replace on-prem email with Microsoft 365).

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📈 Scaling in Cloud

• Vertical Scaling: Increase CPU or RAM
• Horizontal Scaling: Add more servers
• Auto Scaling: Automatic scaling based on load

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🔐 Cloud Security Concepts

• HTTPS (HyperText Transfer Protocol Secure)
• RBAC (Role-Based Access Control)
• NSG (Network Security Group)
• JIT (Just-In-Time)
• MFA (Multi-Factor Authentication)

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🧠 Cloud Computing Interview Questions

What is Cloud Computing?

Delivering IT services over the internet using pay-as-you-go model.

Difference between Backup and DR?

Backup stores data; DR restores systems.

What is Hybrid Cloud?

Combination of on-premise and cloud.

What is RPO and RTO?

RPO - Recovery Point Objective = How much data loss (time wise) is acceptable if a disaster occurs

RTO -Recovery Time Objective = How quickly the system must be back online after a failure.

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💼 Enterprise Real-World Scenarios

• Banking app deployed in multi-region
• Jenkins CI/CD hosted on Azure VM
• Healthcare data stored in India region
• E-learning platform auto scales
• VPN connection from office to cloud

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✅ Key Takeaways

• Cloud computing is scalable and cost-effective
• Security and compliance are critical
• Understanding fundamentals helps interviews
• Azure supports enterprise workloads

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🐧 Linux Shell Scripting for Beginners – Complete Tutorial Series.

• A 13-part practical shell scripting course for DevOps and Middleware Engineers.

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💡 How This Tutorial Series Will Help You

• ✔ Build a strong foundation in Linux Shell scripting — from basics to automation.
• ✔ Automate daily Middleware and DevOps tasks: monitoring, backups, and log management.
• ✔ Write scripts for Middleware platforms like Tomcat, Jenkins, and WebSphere.
• ✔ Debug, schedule, and manage production-ready shell scripts confidently.
• ✔ Perfect for Sysadmins, Middleware, and DevOps Engineers upgrading to Cloud roles.

📚 Complete Course Index

🐚 Part 1: What is a Variable?

Learn how variables store data and simplify automation scripts. Foundation of all shell logic.

📥 Part 2: Reading User Input in Shell

Make interactive scripts using read command with Jenkins and Tomcat examples.

🧩 Part 3: Conditional Statements (if, elif, else)

Use decision-making in your scripts with examples checking files, services, and network health.

🔁 Part 4: Loops in Shell (for, while, until)

Automate repetitive DevOps tasks like log cleanup, backups, and status monitoring.

⚙️ Part 5: Functions in Shell (Reusable Scripts)

Write modular, reusable functions — restart Tomcat or back up Jenkins in one click.

📦 Part 6: Arrays & Arguments

Store multiple values, manage user inputs, and process server lists in scripts.

📁 Part 7: File Handling in Shell

Learn how to read, write, append, and handle configuration or log files safely.

💡 Part 8: Debugging & Logging

Find and fix script errors, use logs, and enable debug mode for safe execution.

🕒 Part 9: Scheduling & Automation

Use cron and @reboot jobs to run scripts automatically for health checks or backups.

🎯 Part 10: Middleware Health Monitoring Project

Create a production-ready monitoring script for Tomcat, Jenkins, and NGINX with auto-restart.

🧾 Part 11: Log Management & Rotation

Automate log rotation with logrotate and custom retention scripts for Middleware systems.

💾 Part 12: Backup & Restore Automation Project

Perform automated backup and restore for Jenkins, Tomcat, and WebSphere with rollback support.

⚙️ Part 13: Subshells, Process Control & Parallel Execution

Run multiple jobs in parallel, monitor background processes, and speed up automation workflows.

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🚀 Why MiddlewareBox Shell Scripting Series?

• ✅ Step-by-step, beginner-friendly explanations.
• ✅ Each topic includes real DevOps & Middleware context.
• ✅ Examples with Output and Error handling.
• ✅ Simple language for better understanding.

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✨ Start Learning Now → Part 1: What is a Variable?
& build your own scripts from scratch! 💪

💻 Top 100+ Linux Commands for Middleware & DevOps Engineers ⚙️

• 💻 Linux is the backbone of every Middleware and DevOps ecosystem — running enterprise tools like WebSphere, JBoss, Jenkins, Docker, and Ansible.
• ⚙️ This post brings together 100+ essential Linux commands — covering file management, networking, SSH, cron jobs, and systemctl operations used daily by engineers.
• 🔐 Learn secure connectivity practices with SSH and SSH-Key management, plus essential testing using Telnet.
• 🚀 Ideal for Middleware Engineers, DevOps professionals, and System Administrators aiming to strengthen their Linux command-line mastery.

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📘 TABLE OF CONTENTS ▼

• 📁 1️⃣ File & Directory Management
• 🧾 2️⃣ Search & Text Processing
• ⚙️ 3️⃣ Process & Performance Monitoring
• 🌐 4️⃣ Network & Connectivity
• 🔑 5️⃣ SSH & Secure Connectivity Commands
• 🔐 6️⃣ SSH-Key Management (Essential for DevOps)
• 🌍 7️⃣ Telnet Commands (Essential)
• 👤 8️⃣ User & Permission Management
• 📦 9️⃣ Compression & Archiving
• 🛠️ 1️⃣0️⃣ System & Service Management
• 📦 1️⃣1️⃣ Package Management
• ⏰ 1️⃣2️⃣ Cron & Scheduling
• 🧠 1️⃣3️⃣ Productivity & Shortcuts

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📁 1️⃣ File & Directory Management

🧩 Command	💡 Description
pwd	Show current directory
ls -lh	List files in readable format
ls -lrt	Sort files by modification time
cd /opt/app	Change directory
mkdir -p /data/logs/archive	Create nested directories
rm -rf /tmp/logs	Remove directory recursively
cp -rp /opt/config /backup/	Copy files with permissions
mv old.log new.log	Rename or move file
cat file.txt	Display file content
du -sh /opt	Show directory size
df -h	Display filesystem usage
touch file.txt	Create an empty file

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🧾 2️⃣ Search & Text Processing

🔍 Command	💡 Description
grep "error" logfile.log	Search keyword in file
grep -i "critical" /var/log/syslog	Case-insensitive search
grep -r "Exception" /opt/app/	Recursive search
awk '{print $1,$3}' logfile.log	Print specific columns
sort -u file.txt	Sort and remove duplicates
uniq -c file.txt	Count unique lines
wc -l file.txt	Count number of lines
head -n 10 file.txt	Show first 10 lines
tail -n 50 logfile.log	Show last 50 lines
tail -f jenkins.log	Watch logs live
sed -i 's/http:/https:/g' nginx.conf	Replace text in file

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⚙️ 3️⃣ Process & Performance Monitoring

⚙️ Command	💡 Description
top	Real-time process viewer
htop	Interactive process viewer
ps -ef | grep java	Show running Java processes
kill -9 <pid>	Kill process by ID
lsof -i :8080	Find process using a port
vmstat 2 5	Show CPU/memory stats every 2s
iostat -x 1	Disk performance summary
free -m	Memory usage (in MB)
uptime	System load average
sar -u 2 3	CPU utilization snapshot
journalctl -u nginx.service -f	Follow logs for systemd service
dmesg | tail -20	Check kernel/system logs

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🌐 4️⃣ Network & Connectivity

🌍 Command	💡 Description
ping www.google.com	Check connectivity
curl -I https://middlewarebox.com	Get HTTP headers
wget https://example.com/file.zip	Download file
ip addr	Display IP addresses
ip route	Show routing table
ss -tulwn	Show listening ports
netstat -plant	Display active connections
nc -zv 10.0.0.5 22	Test port access
traceroute 8.8.8.8	Trace route to host
nslookup middlewarebox.com	DNS lookup
dig middlewarebox.com	Detailed DNS query

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🔑 5️⃣ SSH & Secure Connectivity Commands

🔑 Command	💡 Description
ssh user@hostname	Connect to remote server
ssh -i ~/.ssh/id_rsa user@10.0.0.10	Use specific private key
ssh-copy-id user@server	Copy SSH key for passwordless login
ssh -v user@server	Verbose SSH connection (debug)
scp file.txt user@remote:/tmp/	Securely copy files between systems
rsync -avz /opt/app/ user@server:/backup/	Sync files securely over SSH
ssh-agent bash	Start SSH authentication agent
ssh-add ~/.ssh/id_rsa	Add SSH private key to agent

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🔐 6️⃣ SSH-Key Management (Essential for DevOps)

🔐 Command	💡 Description
ssh-keygen -t rsa -b 4096 -C "your_email@example.com"	Generate a new SSH key pair
ls ~/.ssh/	List existing SSH keys and configs
cat ~/.ssh/id_rsa.pub	View your public key
ssh-copy-id user@server	Copy public key for passwordless login
ssh -i ~/.ssh/id_rsa user@server	Connect using a private key
chmod 700 ~/.ssh	Secure SSH directory
chmod 600 ~/.ssh/id_rsa & chmod 644 ~/.ssh/id_rsa.pub	Set correct key permissions
ssh -T git@github.com	Test SSH auth with GitHub
ssh-agent bash & ssh-add ~/.ssh/id_rsa	Load key into SSH agent

💡 TIP: SSH keys allow secure, passwordless access between servers — commonly used in Jenkins, Ansible, and Git integrations for DevOps automation.

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🌍 7️⃣ Telnet Commands (Essential)

🌍 Command	💡 Description
telnet hostname port	Test basic TCP connectivity
telnet 10.0.0.10 443	Check HTTPS port reachability
telnet mail.server.com 25	Test SMTP mail server connection

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⚙️ 8️⃣ User & Permission Management

👤 Command	💡 Description
whoami	Show current user
id	Display user ID and groups
adduser devops	Create a new user
passwd devops	Set user password
usermod -aG sudo devops	Add user to sudo group
groups devops	Show user group memberships
chmod +x deploy.sh	Make script executable
chown root:root /opt/app	Change file ownership

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📦 9️⃣ Compression & Archiving

📦 Command	💡 Description
tar -cvf backup.tar /data	Create tar archive
tar -xvf backup.tar	Extract tar file
gzip file.txt	Compress file
gunzip file.txt.gz	Decompress file
zip -r backup.zip /opt/app	Create zip archive
unzip backup.zip	Extract zip archive

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🛠️ 1️⃣0️⃣ System & Service Management

🛠️ Command	💡 Description
systemctl status firewalld	Check firewalld service status
systemctl start firewalld	Start firewalld service
systemctl stop firewalld	Stop firewalld service
systemctl enable firewalld	Enable firewalld at boot
systemctl disable firewalld	Disable firewalld from starting at boot

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📦 1️⃣1️⃣ Package Management

📦 Command	💡 Description
apt update	Update package lists (Debian/Ubuntu)
apt install <package>	Install package (Debian/Ubuntu)
yum update	Update packages (RHEL/CentOS)
yum install telnet / apt install telnet	Install Telnet client on RHEL / Ubuntu

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⏰ 1️⃣2️⃣ Cron & Scheduling (Small but essential)

⏰ Command	💡 Description
crontab -l	List current user's cron jobs
crontab -e	Edit current user's cron jobs using the default editor
sudo crontab -e -u username	Edit another user's cron jobs (requires sudo)
cat /etc/crontab	View system-wide cron file

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🧠 🔟 Productivity & Shortcuts

⚡ Command	💡 Description
history	Show previous commands
!!	Re-run last command
!sudo	Run last command as sudo
alias ll='ls -la'	Create command alias
unalias ll	Remove alias
ctrl + r	Search command history
clear	Clear terminal screen

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