DEV Community

akhil mittal
akhil mittal

Posted on

Practical Usage of Shell Scripting in Devops/Cloud Engineer Role

#devops #shell #linux

Shell scripting is an essential tool for DevOps and Cloud Engineers, offering automation, efficiency, and consistency in managing complex environments. Here are some practical use cases of shell scripting in these roles, along with example scripts:

1. Automating Infrastructure Deployment

Use Case: Automate the deployment of infrastructure resources such as EC2 instances, RDS databases, or Kubernetes clusters using CLI tools.

Example Script: Deploying an EC2 instance using AWS CLI.

#!/bin/bash # Variables INSTANCE_TYPE="t2.micro" KEY_NAME="my-key-pair" AMI_ID="ami-0abcdef1234567890" SECURITY_GROUP="sg-0abc1234" SUBNET_ID="subnet-0abc1234" REGION="us-west-2" # Launch EC2 Instance aws ec2 run-instances \ --instance-type $INSTANCE_TYPE \ --key-name $KEY_NAME \ --image-id $AMI_ID \ --security-group-ids $SECURITY_GROUP \ --subnet-id $SUBNET_ID \ --region $REGION \ --count 1 \ --output json echo "EC2 Instance launched successfully."
Enter fullscreen mode Exit fullscreen mode

2. Continuous Integration and Deployment (CI/CD)

Use Case: Automate build, test, and deployment pipelines.

Example Script: Build and deploy a Docker container to AWS ECS.

#!/bin/bash # Variables ECR_REPOSITORY="my-ecr-repo" IMAGE_TAG=$(date +%Y%m%d%H%M%S) CLUSTER_NAME="my-cluster" SERVICE_NAME="my-service" # Authenticate Docker with ECR aws ecr get-login-password --region us-west-2 | docker login --username AWS --password-stdin $ECR_REPOSITORY # Build Docker Image docker build -t $ECR_REPOSITORY:$IMAGE_TAG . # Push Docker Image docker push $ECR_REPOSITORY:$IMAGE_TAG # Update ECS Service aws ecs update-service --cluster $CLUSTER_NAME --service $SERVICE_NAME --force-new-deployment echo "Deployment completed successfully."
Enter fullscreen mode Exit fullscreen mode

3. System Monitoring and Alerts

Use Case: Monitor system health and send alerts if certain thresholds are breached.

Example Script: Check disk usage and send an alert if usage exceeds 80%.

#!/bin/bash # Variables THRESHOLD=80 EMAIL="admin@example.com" HOSTNAME=$(hostname) # Check Disk Usage DISK_USAGE=$(df / | grep / | awk '{ print $5 }' | sed 's/%//g') if [ "$DISK_USAGE" -gt "$THRESHOLD" ]; then echo "Disk usage on $HOSTNAME is above threshold: ${DISK_USAGE}%" | mail -s "Disk Usage Alert" $EMAIL echo "Alert sent to $EMAIL." else echo "Disk usage on $HOSTNAME is within limits: ${DISK_USAGE}%." fi
Enter fullscreen mode Exit fullscreen mode

4. Log Management

Use Case: Aggregate and analyze logs from multiple servers.

Example Script: Collect logs from multiple servers and compress them for archival.

#!/bin/bash # Variables LOG_DIR="/var/log/myapp" ARCHIVE_DIR="/var/archives/logs" TIMESTAMP=$(date +%Y%m%d%H%M%S) ARCHIVE_FILE="$ARCHIVE_DIR/logs-$TIMESTAMP.tar.gz" # Create Archive Directory if Not Exists mkdir -p $ARCHIVE_DIR # Collect Logs tar -czf $ARCHIVE_FILE $LOG_DIR # Remove Old Archives (older than 30 days) find $ARCHIVE_DIR -type f -mtime +30 -exec rm {} \; echo "Logs collected and archived to $ARCHIVE_FILE."
Enter fullscreen mode Exit fullscreen mode

5. Backup and Restore

Use Case: Automate backup processes for databases or file systems.

Example Script: Backup a MySQL database and compress the backup file.

#!/bin/bash # Variables DB_USER="root" DB_PASSWORD="password" DB_NAME="mydatabase" BACKUP_DIR="/backups" TIMESTAMP=$(date +%Y%m%d%H%M%S) BACKUP_FILE="$BACKUP_DIR/db-backup-$TIMESTAMP.sql.gz" # Create Backup mysqldump -u $DB_USER -p$DB_PASSWORD $DB_NAME | gzip > $BACKUP_FILE # Remove Old Backups (older than 7 days) find $BACKUP_DIR -type f -mtime +7 -exec rm {} \; echo "Database backup completed: $BACKUP_FILE."
Enter fullscreen mode Exit fullscreen mode

6. Environment Configuration

Use Case: Set up environment variables and configuration files.

Example Script: Set up environment variables for a web application.

#!/bin/bash # Variables ENV_FILE="/etc/myapp/.env" # Create Environment File echo "DB_HOST=localhost" > $ENV_FILE echo "DB_USER=root" >> $ENV_FILE echo "DB_PASSWORD=password" >> $ENV_FILE echo "PORT=8080" >> $ENV_FILE echo "Environment configuration completed."
Enter fullscreen mode Exit fullscreen mode

Summary

Shell scripting in DevOps and cloud engineering helps automate routine tasks, streamline workflows, and ensure consistency across environments. By writing scripts for infrastructure deployment, CI/CD pipelines, system monitoring, log management, backup, and environment configuration, you can improve efficiency and reduce manual effort in managing and operating cloud and on-premises systems.

Top comments (0)