Lecture 6

Lecture6/README.md

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+## Bash scripts and Automation
+1. Create bash with
+2. backup a directory every day at 2 am.
+2. Create cron job for the bash script.![SetUpCronJob.png](images/SetUpCronJob.png)
+3. Create a bash script to monitor website health
+4. Create cron job for the resource monitoring
+5. Set up systemd timer to run a health-check script every 5 min.
+6. Enable and start the timer.![SetHealthCheckTimer.png](images/SetHealthCheckTimer.png)
+7. Log file for health check results.![HealthCheckLogFile.png](images/HealthCheckLogFile.png)
+8. Create file rotation for acess_test.log. ![LogRotationConf.png](images/LogRotationConf.png)
+9. Test force rotate logrotate -f /etc/logrotate.d/nginx-access-test
+10. View rotated log files. ![RotatedLogFiles.png](images/RotatedLogFiles.png)

cron-backup.sh

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+#!/bin/bash
+# A simple cron job script to back up a directory to a specified backup location everyday at 2 AM.
+SOURCE_DIR="/media/sf_jenkins-project/gs-spring-boot"
+BACKUP_DIR="/media/sf_jenkins-project/backups"
+
+BACKUP_FILE="backup-$(date +'%Y-%m-%d').tar.gz"
+
+if [ -f "$BACKUP_DIR/$BACKUP_FILE" ];then
+  echo "Backing file already exists for today. Skipping backup."
+  exit 0
+else
+    echo "Start backing up $SOURCE_DIR to $BACKUP_DIR"
+    tar -czvf "$BACKUP_DIR/$BACKUP_FILE" -C "$SOURCE_DIR" .
+fi
+
+

health-check.service

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+[Unit]
+Description=Check website availability and write result to a log file
+
+[Service]
+Type=oneshot
+ExecStart=/media/sf_jenkins-project/gs-spring-boot/health-check.sh
+
+[Install]
+WantedBy=multi-user.target

health-check.sh

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+#!/bin/bash
+# A simple health check script to monitor system resources and log the status.
+LOG_DIR="/media/sf_jenkins-project/gs-spring-boot/log"
+LOG_FILE="/media/sf_jenkins-project/gs-spring-boot/log/system_health.log"
+WEB_URL="http://localhost:8082"
+
+# Create log directory if it doesn't exist
+if [ ! -d "$LOG_DIR" ]; then
+    mkdir -p "$LOG_DIR"
+fi
+
+# Enable -e immediately exit in anny command with non-zero exit,
+# -x print executed commands,
+# -u send exception when use undefined variable,
+# -o return exit status of last command in pipe that failed
+set -exuo pipefail
+
+if curl --request GET -fsSL --max-time 5 --url "$WEB_URL" >> "$LOG_FILE"; then
+
+    echo "$(date +'%Y-%m-%d %H:%M:%S') - Web service is up and running." >> "$LOG_FILE"
+else
+    echo "failed to check $WEB_URL $(date +'%Y-%m-%d %H:%M:%S')" >> "$LOG_FILE"
+fi
+

health-check.timer

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+[Unit]
+Description=Run health check script every 5 minutes
+
+[Timer]
+OnBootSec=5min
+OnUnitActiveSec=5min
+Unit=health-check.service
+
+[Install]
+WantedBy=timers.target
+

resource-monitoring.sh

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+#!/bin/bash
+# A simple health check script to monitor system resources and log the status.
+RESOURCE_LOG_DIR="/media/sf_jenkins-project/gs-spring-boot/resource-log"
+RESOURCE_LOG_FILE="$RESOURCE_LOG_DIR/system_resource.log"
+
+# Enable -e immediately exit in anny command with non-zero exit,
+# -x print executed commands,
+# -u send exception when use undefined variable,
+# -o return exit status of last command in pipe that failed
+set -exuo pipefail
+
+
+CPU=$(top -bn1 | grep "Cpu(s)")
+MEMORY=$(free -h | awk 'NR==2{printf "Used: %s / Total: %s (%.2f%%)\n", $3, $2, $3*100/$2 }')
+DISK=$(df -h | awk 'NR=2{print $2, $5}')
+UPTIME=$( uptime -p)
+TOP_PROCESSORS=$( ps -eo pid,comm,%cpu --sort=-%cpu | head -n 6 )
+
+LOG_TITLE="System Resource Status as of $(date +'%Y-%m-%d %H:%M:%S')"
+
+if [ -f "$RESOURCE_LOG_FILE" ]; then
+      echo "Log file exists. Appending new resource status."
+else
+    echo "Log file does not exist. Creating new log file."
+    mkdir -p "$RESOURCE_LOG_DIR"
+    touch "$RESOURCE_LOG_FILE"
+fi
+
+{
+    echo "=============================="
+    echo "$LOG_TITLE"
+    echo "=============================="
+    echo "CPU Usage: $CPU"
+    echo "Memory Usage: $MEMORY"
+    echo "Disk Usage: $DISK"
+    echo "System Uptime: $UPTIME"
+    echo "Top Processes by CPU Usage:"
+    echo "$TOP_PROCESSORS"
+    echo ""
+} >> "$RESOURCE_LOG_FILE"

test-crontab.cron

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+# Run script every day at 2 AM
+0 2 * * * /media/sf_jenkins-project/gs-spring-boot/cron-backup.sh