Troubleshooting Common Issues

This guide covers solutions to common issues you might encounter with your cloud instances.

Cannot Connect via SSH

Check Instance Status

Verify the instance is running in the Cloud Control Panel. If it's stopped, start it.

Verify Network Connectivity

# Ping the instance
ping your-instance-ip

# Check if SSH port is open
telnet your-instance-ip 22
# Or
nc -zv your-instance-ip 22

Check Security Groups

Ensure your security group allows SSH (port 22) from your IP address:

1. Go to Network → Security Groups
2. Select your security group
3. Verify there's an ingress rule for port 22
4. Check the source CIDR allows your IP

Check SSH Keys

# Verify you're using the correct key
ssh -v -i /path/to/private_key user@your-instance-ip

# Check key file permissions (should be 600)
chmod 600 ~/.ssh/id_rsa

Use VNC Console

Access the VNC console through the Control Panel to troubleshoot from inside the instance.

Instance Won't Boot

Check VNC Console

View the VNC console to see boot errors:

1. Select the instance
2. Click Console tab
3. Look for error messages during boot

Common Boot Issues

High CPU Usage

Identify the Culprit

# View top CPU consumers
top

# Or use htop (more user-friendly)
apt install htop
htop

# List processes by CPU usage
ps aux --sort=-%cpu | head -10

Common Causes

• Runaway processes - Kill with kill PID
• Insufficient resources - Consider resizing instance
• DDoS attack - Check logs and implement rate limiting
• Scheduled tasks - Optimize or reschedule

Running Out of Disk Space

Find What's Using Space

# Check overall disk usage
df -h

# Find large directories
du -sh /* | sort -h

# Find large files
find / -type f -size +100M -exec ls -lh {} \;

Common Space Hogs

• Log files - Clean up old logs in /var/log/
• Package cache - Run apt clean or yum clean all
• Docker images - Run docker system prune -a
• Old kernels - Remove with package manager

Clean Up Commands

# Ubuntu/Debian
apt autoremove
apt autoclean

# CentOS/Rocky/Alma
yum autoremove
yum clean all

# Clear systemd journal logs older than 7 days
journalctl --vacuum-time=7d

Network Performance Issues

Test Network Speed

# Install speedtest
apt install speedtest-cli

# Run test
speedtest-cli

# Test specific server
speedtest-cli --server SERVER_ID

Check for Bandwidth Limits

Verify you haven't exceeded your monthly bandwidth allocation in the Cloud Control Panel.

MTU Issues

# Check current MTU
ip link show eth0

# If experiencing issues, try lowering MTU
ip link set dev eth0 mtu 1400

Database Connection Issues

Check Database Service

# Check if MySQL/MariaDB is running
systemctl status mysql
# Or
systemctl status mariadb

# Check if PostgreSQL is running
systemctl status postgresql

# Restart if needed
systemctl restart mysql

Check Connections

# MySQL: View current connections
mysql -e "SHOW PROCESSLIST;"

# Check max connections
mysql -e "SHOW VARIABLES LIKE 'max_connections';"

# PostgreSQL: View connections
psql -c "SELECT * FROM pg_stat_activity;"

Website Not Accessible

Check Web Server Status

# Nginx
systemctl status nginx
nginx -t  # Test configuration

# Apache
systemctl status apache2
apachectl configtest  # Test configuration

Check Firewall

# UFW
ufw status

# firewalld
firewall-cmd --list-all

# iptables
iptables -L -n

Check DNS

# Check if DNS is resolving correctly
dig yourdomain.com
nslookup yourdomain.com

Memory Issues

Check Memory Usage

# View memory usage
free -h

# Check for OOM (Out of Memory) kills
dmesg | grep -i "out of memory"
journalctl | grep -i "out of memory"

Identify Memory Hogs

# List processes by memory usage
ps aux --sort=-%mem | head -10

# Monitor memory in real-time
watch -n 1 free -h

Getting Help

If you can't resolve the issue:

1. Create a snapshot - Preserve current state before making changes
2. Gather information:
   • Error messages from logs
   • Recent changes made to the system
   • When the issue started
   • Steps to reproduce
3. Contact support - Open a ticket with detailed information