System Administration

Linux Monitoring and Troubleshooting

In this chapter we will discover the various techniques and utilities we can use to monitor a Linux machine.

Resource Monitoring and troubleshooting

• vmstat: information about system processes, memory, paging, block I/O, and CPU activity
• free: information about system memory and swap usage.
• df: information about partition and volumes.
• du: information about disk usage
• iostat: input/output statistics for block devices.

Process Monitoring

• ps: show information about processes
• pgrep: grep through process list
• pkill: send a signal to a specific process

Log Monitoring

• /var/log/: where all system logs are stored
• journalctl: Journald client
• syslog: linux logging protocol
• audit logs: auditing and monitoring security-relevant events.

Networking

• iproute2: Linux userpace network utilities
• ping: ICMP utility
• traceroute, mtr: Network path monitoring. Learn More
• curl: HTTP swiss knife
• dig, nslookup: DNS lookup utilities
• tcpdump, wireshark: Packet analyzers
• nmap: Network scanning
• netcat: Networking swiss knife
• tcpstat: Network interface statistics