Diagnose, identify, manage, and troubleshoot processes and services

Joaquin is an actor and producer by day, and a RHEL Sysadmin at Microsoft by night:

• His RHEL Server: Azure_RHEL_Server_1975
• His username: joaquin.phoenix@microsoft.com
• His professional preference: Competent RHEL Sysadmins NEVER run commands as the root user.
• HIs objective: Diagnose, identify, manage, and troubleshoot processes and services.

Joaquin has completed his CompTIA Linux+ and LPIC 1, 2 and 3 certifications, and he wants to complete his LFCS certification next. He must master this objective: Diagnose, identify, manage, and troubleshoot processes and services. Please generate and explain the commands that Joaquin will need to master to master this objective.

As a competent RHEL (Red Hat Enterprise Linux) Sysadmin, Joaquin Phoenix must possess a strong command over various Linux commands and tools to diagnose, identify, manage, and troubleshoot processes and services. Here are some important commands that Joaquin will need to master to achieve his objective:

1. ps: The ps command is used to display information about running processes. It provides details such as process ID (PID), CPU and memory usage, and process status. Joaquin can use the following variations of the command to get specific information:

   • ps aux: Displays a detailed list of all running processes on the system.
   • ps -ef: Shows a full listing of processes with their associated details.

2. top: The top command displays real-time information about system processes, including CPU usage, memory usage, and other relevant statistics. It provides an interactive interface that refreshes periodically. Joaquin can use it to monitor processes and identify resource-intensive ones.

3. systemctl: The systemctl command is used to manage system services (systemd units). Joaquin can use it to start, stop, restart, enable, disable, and view the status of services. Some useful variations of the command include:

   • systemctl start <service_name>: Starts a specific service.
   • systemctl stop <service_name>: Stops a specific service.
   • systemctl restart <service_name>: Restarts a specific service.
   • systemctl enable <service_name>: Enables a specific service to start at boot.
   • systemctl disable <service_name>: Disables a specific service from starting at boot.

4. journalctl: The journalctl command is used to query and view logs from the systemd journal. It helps Joaquin analyze system logs and troubleshoot service-related issues. Some useful variations include:

   • journalctl: Displays the entire systemd journal.
   • journalctl -u <service_name>: Shows logs specific to a particular service.
   • journalctl -f: Follows the log in real-time.

5. lsof: The lsof command lists open files and the processes associated with them. Joaquin can use it to identify which processes are using particular files, sockets, or network connections. For example:

   • lsof -i: Displays processes using internet connections.
   • lsof /path/to/file: Lists processes accessing a specific file.

6. netstat: The netstat command provides information about network connections, routing tables, and network interfaces. Joaquin can use it to monitor network activity and troubleshoot network-related issues. Some common options include:

   • netstat -tuln: Displays listening TCP and UDP ports.
   • netstat -r: Shows the routing table.

These are just a few of the essential commands Joaquin Phoenix will need to master for diagnosing, identifying, managing, and troubleshooting processes and services on a RHEL server. Continuing his learning and hands-on experience with these commands will enhance his skills as a RHEL Sysadmin.