[2023] Top 50 RHCE ( Red Hat Certified Engineer) Interview Questions and Answers

Here is a set of 50 RHCE (Red Hat Certified Engineer) interview questions along with their answers. Please note that these answers are intended to provide general guidance and may need to be adapted based on the specific role and company you're interviewing with.

1. What does the RHCE certification validate?

The RHCE certification validates the skills and knowledge required to design, implement, and manage complex Linux systems using Red Hat technologies.

2. Explain the purpose of the 'nmcli' command.

The 'nmcli' command is used to manage network connections and NetworkManager configurations from the command line.

3. How can you create a new network connection using 'nmcli'?

To create a new network connection, use the 'nmcli con add' command followed by the connection details.

4. What is the 'sysctl' command used for?

The 'sysctl' command is used to view and modify kernel parameters at runtime, helping customize the behavior of the Linux kernel.

5. How do you set up a static IP address using 'nmcli'?

To set up a static IP address using 'nmcli', use the 'nmcli con modify' command to specify the connection details.

6. Explain the purpose of the 'iptables' command for firewall configuration.

The 'iptables' command is used for configuring firewall rules and filtering network traffic on Linux systems.

7. How can you save 'iptables' rules to persist across reboots?

Use the 'service iptables save' command to save 'iptables' rules to the configuration file so they persist after a reboot.

8. What is the purpose of the 'systemctl' command for service management?

The 'systemctl' command is used to manage and control system services, including starting, stopping, and enabling them.

9. How do you add a rule to the 'firewalld' firewall using 'firewall-cmd'?

To add a rule to 'firewalld', use the 'firewall-cmd --add-rule' command followed by the rule specification.

10. Explain the use of the 'journalctl' command for viewing system logs.

The 'journalctl' command is used to view and analyze logs generated by the systemd journal.

11. How can you set up a 'cron' job to run every day at a specific time?

Use the 'crontab -e' command to edit the 'cron' table, and then add a new line with the schedule and command to execute.

12. What is the purpose of the 'yum' command for package management?

The 'yum' command is used to manage software packages on Red Hat systems, including installation, updating, and removal.

13. How do you create a local repository using 'yum'?

To create a local repository, use the 'createrepo' command followed by the path to the directory containing the RPM packages.

14. Explain the use of the 'scp' command for secure file copying.

The 'scp' command is used to securely copy files between hosts over a network.

15. How can you schedule a task to run at system startup using 'systemctl'?

To schedule a task to run at system startup, use the 'systemctl enable' command followed by the service name.

16. What is the 'chroot' command used for?

The 'chroot' command is used to change the root directory for a process or user, isolating it from the rest of the filesystem.

17. How do you create a symbolic link using the 'ln' command?

To create a symbolic link, use the 'ln -s' command followed by the target file and the link name.

18. Explain the use of the 'tar' command for archiving and compression.

The 'tar' command is used to create archives and can include compression options using tools like 'gzip' or 'bzip2'.

19. How can you create an SSH key pair using 'ssh-keygen'?

Use the 'ssh-keygen' command to create an SSH key pair with the '-t' option to specify the key type.

20. What is the purpose of the 'samba' service and how is it managed using 'systemctl'?

The 'samba' service provides file and print sharing capabilities. Use 'systemctl' to manage it, e.g., 'systemctl start smb'.

21. How can you configure an NFS share using 'exports' and 'systemctl'?

Edit the '/etc/exports' file to configure NFS shares, and use 'systemctl' to start and enable the 'nfs-server' service.

22. Explain the use of the 'awk' command for text processing.

The 'awk' command is used for text processing and pattern matching in files, allowing data extraction and manipulation.

23. How do you set up a dynamic DNS client using the 'ddclient' package?

Install 'ddclient', configure '/etc/ddclient.conf', and then use 'systemctl' to start and enable the 'ddclient' service.

24. What is the 'vncserver' service used for? How can you start it?

'vncserver' is used to run a Virtual Network Computing (VNC) server. Start it using 'vncserver' command, e.g., 'vncserver :1'.

25. Explain the use of the 'ip' command for network configuration.

The 'ip' command is used to configure network interfaces, routes, and other networking parameters.

26. How can you configure a dynamic IP address using 'dhclient' and 'nmcli'?

Use 'nmcli con modify' to set the connection to DHCP mode, and then use 'dhclient' to obtain a dynamic IP address.

27. What is the purpose of the 'lvm' command for logical volume management?

The 'lvm' command is used to manage and configure logical volumes in the Linux operating system.

28. How can you resize a logical volume using 'lvextend' and 'resize2fs'?

Use 'lvextend' to extend the logical volume size and 'resize2fs' to resize the filesystem to utilize the new space.

29. Explain the use of the 'find' command for searching files and directories.

The 'find' command is used to search for files and directories based on various criteria, including name, type, and size.

30. What is SELinux? How can you set it to permissive mode using 'setenforce'?

SELinux is a security mechanism that enforces mandatory access controls. Use 'setenforce 0' to set it to permissive mode temporarily.

31. How do you configure a bonded network interface using 'nmcli'?

Use 'nmcli con add' to create a connection, and then use 'nmcli con modify' to configure bonding options.

32. Explain the use of the 'grep' command for pattern matching in files.

The 'grep' command is used to search for patterns in files and display matching lines.

33. What is the purpose of the 'visudo' command?

The 'visudo' command is used to safely edit the '/etc/sudoers' file, which controls 'sudo' privileges.

34. How can you configure the 'crond' service using 'systemctl'?

Use 'systemctl' to start, stop, enable, and disable the 'crond' service responsible for running scheduled tasks.

35. Explain the use of the 'modprobe' command for managing kernel modules.

The 'modprobe' command is used to manage kernel modules by loading or unloading them dynamically.

36. What is 'PAM'? How do you configure authentication using 'pam_unix' in '/etc/pam.d/'?

Pluggable Authentication Modules (PAM) provide authentication mechanisms. Configure 'pam_unix.so' in '/etc/pam.d/' for password authentication.

37. How can you encrypt a file using 'gpg'?

Use 'gpg' to encrypt and decrypt files using public-key cryptography. For example, 'gpg -e file.txt' encrypts 'file.txt'.

38. Explain the purpose of the 'netstat' command for network monitoring.

The 'netstat' command displays network-related information, including open ports, connections, and routing tables.

39. How do you configure a software RAID using 'mdadm'?

Use 'mdadm' to configure software RAID arrays, such as RAID 0, 1, or 5, by creating, assembling, and managing RAID devices.

40. What is 'DNS'? How do you set up a static DNS entry using '/etc/hosts'?

Domain Name System (DNS) translates domain names to IP addresses. Add a static DNS entry to '/etc/hosts' in the format 'IP hostname'.

41. How can you configure SSH to use public-key authentication?

Generate an SSH key pair using 'ssh-keygen', and then add the public key to the 'authorized_keys' file on the remote server.

42. Explain the use of the 'curl' command for transferring data using various protocols.

The 'curl' command is used to transfer data using various protocols, such as HTTP, FTP, and SCP.

43. What is the 'grpconv' command used for?

The 'grpconv' command is used to convert the '/etc/gshadow' file from the shadow suite to the '/etc/group' format.

44. How do you configure a time synchronization client using 'chronyd'?

Use 'chronyc sources' to view available time sources and 'chronyc -a makestep' to synchronize time immediately.

45. Explain the use of the 'hdparm' command for managing hard drive parameters.

The 'hdparm' command is used to view and configure hard drive parameters, including performance and power management.

46. What is the purpose of the 'ab' command?

The 'ab' command is used to benchmark Apache HTTP server performance by sending multiple requests to a web server.

47. How can you configure NTP time synchronization using 'chronyd'?

Edit the '/etc/chrony/chrony.conf' file to configure NTP time sources, and then use 'systemctl' to start and enable 'chronyd'.

48. Explain the use of the 'setfacl' command for managing file ACLs.

The 'setfacl' command is used to set or modify Access Control Lists (ACLs) for files and directories.

49. How do you configure a bridged network interface using 'nmcli'?

Use 'nmcli con add' to create a new connection with the 'connection.interface-name' property set to the interface name.

50. What is the 'semanage' command used for?

The 'semanage' command is used to manage SELinux policy, including port labeling, module management, and user mapping.

These questions provide a solid foundation for discussing Red Hat Certified Engineer (RHCE) skills during an interview. Be sure to understand the concepts behind these questions and tailor your responses to match your experience and the role you're interviewing for.