LINUX ADMINISTRATION

Question 1

Block vs File Storage?

Answer 1

Block storage manages data in fixed-sized blocks, providing low-level access to storage devices. (LESS STRUCTURED data storage)

File storage, on the other hand, organizes data into files and directories, allowing for higher-level access and management. (MORE STRUCTURED data storage)

Question 1

Please explain the patching process.

Answer 1

Patching involves:
identifying vulnerabilities
applying patches to address them
testing to ensure system stability and security

Question 2

Describe a time where you had to troubleshoot a MEMORY issue?

Answer 2

I once fixed a server performance issue by identifying and resolving a memory leak in an application, which was causing excessive memory usage and system crashes.

Question 3

Major Difference between Rhel 7 vs Rhel 8?

Answer 3

RHEL 8:
-introduced systemd as the default init system
-application streams for managing software versions
-XFS as the default filesystem
-improved security features.

Question 4

Major Difference between Rhel 6 vs Rhel 7?

Answer 4

RHEL 7 :
- replaced the init system with systemd
- improved virtualization support with KVM
- introduced XFS as the default filesystem
- enhanced security with SELinux.

Question 5

In Linux, how can you lock a user account?

Answer 5

To lock a user account in Linux, you can use the passwd command with the -l option followed by the username. For example, sudo passwd -l username. This disables the account by setting an invalid password hash in the password file.

Question 6

How do you manage users in your environment?

Answer 6

We manage users using command-line tools like useradd, usermod, and userdel

Question 7

Describe a time where you had to troubleshoot a PERFORMANCE issue?

Answer 7

Website on instances were slow during peak times.

I addressed this by monitoring CPU utilization on Cloudwatch and implementing a scheduled auto scaling solution to add more servers

Question 8

Describe a time where you had to troubleshoot a FILESYSTEM issue?

Answer 8

I fixed a disk space exhaustion issue by identifying and cleaning up excessive temporary files, and adjusting filesystem quotas to prevent future incidents.

Question 9

What is umask?

Answer 9

umask is a command in Unix and Unix-like operating systems that sets default permissions for newly created files and directories.

Question 10

Where are the kernel modules located?

Answer 10

Kernel modules in Linux are located in the /lib/modules directory.

Question 11

How to use NFS to share a directory?

Answer 11

To use NFS to share a directory, you need to configure the NFS server by editing the /etc/exports file to specify which directories to share and their permissions. Then, you need to start the NFS service and export the shared directories.

Question 12

In Linux, how many permissions are there?

Answer 12

In Linux, there are three types of permissions: read (r), write (w), and execute (x).

Question 13

Tell me the difference between ext4 and xfs file systems?

Answer 13

Ext4 is MORE WIDLY USED and has better compatibility with older Linux systems, while XFS is known for its scalability and performance on large storage systems.

Question 14

What is the /proc file system?

Answer 14

The /proc filesystem in Linux is a virtual filesystem that provides information about system processes and configurations in a hierarchical structure. It allows access to kernel data structures and parameters as if they were files.

Question 15

Tell me about grep command?

Answer 15

The grep command in Linux is used to search for patterns in text files.

Question 16

Tell me about the contents of /usr/local.

Answer 16

The /usr/local directory in Linux is typically used for installing software manually, separate from packages managed by the system’s package manager. It often contains user-installed software and libraries.

Question 17

How to stop an ongoing process?

Answer 17

To stop an ongoing process in Linux, you can use the kill command followed by the process ID (PID) of the process you want to stop. For example, kill PID or kill -9 PID to forcefully terminate the process.

Question 18

How to calculate the directory size?

Answer 18

To calculate the size of a directory in Linux, you can use the du (disk usage) command with the -sh options followed by the directory path. For example, du -sh directory_name.

Question 19

Which command will you use to find the status of a process?

Answer 19

To find the status of a process in Linux, you can use the ps command. For example, ps aux will display information about all processes running on the system.

Question 20

How will you check the status of memory?

Answer 20

To check the status of memory in Linux, you can use commands like free or vmstat to display memory usage and statistics.

Question 21

How to use the Terminal to find a file?

Answer 21

To find a file in Linux using the Terminal, you can use the find command followed by the directory to search and options like -name to specify the filename pattern. For example, find /path/to/directory -name filename.

Question 22

What is a Stateless Linux Server?

Answer 22

A stateless Linux server is a server configuration where the operating system does not store any persistent data locally. Instead, all configuration and data are managed externally, typically through network storage or cloud services. This allows for easy scalability and simplified management.

Question 23

Why should we use LINUX?

Answer 23

stability
security
flexibility
COST-EFFETIVENESS
large community of users and developers contributing

Question 24

What is a Zombie Process?

Answer 24

A Zombie Process is a process that has completed execution but still has an entry in the process table.

Question 25

Explain the concept of Redirection?

Answer 25

Redirection is the process of changing the standard input, output, or error streams of a command in Linux.

Question 26

How will you restrict IP so that the restricted IP’s may not use the FTP Server?

Answer 26

configuring firewall rules or using TCP wrappers.

For example, you can edit the /etc/hosts.deny file and add an entry like vsftpd: ALL EXCEPT <allowed_IP> to deny access to all IP addresses except the allowed ones.</allowed_IP>

Question 27

What is the advantage of open source?

Answer 27

The advantage of open source software is that it allows users to view, modify, and distribute the source code freely.

Question 28

What is Samba? Why is it used?

Answer 28

Samba is an open-source software suite that provides file and print services interoperability between Linux/Unix and Windows systems. It allows Linux servers to act as file and print servers for Windows clients, enabling seamless integration of heterogeneous network environments.

Question 29

What does the curl command do in Linux?

Answer 29

The curl command in Linux is used to transfer data to or from a server using various protocols such as HTTP, HTTPS, FTP, SCP, etc. It supports a wide range of options for performing various types of data transfers, including downloading and uploading files, sending requests to web services, and testing network connectivity.

Question 30

What are symbolic links?

Answer 30

Symbolic links, also known as symlinks or soft links, are special files that point to another file or directory in the filesystem. Unlike hard links, which point directly to the inode of the target file, symbolic links contain the path to the target file, allowing for flexibility and cross-directory linking.

Question 31

What are filenames that are preceded by a dot?

Answer 31

Filenames that are preceded by a dot in Linux are typically hidden files or directories.

Question 32

What are daemons?

Answer 32

Daemons are background processes that run continuously on a Unix-like operating system, usually initiated at system startup. They perform various tasks such as providing services, managing hardware devices, or monitoring system activities. Examples include web servers (e.g., Apache), database servers (e.g., MySQL), and system services (e.g., syslogd).

Question 33

What are environmental variables?

Answer 33

Environmental variables are dynamic values that affect the behavior of processes and programs in the operating system environment. They define various parameters such as system paths, user preferences, and configuration settings, which are used by programs to perform specific tasks or customize their behavior.

Question 34

How do you insert comments in the command line prompt?

Answer 34

Comments in the command line prompt in Linux are inserted using the # symbol at the beginning of a line.