Introduction to Linux System Administration Interview Questions and Answers

Linux System Administration is the process of administering the Linux System and its processes by configuring, maintaining and upgrading the Linux Systems which runs on any of the major Linux Distribution Systems such as Red Hat Linux, Debian, and Ubuntu etc. It contains the management of enterprise Linux infrastructure. Different Programs and Processes can be managed and maintained in Linux administration. The other administering elements involved in the Linux System Administration are Process limits, creating processes, processing states, Daemons, libraries, execution modes, software packaging, Red Hat Package Manager, Debian Package, memory tuning and monitoring, network monitoring, I/O scheduling and monitoring, partition and formatting disks, formatting file systems, Kernel and module configuration, Virtualization, user and group management, Firewalls, Back-up, Restore methods, basic troubleshooting and system security etc.

Below are the top-most questions asked in the interview:

Now, if you are looking for a job which is related to Linux System Administration then you need to prepare for the 2022 Linux System Administration interview questions. It is true that every interview is different as per the different job profiles. Here, we have prepared the important Linux System Administration interview questions and answers which will help you get success in your interview. These questions are divided into two parts are as follows:

Part 1 – Linux System Administration Interview Questions (Basic)

This first part covers the basic Interview Questions and Answers.

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Q1. What is a Linux Loader?

Answer:
A Linux Loader (LILO) is a bootloader which is used in the Linux Operating System to load the operating system and start it. Linux Loader can also be customized while loading the operating system. The configuration of the Linux Loader is a lilo.conf file which can be customized as per the requirement of the operating system. Linux Loader loads the Personal Computer Basic Input Output System into the main memory of the computer system. It locates the Linux kernel and loads the programs.

Q2. What are Network bonding and its different types?

Answer:
This is the common Linux System Administration interview questions asked in an interview. The Network Bonding is the process of combining two or more networks into a single network. It will enhance the network performance and will increase the bandwidth and reduces the latency.

The different types of Network Bonding involved in a Linux are–

Mode – 0 (Balance – rr): This mode is a type of Round Robin fashion and is also called as a default mode.
Mode – 1 (Activate Backup): This mode is a type of activate backup policy where only one responds or works at the time of failure of other nodes.
Mode -2 (Balance – XOR): This step will set the source address of the MAC (Media Access Control) to XOR mode for fault tolerance.
Mode – 3 (Broadcast): This step will work on broadcast policy where the transmission occurs to every slave interface.
Mode – 4 (802.3 AD): This step is based on IEEE 802.3ad standard which is also called Dynamic Aggregation Mode. It requires a switch that supports the dynamic link of the above standard.
Mode – 6 (Balance – TLB): This mode is also called Adaptive Transmit Loading, where the traffic will be loaded based on each slave of the network.
Mode – 7 (Balance – ALB): This mode is called Adaptive Load Balancing which does not require any Switch balancing.

Q3. What is the Linux Kernel?

Answer:
The Linux Kernel is a part of an operating system which acts as an interface between the operating system and system resources to establish or provide an access to it. The Linux kernel contains an API called Linux Kernel API (Application Programming Interface) by which the user programs access and interact with the Linux kernel and is also a very stable API and provides great performance in the case of multi-tasking or multi-user functionalities.

Q4. Explain briefly about the Linux architecture?

Answer:
The below are the two properties in the .NET to which performs as accessors to read or write the properties of the Windows Forms or any kind of class or object. The two property accessors are GET and SET:

GET: The GET property accessor is required to return the property value based on the different access levels as defined. The read-only property has to GET accessor but not a SET.
SET: The SET property accessor is required to assign a value, mostly a new value on the basis of the access level defined. Write only property have SET accessor but not a GET.

Q5. What are the different functionalities and responsibilities of a Linux System Administrator?

Answer:
The different functionalities those will normally be performed by a Linux System Administrator are as below:

To support and train the Linux server administrators.
Able to access all the processes, files and system applications in the server.
User and group management.
To ensure security and perform housekeeping maintenance.
To install and upgrade necessary important updates and security tools enhancement.
To use all Linux commands and access the Linux Kernel and its processes to efficiently run the Linux Server.
To configure update and maintain the system hardware configurations.

Q6. What are Kernel modules in Linux?

Answer:
The Kernel modules are the set of programs or code which can be loaded as per the requirement or demand which can be implemented without the process of rebooting the system. Each and every kernel is a module and is easily loadable. There will also be an automatic module handling.

Q7. What is umask and what is its use in Linux?

Answer:
The umask is a command which is often called as user file creation mask which is used to create file mask for the user that determines which file or directory permissions are available for the user based on the read or write or modify type.

Part 2 – Linux System Administration Interview Questions (Advanced)

Let us now have a look at the advanced Interview Questions.

Q8. What is the routing table in Linux?

Answer:
The routing table is a method in which how all the networks and devices are interconnected with each other to efficiently establish communication with each other.

Q9. What is Puppet?

Answer:
The Puppet is open source software that is used for software configuration management that runs on systems similar to that of UNIX. It is secure and scalable to use. It provides automation features in DevOps and Cloud environment.

Q10. What is automounting in Linux?

Answer:
The automounting is a process of automatically mounting all the partitions on a hard disk on a Linux or Unix System while booting the system. fstab property can be used to automount the hard drives on Linux.

Q11. List the fields in /etc/passwd file.

Answer:
The fields that are present in /etc/passwd file are Username, Password, User ID, Group ID, Comments, HomeDir and LoginShell. The /etc/passwd file has contents as below:

redhat:x:500:500:Redhat User:/home/redhat:/bin/bash

mssm:x:501:501:another user:/home/mssm:/bin/bash

– “x” in the password column indicates that the encrypted password is stored in /etc/shadow file.

Q12. Explain each system call used for process management in Linux.

Answer:
This is the most popular Linux System Administration interview questions asked in an interview. The system calls that are used for process management are as follows:

Fork(): This is used to create a new process from an existing one.

Exec(): This is used to execute a new program.

Wait(): This is used to wait until the given process finishes the execution.

Exit(): This is used to exit from the process.

Getpid(): This helps in getting the unique process id of a particular process.

Getppid(): This helps in getting a parent process unique id.

Nice(): This is used to bias the existing property of the process.

Let us move to the next Linux System Administration Interview Questions.

Q13. Explain the steps to increase the size of the LVM partition.

Answer:
The steps that need to be followed to increase the size of the LVM partition are as follows:

Run the below command: lvextend -L +500M /dev/<Name of the LVM Partition>.

Once this is done we can increase the size of the LVM partition by 500MB. A user can check the size of the partition by using ‘df -h’ command. The resizing can be done by resize2fs /dev/<Name of the LVM Partition>.

Q14. Which utility can be used to create the partition from a raw disk?

Answer:
To create a partition from a raw disk the utility that is used is fdisk utility. To create a partition you can follow the below steps:

Run this command: fdisk /dev/hd* (IDE) or /dev/sd* (SCSI).
Type n to create a new partition.
Once a partition is created then you can write the changes to this partition table. To write these changes type w.

Q15. Explain the steps to create a new user and set a password for the user from a shell prompt in Linux.

Answer:
To create a new user account from shell prompt following steps are to be performed:

Firstly login as a root user if you are not logged in as root use su – command.
Enter the root password.
The command to add a new user is useradd command and can be used in Linux. Use this command and then type the username you would like to create.

Eg: useradd sue

Once a user is created to set the password to follow below steps:

To set a password for user sue type command: passwd sue.
It will prompt the user to enter a new password.
Once this is done it will also ask the user to retype password thereby setting up the password for the user.

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