Top Ubuntu Server Interview Questions and Answers for 2023

Landing a job as an Ubuntu server administrator requires strong Linux skills and expertise in Ubuntu server To ace your next Ubuntu admin interview, you need to demonstrate your hands-on knowledge of everything from server setup and configuration to troubleshooting common issues

In this comprehensive guide, I’ll share the top Ubuntu server interview questions and detailed answers to help you prepare. Whether you’re a beginner looking to break into Linux administration or a seasoned pro preparing to switch jobs, this guide will boost your confidence for that big interview day.

Common Ubuntu Server Interview Questions

Here are some of the most frequently asked Ubuntu server interview questions

Q1. What is Ubuntu Server and how is it different from the desktop version?

Ubuntu Server is a free, open source operating system optimized for business use cases like web hosting, cloud computing, and backend infrastructure. It offers long-term support releases ideal for stable, secure server deployments.

The key differences from the desktop version are:

• No graphical user interface – Ubuntu Server uses a command line interface
• Smaller footprint – less disk space and memory required
• Tight security – firewall enabled by default, AppArmor for restricting apps
• Advanced networking – load balancing, firewall management, SSL termination
• Centralized management – Landscape for remote server administration

Overall, Ubuntu Server provides a lean, optimized and hardened server platform. The desktop version adds a GUI and apps for end user productivity.

Q2. Explain the Ubuntu Server release cycle and support duration

Ubuntu Server has two types of releases:

• Long Term Support (LTS) – Major releases every 2 years with 5 years support
• Standard releases – Every 6 months with 9 months support

For example, Ubuntu 18.04 LTS was released in 2018 and receives updates until 2023. Ubuntu 19.10 was released in Oct 2019 with support until July 2020.

LTS versions like 18.04 and 16.04 are recommended for production since they receive security patches and updates for a longer duration. Standard releases are best suited for trying new features.

Q3. How do you install Ubuntu Server and what are the minimal requirements?

The minimal requirements for installing Ubuntu Server are:

• 1 GHz dual-core processor
• 1 GB RAM
• 10 GB disk space

To install, you can choose from:

• Download the ISO, burn it to a DVD or create a bootable USB stick, and boot the server from it to start the installation
• Use a PXE server to network boot the installation media
• Install a bare metal hypervisor like VMware ESXi and create a new Ubuntu VM
• Create an Ubuntu Server virtual machine instance in the cloud

The installer will guide you through selecting language, keyboard config, network settings, disk partitioning, and setting up users/passwords.

Q4. How do you access Ubuntu Server since there is no GUI?

Without a graphical desktop, you administer Ubuntu Server using the command line interface (CLI) accessed via SSH.

To enable remote SSH access:

1. Install the SSH server using sudo apt install openssh-server
2. Edit /etc/ssh/sshd_config to allow root login and set permitted user access
3. Restart the ssh service: sudo systemctl restart sshd

Now you can SSH from your desktop terminal using ssh root@server_ip and provide the root password.

The default credentials are username ubuntu and password ubuntu. Make sure to change the root password after logging in.

Q5. How do you add/remove users and manage permissions on Ubuntu Server?

To add a new user, use the adduser command. For example:

sudo adduser john

This will prompt you to set the password and add optional info like name and phone number.

To remove a user, use deluser:

sudo deluser john

For managing permissions, Ubuntu uses the standard Linux file permissions of owner/group/others read/write/execute. Use chown to change ownership and chmod to modify read/write/execute permissions.

Q6. How do you manage software packages on Ubuntu Server?

Ubuntu Server includes the apt package manager for installing, updating, removing and managing software packages.

• apt update – Fetch latest list of packages
• apt upgrade – Install available upgrades of all packages
• apt install nginx – Install a new package
• apt remove nginx – Uninstall a package

You can also use apt for more advanced operations like fixing broken packages, purging configuration files of removed packages, and cleaning cached packages from the disk.

Overall, apt provides a simple and efficient way to manage an Ubuntu server’s software lifecycle.

Q7. How do you configure networking on Ubuntu Server?

The main networking configuration files on Ubuntu Server are:

• /etc/network/interfaces – Defines IP, netmask, gateway for each NIC
• /etc/resolv.conf – Sets DNS nameservers
• /etc/hosts – Defines static hostname to IP mappings

For a static IP setup, edit /etc/network/interfaces like:

auto enp0s3 iface enp0s3 inet static       address 192.168.0.10       netmask 255.255.255.0       gateway 192.168.0.1

Restart networking or reboot the server for changes to take effect.

For dynamic IP, set iface enp0s3 inet dhcp in the config file.

You can also manage networking through the ip and ifconfig commands.

Q8. How do you partition disks and configure LVM on Ubuntu Server?

For partitioning disks, use utilities like fdisk or parted. To manage Logical Volume Management (LVM):

1. Create physical volumes using pvcreate
2. Group PVs into volume groups using vgcreate. For example:

vgcreate webdata-vg /dev/sda1 

1. Create logical volumes from volume groups using lvcreate. For example:

lvcreate -n logs -L 10G webdata-vg

This carves out a 10GB logical volume called ‘logs’ from the ‘webdata-vg’ volume group.

1. Format the logical volumes with filesystems like ext4 and mount them.

LVM allows easily resizing, snapshotting and dynamically changing logical volumes as needed.

Q9. How do you monitor and get details of running processes on Ubuntu Server?

The standard commands for viewing processes on Ubuntu Server are:

• ps – Snapshot of currently running processes
• top – Real-time view of system resource usage by processes
• htop – Interactive process viewer

Some useful options for ps are:

• ps aux – Show processes for all users
• ps -ef – Print full command line used to start each process
• ps -eLf – Show threads for each process

top and htop allow viewing sortable per-process info like CPU/memory usage, user, and start time.

Q10. How do you troubleshoot when an application or service fails to start on Ubuntu Server?

Some steps for troubleshooting failed services:

• Check status using systemctl status servicename
• View logs in /var/log/ like /var/log/nginx/error.log
• Use journalctl -xe to view system logs and filter by service
• Check AppArmor /SELinux restrictions with aa-status / getenforce
• Verify dependencies are installed
• Try starting service manually to check for errors
• Reconfigure any incorrect settings in config files like /etc/nginx/nginx.conf
• Search Ubuntu forums and askubuntu.com for known issues

Following structured troubleshooting helps identify the root cause – whether it’s a config issue, dependency problem, AppArmor blocking access, etc.

Intermediate Ubuntu Server Interview Questions

Let’s move on to some more challenging Ubuntu server questions:

Q11. How do you optimize Ubuntu Server for performance?

Some best practices for optimizing Ubuntu Server performance are:

• Use a minimal install to reduce bloat
• Configure swap correctly based on RAM amount and expected load
• Enable persistent journaling for write-heavy workloads
• Tune swappiness and dirty page settings for caching behavior
• Select the fastest mirrors using netselect-apt
• Increase file handle limits for high-traffic servers
• Enable HTTP keepalive and compression
• Tune TCP buffer limits for high-bandwidth networks
• Benchmark disk I/O and tune I/O scheduler as needed
• Monitor top resource consumers with tools like top and iotop

Continuously monitor server performance under load and fine-tune Linux kernel settings for your specific workloads.

Q12. How can you enhance security for an internet-facing Ubuntu Server?

Some steps to harden an internet-facing Ubuntu Server: