Server & Cloud Setup

AWS calls the private network your EC2 instances live in a VPC. What isolation guarantee does that provide?

Why do most server installations deliberately run in text mode with no GUI, rather than just reusing a desktop image?

Where does the term root server come from, and what does it imply about your control of the machine?

A colleague sets up a cloud instance and wants to configure RAID-1 and LVM the way they would on bare metal. What is the catch?

On real hardware or a provider root server, what disk-redundancy setup is recommended, and why does that recommendation flip on a VM or cloud instance?

You give a new internet-facing server the bare domain example.com as its hostname. Why will this decision come back to bite you?

To make a hostname reachable on the internet over both IPv4 and IPv6, which DNS records must exist?

You're on an unfamiliar Linux box and need to know whether it booted via EFI or legacy BIOS. What is the quick check?

When mirroring disks with RAID-1 on an EFI server, why can't you just put the EFI partition into the RAID array like the boot partition?

On a BIOS server whose boot partition is mirrored with RAID-1, one small detail decides whether it still boots after the first disk is swapped out. What is it?

In the fstab entries for two mirrored EFI partitions, why is the nofail mount option the critical detail?

You've set up a second EFI partition on the backup disk and put it in fstab. What extra step makes the firmware actually consider it at boot if the primary disk dies?

In the RHEL/Fedora installer, what does choosing Minimal Installation give you instead of the default Server with GUI, and how much smaller is it?

Ubuntu Server uses the same packages and repositories as desktop Ubuntu. So what actually makes it a separate server product?

What does Ubuntu Pro add over plain Ubuntu LTS, and what does that convenience cost on a cloud provider like AWS?

Since 2017 Ubuntu Server ships the Subiquity installer. What partitioning work can it do automatically on the whole disk?

During an Ubuntu Server install, how can you avoid depending on password login for SSH right from first boot?

Unlike Ubuntu, Debian ships no dedicated server edition. So how do you install Debian for server use with RAID and LVM?

What is the recommended lean starting point for a Debian server in the installer's software selection?

What is Amazon EC2 at its core, and which characteristics vary when you pick one instance type over another?

On EC2 on-demand pricing, why does an RHEL instance cost far more per hour than an identically-sized Ubuntu one?

On EC2, which direction of internet traffic costs money, and how do Saving Plans change the compute bill?

For EC2 SSH access, why is uploading your own public key safer than letting Amazon generate the key pair for you?

When you add an EBS volume to an EC2 instance, which type is the default, and when would you reach for a different one?

In EC2 terminology, where are an instance's firewall rules defined, and what does the auto-generated group allow out of the box?

You launch an EC2 instance and try to ssh in as root, but it fails. What account does AWS actually expect, and how do you point ssh at a non-default key?

Your ssh to a brand-new EC2 instance just times out with no response. What is the most likely cause, and the fix?

In the EC2 console, what is the crucial difference between Stop and Terminate on an instance?

You need to resize an EBS volume that's running low. What can you do, what can't you, and does the instance have to be off?

You enlarged an EBS volume in the AWS console but df still shows the old size inside the instance. What two layers do you still have to grow, and with what?

Why does a stopped-and-restarted EC2 instance usually come back with a new public IP, and how do you keep a stable address?

You terminated an instance but keep getting charged for its reserved Elastic IP. Why, and how do you stop the bill?

Running ip addr on an EC2 instance shows a 172.31.x.x address, not the public IP you connect to. Why the mismatch?

By default an EC2 instance won't even answer a ping. Which single port does the auto-created security group open, and what must you do for a web server?

Amazon Linux 2023 is a Fedora clone, yet it ships without FirewallD, which is active by default in Fedora. Why leave it out?

Once an EC2 instance is running, how can you tell from inside whether AWS placed it on Xen or KVM?