How to Install an OS on a Dedicated Server from the Panel

CubePath dedicated servers are delivered in rescue mode, without an operating system installed on the disks. You install the operating system yourself from the client area with the Rebuild server option, which also lets you choose the user, password and RAID layout. In this guide you will install an operating system on your dedicated server, log in for the first time and apply a basic security baseline.

Prerequisites

To follow this guide you need:

An active CubePath dedicated server and access to the client area.
An SSH client on your computer (the ssh command on Linux and macOS, or the built-in OpenSSH client on Windows 10 and later).
A strong password ready for the initial user. Use a password manager to generate it.

Warning

Rebuilding a server reinstalls it from scratch and erases the data on its disks. If you are reinstalling a server that is already in use, back up everything you need first.

Step 1 - Opening the Rebuild server section

Log in to the client area and select the dedicated server you want to install. In the menu on the left side, click Rebuild server.

Rebuild server option in the server menu

In this section, press the Rebuild button to open the installation options.

Rebuild button

Step 2 - Choosing the installation options

The rebuild form shows the reinstallation options, including the operating system, the user, the password and the RAID type. Consider the following when filling it in:

Operating system: choose a current long-term support release, such as Ubuntu 24.04 LTS or Debian 12, unless your software requires something else.
User and password: this is the account you will use for the first SSH login. Use a long, unique password.
RAID type: the choice depends on how many disks the server has and what matters most to you:

RAID level	Minimum disks	Usable space	Survives
RAID 0	2	Sum of all disks	No disk failures
RAID 1	2	One disk	Failure of one disk (in a pair)
RAID 10	4	Half of the total	One disk per mirrored pair

For most servers with two disks, RAID 1 is the sensible default: you lose half the raw capacity, but the server keeps running if a disk fails. Use RAID 0 only for data you can afford to lose, such as caches or scratch space.

Step 3 - Starting the installation

Confirm the form. The server starts reinstalling immediately, and during the installation it is not reachable over SSH. The server reboots into the new operating system when the process finishes, which can take several minutes. Give it time to finish before connecting.

Step 4 - Logging in for the first time

Connect over SSH with the user and password you chose in Step 2. Replace your_user and your_server_ip with your values:

ssh your_user@your_server_ip

The first time you connect, SSH asks you to confirm the server's host key. Type yes:

The authenticity of host 'your_server_ip (your_server_ip)' can't be established.
ED25519 key fingerprint is SHA256:...
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes

Check that the expected operating system is installed:

cat /etc/os-release

PRETTY_NAME="Ubuntu 24.04.3 LTS"
NAME="Ubuntu"
VERSION_ID="24.04"
...

Step 5 - Checking the disks and RAID

Review the disk layout to confirm that all disks are in use as expected:

lsblk

If you selected a software RAID level, check the state of the array. Every array should be listed as active, with [UU] for a healthy two-disk mirror:

cat /proc/mdstat

Personalities : [raid1]
md0 : active raid1 sdb2[1] sda2[0]
      936568832 blocks super 1.2 [2/2] [UU]
      [==>..................]  resync = 12.4% (116234752/936568832) finish=70.1min speed=195000K/sec

A resync in progress right after installation is normal: the array keeps working while it synchronizes the disks.

Step 6 - Updating and securing the server

Install the latest security updates. The commands below are for Ubuntu and Debian:

sudo apt update
sudo apt upgrade -y

Set up key-based SSH authentication. On your local computer, create a key if you do not have one, and copy it to the server:

ssh-keygen -t ed25519
ssh-copy-id your_user@your_server_ip

Confirm that you can log in with the key before changing anything else:

ssh your_user@your_server_ip

Enable the UFW firewall, making sure SSH stays allowed:

sudo ufw allow OpenSSH
sudo ufw enable
sudo ufw status

Status: active

To                         Action      From
--                         ------      ----
OpenSSH                    ALLOW       Anywhere
OpenSSH (v6)               ALLOW       Anywhere (v6)

Once key login works, you can disable password authentication for SSH by setting PasswordAuthentication no in /etc/ssh/sshd_config and restarting the service with sudo systemctl restart ssh.

Troubleshooting

WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! after a reinstall. This is expected, because the new installation generated new host keys. Remove the old key from your computer with ssh-keygen -R your_server_ip and connect again.
SSH connection refused or timing out. The installation may still be running. Wait a few more minutes and try again. If it still fails, contact CubePath support.
A RAID array shows [U_]. One disk is missing from the array. Open a support ticket with the output of cat /proc/mdstat and lsblk.

Conclusion

Your dedicated server now runs the operating system you selected in the control panel, with the RAID layout you chose, current updates, key-based SSH access and a firewall. From here you can install your application stack, such as a web server, Docker or a database. Keep in mind that the Rebuild server option is also the way to reinstall the server later from scratch.

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