OS images

The catalogue

Every FastNode plan in London can boot any of the images below. There is no premium tier for a particular distribution and no plan that restricts your choice. The image decides your package manager, your default firewall front-end, your security tooling and, most importantly, how long you get free security patches.

Dates come from the upstream projects and can shift. Check the vendor's own lifecycle page before you commit a production system to a release.

Pick by lifecycle first

A server you deploy this week may still be running in four years. Work backwards from that. If the box will live past 2027, Ubuntu 22.04 and Debian 12 are the wrong starting point: both are already in, or close to, their tail end. Start on Ubuntu 24.04 LTS or Debian 13 and you skip an in-place major upgrade for years.

For short-lived machines the calculation flips. A CI runner rebuilt every month, or a staging box torn down after a release, can sit on whichever image matches production. Matching production beats running the newest release.

Pick by tooling second

The apt family (Ubuntu, Debian) and the dnf family (AlmaLinux, Rocky) differ in more than the install command:

• Firewall front-end. Ubuntu ships ufw. Debian ships nothing active; you add nftables rules or install ufw. Alma and Rocky use firewalld zones.
• Mandatory access control. Ubuntu uses AppArmor. Alma and Rocky enforce SELinux by default, which breaks naive setups that write to unexpected paths, and protects you when something gets popped.
• Automatic patching. unattended-upgrades on apt systems, dnf-automatic on RHEL-family systems. Neither is a substitute for rebooting into new kernels.
• Package freshness. Ubuntu and Debian ship newer language runtimes in the base archive. The RHEL family ships older bases and adds newer versions through AppStream modules.

If your team has years of muscle memory on one family, stay there. Debugging a firewall at 2 a.m. is not the moment to learn firewalld.

When to choose Windows

Pick Windows Server 2025 only when the workload needs it: .NET Framework services that never moved to modern .NET, IIS sites, a Windows build agent, or a vendor tool with no Linux port. Windows wants more memory than Linux does. Plan on Turbo or larger, and talk to support about licensing before you order.

Sizing by image

A minimal Debian 13 install idles in well under 200 MB of RAM. Ubuntu 24.04 with snapd sits a little higher. Alma and Rocky land in between. All three Linux families run comfortably on Spark for a single small service. Windows Server needs several gigabytes before your application loads. The plan pages break this down: Boost suits most single-app Linux deployments, Warp and Hyper suit databases and build hosts.

Reinstalling and rescue

The portal can reinstall any image on an existing server. A reinstall wipes the disk. Snapshot first if anything on it matters. If you lock yourself out, with a broken sshd_config or a firewall rule that drops your own IP, use the browser console or boot into rescue mode and mount the disk. You don't need to reinstall to recover access.

What every image gets

Every image boots as a VMware virtual machine with NVMe-backed storage, a 1 Gbps port, unmetered traffic and one IPv4 address. You get root (or Administrator) from the first boot. SSH keys added in the portal are available at deploy time. Outbound port 25 is blocked by default on every image. Request an unblock in the portal if you genuinely run a mail server.