Ubuntu Server 24.04 LTS with an LVM disk layout, so you can grow the root filesystem online and reshape storage without repartitioning.
Ubuntu Server 24.04 LTS LVM is the long term support Ubuntu release cut with an LVM root layout: the root filesystem lives on a logical volume (ubuntu-vg/ubuntu-lv, the standard Ubuntu Server LVM naming) inside a volume group rather than on a fixed raw partition. There is no application layered on top: the operating system is the product. The LVM layout means you can extend the root volume onto a larger disk while the system is running, add new volumes for data or applications, and reshape storage with standard LVM tooling instead of being locked to the size and shape the image shipped with.
cloudimg builds the LVM layout from its own hardened Ubuntu Server 24.04 LTS base, brings it to a fully patched state at capture, verifies the LVM layout is genuinely in place with a proven online grow, and hardens it before it ships. There is no default login: SSH access is by the key you supply at launch, password authentication is off and the root account is locked. AppArmor ships enforcing, unattended security updates are armed and proven with a real dry run, machine identity and SSH host keys are regenerated uniquely on every instance, and the image is backed by a paired deploy guide and 24/7 support.