Tsukaeru Cloud VPS (Linux) comes with preinstalled CentOS 6. You can choose different distribution or version by recreating a server. However, it is not possible to change OS without recreating server, so be careful with your choice.
Below is a list of available OSes:
- Centos 6 (default)
- Centos 5
- Centos 7
- Ubuntu 14.04
- Debian 6
- Debian 7
- Debian 8
- Scientific Linux 6