Types of MetaCentrum machines
|List of available hardware||
According to login behavior you can meet with four types of machines in MetaCentrum. These are frontends and computing machines, and virtual machines and their controllers. This page describes the ability of user to login on each type of machine.
Due to the effectivity reasons are some machines in MetaCentrum virtual. This means that there is one physical machine which runs the XEN software to become several virtual machines. Eg. one machine runs several operating systems which might be even different. We use this technology mainly for operation of frontends (described later) and also for Cloud operation.
Physical machine which contains several virtual machines is called dom0 and the virtual machine is domU. From the perspective of possibility of user login on the machines you:
- cannot login to dom0 machine,
- domU machine is fully accessible (with root privileges) when it's a part of cloud, otherwise while used as a frontend, you have the common user rights.
Frontends and working nodes
Frontends are used for setting up of job and for receiving of results or any other interactive work. These are the machines which you can log in anytime. Their list is available here. The most of the frontends are virtual machines. Topical guide How to compute provides information about using frontends for computing.
Working nodes are machines which physically count the user jobs. So they are mainly used for non-interactive work which is assigned to them by scheduling system. You can login in them only with a good reason, for example for cleaning up a mess after failed job or for downloading the data after job failure. Imagine that the working node is in time of your login used by someone's else job which you will slow down by your activity.