# Cloud servers

> What a cloud server is, what you choose when you order one, and how virtual machines and containers share a physical machine.

Source: https://www.coritan.com/docs/learn/cloud-servers/

A *server* is a computer that stays on and connected to the internet, and answers requests from others: visitors to a website, players in a game, apps that store data. Coritan's servers are physical machines in data centres, and you rent a share of one. That share is what people mean by a *cloud server*.

## How a physical machine is shared

A physical machine has far more processor, memory and disk than one customer usually needs, so it runs many customers' servers side by side, each kept apart from the others. There are two ways to share it:

*Virtual machine*
: Software on the physical machine acts as a whole computer, with its own processors, memory, disk and operating system. You control everything inside it, as you would on a computer of your own. A Cloud Compute *instance* is a virtual machine.

*Container*
: A program runs in a space of its own, with its own files and a set share of the machine, and you have no operating system to look after. A Container Apps *server* runs in a container, and so does each replica of an app.

## What you choose

When you order a server or an instance, the order page asks for these:

*Plan*
: The size: how many virtual processors (vCPUs), how much memory and how much disk. Memory holds what the software is working on, such as the game world your players are in. The disk keeps the operating system, your files and your data when the machine restarts.

*Location*
: The data centre it runs in. Choose the one closest to the people who use it, so that their traffic has less far to travel ([Data centres and locations](/docs/platform/data-centres/)).

*Software*
: The operating system image of an instance, or the software a server runs, such as Minecraft or PostgreSQL.

The order page shows the plans, prices and locations you can order at the time.

## Reaching your server

- An instance has a public IPv4 address. You sign in to it over SSH with a key or a password, or use its console in the dashboard ([Connect to an instance over SSH](/docs/cloud-compute/connect-to-an-instance/)).
- A server has an address and a port that players or apps connect to. You run it from the dashboard, with a console, a file manager and SFTP ([Container Apps](/docs/managed-containers/)).

## Who looks after what

On Cloud Compute, you look after everything inside the instance, such as installing software and keeping it up to date. On Container Apps, Coritan installs the software you chose and keeps it running, and you look after its settings and its data. [Container Apps, Cloud Compute and Apps compared](/docs/learn/choose-a-compute-product/) helps you choose between them.

## Paying by the hour or the month

A plan can have a price per hour as well as per month or year. An hourly service takes its price from your credit balance each hour, up to a monthly cap, which suits trying a server out. Your account needs a minimum total of deposits before you can choose it. A stopped server costs nothing by the hour, and an instance costs the same stopped or running until you cancel it ([How hourly billing works](/docs/billing/hourly-billing/)).

## Next steps

- [Get a cloud server](/docs/get-started/get-a-cloud-server/)
- [Create an instance](/docs/cloud-compute/create-an-instance/)
- [Order a server](/docs/managed-containers/order-a-server/)
- [Container Apps, Cloud Compute and Apps compared](/docs/learn/choose-a-compute-product/)
- The [Cloud Compute](https://www.coritan.com/servers/cloud-compute) and [Container Apps](https://www.coritan.com/servers/container-apps) product pages on coritan.com