Cloud Computing

From FEFF

Using the JFEFF GUI, one can run feff calculations on the EC2 cloud. JFEFF will then send a request to EC2 to prepare a high-performance cloud cluster containing a specified number of nodes. The feff calculation is then run on the cloud cluster and the results are copied back to the user’s local machine when finished. This way of performing calculations, which we call Scientific Cloud Computing, is an alternative to traditional parallel computing. It allows one to run demanding calculations that would traditionally require expensive and hard-to-maintain local clusters.

Note that it takes a short time (typically 3-4 minutes) to prepare the cloud cluster. Therefore, it makes no sense to use Scientific Cloud Computing for very short calculations.

Cloud computing is not a free service. EC2 charges its users per hour and per node. The user needs to set up a customer account with Amazon Web Services (AWS). This is very easy but requires a credit card. EC2 usage charges are then billed to this account. We have found that these charges are typically reasonable and much cheaper than buying one’s own hardware unless one has a constant demand for computational power.

In the JFEFF Settings window you can specify the credentials identifying your AWS ac- count. Once this is done, deploying a calculation to the EC2 cloud is as easy as setting the slider on the main panel to ”Cloud” and pressing ”Save & Run”. The calculation will then be run on the cloud. This takes a few minutes to set up the cloud cluster, plus calculation time depending on the calculation you request and the number of nodes you make available. Typically, we recommend running the feff code on 1-64 threads. Note that in the current implementation the cloud cluster will be terminated when the calculation ends, to avoid being charged for a cluster you accidentally forget to terminate. However, this means that if you start many short calculations on the cloud that each take only a few minutes, each will be billed for an hour of EC2 time. All the feff output files will automatically be copied back to your own computer when the calculation finishes. There is absolutely no need for you to log in to the cloud cluster, or to do anything from the command line on your own computer.

To give you the opportunity to try out Scientific Cloud Computing before you set up your own AWS account, JFEFF installs a ”Demo Mode”. This means that you can run a cloud calculation ”on the house”. You don’t need to do anything to activate the Demo Mode. If you simply put the slider of the ”Run” panel to ”Cloud”, it will automatically launch using demo mode if you haven’t yet configured your own account. Please don’t abuse this privilege - all these calculations are billed to the feff project and we are not able to fund your research project. We only intend this to be used for demo (”try before you buy”) purposes. Also, as a safety feature, any such calculations are limited to using a maximum of 8 nodes, and each node will be of the ”small” type. AWS offers other node types that are much faster, but somewhat more expensive.

If you require any help with this new development, please contact us. We are currently looking for ”beta users”.

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