> For the complete documentation index, see [llms.txt](https://blueprint.onehilltech.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://blueprint.onehilltech.com/developer-guide/blueprint-cluster/background.md).

# What is a Blueprint Cluster?

[Clustering](https://nodejs.org/api/cluster.html) in NodeJS is the process of running multiple instances of a NodeJS application such that one process is the master process and the other processes are worker processes. This is necessary feature because a NodeJS application is single-threaded. This means that all events are processed by the same execution thread. We you run a NodeJS application on a multi-core machine, it is hard for the NodeJS application to take advantage of computing power available via the many cores on the machine.

We understand the importance of [running a NodeJS cluster](https://nodejs.org/api/cluster.html) when it relates to scaling an NodeJS application to handle large numbers of requests. We therefore have integrated cluster support into Blueprint.

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A *Blueprint cluster* is when you run a Blueprint application as a NodeJS cluster.
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Blueprint cluster is an experimental feature. Its functionality may change in the future as we learn more about its usage in the wild.
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