# Juju

> Juju is an open source orchestration engine for deploying, integrating, and managing applications across Kubernetes, VMs, and bare metal using software operators called charms.


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## Pages in this subsection

- [Upgrading things](https://documentation.ubuntu.com/juju/4.0/reference/upgrading-things.md): Juju upgrade reference: upgrade CLI clients, controllers, models, applications, and machines with version compatibility guidance.

## Optional

- [Top-level llms.txt](https://documentation.ubuntu.com/juju/4.0/llms.txt): Complete documentation index.