This article has multiple issues. Please help to improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)
|Initial release||May 5, 2011|
2.9.3 / 7 June 2021
|Written in||Go, Python|
|Operating system||Ubuntu, macOS, CentOS|
|License||GNU Affero General Public License|
Juju is a free and open source application modeling tool developed by Canonical Ltd. Juju focuses on reducing the operation overhead of software by facilitating deploying, configuring, scaling, integrating, and performing operational tasks on public and private cloud services along with bare-metal servers and local container-based deployments.
Juju modeling complex software topologies
Juju aims to provide a modeling language that abstracts the specifics of operating complex software topologies in order to reduce the cost of operations and provide flexibility. A Juju model is an environment to manage and operate a set of software applications. Models can be operated on a variety of public clouds.
A Juju controller is the service that tracks the events, state, and user activity across multiple models. A controller and models are analogous to a database server and databases available on the server. Each model can have different configurations, sets of operating software, and users with various levels of access. Examples of models include a web application, load balancer, and database in a "web-app" model. Models allow deployments to be isolated into logical solutions and managed separately.
The central mechanism behind Juju is called charms. Charms can be written in any programming language that can be executed from the command line. A charm is a collection of YAML configuration files and a selection of hooks. A hook is an executable file that can be used to install software, start or stop a service, manage relationships with other charms, upgrade charms, scale charms, configure charms, etc. Charms can have many properties. Charm helpers allow boiler-plate code to be automatically generated, thus accelerating the creation of charms.
Juju client and environments
Juju has two components: a client and a bootstrap node. After installing the client, one or more environments can be bootstrapped. Juju environments can be bootstrapped on various clouds. By creating a Juju Provider, additional cloud environments can be supported.
Juju can also be bootstrapped on bare-metal servers. Large deployments can use Canonical's Metal as a Service. Small deployments can use the manual provider, which allows any SSH Ubuntu machine to be converted into a Juju-managed machine. Juju can also be installed on a local Ubuntu machine via LXC operating system–level virtualization and the local provider.
Command line and GUI
Juju has both a command line and a GUI. Automatically available on every controller, the Juju GUI and allows users to visually see what software is currently running in which models. It also lets users search the Charm Store and browse results with detailed charm information presented. Complex software stacks can be deployed via drag-and-drop.
Juju also has a concept of bundles. A bundle is a portable specification for a model with charms, configuration, and relations, all specified in a declarative YAML format. A bundle YAML file can later be imported into another Juju model and shared with others. Bundles can also be uploaded to the Charm Store, allowing others deploy them.
services: mediawiki: charm: mediawiki num_units: 1 options: debug: false name: Please set name of wiki skin: vector mysql: charm: mysql num_units: 1 options: binlog-format: MIXED dataset-size: 80% tuning-level: safest series: trusty relations: - - mediawiki:db - mysql:db
The Juju Charm Store launched on April 3, 2012. The Charm Store regularly tests charms to notify charm authors when code breaks in addition to ensuring that Juju users have access to the latest versions of charms.
- "Release 2.9.3". 7 June 2021. Retrieved 21 June 2021.
- Castro, Jorge O. (April 3, 2012). "Why the juju charm store will change the way you use Ubuntu Server". Jorge's Stompbox. Retrieved September 1, 2012.[dead link]
- "CentOS userdata by aznashwan · Pull Request #2066 · juju/juju". GitHub. Retrieved 2021-05-27.
- "Add windows userdata by gabriel-samfira · Pull Request #189 · juju/juju". GitHub. Retrieved 2021-05-27.