Mcollective, short for Marionette Collective, is a powerful orchestration framework that plays a significant role in DevOps practices. This open-source tool, initially developed by Puppet Labs, is designed to manage server orchestration, parallel job execution, and choreography of complex deployment and system management scenarios. Mcollective provides real-time discovery of network resources, enabling DevOps teams to perform specific actions on selected systems simultaneously.
DevOps, a portmanteau of 'development' and 'operations', is a software development methodology that bridges the gap between software developers and IT operations. It promotes a culture of collaboration and communication between these two traditionally siloed teams, facilitating faster and more reliable software releases. Mcollective is one of the tools that support this culture by providing a framework for managing and coordinating tasks across a network of servers.
Definition of Mcollective
Mcollective is an orchestration tool that allows for the management of a large number of servers in real-time. It is built to handle the complex orchestration needs of large-scale infrastructure, providing a way to execute actions on multiple servers simultaneously. Mcollective uses a publish-subscribe middleware, such as ActiveMQ or RabbitMQ, to send and receive messages between the central server and the nodes in the network.
It is important to note that Mcollective is not a configuration management tool like Puppet or Chef. Instead, it complements these tools by providing orchestration capabilities. While configuration management tools are designed to ensure that servers are in a desired state, Mcollective is designed to perform actions on servers, such as restarting services or deploying applications.
Components of Mcollective
Mcollective consists of several components that work together to provide its functionality. These include the Server, which runs on each node and executes the actions; the Client, which sends requests to the servers; the Middleware, which facilitates communication between the clients and servers; and the Agents, which are plugins that define the actions that can be performed.
The Server component of Mcollective runs as a daemon on each node in the network. It listens for messages from the Middleware and executes the requested actions. The Client component is used to send requests to the servers. It communicates with the servers through the Middleware, which acts as a message broker. The Agents are plugins that define the actions that can be performed by the servers. They are written in Ruby and can be customised to perform any action that can be scripted.
Explanation of DevOps
DevOps is a software development methodology that aims to bridge the gap between development and operations teams. It promotes a culture of collaboration and communication, with the goal of delivering software products faster and with fewer bugs. DevOps achieves this by automating and streamlining the software development process, from design, through development, to production.
The term 'DevOps' was first coined in 2009 by Patrick Debois, a Belgian IT consultant, during a conference in Belgium. The concept was born out of the need to improve the collaboration between development and operations teams, which traditionally worked in silos. By breaking down these silos, DevOps aims to create a culture where both teams work together towards a common goal: delivering high-quality software products quickly and reliably.
Principles of DevOps
DevOps is built on several key principles. These include Continuous Integration, Continuous Delivery, Infrastructure as Code, Microservices, Monitoring and Logging, and Communication and Collaboration. Each of these principles plays a crucial role in achieving the goals of DevOps.
Continuous Integration (CI) is a practice where developers frequently merge their code changes into a central repository, after which automated builds and tests are run. Continuous Delivery (CD) is a practice where code changes are automatically built, tested, and prepared for a release to production. Infrastructure as Code (IaC) is a practice where infrastructure is provisioned and managed using code and software development techniques, such as version control and continuous integration.
History of Mcollective
Mcollective was initially developed by Puppet Labs, a company known for its configuration management tool, Puppet. The goal was to create a tool that could handle the orchestration needs of large-scale infrastructure. Mcollective was designed to work with Puppet, but it can also be used independently or with other configuration management tools.
In 2015, Puppet Labs was renamed to Puppet, and Mcollective became a part of the Puppet product suite. However, in 2018, Puppet announced the end of life for Mcollective. Despite this, Mcollective remains a powerful tool for orchestration and is still used by many organizations.
Development of Mcollective
The development of Mcollective was driven by the need for a tool that could handle the orchestration needs of large-scale infrastructure. As infrastructure grew in size and complexity, managing and coordinating tasks across a network of servers became increasingly challenging. Mcollective was designed to address this challenge by providing a framework for executing actions on multiple servers simultaneously.
One of the key features of Mcollective is its use of a publish-subscribe middleware for communication. This allows for real-time discovery of network resources and enables actions to be performed on selected systems simultaneously. This feature, combined with its ability to integrate with other tools, has made Mcollective a popular choice for orchestration in DevOps practices.
Use Cases of Mcollective
Mcollective has a wide range of use cases, particularly in DevOps environments. It can be used for tasks such as deploying applications, managing services, and executing scripts on multiple servers simultaneously. Mcollective's real-time discovery feature also makes it a powerful tool for managing and monitoring large-scale infrastructure.
For example, Mcollective can be used to deploy an application to a group of servers simultaneously. This can significantly reduce the time required for deployment, as well as the risk of errors. Similarly, Mcollective can be used to restart a service on multiple servers at the same time. This can be particularly useful in situations where a service needs to be restarted quickly to resolve an issue.
Examples of Mcollective Use
One specific example of Mcollective use is in the deployment of applications. In a traditional deployment process, an application would be deployed to each server individually. This can be a time-consuming and error-prone process, particularly when dealing with a large number of servers. With Mcollective, the application can be deployed to all servers simultaneously, reducing the time required for deployment and minimizing the risk of errors.
Another example of Mcollective use is in the management of services. For instance, if a service needs to be restarted on a group of servers, this can be done simultaneously using Mcollective. This can significantly reduce the time required to resolve issues and can help to minimize downtime.
Conclusion
In conclusion, Mcollective is a powerful orchestration tool that plays a significant role in DevOps practices. It provides a framework for managing and coordinating tasks across a network of servers, enabling DevOps teams to perform specific actions on selected systems simultaneously. Despite its end of life announcement, Mcollective remains a valuable tool for many organizations due to its robust capabilities and flexibility.
DevOps, on the other hand, is a software development methodology that promotes a culture of collaboration and communication between development and operations teams. By using tools like Mcollective, DevOps teams can automate and streamline the software development process, resulting in faster and more reliable software releases.