Why Configuration Management?

DevOps and CM(Configuration Management) are different. DevOps is about collaboration between people, while CM tools are just that: tools for automating the application of configuration states. Like any other tools, they are designed to solve certain problems in certain ways.
Using CM you can make changes very quickly, but needs to validate those changes. In considering which configuration management tool to select, you should also think about which complementary tool(s) you will use to avoid the costly effects of automating the deployment of bugs in your infrastructure-as-code.  

The advantages of software configuration management (SCM) are:

   –  It reduces redundant work
   –  It effectively manages simultaneous updates
   –  It avoids configuration related problems
   –  It simplifies coordination between team members
   –  It is helpful in tracking defects

Top five(5) tools for configuration management
    
1) Chef –

Like Puppet, Chef is also written in Ruby, and its uses a Ruby-based DSL. Chef utilizes a master-agent model, and in addition to a solo mode call chef-solo.
Chef is one of the most popular SCM tools. It is basically a framework for infrastructure development. It provides support and packages for framing ones infrastructure as code. It offers libraries for building up an infrastructure, which can be deployed easily. It produces consistent, shareable and reusable components, which are known as recipes and are used to automate infrastructure. It comprises the Chef server, workstation, repository and the Chef client.

2) Puppet –
Another SCM tool commonly used is Puppet. It was first introduced in 2005 as an open source configuration management tool. It is written in Ruby. This CM system allows defining the state of the IT infrastructure, and then automatically enforces the correct state. The user describes the systems resources and their state, either by using Puppets declarative language or a Ruby DSL. This information is stored in files known as Puppet manifests. It discovers system information through a utility called Facter and compiles it into a system-specific catalogue containing resources and their dependencies, which are applied against the target systems.

It is frequently stated that Puppet is a tool that was built with sysadmins in mind. The learning curve is less imposing due to Puppet being primarily model driven. Getting your head around JSON data structures in Puppet manifests is far less daunting to a sysadmin who has spent their life at the command line than Ruby syntax is.

3) Ansible –

A newer offering on the market, Ansible has nonetheless gained a solid footing in the industry.
Ansible is an open source platform for CM, orchestration and deployment of compute resources. It manages resources with the use of SSH (Paramiko, a Python SSH2 implementation, or standard SSH). Currently their solutions consists of two offerings: Ansible and Ansible Tower, the latter featuring the platform’s UI and dashboard. Despite being a relatively new player in the arena when compared to competitors like Chef or Puppet, it’s gained quite a favorable reputation amongst DevOps professionals for its straightforward operations and simple management capabilities.

4) SaltStack –

Salt is an open source multitasking CM and remote execution tool. It has a Python-based approach to represent infrastructure as a code philosophy. The remote execution engine is the heart of Salt. It creates a high speed and bi-directional communication network for a group of resources. A Salt state is a fast and flexible CM system on top of the communication system provided by the remote execution engine. It is a CLI-based tool.
It was also developed in response to dissatisfaction with the Puppet/ Chef hegemony, especially their slow speed of deployment and restricting users to Ruby. Salt is sort of halfway between Puppet and Ansible – it supports Python, but also forces users to write all CLI commands in either Python, or the custom DSL called PyDSL. It uses a master server and deployed agents called minions to control and communicate with the target servers, but this is implemented using the ZeroMq messaging lib at the transport layer, which makes it a few orders of magnitude faster than Puppet/ Chef.

5) Juju –

Juju is an open source configuration management and orchestration management tool. It enables applications to be deployed, integrated and scaled on various types of cloud platforms faster and more efficiently. It allows users to export and import application architectures and reproduce the same environment at different phases on cloud platforms such as Joyent, Amazon Web Services, Windows Azure, HP Cloud and IBM.

The main mechanism behind Juju is known as Charms that can be written in any programming language, whose execution is supported via the command line. They are a collection of YAML configuration files.
Clients are available for Ubuntu, Windows and Mac operating systems. Once you install the client, environments can be bootstrapped on various cloud platforms such as Windows Azure, HP Cloud, Joyent, Amazon Web Services and IBM.

Thank you,
Arun Bagul