51-infrastructure-as-code.rst

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Infrastructure As Code (IAC)

Definition:

Infrastructure as Code (IAC) is a type of IT infrastructure that operations teams can automatically manage and provision through code, rather than using a manual process. Infrastructure as Code is sometimes referred to as programmable infrastructure.

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• Concept of IAC is similar to programming scripts

• IAC uses higher-level or descriptive language to code:

  • Versatile and adaptive provisioning
  • Deployment process(es)

• IAC process closely resembles formal software design practices:

  • Developers carefully control code versions
  • Test code iterations
  • Limit deployment until the software is proven and approved for production

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Example

Using Ansible (or Vagrant/Puppet/Chef/Salt...), an IT management and configuration tool, one could:

• Install MySQL server,
• Verify that MySQL is running properly,
• Create a user account and password,
• Set up a new database and remove unneeded databases

-> all through code.

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Using code to provision and deploy servers and applications is particularly interesting to software developers:

• No dependency on system administrators to provision and manage the operations aspect of a DevOps environment
• IAC process can provision and deploy a new application for quality assurance or experimental deployment

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IAC also introduces potential disadvantages:

• IAC code development may require additional tools that could introduce learning curves and room for error
• Errors in IAC code can proliferate quickly through servers
• Monitoring/peer review for version control and comprehensive pre-release testing is mandatory

• If administrators can change server configurations without changing IAC code:

  • Potential for configuration drift
  • Inconsistent configurations across data centers

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It is therefor important to fully integrate IAC into:

• Systems administration
• IT operations
• DevOps processes
• With well-documented policies and procedures

1, 2, automate

DevOps mantra meaning you should consider automating everything you envision to do more than 2 times in the foreseable future.

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IAC @ Citrix

• Jenkins node itself is build and deployed using Jenkins job

  • Jenkins service and ELB as two cloud formations

• Build slave images are created using Jenkins jobs

• Jenkins can run build jobs inside docker containers

  • A generic docker build slave can be reused by different jobs
  • The docker images are build with Jenkins jobs

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Jenkins Deploys Jenkins

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Docker Image Creation