Provisioners

Provisioners are components used in infrastructure automation to perform tasks on a machine after it has been created, installing software, configuring services, and applying settings. They are commonly employed in image builders, cloud provisioning workflows, and development environments to bring a system to a desired state.

Provisioners operate by executing commands or scripts, transferring files, or invoking configuration management tools. They may be built into provisioning frameworks or provided as plugins, and can deploy across virtual machines, containers, and physical servers. Examples include shell or script provisioners that run shell, PowerShell, or Python scripts; file provisioners that copy configuration files; and adapters for configuration management systems such as Chef, Puppet, Ansible, and Salt. In some ecosystems, tools like Packer or Vagrant expose provisioners to automate post-deployment steps.

Common use cases include installing and updating software, configuring services, creating users and permissions, applying security hardening, and validating that the system is ready for use. Provisioners help automate repetitive setup tasks and improve reproducibility across environments.

Key considerations include idempotence and reproducibility, as re-running provisioning should not or should safely be able to handle repeated executions. Security concerns involve handling credentials and sensitive data; access to the target system must be restricted and audited. Provisioners are often complemented by configuration management and immutable infrastructure patterns; for some workflows, immutable images with baked-in configuration reduce the need for provisioning at run time.

See also: Packer, Vagrant, Terraform, configuration management tools, infrastructure as code.