Infrastructure as Code (IaC)

IaC is a process to set up a development or production environment (infrastructure) which includes servers, databases, applications etc. declaratively by using languages such as YAML and HashiCorp Configuration Language (HCL). We can imagine it as the tool could use the blueprint to automatically construct a house without manual labour to do so.

It makes the underlying infrastructure scalable especially for cloud environment# environment. Since the set-up is coded into a file, Version Control System (VCS)# could be used on it, where human errors can be traced and reverted easily to reduce inconsistency.

IaC tools could be categorised according to their functions and their role during the set-up:

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Terraform Data Source

#HashiCorp Terraform could provision other resources that are managed by other Infrastructure as Code (IaC) tools or manual maintenance using Data Sources. However, it doesn’t have any permission other than reading the infrastructure in contrast to Terraform Providers. It can be defined in HashiCorp Configuration Language (HCL)# as follows:
Server Templating

Server Templating tools are often used to set up an Immutable Infrastructure# using Virtual Machine (VM)# and Container# images. To modify the underlying infrastructure in demands of changing requirements, it can simply update the existing images without affecting other already running environment. #Infrastructure as Code (IaC) sometimes involves Server Templating.
Infrastructure Provisioning

Infrastructure Provisioning is necessary when there is a need for the automatic set-up of #infrastructure components such as servers, databases, network, security etc. across multiple platforms or providers.
Infrastructure Configuration Management

Infrastructure Configuration Management involves the installation of software and the management of its dependencies. All changes will be done idempotent (change only if necessary) adhere to the defined configuration. Sometimes, version control will be included into the process. It is part of the #Infrastructure as Code (IaC) procedure.
Immutable Infrastructure

Immutable Infrastructure is a server deployment paradigm where services are replaced instead of being updated in place. The soon-to-be replaced service doesn’t get changed, the new service with the appropriate changes will be created, and the old service will simply be destroyed (with the help from Infrastructure as Code (IaC)# tools). It eases the work of versioning (updating services), rollback, recovery, and scaling.
HashiCorp Terraform

A usual Terraform workflow should start with initialising the project and identify the Terraform Providers# to be used for the target environment using the command terraform init (initialise phase). Then, dry-run or test blueprint for each target environment by laying out the action that will be carried out with the command terraform plan (planning phase). Finally, apply the blueprint and make necessary changes for the target environment accordingly by running terraform apply (apply phase). Both terraform plan and terraform apply change the state of Terraform. The state of the resources is recorded in the file terraform.tfstate. If there is a disparity between current environment and the blueprint such as missing plugins#, Terraform will fix it in order to adhere to the specified requirements. Otherwise, one could simply run terraform refresh to synchronise the state of Terraform and the underlying infrastructure. We can import resources that is created manually or providers that is outside Terraform Registry# (from other #Infrastructure as Code (IaC) tools).

Terraform is an #open source automation tool used for #Infrastructure as Code (IaC) which is available in multiple platforms such as Windows, Apple and Linux. It can manage on-premise server, Cloud Computing# (AWS, Azure, Google Could Platform), #Virtual Machine (VM) (VMWare), Version Control System (VCS) and protocol (HTTP, TLS, Domain Name Server (DNS)) using Terraform Providers# available in Terraform Registry#.
Ansible

Ansible is an open source automation tool for system administration especially in 202204081225. It could be used for system monitoring, #202205041217, disaster recovery, system maintenance, policy enforcement etc. It is one of the widely adopted #202206061419 tool.

#devops #iac #automation