Terraform vs. Ansible: Understanding the Key Differences

Once the end state is defined, the tool automatically executes the necessary steps to achieve it. Users can describe the desired state and automate the transition process from one state to another.

Ad hoc commands are executed for the implementation of procedural configurations.

The Ansible documentation contains in-depth insights on its approach and teaches users the effects of adding and subtracting resources for achieving the desired results. It is important to explicitly indicate the resource requirements when leveraging Ansible.

Users can create reusable configurations for provisioning across environments. Reusable components can also be created within configuration files via modules.

Terraform also features managed states, with state files monitoring all modifications within the environment. Changes are tracked and cannot occur without explicit user specification. Automation allows Terraform to spot and fix config drifts to ensure the desired state is met at all times.

Terraform simplifies rollbacks through version-controlled configurations and managed states, thus removing the need for complicated reconfigurations.

Finally, Terraform’s workflow allows for simplified integration with any CI/CD pipeline, thus driving the end-to-end automation of infrastructure management.

Ansible does not use a dependency system, thus executing tasks sequentially and stopping once an error is identified. This simplifies troubleshooting–even for beginners.

Another key feature of Ansible is the use of the human-readable Python language, which makes setup simple via Python libraries that are present on most Linux distributions.

Any language can be used for creating Ansible modules as long as data is returned in JSON format.

Playbooks, as Ansible configuration files are known, are written in YAML. This allows for easy readability, support for comments, and the use of anchors for referencing, and helps boost Ansible’s automation and configuration management capabilities.

All Ansible master-agent communications run via Paramiko or Standard SSH. This removes the need for installing agents for managing remote systems and minimizes performance degradation and maintenance overheads.

Finally, the Ansible Galaxy is useful for sharing and receiving Ansible-related content. For instance, a user can download reusable roles for installing applications and configuring servers. This can potentially boost the speed of deployments.

Modules have an input variable as well as an output variable. While the former accepts values from a calling module, the latter returns data to the calling module. Configurations are sped up through modules calling each other.

The Terraform Registry is a centralized repository for sharing modules. It enables users to discover and access Terraform modules and is available in public and private variants. 

While the former contains services that support API interactions for exposing and managing particular resource and community-sourced modules, the latter contains services for modules used internally by enterprises.

Publishing modules to the Terraform Registry requires them to have a naming structure, a standard module structure, a repository description, a compatible version control system, and release tags.

If an endpoint with a different version of the software is detected, Ansible will determine the operating system of that endpoint and execute the steps to update the software accordingly. In this example, all endpoints in the organization are updated overnight!

However, infrastructure maintenance is more than simply checking software versions. Using Ansible essentially means using its modules, as each module performs a particular task.

If users need to automate a specific process across multiple endpoints, they will need to first locate the best-suited module for the task at hand. Then, they must install Ansible, configure the module, and execute it. Users with programming experience can also write custom modules for specialized tasks.

Finally, if any user deems a module to be useful for others and wishes to share it, they may do so by submitting it to the Ansible Project for inclusion.

States are responsible for both, providing and monitoring configuration changes. All state files map the most recent configuration of infrastructure resources.

Users can import preexisting resources under Terraform management by using state files from external infrastructure.

Finally, users can query state files to gain insights into infrastructure components and their present characteristics.

Since configuration management is a key feature of Ansible and immutable infrastructure is assumed by default, modifications made to the configuration are executed automatically on the target resource.

• Simplifying collaboration:

Terraform Cloud can directly connect with the user’s version control system (VCS) provider. This helps ensure effective version control in IaC and enables team-level collaboration on infrastructure. Users get specific code versions that can be used for creating different environments for testing or other applications.

• Creating reproducible and transient environments:

Terraform lets users share and reuse infrastructure and allows for environments to be recreated repeatedly. For instance, the production environment can be codified and then distributed for QA, development, or staging. Each configuration can be used for the swift creation of new testing environments and then disposed of.

• Multicloud:

Existing infrastructure management solutions are often cloud-specific, making multicloud deployments challenging. By being cloud-agnostic, Terraform enables users to leverage one configuration for managing multiple providers and administering cross-cloud dependencies. Multicloud orchestration and management become easy with Terraform, allowing for seamless large-scale infrastructure deployments.

• Multi-tier applications:

A collection of resources can be referred to as a tier. With Terraform, the dependencies among tiers are managed automatically. For instance, the database tier is made available prior to the web servers commencing operations, and the web nodes are visible to the load balancers. 

The scaling of tiers is simplified with Terraform, as a user only needs to modify a single count configuration value. Through the codified and automated creation and provisioning of resources, elastic scaling with load is simplified.

• Software defined networking (SDN):

Terraform’s readability allows network engineers to simplify the codification of SDN configuration.

• Prepackaged configurations:

Registries simplify locating prepackaged configurations that can be tweaked to fulfill a specific goal or even leveraged as is.

• Resource scheduling:

Terraform modules are capable of allowing Kubernetes to schedule Docker containers and for stopping and starting resources on the cloud.

• External resource management:

Finally, Terraform is compatible with cloud infrastructure (both public and private), software as a service (SaaS) deployments, and network appliances.

• Configuration management:

Lightweight, secure, and reliable, Ansible simplifies the automation of day-to-day IT processes. It has a gentle learning curve and can be practiced easily by developers, administrators, and other IT personnel alike. Ansible features data descriptions for infrastructure that are easily decipherable for both humans and machines. This allows users to easily understand the details of configuration tasks.

• Infrastructure provisioning:

Ansible makes it easy to prepare infrastructure such as cloud platforms or servers for application installation and configuration. It removes the strain associated with provisioning hundreds of servers manually and allows for swift and reliable scaling of IT infrastructure. 

Using the right Ansible playbook allows users to build a single instance and replicate it on numerous servers with similar infrastructure parameters. Once provisioned, the environment can be configured using Ansible’s effective IT operational lifecycle management capabilities.

• Application deployment:

Ansible is used for the reliable and consistent deployment of multi-tier applications from a single common framework. It also allows users to configure the required services and push application artifacts from a common system.

Additionally, it removes the need for custom code for system automation, enabling users to get the same results by writing simple task descriptions that any team member can understand. This helps make the DevOps process dynamic and cost-effective, especially over the long term.

• Cloud provisioning:

Similar to infrastructure provisioning, Ansible is an effective automation tool for cloud provisioning. It supports multiple cloud platforms, network devices, bare-metal servers, and virtualized hosts.

• Security and compliance:

Finally, Ansible is an effective tool for automating the implementation of enterprise-wide security policies such as locking down users or adding firewall rules.

The user simply needs to configure the relevant security parameters on the control machine and execute the associated playbook. Ansible will automatically update all target hosts remotely. It also removes the need for the manual monitoring of individual endpoints for security compliance. And, as an added security measure, admin credentials cannot be retrieved in plaintext on Ansible.