mirror of https://github.com/hashicorp/consul
53 lines
2.2 KiB
Markdown
53 lines
2.2 KiB
Markdown
---
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layout: docs
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page_title: Architecture
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sidebar_title: Architecture
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description: >-
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Consul-Terraform-Sync Architecture
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---
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# Consul-Terraform-Sync Architecture
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Consul-Terraform-Sync is a service-oriented tool for managing
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network infrastructure near real-time. Consul-Terraform-Sync runs as a daemon
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and integrates the network topology maintained by your Consul cluster with your
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network infrastructure to dynamically secure and connect services.
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## 10,000 Foot View
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[](/img/nia-highlevel-diagram.png)
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The diagram shows Consul-Terraform-Sync monitoring the Consul service catalog
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for updates and utilizing Terraform to update the state of the infrastructure.
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There are two principal aspects of Sync to know about corresponding to the
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lines to Consul and Terraform in the diagram above. The line to Consul
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represents the Watchers monitoring the state of Consul's service catalog (and
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possibly KV store) while the line to Terraform represents tasks being run to
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update the infrastructure.
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## Watcher and Views
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Consul-Terraform-Sync monitors Consul for updates utilizing Consul's [Blocking
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Queries](/api-docs/features/blocking) whenever supported, falling back on
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polling when not. The watcher maintains a separate thread (known internally as
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a view) for each value monitored, running any tasks that depend on that watched
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value whenever it's updated. Say, for example, running a task to update a
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proxy when an instance goes unhealthy.
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## Tasks
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A task is the action triggered by the updated data monitored in Consul. It
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takes the that dynamic service data and translates it into a call to the
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infrastructure application to configure it with the updates. It uses a driver
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to push out these updates, the initial driver being a local Terraform run. An
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example of a task is to automate a firewall security policy rule with
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discovered IP addresses for a set of Consul services.
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## Drivers
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A driver encapsulates the resources required to communicate the updates to the
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network infrastructure. Terraform is the initial supported driver. It comes
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with a set of providers that [enables supporting](/docs/nia/installation/requirements#how-to-create-a-compatible-terraform-module) a wide variety of
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infrastructure applications.
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