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