58 lines
2.9 KiB
Markdown
58 lines
2.9 KiB
Markdown
---
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layout: "intro"
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page_title: "Consul Example"
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sidebar_current: "examples-consul"
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description: |-
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Consul is a tool for service discovery, configuration and orchestration. The Key/Value store it provides is often used to store application configuration and information about the infrastructure necessary to process requests.
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---
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# Consul Example
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[**Example Source Code**](https://github.com/terraform-providers/terraform-provider-consul/tree/master/examples/kv)
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[Consul](https://www.consul.io) is a tool for service discovery, configuration
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and orchestration. The Key/Value store it provides is often used to store
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application configuration and information about the infrastructure necessary
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to process requests.
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Terraform provides a [Consul provider](/docs/providers/consul/index.html) which
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can be used to interface with Consul from inside a Terraform configuration.
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For our example, we use the [Consul demo cluster](https://demo.consul.io/)
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to both read configuration and store information about a newly created EC2 instance.
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The size of the EC2 instance will be determined by the `tf_test/size` key in Consul,
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and will default to `m1.small` if that key does not exist. Once the instance is created
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the `tf_test/id` and `tf_test/public_dns` keys will be set with the computed
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values for the instance.
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Before we run the example, use the [Web UI](https://demo.consul.io/ui/dc1/kv/)
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to set the `tf_test/size` key to `t1.micro`. Once that is done,
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copy the configuration into a configuration file (`consul.tf` works fine).
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Either provide the AWS credentials as a default value in the configuration
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or invoke `apply` with the appropriate variables set.
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Once the `apply` has completed, we can see the keys in Consul by
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visiting the [Web UI](https://demo.consul.io/ui/dc1/kv/). We can see
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that the `tf_test/id` and `tf_test/public_dns` values have been
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set.
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You can now [tear down the infrastructure](https://learn.hashicorp.com/tutorials/terraform/aws-destroy?in=terraform/aws-get-started&utm_source=WEBSITE&utm_medium=WEB_IO&utm_offer=ARTICLE_PAGE&utm_content=DOCS).
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Because we set the `delete` property of two of the Consul keys, Terraform
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will clean up those keys on destroy. We can verify this by using
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the Web UI.
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This example has shown that Consul can be used with Terraform both to read
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existing values and to store generated results.
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Inputs like AMI name, security groups, Puppet roles, bootstrap scripts,
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etc can all be loaded from Consul. This allows the specifics of an
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infrastructure to be decoupled from its overall architecture. This enables
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details to be changed without updating the Terraform configuration.
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Outputs from Terraform can also be easily stored in Consul. One powerful
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feature this enables is using Consul for inventory management. If an
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application relies on ELB for routing, Terraform can update the application's
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configuration directly by setting the ELB address into Consul. Any resource
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attribute can be stored in Consul, allowing an operator to capture anything
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useful.
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