github.com/aspring/packer@v0.8.1-0.20150629211158-9db281ac0f89/website/source/docs/templates/builders.html.markdown (about) 1 --- 2 layout: "docs" 3 page_title: "Templates: Builders" 4 description: |- 5 Within the template, the builders section contains an array of all the builders that Packer should use to generate a machine images for the template. 6 --- 7 8 # Templates: Builders 9 10 Within the template, the builders section contains an array of all the 11 builders that Packer should use to generate a machine images for the template. 12 13 Builders are responsible for creating machines and generating images from 14 them for various platforms. For example, there are separate builders for 15 EC2, VMware, VirtualBox, etc. Packer comes with many builders by default, 16 and can also be extended to add new builders. 17 18 This documentation page will cover how to configure a builder in a template. 19 The specific configuration options available for each builder, however, 20 must be referenced from the documentation for that specific builder. 21 22 Within a template, a section of builder definitions looks like this: 23 24 ```javascript 25 { 26 "builders": [ 27 // ... one or more builder definitions here 28 ] 29 } 30 ``` 31 32 ## Builder Definition 33 34 A single builder definition maps to exactly one [build](/docs/basics/terminology.html#term-build). 35 A builder definition is a JSON object that requires at least a `type` key. The 36 `type` is the name of the builder that will be used to create a machine image 37 for the build. 38 39 In addition to the `type`, other keys configure the builder itself. For 40 example, the AWS builder requires an `access_key`, `secret_key`, and 41 some other settings. These are placed directly within the builder definition. 42 43 An example builder definition is shown below, in this case configuring 44 the AWS builder: 45 46 ```javascript 47 { 48 "type": "amazon-ebs", 49 "access_key": "...", 50 "secret_key": "..." 51 } 52 ``` 53 54 ## Named Builds 55 56 Each build in Packer has a name. By default, the name is just the name 57 of the builder being used. In general, this is good enough. Names only serve 58 as an indicator in the output of what is happening. If you want, however, 59 you can specify a custom name using the `name` key within the builder definition. 60 61 This is particularly useful if you have multiple builds defined that use 62 the same underlying builder. In this case, you must specify a name for at least 63 one of them since the names must be unique. 64 65 ## Communicators 66 67 Every build is associated with a single 68 [communicator](/docs/templates/communicator.html). Communicators are 69 used to establish a connection for provisioning a remote machine (such 70 as an AWS instance or local virtual machine). 71 72 All the examples for the various builders show some communicator (usually 73 SSH), but the communicators are highly customizable so we recommend 74 reading the 75 [communicator documentation](/docs/templates/communicator.html).