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README.md
terraform-bundle
terraform-bundle
is a helper program to create "bundle archives", which are
zip files that contain both a particular version of Terraform and a number
of provider plugins.
Normally terraform init
will download and install the plugins necessary to
work with a particular configuration, but sometimes Terraform is deployed in
a network that, for one reason or another, cannot access the official
plugin repository for automatic download.
In some cases, this can be solved by installing provider plugins into the user plugins directory. However, this doesn't always meet the needs of automated deployments.
terraform-bundle
provides an alternative, by allowing the auto-download
process to be run out-of-band on a separate machine that does have access
to the repository. The result is a zip file that can be extracted onto the
target system to install both the desired Terraform version and a selection
of providers, thus avoiding the need for on-the-fly plugin installation.
Building
To build terraform-bundle
from source, set up a Terraform development
environment per Terraform's own README and then install
this tool from within it:
$ go install ./tools/terraform-bundle
This will install terraform-bundle
in $GOPATH/bin
, which is assumed by
the rest of this README to be in PATH
.
terraform-bundle
is a repackaging of the module installation functionality
from Terraform itself, so for best results you should build from the tag
relating to the version of Terraform you plan to use. For example, use the v0.12
tag to build a version of terraform-bundle compatible with Terraform v0.12*.
Usage
terraform-bundle
uses a simple configuration file to define what should
be included in a bundle. This is designed so that it can be checked into
version control and used by an automated build and deploy process.
The configuration file format works as follows:
terraform {
# Version of Terraform to include in the bundle. An exact version number
# is required.
version = "0.10.0"
}
# Define which provider plugins are to be included
providers {
# Include the newest "aws" provider version in the 1.0 series.
aws = {
versions = ["~> 1.0"]
}
# Include both the newest 1.0 and 2.0 versions of the "google" provider.
# Each item in these lists allows a distinct version to be added. If the
# two expressions match different versions then _both_ are included in
# the bundle archive.
google = {
versions = ["~> 1.0", "~> 2.0"]
}
# Include a custom plugin to the bundle. Will search for the plugin in the
# plugins directory and package it with the bundle archive. Plugin must have
# a name of the form: terraform-provider-*, and must be built with the operating
# system and architecture that terraform enterprise is running, e.g. linux and amd64.
customplugin = {
versions = ["0.1"]
source = "myorg/customplugin"
}
}
The terraform
block defines which version of Terraform will be included
in the bundle. An exact version is required here.
The providers
block defines zero or more providers to include in the bundle
along with core Terraform. Each attribute is a provider name, and its value is a
block with the list of version constraints and (optional) source. For each given
constraint, terraform-bundle
will find the newest available version matching
the constraint and include it in the bundle.
It is allowed to specify multiple constraints for the same provider, in which case multiple versions can be included in the resulting bundle. Each constraint string given results in a separate plugin in the bundle, unless two constraints resolve to the same concrete plugin.
Including multiple versions of the same provider allows several configurations running on the same system to share an installation of the bundle and to choose a version using version constraints within the main Terraform configuration. This avoids the need to upgrade all configurations to newer versions in lockstep.
After creating the configuration file, e.g. terraform-bundle.hcl
, a bundle
zip file can be produced as follows:
$ terraform-bundle package terraform-bundle.hcl
By default the bundle package will target the operating system and CPU
architecture where the tool is being run. To override this, use the -os
and
-arch
options. For example, to build a bundle for on-premises Terraform
Enterprise:
$ terraform-bundle package -os=linux -arch=amd64 terraform-bundle.hcl
The bundle file is assigned a name that includes the core Terraform version number, a timestamp to the nearest hour of when the bundle was built, and the target OS and CPU architecture. It is recommended to refer to a bundle using this composite version number so that bundle archives can be easily distinguished from official release archives and from each other when multiple bundles contain the same core Terraform version.
Custom Plugins
To include custom plugins in the bundle file, create a local directory
"./plugins" and put all the plugins you want to include there, under the
required sub directory. Optionally, you can use the
-plugin-dir
flag to specify a location where to find the plugins. To be
recognized as a valid plugin, the file must have a name of the form
terraform-provider-<NAME>
. In addition, ensure that the plugin is built using
the same operating system and architecture used for Terraform Enterprise.
Typically this will be linux
and amd64
.
Plugins Directory Layout
To include custom plugins in the bundle file, you must specify a "source" attribute in the configuration and place the plugin in the appropriate subdirectory under "./plugins". The directory must have the following layout:
./plugins/$SOURCEHOST/$SOURCENAMESPACE/$NAME/$VERSION/$OS_$ARCH/
When installing custom plugins, you may choose any arbitrary identifier for the $SOURCEHOST and $SOURCENAMESPACE subdirectories.
For example, given the following configuration and a plugin built for Terraform Enterprise:
providers {
customplugin = {
versions = ["0.1"]
source = "example.com/myorg/customplugin"
}
}
The binary must be placed in the following directory:
./plugins/example.com/myorg/customplugin/0.1/linux_amd64/
Provider Resolution Behavior
Terraform's provider resolution behavior is such that if a given constraint can be resolved by any plugin already installed on the system it will use the newest matching plugin and not attempt automatic installation.
Therefore if automatic installation is not desired, it is important to ensure
that version constraints within Terraform configurations do not exclude all
of the versions available from the bundle. If a suitable version cannot be
found in the bundle, Terraform will attempt to satisfy that dependency by
automatic installation from the official repository. If you want
terraform init
to explicitly fail instead of contacting the repository, pass
the -get-plugins=false
option.
For full details about provider resolution, see How Terraform Works: Plugin Discovery.
The downloaded provider archives are verified using the same signature check that is used for auto-installed plugins, using Hashicorp's release key. At this time, the core Terraform archive itself is not verified in this way; that may change in a future version of this tool.
Installing a Bundle in Terraform Enterprise
If using a Terraform Enterprise instance in an "air-gapped" environment, this tool can produce a custom Terraform version package, which includes a set of provider plugins along with core Terraform.
To create a suitable bundle, use the -os
and -arch
options as described
above to produce a bundle targeting linux_amd64
. You can then place this
archive on an HTTP server reachable by the Terraform Enterprise hosts and
install it as per
Administration: Managing Terraform Versions.
After clicking the "Add Terraform Version" button:
- In the "Version" field, enter the generated bundle version from the bundle
filename, which will be of the form
N.N.N-bundleYYYYMMDDHH
. - In the "URL" field, enter the URL where the generated bundle archive can be found.
- In the "SHA256 Checksum" field, enter the SHA256 hash of the file, which can
be found by running
sha256sum <FILE>
orshasum -a256 <FILE>
.
The new bundle version can then be selected as the Terraform version for any workspace. When selected, configurations that require only plugins included in the bundle will run without trying to auto-install.
Note that the above does not apply to Terraform Pro, or to Terraform Premium when not running a private install. In these packages, Terraform versions are managed centrally across all organizations and so custom bundles are not supported.
For more information on the available Terraform Enterprise packages, see the Terraform product site.