README
¶
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. There is some slack in
this requirement due to the fact that the module installation behavior changes
rarely, but please note that in particular bundles for versions of
Terraform before v0.12 must be built from a terraform-bundle built against
a Terraform v0.11 tag at the latest, since Terraform v0.12 installs plugins
in a different way that is not compatible.
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 = ["~> 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 = ["~> 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 build with the operating
# system and architecture that terraform enterprise is running, e.g. linux and amd64
customplugin = ["0.1"]
}
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 in this block is a provider name,
and its value is a list of version constraints. 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.
To include custom plugins in the bundle file, create a local directory "./plugins"
and put all the plugins you want to include there. 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>_v<VERSION>. 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.
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 On-premises Terraform Enterprise
If using a private install of Terraform Enterprise 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.
Documentation
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Overview ¶
terraform-bundle is a tool to create "bundle archives" that contain both a particular version of Terraform and a set of providers for use with it.
Such bundles are useful for distributing a Terraform version and a set of providers to a system out-of-band, in situations where Terraform's auto-installer cannot be used due to firewall rules, "air-gapped" systems, etc.
When using bundle archives, it's suggested to use a version numbering scheme that adds a suffix that identifies the archive as being a bundle, to make it easier to distinguish bundle archives from the normal separated release archives. This tool by default produces files with the following naming scheme:
terraform_0.10.0-bundle2017070302_linux_amd64.zip
The user is free to rename these files, since the archive filename has no significance to Terraform itself and the generated pseudo-version number is not referenced within the archive contents.
If using such a bundle with an on-premises Terraform Enterprise installation, it's recommended to use the generated version number (or a modification thereof) as the tool version within Terraform Enterprise, so that bundle archives can be distinguished from official releases and from each other even if the same core Terraform version is used.
Terraform providers in general release more often than core, so it is intended that this tool can be used to periodically upgrade providers within certain constraints and produce a new bundle containing these upgraded provider versions. A bundle archive can include multiple versions of the same provider, allowing configurations containing provider version constrants to be gradually migrated to newer versions.
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