Jenkins X GKE Module

NOTE: While the required minimum Terraform version is 0.12.0, automated CI tests are performed with 0.13 only. The only expected compatibility issues to be aware of are around provider requirements. For more information see here

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This repo contains a Terraform module for provisioning a Kubernetes cluster for Jenkins X on Google Cloud.

• What is a Terraform module
• How do you use this module
  • Prerequisites
  • Cluster provisioning
    • Inputs
    • Outputs
  • Running jx boot
  • Using a custom domain
  • Production cluster considerations
  • Configuring a Terraform backend
• FAQ
  • How do I get the latest version of the terraform-google-jx module
  • How to I specify a specific google provider version
  • Why do I need Application Default Credentials
• Development
  • Releasing
• How do I contribute

What is a Terraform module

A Terraform "module" refers to a self-contained package of Terraform configurations that are managed as a group. For more information around modules refer to the Terraform documentation.

How do you use this module

Prerequisites

To make use of this module, you need a Google Cloud project. Instructions on how to setup such a project can be found in the Google Cloud Installation and Setup guide. You need your Google Cloud project id as an input variable for using this module.

You also need to install the Cloud SDK, in particular gcloud. You find instructions on how to install and authenticate in the Google Cloud Installation and Setup guide as well.

Once you have gcloud installed, you need to create Application Default Credentials by running:

gcloud auth application-default login

Alternatively, you can export the environment variable GOOGLE_APPLICATION_CREDENTIALS referencing the path to a Google Cloud service account key file.

Last but not least, ensure you have the following binaries installed:

• gcloud
• kubectl ~> 1.14.0
  • kubectl comes bundled with the Cloud SDK
• terraform ~> 0.12.0
  • Terraform installation instruction can be found here

Cluster provisioning

A default Jenkins X ready cluster can be provisioned by creating a file main.tf in an empty directory with the following content:

module "jx" {
  source  = "jenkins-x/jx/google"

  gcp_project = "<my-gcp-project-id>"
}

output "jx_requirements" {
  value = module.jx.jx_requirements
}  

You can then apply this Terraform configuration via:

terraform init
terraform apply

This creates a cluster within the specified Google Cloud project with all possible configuration options defaulted.

⚠️ Note: This example is for getting up and running quickly. It is not intended for a production cluster. Refer to Production cluster considerations for things to consider when creating a production cluster.

On completion of terraform apply a jx_requirements output is available which can be used as input to jx boot. Refer to Running jx boot for more information.

In the default configuration, no custom domain is used. DNS resolution occurs via nip.io. For more information on how to configure and use a custom domain, refer to Using a custom domain.

If you just want to experiment with Jenkins X, you can set force_destroy to true. This allows you to remove all generated resources when running terraform destroy, including any generated buckets including their content.

The following two paragraphs provide the full list of configuration and output variables of this Terraform module.

Inputs

Name	Description	Type	Default	Required
bucket_location	Bucket location for storage	string	"US"	no
cluster_location	The location (region or zone) in which the cluster master will be created. If you specify a zone (such as us-central1-a), the cluster will be a zonal cluster with a single cluster master. If you specify a region (such as us-west1), the cluster will be a regional cluster with multiple masters spread across zones in the region	string	"us-central1-a"	no
cluster_name	Name of the Kubernetes cluster to create	string	""	no
create_ui_sa	Whether the service accounts for the UI should be created	bool	false	no
dev_env_approvers	List of git users allowed to approve pull request for dev enviornment repository	list(string)	[]	no
enable_backup	Whether or not Velero backups should be enabled	bool	false	no
force_destroy	Flag to determine whether storage buckets get forcefully destroyed	bool	false	no
gcp_project	The name of the GCP project to use	string	n/a	yes
git_owner_requirement_repos	The git id of the owner for the requirement repositories	string	""	no
gsm	Enables Google Secrets Manager, not available with JX2	bool	false	no
jenkins_x_namespace	Kubernetes namespace to install Jenkins X in	string	"jx"	no
jx2	Is a Jenkins X 2 install	bool	true	no
lets_encrypt_production	Flag to determine wether or not to use the Let's Encrypt production server.	bool	true	no
max_node_count	Maximum number of cluster nodes	number	5	no
min_node_count	Minimum number of cluster nodes	number	3	no
node_disk_size	Node disk size in GB	string	"100"	no
node_disk_type	Node disk type, either pd-standard or pd-ssd	string	"pd-standard"	no
node_machine_type	Node type for the Kubernetes cluster	string	"n1-standard-2"	no
node_preemptible	Use preemptible nodes	bool	false	no
parent_domain	The parent domain to be allocated to the cluster	string	""	no
release_channel	The GKE release channel to subscribe to. See https://cloud.google.com/kubernetes-engine/docs/concepts/release-channels	string	"UNSPECIFIED"	no
resource_labels	Set of labels to be applied to the cluster	map	{}	no
tls_email	Email used by Let's Encrypt. Required for TLS when parent_domain is specified	string	""	no
vault_url	URL to an external Vault instance in case Jenkins X shall not create its own system Vault	string	""	no
velero_namespace	Kubernetes namespace for Velero	string	"velero"	no
velero_schedule	The Velero backup schedule in cron notation to be set in the Velero Schedule CRD (see default-backup.yaml)	string	"0 * * * *"	no
velero_ttl	The the lifetime of a velero backup to be set in the Velero Schedule CRD (see default-backup.yaml)	string	"720h0m0s"	no
version_stream_ref	The git ref for version stream to use when booting Jenkins X. See https://jenkins-x.io/docs/concepts/version-stream/	string	"master"	no
version_stream_url	The URL for the version stream to use when booting Jenkins X. See https://jenkins-x.io/docs/concepts/version-stream/	string	"https://github.com/jenkins-x/jenkins-x-versions.git"	no
webhook	Jenkins X webhook handler for git provider	string	"lighthouse"	no
zone	Zone in which to create the cluster (deprecated, use cluster_location instead)	string	""	no

Outputs

Name	Description
backup_bucket_url	The URL to the bucket for backup storage
cluster_location	The location of the created Kubernetes cluster
cluster_name	The name of the created Kubernetes cluster
connect	The cluster connection string to use once Terraform apply finishes
gcp_project	The GCP project in which the resources got created
jx_requirements	The jx-requirements rendered output
log_storage_url	The URL to the bucket for log storage
report_storage_url	The URL to the bucket for report storage
repository_storage_url	The URL to the bucket for artifact storage
vault_bucket_url	The URL to the bucket for secret storage

Running jx boot

A terraform output (jx_requirements) is available after applying this Terraform module.

terraform output jx_requirements

This jx_requirements output can be used as input to Jenkins X Boot which is responsible for installing all the required Jenkins X components into the cluster created by this module.

⚠️ Note: The generated jx-requirements is only used for the first run of jx boot. During this first run of jx boot a git repository containing the source code for Jenkins X Boot is created. This (new) repository contains a jx-requirements.yml (which is now ahead of the jx-requirements output from terraform) used by successive runs of jx boot.

Execute:

terraform output jx_requirements > <some_empty_dir>/jx-requirements.yml
# jenkins-x creates the environment repository directory localy before pushing to the Git server of choice
cd <some_empty_dir>
jx boot --requirements jx-requirements.yml

You are prompted for any further required configuration. The number of prompts depends on how much you have pre-configured via your Terraform variables.

Using a custom domain

If you want to use a custom domain with your Jenkins X installation, you need to provide values for the variables parent_domain and tls_email. parent_domain is the fully qualified domain name you want to use and tls_email is the email address you want to use for issuing Let's Encrypt TLS certificates.

Before you apply the Terraform configuration, you also need to create a Cloud DNS managed zone, with the DNS name in the managed zone matching your custom domain name, for example in the case of example.jenkins-x.rocks as domain:

When creating the managed zone, a set of DNS servers get created which you need to specify in the DNS settings of your DNS registrar.

It is essential that before you run jx boot, your DNS servers settings are propagated, and your domain resolves. You can use DNS checker to check whether your domain settings have propagated.

When a custom domain is provided, Jenkins X uses ExternalDNS together with cert-manager to create A record entries in your managed zone for the various exposed applications.

If parent_domain id not set, your cluster will use nip.io in order to create publicly resolvable URLs of the form http://<app-name>-<environment-name>.<cluster-ip>.nip.io.

Production cluster considerations

The configuration as seen in Cluster provisioning is not suited for creating and maintaining a production Jenkins X cluster. The following is a list of considerations for a production usecase.

• Specify the version attribute of the module, for example:

  module "jx" {
    source  = "jenkins-x/jx/google"
    version = "1.2.4"
    # insert your configuration
  }
  
  output "jx_requirements" {
   value = module.jx.jx_requirements
  }

  Specifying the version ensures that you are using a fixed version and that version upgrades cannot occur unintented.

• Keep the Terraform configuration under version control, by creating a dedicated repository for your cluster configuration or by adding it to an already existing infrastructure repository.

• Setup a Terraform backend to securely store and share the state of your cluster. For more information refer to Configuring a Terraform backend.

Configuring a Terraform backend

A "backend" in Terraform determines how state is loaded and how an operation such as apply is executed. By default, Terraform uses the local backend which keeps the state of the created resources on the local file system. This is problematic since sensitive information will be stored on disk and it is not possible to share state across a team. When working with Google Cloud a good choice for your Terraform backend is the gcs backend which stores the Terraform state in a Google Cloud Storage bucket. The examples directory of this repository contains configuration examples for using the gcs backed with and without optionally configured customer supplied encryption key.

To use the gcs backend you will need to create the bucket upfront. You can use gsutil to create the bucket:

gsutil mb gs://<my-bucket-name>/

It is also recommended to enable versioning on the bucket as an additional safety net in case of state corruption.

gsutil versioning set on gs://<my-bucket-name>

You can verify whether a bucket has versioning enabled via:

gsutil versioning get gs://<my-bucket-name>

FAQ

How do I get the latest version of the terraform-google-jx module

terraform init -upgrade

How to I specify a specific google provider version

provider "google" {
  version = "~> 2.12.0"
  project = var.gcp_project
}

provider "google-beta" {
  version = "~> 2.12.0"
  project = var.gcp_project
}

Why do I need Application Default Credentials

The recommended way to authenticate to the Google Cloud API is by using a service account. This allows for authentication regardless of where your code runs. This Terraform module expects authentication via a service account key. You can either specify the path to this key directly using the GOOGLE_APPLICATION_CREDENTIALS environment variable or you can run gcloud auth application-default login. In the latter case gcloud obtains user access credentials via a web flow and puts them in the well-known location for Application Default Credentials (ADC), usually ~/.config/gcloud/application_default_credentials.json.

Development

Releasing

At the moment there is no release pipeline defined in jenkins-x.yml. A Terraform release does not require building an artifact, only a tag needs to be created and pushed. To make this task easier and there is a helper script release.sh which simplifies this process and creates the changelog as well:

./scripts/release.sh

This can be executed on demand whenever a release is required. For the script to work the envrionment variable $GH_TOKEN must be exported and reference a valid GitHub API token.

How do I contribute

Contributions are very welcome! Check out the Contribution Guidelines for instructions.