Terraform Kubernetes Istio Operator

Introduction

This module installs the Istio Operator v1.7.8. It attempts to replicate the installation via:

istioctl operator init

The ability to specify the tag of the image is available, however, this may cause issues since this module uses the manifests of a specific version.

Security Controls

The following security controls can be met through configuration of this template:

• TBD

Requirements

• The namespace where Istio Operator is to be installed should already be created. (default istio-operator)
• Terraform v0.13+
• terraform-provider-kubernetes 2.4+
• terraform-provider-helm 2.0+

Namespace Label Requirements

The namespace provided as the namespace variable requires the following labels:

• istio-operator-managed=Reconcile
• istio-injection=disabled

Module Versioning

As of release v2.0.0, versioning will return to SEMVER so as to simplify releases.

Optional (depending on options configured):

• None

Usage

module "istio_operator" {
  source = "git::https://github.com/canada-ca-terraform-modules/terraform-kubernetes-istio-operator.git?ref=v2.1.0"

  # The following are variables that can be specified, but come with sane defaults
  namespace        = "istio-operator"
  watch_namespaces = ["istio-system"]
}

Variables Values

Name	Type	Required	Default Value	Description
namespace	string	no	"istio-operator"	The namespace in which to install the Istio Operator.
hub	string	no	"docker.io/istio"	The hub where the image repositories are located.
resources	object	no	see variables.tf	The resource requests and limits for the deployment.
tag	string	no	"1.7.8"	The tag of the image to use. WARNING: Use at own risk.
wait_for_resources_timeout	number	no	300	The amount of seconds that the operator should wait for a timeout.
watch_namespaces	list(string)	no	["istio-system"]	The namespaces that the Operator should watch for IstioOperator manifests. Empty for all Namespaces.

Updating Modules

Migrating to v2+

There are 4 major changes in v2.0.0:

• Labels on the namespace are no longer being set by the module (see Namespace Label Requirements)
• Use of a Helm chart to deploy CRDs via helm_release resource instead of kubectl via the null_resource Note: the terraform-provider-kubernetes kubernetes_manifest was attempted to be used, however, in its current beta state it has difficulties reconciling resources and is still in beta.
• Extracting the deployment of the IstioOperator manifest to allow for multiple IstioOperator configuration (important for Canary deployments)
• Change of the istio_namespace variable to watch_namespaces for configurations that are more contextualized to the operator. This allows for the IstioOperator manifest to be deployed and actioned by the controller in these namespaces.

To ensure the , the following commands will need to be run:

module_name=istio_operator; # The label used for the module. Change based on your usage.
namespace=istio-operator; # Value entered as namespace in module < v2.0.0

# Labels are no longer being modified by the module
terraform state rm module.$module_name.null_resource.istio_operator_namespace_label;

# The IstioOperator manifest is no longer being deployed in this module.
# Please see: https://gitlab.k8s.cloud.statcan.ca/cloudnative/terraform/modules/terraform-kubernetes-istio-operator-instance
terraform state rm module.$module_name.null_resource.istio_operator;

# istio-operator Deployment can now be deployed with the provider due
# to fieldRefs being added.
terraform state rm module.$module_name.null_resource.istio_operator_controller

# Remove the installation of the CRD via null_resource
terraform state rm module.$module_name.null_resource.istio_operator_crd;

# Replace istio-operator namespace if not in default location
terraform import module.$module_name.kubernetes_deployment.istio_operator_controller $namespace/istio-operator;

CRD Installation

There seem to be some regressions when it comes to the CRD that is installed via istioctl. Following is a table of the CRD versions that are installed in each istioctl version:

istioctl Version	CRD Version
v1.6.14	CustomResourceDefinition.apiextensions.k8s.io/v1beta1
v1.7.8	CustomResourceDefinition.apiextensions.k8s.io/v1
v1.8.6	CustomResourceDefinition.apiextensions.k8s.io/v1beta1

Note: the v1beta1 CRDs are missing the type parameter under spec.validation.openAPIV3Schema which causes some validation issues with kubernetes_manifest resources.

To combat this, the v1 CRD has been backported to v2.0.0 to simplify installations.

History

Date	Release	Change
20200821	v1.0.0	1st release
20210204	v1.6.14	Update to use the manifest dump of Istio Operator 1.6.14.
20210824	v1.0.1-tf13	Align module to work with Terraform v0.13
20210830	v2.0.0	Use new kubernetes_manifest resource from provider 2.4+
-	-	Move out the installation of the IstioOperator manifest
20210831	v2.1.0	Update resources for Istio 1.7.8
20211021	v2.1.1	Add ability to specify resources.