Improve base module docs (#108)

* Improve base module docs

* Update readme and concepts
- Encourage release tags
- make grafana_api_key as required

* Update wording

README.md

@@ -33,34 +33,41 @@ to enable monitoring to an existing EKS cluster.
 The base module allows you to configure the AWS Observability services for your cluster and
 the AWS Distro for OpenTelemetry (ADOT) Operator as the signals collection mechanism.
 
-This is the minimum configuration to have a new Managed Grafana Workspace, Amazon Managed
-Service for Prometheus Workspace, ADOT Operator deployed for you and ready to receive your
-data.
+This is the minimum configuration to have a new Amazon Managed Service for Prometheus Workspace
+and ADOT Operator deployed for you and ready to receive your data.
+The base module serve as an anchor to the workload modules and cannot run on its own.
 
 ```hcl
 module "eks_observability_accelerator" {
-  source = "aws-observability/terraform-aws-observability-accelerator"
-  aws_region = "eu-west-1"
+  # use release tags and check for the latest versions
+  # https://github.com/aws-observability/terraform-aws-observability-accelerator/releases
+  source = "github.com/aws-observability/terraform-aws-observability-accelerator?ref=v1.6.1
+
+  aws_region     = "eu-west-1"
   eks_cluster_id = "my-eks-cluster"
+
+  # As Grafana shares a different lifecycle, it's best to use an existing workspace.
+  managed_grafana_workspace_id = var.managed_grafana_workspace_id
+  grafana_api_key              = var.grafana_api_key
 }
 ```
 
-You can optionally reuse existing Workspaces:
+You can optionally reuse an existing Amazon Managed Servce for Prometheus Workspace:
 
 ```hcl
 module "eks_observability_accelerator" {
-  source = "aws-observability/terraform-aws-observability-accelerator"
-  aws_region = "eu-west-1"
+  # use release tags and check for the latest versions
+  # https://github.com/aws-observability/terraform-aws-observability-accelerator/releases
+  source = "github.com/aws-observability/terraform-aws-observability-accelerator?ref=v1.6.1
+
+  aws_region     = "eu-west-1"
   eks_cluster_id = "my-eks-cluster"
 
   # prevents creation of a new Amazon Managed Prometheus workspace
   enable_managed_prometheus = false
 
   # reusing existing Amazon Managed Prometheus Workspace
-  managed_prometheus_workspace_id     = "ws-abcd123..."
-
-  # prevents creation of a new Amazon Managed Grafana workspace
-  enable_managed_grafana       = false
+  managed_prometheus_workspace_id  = "ws-abcd123..."
 
   managed_grafana_workspace_id = "g-abcdef123"
   grafana_api_key              = var.grafana_api_key
@@ -163,8 +170,8 @@ If you are interested in contributing, see the [Contribution guide](https://gith
 | <a name="input_enable_cert_manager"></a> [enable\_cert\_manager](#input\_enable\_cert\_manager) | Allow reusing an existing installation of cert-manager | `bool` | `true` | no |
 | <a name="input_enable_managed_grafana"></a> [enable\_managed\_grafana](#input\_enable\_managed\_grafana) | Creates a new Amazon Managed Grafana Workspace | `bool` | `true` | no |
 | <a name="input_enable_managed_prometheus"></a> [enable\_managed\_prometheus](#input\_enable\_managed\_prometheus) | Creates a new Amazon Managed Service for Prometheus Workspace | `bool` | `true` | no |
-| <a name="input_grafana_api_key"></a> [grafana\_api\_key](#input\_grafana\_api\_key) | Grafana API key for the Amazon Managed Grafana workspace | `string` | `null` | no |
-| <a name="input_irsa_iam_permissions_boundary"></a> [irsa\_iam\_permissions\_boundary](#input\_irsa\_iam\_permissions\_boundary) | IAM permissions boundary for IRSA roles | `string` | `null` | no |
+| <a name="input_grafana_api_key"></a> [grafana\_api\_key](#input\_grafana\_api\_key) | Grafana API key for the Amazon Managed Grafana workspace | `string` | n/a | yes |
+| <a name="input_irsa_iam_permissions_boundary"></a> [irsa\_iam\_permissions\_boundary](#input\_irsa\_iam\_permissions\_boundary) | IAM permissions boundary for IRSA roles | `string` | `""` | no |
 | <a name="input_irsa_iam_role_path"></a> [irsa\_iam\_role\_path](#input\_irsa\_iam\_role\_path) | IAM role path for IRSA roles | `string` | `"/"` | no |
 | <a name="input_managed_grafana_workspace_id"></a> [managed\_grafana\_workspace\_id](#input\_managed\_grafana\_workspace\_id) | Amazon Managed Grafana Workspace ID | `string` | `""` | no |
 | <a name="input_managed_prometheus_workspace_id"></a> [managed\_prometheus\_workspace\_id](#input\_managed\_prometheus\_workspace\_id) | Amazon Managed Service for Prometheus Workspace ID | `string` | `""` | no |

docs/concepts.md

@@ -31,35 +31,44 @@ you need to track changes as part of a Git repository or CI/CD pipeline.
 
 ## Base module
 
-The base module allows you to configure the AWS Observability services for your cluster and the AWS Distro for OpenTelemetry (ADOT) Operator as the signals collection mechanism.
+The base module allows you to configure the AWS Observability services for your cluster and
+the AWS Distro for OpenTelemetry (ADOT) Operator as the signals collection mechanism.
 
-Here is the minimum configuration to have a new Managed Grafana Workspace, Amazon Managed Service for Prometheus Workspace, ADOT Operator deployed for you and ready to receive your data.
+This is the minimum configuration to have a new Amazon Managed Service for Prometheus Workspace
+and ADOT Operator deployed for you and ready to receive your data.
+The base module serve as an anchor to the workload modules and cannot run on its own.
 
 ```hcl
 module "eks_observability_accelerator" {
-  source = "aws-observability/terraform-aws-observability-accelerator"
-  aws_region = "eu-west-1"
+  # use release tags and check for the latest versions
+  # https://github.com/aws-observability/terraform-aws-observability-accelerator/releases
+  source = "github.com/aws-observability/terraform-aws-observability-accelerator?ref=v1.6.1
+
+  aws_region     = "eu-west-1"
   eks_cluster_id = "my-eks-cluster"
+
+  # As Grafana shares a different lifecycle, it's best to use an existing workspace.
+  managed_grafana_workspace_id = var.managed_grafana_workspace_id
+  grafana_api_key              = var.grafana_api_key
 }
 ```
 
-You can optionally reuse existing Workspaces to dissociate their lifecycle from the
-Terraform state.
+You can optionally reuse an existing Amazon Managed Servce for Prometheus Workspace:
 
 ```hcl
 module "eks_observability_accelerator" {
-  source = "aws-observability/terraform-aws-observability-accelerator"
-  aws_region = "eu-west-1"
+  # use release tags and check for the latest versions
+  # https://github.com/aws-observability/terraform-aws-observability-accelerator/releases
+  source = "github.com/aws-observability/terraform-aws-observability-accelerator?ref=v1.6.1
+
+  aws_region     = "eu-west-1"
   eks_cluster_id = "my-eks-cluster"
 
   # prevents creation of a new Amazon Managed Prometheus workspace
   enable_managed_prometheus = false
 
   # reusing existing Amazon Managed Prometheus Workspace
-  managed_prometheus_workspace_id     = "ws-abcd123..."
-
-  # prevents creation of a new Amazon Managed Grafana workspace
-  enable_managed_grafana       = false
+  managed_prometheus_workspace_id  = "ws-abcd123..."
 
   managed_grafana_workspace_id = "g-abcdef123"
   grafana_api_key              = var.grafana_api_key

variables.tf

@@ -70,7 +70,6 @@ variable "managed_grafana_workspace_id" {
 variable "grafana_api_key" {
   description = "Grafana API key for the Amazon Managed Grafana workspace"
   type        = string
-  default     = null
 }
 
 variable "tags" {