feat: added remote leader support (#66)

Author: iamar7

README.md

@@ -33,6 +33,19 @@ You need the following permissions to run this module.
     - **Databases for PostgreSQL** service
         - `Editor` role access
 <!-- END MODULE HOOK -->
+
+## Read-only Replica considerations
+
+- **There are additional considerations when setting the variables in the read-only-replica example.** Refer [configuring read-only replicas](https://cloud.ibm.com/docs/databases-for-postgresql?topic=databases-for-postgresql-read-only-replicas)
+
+| Variable | Description |
+|------|---------|
+|  <a name="input_region"></a> [region](#input\_region)| The read-only replica can exist in the same region as the source formation or in different one, enabling your data to be replicated across regions. |
+| <a name="input_member_memory_mb"></a> [member\_memory\_mb](#input\_member\_memory\_mb) | The minimum RAM size of a read-only replica is 3 GB |
+| <a name="input_member_disk_mb"></a> [member\_disk\_mb](#input\_member\_disk\_mb)  | The minimum disk size of a read-only replica is 15 GB |
+| <a name="input_member_cpu_count"></a> [member\_cpu\_count](#input\_member\_cpu\_count) | The minimum CPU allocation required for read-only replica is 9 |
+| <a name="input_members"></a> [members](#input\_members)| A read-only replica is a deployment with single data member and does not have any internal high availability.|
+
 <!-- BEGIN EXAMPLES HOOK -->
 ## Examples
 
@@ -41,6 +54,7 @@ You need the following permissions to run this module.
 - [ Complete example with byok encryption, CBR rules and storing credentials in secrets manager](examples/complete)
 - [ Default example](examples/default)
 - [ Financial Services Cloud profile example](examples/fscloud)
+- [ Replica example](examples/replica)
 <!-- END EXAMPLES HOOK -->
 <!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
 ## Requirements
@@ -82,6 +96,7 @@ You need the following permissions to run this module.
 | <a name="input_pg_version"></a> [pg\_version](#input\_pg\_version) | Version of the postgresql instance | `string` | `null` | no |
 | <a name="input_plan_validation"></a> [plan\_validation](#input\_plan\_validation) | Enable or disable validating the database parameters for postgres during the plan phase | `bool` | `true` | no |
 | <a name="input_region"></a> [region](#input\_region) | The region postgresql is to be created on. The region must support BYOK if key\_protect\_key\_crn is used | `string` | `"us-south"` | no |
+| <a name="input_remote_leader_crn"></a> [remote\_leader\_crn](#input\_remote\_leader\_crn) | The CRN of the leader database to make the replica(read-only) deployment. | `string` | `null` | no |
 | <a name="input_resource_group_id"></a> [resource\_group\_id](#input\_resource\_group\_id) | The resource group ID where the postgresql will be created | `string` | n/a | yes |
 | <a name="input_resource_tags"></a> [resource\_tags](#input\_resource\_tags) | Optional list of tags to be added to created resources | `list(string)` | `[]` | no |
 | <a name="input_service_credential_names"></a> [service\_credential\_names](#input\_service\_credential\_names) | Map of name, role for service credentials that you want to create for the database | `map(string)` | `{}` | no |

examples/replica/README.md

@@ -0,0 +1,7 @@
+# Replica example
+
+An end-to-end example that uses the module's default variable values. This example uses the IBM Cloud terraform provider to:
+
+- Create a new resource group if one is not passed in.
+- Create a new ICD Postgresql database instance.
+- Create a read-only replica of the leader Postgresql database instance.

examples/replica/main.tf

@@ -0,0 +1,38 @@
+##############################################################################
+# Resource Group
+##############################################################################
+
+module "resource_group" {
+  source = "git::https://github.com/terraform-ibm-modules/terraform-ibm-resource-group.git?ref=v1.0.5"
+  # if an existing resource group is not set (null) create a new one using prefix
+  resource_group_name          = var.resource_group == null ? "${var.prefix}-resource-group" : null
+  existing_resource_group_name = var.resource_group
+}
+
+##############################################################################
+# ICD postgresql primary/leader database
+##############################################################################
+
+module "postgresql_db" {
+  source            = "../.."
+  resource_group_id = module.resource_group.resource_group_id
+  name              = "${var.prefix}-primary"
+  region            = var.region
+  resource_tags     = var.resource_tags
+}
+
+##############################################################################
+# ICD postgresql read-only-replica
+##############################################################################
+
+module "read_only_replica_postgresql_db" {
+  source            = "../.."
+  resource_group_id = module.resource_group.resource_group_id
+  name              = "${var.prefix}-read-only-replica"
+  region            = var.region
+  resource_tags     = var.resource_tags
+  remote_leader_crn = module.postgresql_db.crn
+  member_memory_mb  = var.member_memory_mb
+  member_disk_mb    = var.member_disk_mb
+  member_cpu_count  = var.member_cpu_count
+}

examples/replica/outputs.tf

@@ -0,0 +1,23 @@
+##############################################################################
+# Outputs
+##############################################################################
+
+output "id" {
+  description = "Postgresql instance id"
+  value       = module.postgresql_db.id
+}
+
+output "replica_id" {
+  description = "Postgresql read-only replica instance id"
+  value       = module.read_only_replica_postgresql_db.id
+}
+
+output "version" {
+  description = "Postgresql instance version"
+  value       = module.postgresql_db.version
+}
+
+output "replica_version" {
+  description = "Postgresql read-only replica instance version"
+  value       = module.read_only_replica_postgresql_db.version
+}

examples/replica/provider.tf

@@ -0,0 +1,4 @@
+provider "ibm" {
+  ibmcloud_api_key = var.ibmcloud_api_key
+  region           = var.region
+}

examples/replica/variables.tf

@@ -0,0 +1,68 @@
+variable "ibmcloud_api_key" {
+  type        = string
+  description = "The IBM Cloud API Key"
+  sensitive   = true
+}
+
+variable "region" {
+  type        = string
+  description = "Region to provision all resources created by this example."
+  default     = "us-south"
+}
+
+variable "prefix" {
+  type        = string
+  description = "Prefix to append to all resources created by this example"
+  default     = "postgres"
+}
+
+variable "resource_group" {
+  type        = string
+  description = "An existing resource group name to use for this example, if unset a new resource group will be created"
+  default     = null
+}
+
+variable "resource_tags" {
+  type        = list(string)
+  description = "Optional list of tags to be added to created resources"
+  default     = []
+}
+
+variable "member_memory_mb" {
+  type        = string
+  description = "Memory allocation required for postgresql read-only replica database"
+  default     = "3072"
+  validation {
+    condition = alltrue([
+      var.member_memory_mb >= 3072,
+      var.member_memory_mb <= 114688
+    ])
+    error_message = "member group memory must be >= 3072 and <= 114688 in increments of 384"
+  }
+}
+
+variable "member_disk_mb" {
+  type        = string
+  description = "Disk allocation required for postgresql read-only replica database"
+  default     = "15360"
+  validation {
+    condition = alltrue([
+      var.member_disk_mb >= 15360,
+      var.member_disk_mb <= 4194304
+    ])
+    error_message = "member group disk must be >= 15360 and <= 4194304 in increments of 1536"
+  }
+}
+
+variable "member_cpu_count" {
+  type        = string
+  description = "CPU allocation required for the postgresql read-only replica database"
+  default     = "9"
+  validation {
+    condition = alltrue([
+      var.member_cpu_count >= 9,
+      var.member_cpu_count <= 28
+    ])
+    error_message = "member group cpu must be >= 9 and <= 28 in increments of 1"
+  }
+}

examples/replica/version.tf

@@ -0,0 +1,10 @@
+terraform {
+  required_version = ">= 1.3.0"
+  required_providers {
+    # Pin to the lowest provider version of the range defined in the main module's version.tf to ensure lowest version still works
+    ibm = {
+      source  = "IBM-Cloud/ibm"
+      version = "1.49.0"
+    }
+  }
+}

main.tf

@@ -18,6 +18,7 @@ resource "ibm_database" "postgresql_db" {
   plan              = "standard" # Only standard plan is available for postgres
   backup_id         = var.backup_crn
   plan_validation   = var.plan_validation
+  remote_leader_id  = var.remote_leader_crn
   version           = var.pg_version
   tags              = var.resource_tags
   service_endpoints = var.service_endpoints
@@ -44,9 +45,11 @@ resource "ibm_database" "postgresql_db" {
     cpu {
       allocation_count = var.member_cpu_count
     }
-
-    members {
-      allocation_count = var.members
+    dynamic "members" {
+      for_each = var.remote_leader_crn == null ? [1] : []
+      content {
+        allocation_count = var.members
+      }
     }
   }