dms

Terraform module for AWS DMS

overview

the module create a target RDS Instance and if set also the replicas for the master instance.
Its also create a dms instance and endpoints for source and target RDS Instance. And a migration 
task that not startet automaticly. 

example

module "dms" {
  count  = var.enable_dms_replica ? 1 : 0
  source = "../../modules/dms"

  depends_on = [aws_db_instance.master, random_string.database_pass]

  dms_instance_name = var.override_db_master_name != "" ? var.override_db_master_name : "${local.basename}"

  source_address                       = aws_db_instance.master.address
  source_subnet_ids                    = data.terraform_remote_state.db-vpc.outputs.private_subnets
  source_vpc_security_group_ids        = [aws_security_group.sg-db.id]
  source_database_name                 = aws_db_instance.master.db_name
  source_engine                        = var.engine
  source_password                      = random_string.database_pass.result
  source_username                      = var.username
  source_port                          = var.port
  source_instance_subnet_group_name    = aws_db_subnet_group.default.name
  dms_replication_instance_kms_key_arn = data.aws_kms_key.dms.arn

  target_engine                        = var.engine
  target_db_multi_az                   = var.db_multi_az
  target_allocated_storage             = var.target_allocated_storage != "" ? var.target_allocated_storage : var.allocated_storage
  target_instance_name                 = var.target_instance_name
  target_instance_type                 = var.target_instance_type
  target_instance_engine_version       = var.target_instance_engine_version
  target_instance_parameter_group_name = var.target_instance_parameter_group_name
  target_replica_count                 = var.replica_count
  target_storage_encrypted             = var.target_storage_encrypted
  target_instance_kms_key_id           = var.target_storage_encrypted ? data.aws_kms_key.rds.arn : null
}

ToDos

• Set the rds.logical_replication parameter in your DB CLUSTER parameter group to 1
• Set wal_sender_timeout parameter to 0 in your DB CLUSTER parameter group
  • see https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.PostgreSQL.html#CHAP_Source.PostgreSQL.RDSPostgreSQL
• reboot the source RDS Instance
  • use AWS Systems Manager for schedule reboot.
  • see https://aws.amazon.com/de/blogs/database/schedule-amazon-rds-stop-and-start-using-aws-systems-manager/
• start manually the migration task
  • on errors see https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Tasks.AssessmentReport1.html
• take care of hibernate sequence
  • AWS DMS doesn't migrate your secondary indexes, sequences, default values, stored procedures, triggers, synonyms, views, and other schema objects that aren't specifically related to data migration.
• switch the application to the target RDS Instance
• Stop the migration task
• Remove the target Instance and Replicas from terraform state before removing all resources.
  • terragrunt state rm "module.dms[0].aws_db_instance.target_master_instance"

Requirements

No requirements.

Providers

Name	Version
aws	n/a

Modules

No modules.

Resources

Name	Type
aws_db_instance.target_master_instance	resource
aws_db_instance.target_read_replica	resource
aws_dms_endpoint.source	resource
aws_dms_endpoint.target	resource
aws_dms_replication_instance.dms_instance	resource
aws_dms_replication_subnet_group.dms-replication-subnet-group	resource
aws_dms_replication_task.initial	resource
aws_iam_role.dms-access-for-endpoint	resource
aws_iam_role.dms-cloudwatch-logs-role	resource
aws_iam_role.dms-vpc-role	resource
aws_iam_role_policy_attachment.dms-access-for-endpoint-AmazonDMSRedshiftS3Role	resource
aws_iam_role_policy_attachment.dms-cloudwatch-logs-role-AmazonDMSCloudWatchLogsRole	resource
aws_iam_role_policy_attachment.dms-vpc-role-AmazonDMSVPCManagementRole	resource
aws_iam_policy_document.dms_assume_role	data source

Inputs

Name	Description	Type	Default	Required
certificate_arn	(Optional, Default: empty string) ARN for the certificate.	string	""	no
dms_availability_zone	n/a	string	"eu-central-1a"	no
dms_instance_class	n/a	string	"dms.t3.micro"	no
dms_instance_name	n/a	string	n/a	yes
dms_replication_instance_kms_key_arn	n/a	string	null	no
dms_replication_instance_multi_az	n/a	bool	false	no
engine_version	n/a	string	"3.4.7"	no
extra_connection_attributes	(Optional) Additional attributes associated with the connection. For available attributes see Using Extra Connection Attributes with AWS Database Migration Service.	string	""	no
kms_key_arn	n/a	string	null	no
source_address	endpoint address of source	string	n/a	yes
source_database_name	Required) Database endpoint identifier. Identifiers must contain from 1 to 255 alphanumeric characters or hyphens, begin with a letter, contain only ASCII letters, digits, and hyphens, not end with a hyphen, and not contain two consecutive hyphens.	string	"source"	no
source_engine	(Required) Type of engine for the source endpoint. Valid values are aurora, aurora-postgresql, azuredb, db2, docdb, dynamodb, elasticsearch, kafka, kinesis, mariadb, mongodb, mysql, opensearch, oracle, postgres, redshift, s3, sqlserver, sybase. Please note that some of engine names are available only for target endpoint type (e.g. redshift).	string	n/a	yes
source_instance_subnet_group_name	n/a	string	n/a	yes
source_password	(Optional) Password to be used to login to the endpoint database.	string	"test"	no
source_port	n/a	number	5432	no
source_subnet_ids	n/a	list(string)	[]	no
source_username	(Optional) User name to be used to login to the endpoint database.	string	"test"	no
source_vpc_security_group_ids	n/a	list(string)	[]	no
target_allocated_storage	The acclocated storage of the target database	number	20	no
target_availability_zones	AZ for the replicas	list(string)	[ "eu-central-1a", "eu-central-1b", "eu-central-1c" ]	no
target_db_multi_az	(Optional) Specifies if the target RDS instance is multi-AZ	bool	false	no
target_engine	(Required) Type of engine for the target endpoint. Valid values are aurora, aurora-postgresql, azuredb, db2, docdb, dynamodb, elasticsearch, kafka, kinesis, mariadb, mongodb, mysql, opensearch, oracle, postgres, redshift, s3, sqlserver, sybase. Please note that some of engine names are available only for target endpoint type (e.g. redshift).	string	n/a	yes
target_instance_engine_version	the engine version of the target db	string	"13.4"	no
target_instance_kms_key_id	n/a	string	null	no
target_instance_name	Name of the target replica	string	"test"	no
target_instance_parameter_group_name	n/a	string	n/a	yes
target_instance_type	instance type of the target instance	string	"db.t3.micro"	no
target_replica_count	Amount of the target read replicas	number	0	no
target_storage_encrypted	(Optional) Specifies whether the DB instance is encrypted. The default is true if not specified.	bool	true	no
target_storage_type	n/a	string	"gp2"	no
upgrade_apply_immediately	(Optional) Specifies whether any database modifications are applied immediately, or during the next maintenance window. Default is false. See Amazon RDS Documentation for more information.	bool	false	no

Outputs

No outputs.