How-to setup a HA/DR database in AWS? [3 - Simple database]

In this post, we will see how to create a simple database in AWS with Terraform and how we can configure it.

How to create a database ?

The minimum configuration looks like this:

resource "aws_db_instance" "default" {
  allocated_storage    = 10
  engine               = "mysql"
  engine_version       = "5.7"
  instance_class       = "db.t3.micro"
  name                 = "mydb"
  username             = "random_user"
  password             = "random_pwd"
  parameter_group_name = "default.mysql5.7"
  skip_final_snapshot  = true
}

How to create a custom parameter group ?

We saw that we can define a parameter group to override some database configurations.

To do it create an aws_db_parameter_group, and like the following example, you can change the encoding.

resource "aws_db_parameter_group" "default" {
  name   = "rds-group-perso"
  family = "mysql5.6"

  parameter {
    name  = "character_set_server"
    value = "utf8"
  }

  parameter {
    name  = "character_set_client"
    value = "utf8"
  }
}

All the available parameters are listed in the AWS documentation :

• MySQL : https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraMySQL.Reference.html
• PostgreSQL : https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/AuroraPostgreSQL.Reference.ParameterGroups.html
• Maria DB : https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Appendix.MariaDB.Parameters.html
• PostgreSQL : https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Appendix.PostgreSQL.CommonDBATasks.html#Appendix.PostgreSQL.CommonDBATasks.Parameters

Then, you can update the value properly in your aws_db_instance to use this newly created parameter group.

resource "aws_db_instance" "default" {
  ...
  parameter_group_name = aws_db_parameter_group.aws_db_parameter_group.id
  ...
}

NOTE: You can set parameter_group_name = "rds-group-perso" in the aws_db_instance and it will also work. But using the parameter from the created resource is cleaner.

Other interesting configurable parameters

• port - If you want to change the default port to access to the database
• storage_encrypted - If you want to encrypt the data stored
• kms_key_id - The KMS key id of the key to use for the encryption
• enabled_cloudwatch_logs_exports - To set all the logs types you want to export in CloudWatch.
• backup_window - Period of the day where daily backups are generated
• backup_retention_period - Number of days you want to retain backups.
• security_group_names - List of security groups to add to the database. This one is a really important one to control correctly who can access to your database.
• maintenance_window - The window to perform maintenance in.

There are some other parameters available, please check the Terraform documentation to see them.

Links

Terraform

• aws_db_instance : https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/db_instance
• aws_db_parameter_group : https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/db_parameter_group

I hope it will help you! 🍺

And see you soon for the next part of this serie. 😀

Serie link

• 1 - Start : https://dev.to/adaendra/how-to-setup-a-hadr-database-in-aws-1-1ko7
• 2 - Definitions : https://dev.to/adaendra/how-to-setup-a-hadr-database-in-aws-2-definitions-93p
• 3 - Simple database : https://dev.to/adaendra/how-to-setup-a-hadr-database-in-aws-3-simple-database-a9o
• 4 - HA Database : https://dev.to/adaendra/how-to-setup-a-hadr-database-in-aws-4-ha-database-4kek
• 5 - DR database : https://dev.to/adaendra/how-to-setup-a-hadr-database-in-aws-5-dr-database-278b
• 6 - Create from snapshot : https://dev.to/adaendra/how-to-setup-a-hadr-database-in-aws-6-create-from-snapshot-2mbf
• 7 - Dynamic Terraform backend definition : https://dev.to/adaendra/how-to-setup-a-hadr-database-in-aws-7-dynamic-terraform-backend-definition-3aga
• 8 - Multiple instances in multiple regions : https://dev.to/adaendra/how-to-setup-a-hadr-database-in-aws-8-multiple-instances-in-multiple-regions-210d
• 9 - Generate a random value : https://dev.to/adaendra/how-to-setup-a-hadr-database-in-aws-9-generate-a-random-value-5g8a