Getting Started with MariaDB Galera Cluster

Who hasn't desired to install a MariaDB GaleraDB cluster? There is a new best practice guide to follow.

Amazon RDS and Option Groups

Amazon RDS provides an empty default option group for each new DB instance.

You cannot modify this default option group, but any new option group that you create derives its settings from the default option group.

To apply an option to a DB instance, you must do the following:

1. Create a new option group, or copy or modify an existing option group.
2. Add one or more options to the option group.
3. Associate the option group with the DB instance.

snapshots Both DB instances and DB snapshots can be associated with an option group.

more memory Options require additional memory to run on a DB instance

Cloudformation UpdateReplacePolicy Attribute

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-updatereplacepolicy.html

When you initiate a stack update, AWS CloudFormation updates resources based on differences between what you submit and the stack's current template and parameters. If you update a resource property that requires that the resource be replaced, AWS CloudFormation recreates the resource during the update. Recreating the resource generates a new physical ID.

Cloudformation nested stacks

The AWS::CloudFormation::Stack type nests a stack as a resource in a top-level template.https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-stack.html

You can add output values from a nested stack within the containing template. You use the GetAtt function with the nested stack's logical name and the name of the output value in the nested stack in the format Outputs.NestedStackOutputName.