Working with Amazon RDS Custom - Amazon Relational Database Service
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Working with Amazon RDS Custom

Amazon RDS Custom automates database administration tasks and operations. RDS Custom makes it possible for you as a database administrator to access and customize your database environment and operating system. With RDS Custom, you can customize to meet the requirements of legacy, custom, and packaged applications.

For the latest webinars and blogs about RDS Custom, see Amazon RDS Custom resources.

Addressing the challenge of database customization

Amazon RDS Custom brings the benefits of Amazon RDS to a market that can't easily move to a fully managed service because of customizations that are required with third-party applications. Amazon RDS Custom saves administrative time, is durable, and scales with your business.

If you need the entire database and operating system to be fully managed by Amazon, we recommend Amazon RDS. If you need administrative rights to the database and underlying operating system to make dependent applications available, Amazon RDS Custom is the better choice. If you want full management responsibility and simply need a managed compute service, the best option is self-managing your commercial databases on Amazon EC2.

To deliver a managed service experience, Amazon RDS doesn't let you access the underlying host. Amazon RDS also restricts access to some procedures and objects that require high-level privileges. However, for some applications, you might need to perform operations as a privileged operating system (OS) user.

For example, you might need to do the following:

  • Install custom database and OS patches and packages.

  • Configure specific database settings.

  • Configure file systems to share files directly with their applications.

Previously, if you needed to customize your application, you had to deploy your database on-premises or on Amazon EC2. In this case, you bear most or all of the responsibility for database management, as summarized in the following table.

Feature

On-premises responsibility

Amazon EC2 responsibility

Amazon RDS responsibility

Application optimization

Customer

Customer

Customer

Scaling

Customer

Customer

Amazon

High availability

Customer

Customer

Amazon

Database backups

Customer

Customer

Amazon

Database software patching

Customer

Customer

Amazon

Database software install

Customer

Customer

Amazon

OS patching

Customer

Customer

Amazon

OS installation

Customer

Customer

Amazon

Server maintenance

Customer

Amazon

Amazon

Hardware lifecycle

Customer

Amazon

Amazon

Power, network, and cooling

Customer

Amazon

Amazon

When you manage database software yourself, you gain more control, but you're also more prone to user errors. For example, when you make changes manually, you might accidentally cause application downtime. You might spend hours checking every change to identify and fix an issue. Ideally, you want a managed database service that automates common DBA tasks, but also supports privileged access to the database and underlying operating system.

Management model and benefits for Amazon RDS Custom

Amazon RDS Custom is a managed database service for legacy, custom, and packaged applications that require access to the underlying operating system and database environment. RDS Custom automates setup, operation, and scaling of databases in the Amazon Web Services Cloud while granting you access to the database and underlying operating system. With this access, you can configure settings, install patches, and enable native features to meet the dependent application's requirements. With RDS Custom, you can run your database workload using the Amazon Web Services Management Console or the Amazon CLI.

RDS Custom supports only the Oracle Database and Microsoft SQL Server DB engines.

Shared responsibility model in RDS Custom

With RDS Custom, you use the managed features of Amazon RDS, but you manage the host and customize the OS as you do in Amazon EC2. You take on additional database management responsibilities beyond what you do in Amazon RDS. The result is that you have more control over database and DB instance management than you do in Amazon RDS, while still benefiting from RDS automation.

Shared responsibility means the following:

  1. You own part of the process when using an RDS Custom feature.

    For example, in RDS Custom for Oracle, you control which Oracle database patches to use and when to apply them to your DB instances.

  2. You are responsible for making sure that any customizations to RDS Custom features work correctly.

    To help protect against invalid customization, RDS Custom has automation software that runs outside of your DB instance. If your underlying Amazon EC2 instance becomes impaired, RDS Custom attempts to resolve these problems automatically by either rebooting or replacing the EC2 instance. The only user-visible change is a new IP address. For more information, see Amazon RDS Custom host replacement.

The following table details the shared responsibility model for different features of RDS Custom.

Feature

Amazon EC2 responsibility

Amazon RDS responsibility

RDS Custom for Oracle responsibility

RDS Custom for SQL Server responsibility

Application optimization

Customer

Customer

Customer

Customer

Scaling

Customer

Amazon

Shared

Shared

High availability

Customer

Amazon

Customer

Amazon

Database backups

Customer

Amazon

Shared

Amazon

Database software patching

Customer

Amazon

Shared

Amazon for RPEV, Customer for CEV1

Database software install

Customer

Amazon

Shared

Amazon for RPEV, Customer for CEV1

OS patching

Customer

Amazon

Customer

Amazon for RPEV, Customer for CEV1

OS installation

Customer

Amazon

Shared

Amazon

Server maintenance

Amazon

Amazon

Amazon

Amazon

Hardware lifecycle

Amazon

Amazon

Amazon

Amazon

Power, network, and cooling

Amazon

Amazon

Amazon

Amazon

1 A custom engine version (CEV) is a binary volume snapshot of a database version and Amazon Machine Image (AMI). An RDS provided engine version (RPEV) is the default Amazon Machine Image (AMI) and Microsoft SQL Server installation.

You can create an RDS Custom DB instance using Microsoft SQL Server. In this case:

  • You can choose from two licensing models: License Included (LI) and Bring Your Own Media (BYOM).

  • With LI, you don't need to purchase SQL Server licenses separately. Amazon holds the license for the SQL Server database software.

  • With BYOM, you provide and install your own Microsoft SQL Server binaries and licensing.

You can create an RDS Custom DB instance using Oracle Database. In this case, you do the following:

  • Manage your own media.

    When using RDS Custom, you upload your own database installation files and patches. You create a custom engine version (CEV) from these files. Then you can create an RDS Custom DB instance by using this CEV.

  • Manage your own licenses.

    You bring your own Oracle Database licenses and manage licenses by yourself.

Support perimeter and unsupported configurations in RDS Custom

RDS Custom provides a monitoring capability called the support perimeter. This feature ensures that your host and database environment are configured correctly. If you make a change that causes your DB instance to go outside the support perimeter, RDS Custom changes the instance status to unsupported-configuration until you manually fix the configuration problems. For more information, see RDS Custom support perimeter.

Key benefits of RDS Custom

With RDS Custom, you can do the following:

  • Automate many of the same administrative tasks as Amazon RDS, including the following:

    • Lifecycle management of databases

    • Automated backups and point-in-time recovery (PITR)

    • Monitoring the health of RDS Custom DB instances and observing changes to the infrastructure, operating system, and database processes.

    • Notification or taking action to fix issues depending on disruption to the DB instance

  • Install third-party applications.

    You can install software to run custom applications and agents. Because you have privileged access to the host, you can modify file systems to support legacy applications.

  • Install custom patches.

    You can apply custom database patches or modify OS packages on your RDS Custom DB instances.

  • Stage an on-premises database before moving it to a fully managed service.

    If you manage your own on-premises database, you can stage the database to RDS Custom as-is. After you familiarize yourself with the cloud environment, you can migrate your database to a fully managed Amazon RDS DB instance.

  • Create your own automation.

    You can create, schedule, and run custom automation scripts for reporting, management, or diagnostic tools.