Configuring upgrades

This topic provides reference content about upgrading database instances in Amazon Aurora MySQL. You can learn about the reasons for database upgrades, the differences between upgrading SQL Server and Aurora MySQL, and the process of performing upgrades in Aurora MySQL.

SQL Server Usage

As a database administrator, from time to time a database upgrade is required, it can be either for security fix, bugs fixes, compliance, or new database features.

The database upgrade approach can be planned to minimize the database downtime and risk. You can perform an upgrade in-place or migrate to a new installation.

Upgrade In-Place

With this approach, we are retaining the current hardware and OS version by adding the new SQL Server binaries on the same server and then upgrade the SQL Server instance.

Before upgrading the database engine, review the SQL Server release notes for the intended target release version for any limitations and known issues to help you plan the upgrade.

In general, these will be the steps to perform the upgrade:

Prerequisites steps

Steps for upgrade

Post upgrade tasks

Migrate to a New Installation

This approach maintains the current environment while building a new SQL Server environment. This is usually done when migrating on a new hardware and with a new version of the operating system. In this approach migrate the system objects so that they are same as the existing environment, then migrate the user database either using backup and restore.

For more information, see Upgrade Database Engine in the SQL Server documentation.

MySQL Usage

After migrating your databases to Amazon Aurora MySQL-Compatible Edition (Aurora MySQL), you will still need to upgrade your database instance from time to time, for the same reasons you have done it in the past like new features, bugs and security fixes.

In a managed service like Amazon Relational Database Service (Amazon RDS), the upgrade process is much easier and simpler compare to the on-prem SQL Server process.

To determine the current Aurora MySQL version being used, you can use the following AWS CLI command:

aws rds describe-db-engine-versions --engine aurora-mysql --query '*[].[EngineVersion]' --output text --region your-AWS-Region

This can also be queried from the database, using the following queries:

SELECT AURORA_VERSION();

In an Aurora MySQL version number scheme, for example 2.08.1, the first digit represents the major version. Aurora MySQL version 1 is compatible with MySQL 5.6 and Aurora MySQL version 2 is compatible with MySQL 5.7. To find all Amazon Aurora and MySQL versions mapping, see Database engine updates for Amazon Aurora MySQL version 2.

AWS doesn’t apply major version upgrades on Amazon Aurora automatically. Major version upgrades contains new features and functionality which often involves system table and other code changes. These changes may not be backward-compatible with previous versions of the database so applications testing is highly recommended.

Applying automatic minor upgrades can be set by configuring the Amazon RDS instance to allow it.

You can use the following AWS CLI command (Linux) to determine the current automatic upgrade minor versions.

aws rds describe-db-engine-versions --output=table --engine mysql --engine-version minor-version --region region

When enabled, the instance will be automatically upgraded during the scheduled maintenance window.

If you want to upgrade your cluster to a compatible cluster, you can do so by running an upgrade process on the cluster itself. This kind of upgrade is an in-place upgrade, in contrast to upgrades that you do by creating a new cluster. The upgrade is relatively fast because it doesn’t require copying all your data to a new cluster volume. In place upgrade preserves the endpoints and set of DB instances for your cluster.

To verify application compatibility, performance and maintenance procedures for the upgraded cluster, you can perform a simulation of the upgrade by doing following

For major upgrades, this is the recommended:

Aurora MySQL performs a major version upgrade in multiple steps. As each step begins, Aurora MySQL records an event. You can monitor the current status and events as they occur on the Events page in the Amazon RDS console.

Amazon Aurora performs a series of checks before beginning the upgrade process. If any issues are detected during these checks, resolve the issue identified in the event details and restart the upgrade process.

Aurora takes the cluster offline, performs a similar set of tests as in the previous step. If no new issues are identified, then Aurora moves with the next step. If any issues are detected during these checks, resolve the issue identified in the event details and restart the upgrade process again.

Aurora backups up the MySQL cluster by creating a snapshot of the cluster volume.

Aurora clones the cluster volume. If any issues are encountered during the upgrade, Aurora reverts to the original data from the cloned cluster volume and brings the cluster back online.

Aurora performs a clean shutdown and it rolls back any uncommitted transactions.

Aurora upgrades the engine version. It installs the binary for the new engine version and uses the writer DB instance to upgrade your data to new to MySQL compatible format. During this stage, Aurora modifies the system tables and performs other conversions that affect the data in your cluster volume.

The upgrade process is completed. Aurora records a final event to indicate that the upgrade process completed successfully. Now DB cluster is running the new major version.

Upgrade can be done through the AWS Console or AWS CLI.

Console

AWS CLI

To upgrade the major version of an Aurora MySQL DB cluster, use the AWS CLI modify-db-cluster command with the following required parameters:

For Linux, macOS, or Unix:

aws rds modify-db-cluster \
--db-cluster-identifier sample-cluster \
--engine aurora-mysql \
--engine-version 5.7.mysql_aurora.2.09.0 \
--allow-major-version-upgrade \
--apply-immediately

For Windows:

aws rds modify-db-cluster ^
--db-cluster-identifier sample-cluster ^
--engine aurora-mysql ^
--engine-version 5.7.mysql_aurora.2.09.0 ^
--allow-major-version-upgrade ^
--apply-immediately

Summary

For more information, see Upgrading Amazon Aurora MySQL DB clusters in the User Guide for Aurora.