November 21st, 2024

Machine translation is used partially for this article. See the Japanese version for the original article.

Introduction

We will introduce the points to consider when migrating an HA cluster built with EXPRESSCLUSTER from an on-premises environment to an AWS environment.

EXPRESSCLUSTER can be used in any environment, whether on-premises or cloud. However, because the features available vary depending on the environment, you will need to consider the connection destination switching method and data transfer method when migrating. Also, if there is a period during the migration period in which the old and new servers will be running in parallel, you will need to be careful about how you handle licenses.

This article is divided into two parts: "Configuration Considerations Section", which introduces points to consider when migrating from an on-premises environment to an AWS environment, and "Configuration Changes Section", which describes how to change settings by reusing the cluster configuration data file, which is a configuration file for EXPRESSCLUSTER, when actually migrating. This article will cover the "Configuration Considerations Section". For information on how to modify the cluster configuration data file, please refer to the article in Configuration Changes Section.

Contents

1. Points to Consider When Migrating from an On-premises Environment to an AWS Environment

We will introduce the points to consider when migrating from an on-premises environment to an AWS environment.
Because there are differences in the available EXPRESSCLUSTER features(resources) between on-premises and AWS environments, you will need to consider replacing resources and changing parameters when migrating.

The features differences between EXPRESSCLUSTER in the on-premises and AWS environments are as follows:

In addition, the following guides also contain information about features differences and points to note, so please refer to them as well.

Some of the features introduced here may not be available depending on the version of EXPRESSCLUSTER, so we recommend using the latest version. For example, AWS DNS resources are available in EXPRESSCLUSTER X 4.0 and later, and forced stop resources are available in EXPRESSCLUSTER X 5.0 and later.

1.1 About the Connection Destination Switching Method

As summarized in the features differences, floating IP resources and virtual IP resources cannot be used in an AWS environment.

Therefore, if you want to access the server on which your business is running using an IP address from a client, as in an on-premises environment, you will need to consider replacing the connection destination switching method with an AWS virtual IP resource, for example.

Please refer to the articles We Have Summarized the Standard Configurations of EXPRESSCLUSTER X on AWS and Introducing the Function of EXPRESSCLUSTER: AWS Secondary IP Resource or various guides for information on the features, uses, and precautions of the connection destination switching method that can be used in AWS environments.

1.2 About the Data Transfer Method

In an AWS environment, it is possible to build shared disk, mirror disk, or hybrid disk type HA clusters, just as in an on-premises environment.

AWS offers services and features equivalent to shared disks. HA cluster using the Multi-Attach feature of Amazon EBS are one option for environments where I/O performance is more important. However, because this is essentially a Single-AZ cluster, availability is lower than with Multi-AZ or across regions clusters. In an AWS, configurations that place EC2 instances in multiple AZs or regions qualify for higher service level agreements (hereinafter called “SLA“). For details, please refer to the SLA of AWS.

To achieve a configuration with higher availability, mirror disk or hybrid disk type HA clusters are more suitable. This is because you can place servers multiple AZs or across regions, allowing you to be applied by higher SLAs. A hybrid disk type cluster is a configuration that combines a shared disk type and a mirror disk type HA cluster.
Please refer to the article Points to Consider and Recommended Settings When Building a Mirror Disk Type Cluster for points to consider and recommended values ​​to consider before building a mirror disk type or hybrid disk type HA cluster.

In addition, for Linux OS, it is possible to build an HA cluster using Amazon Elastic File System as shared storage between servers. However, because Amazon EFS distributes and writes data across multiple Availability Zones, the latency of writing data may increase.

If you wish to use some resources, such as mirror disk resources, for the new, you will need an additional license.

1.3 About NP Resolution and Forced Stop Settings

In an AWS environment, we recommend a configuration that sets up an HTTP NP resolution resource as the NP resolution method. We also recommend using a forced stop resource in addition to the NP resolution resource. For details on setting up the NP resolution resource and the forced stop resource, please refer to the article How to Prevent Both-System Activation on AWS.

1.4 Other Points to Note

Here are some other points to note when considering migrating to an AWS environment:

In addition, the following FAQ is in Japanese page, but it contains information about server migration to a virtual environment (P2V/V2V). It also contains information about the precautions to take when using the license in the destination, so please refer to it as well.

If there is a period during the migration period in which the old and new servers will be running in parallel, we also have fixed term licenses available on a monthly basis, so please consider using them.

Conclusion

This time, we introduced the points to consider when migrating an HA cluster built with EXPRESSCLUSTER from an on-premises environment to an AWS environment. Since the type of cluster built on AWS varies depending on the system requirements, the points introduced here do not necessarily need to be reviewed in all environments, but you will use this as a reference if you are considering migrating your environment from on-premises to AWS.

When actually migrating to an AWS environment, the method for changing settings by reusing the cluster configuration data file is described in the Configuration Changes Section. Please take a look at this as well.

If you consider introducing the configuration described in this article, you can perform a validation with the trial module of EXPRESSCLUSTER. Please do not hesitate to contact us if you have any questions.