Hello and welcome to session one. An introduction to Alibaba's relational database service called ApsaraDB RDS, or commonly referred to as just RDS.

What is RDS? RDS is a stable, reliable and scalable online managed relational database service built with a distributed file system and integrated with high-performance SSD disks. It's simple to deploy, easy to scale, and is cost effective.

RDS provides a complete suite of database operation and maintenance solutions such as disaster recovery, backup, restoration, monitoring and migration. There is a choice of different database engines to choose from as well as different additions such as MySQL, MariaDB, SQL Server and PostgreSQL.

It can provide high availability and high performance and it's a completely managed service. It's easy to scale and operate and you can run as many or as few systems as you require.

As a managed service, RDS comes under Platform as a Service or PaaS. You don't need to worry about the underlying hardware or the operating system, or even the runtime environment. Alibaba is responsible for the running and maintenance of the host and operating system. You have no access to the database host operating system and limited ability to modify the configuration that's on the host system. Alibaba manages all that functionality for you.

You will have at a minimum, a primary instance running in a cluster and potentially backup instances running in another cluster. RDS has a guaranteed up to 99.99% service level agreement for business availability. RDS provides automatic fail-over to a backup or secondary instance, if the primary instance is not available. This is however dependent on the addition that is selected. It also provides inbuilt monitoring and security tools.

RDS has fully managed storage and supports up to 120,000 IOPS and up to three terabytes of storage per instance. You can use the upgrade or downgrade feature to extend or reduce instance memory and disk space according to your requirements.

If you were to compare providing a traditional on-premise database as opposed to Alibaba cloud-based RDS service, building this type of service manually on premise would require preparing the hardware in your on-premise data center, installing an operating system, installing and configuring the database software, just to get to the point where you can then configure the database. This could potentially take hours to complete. With RDS, you choose the payment type, the location, select the database engine and edition that you require. And in around 10 minutes, you're ready to configure your database.

The underlying architecture supports a high availability control system, a backup system, an online migration system, a task scheduling system for creating and deleting instances and a monitoring and logging system. This can all be controlled through the Alibaba portal web interface, APIs, or from cloud shell's command line.

Alibaba provides its RDS services all over the world by using different regions. A region will cover an area such as China Hong Kong, UK London, or Germany Frankfurt, to name a few. Each region will generally have between one and up to three availability zones. These are individual data centers in the region that have their own power and network supplies.

Alibaba provides inexpensive low latency network connectivity to other availability zones in the same region. So it's recommended to choose a region to optimize latency, minimize costs and address any regulatory requirements you may have.

It's recommended to connect to your RDS instance from the internal ECS instance in a private network. The default option for RDS instances is to have a private network IP once it's created.

There are two reasons for doing so: First it provides better security since in this setting, RDS can only be accessed internally. And the other reason is it can help save cost. There is no charge for private network traffic.

An example of the architecture is shown in the following graphic. This graphic depicts the UK London region and its availability zone, zone A. There's an RDS instance, RDS one in London zone A and it's recommended best practice to connect to this instance using the private network.

So in this case, we have a client server, which is ECS one in the zone and it connects to RDS one using the private network. If we had another London zone, zone B and another ECS instance, ECS two into zone B, you can connect to RDS one using the private network because in Alibaba cloud, the private network supports cross zone private network connections. So both ECS one and ECS two, although in different zones can connect to RDS one in zone A using a private network.

If you have the client servers in other regions, or you need to connect and manage the RDS instance over the public network, then from within the RDS management console you can apply for a public IP address. Your RDS instance will then become accessible over a public network. The trade-off using this method, however, is potential reduced security and possible network charges for accessing over the public internet.

So let's recap what we've covered in this session. RDS is a Platform as a Service offering that provides a fully scalable, online managed relational database solution. There was a choice of different database engines to choose from: MySQL, SQL Server, MariaDB, PostgreSQL.

RDS provides a complete suite of database operation and maintenance solutions such as disaster recovery, backup, restoration, monitoring and migration. And there are multiple regions around the world so that you can provision your databases closer to your end users to reduce network latency and cost.

That concludes this introduction to Alibaba's relational database service. I look forward to speaking to you in the next session, RDS components.