To continue our journey to Moodle on Oracle Cloud Infrastructure using Ampere compute instances and MySQL HeatWave Database Service [1] [2], in this article we will see how to scale our architecture using multiple Moodle instances, High Availability for the Database and Read Scale-Out.

This is the architecture we will deploy:

The same principles can be applied to other projects, not just Moodle.

Multiple Compute Instances & MySQL HeatWave High Availability

The first step is to use again the Stack to deploy the initial resources. We must insure that we use a MySQL Shape that has at least 4 OCPUs …

In the previous post, we saw how to quickly deploy Moodle to Oracle Cloud Infrastructure on Ampere compute instances and using MySQL HeatWave.

In this post, we will explore some other features and the benefits of running on OCI and MySQL HeatWave to extend our architecture dedicated to Moodle in the Cloud.

Read Replicas

Moodle natively offers the possibility of distributing the load between reads and writes. When using MySQL HeatWave Database Service, adding read replicas is also a very easy task. Let’s see how we can benefit from it.

To be able to use MySQL HeatWave Read Replicas, the MySQL shape must have at least 4 OCPUs.

Let’s modify the moodle stack and deploy it again but this time we choose a bigger shape for MySQL:

When everything is ready, …

If you want to deploy Moodle on OCI, you can use Ampere compute instances as application server and MySQL HeatWave Database Service to store the data.

Depending on your requirements, MySQL HeatWave can provide High Availability and Query Acceleration.

In this post, we will see the easiest and fasted way to deploy the following basic architecture:

In OCI to quickly deploy an architecture and all the required resources, it’s recommended to use a Stack (Terraform recipes and modules).

So deploy all the resources we need (VCN, Subnets, Security Lists, Internet Gateways, Compute Instances…) we just need to click on the following button:

…

I already wrote on how to deploy WordPress on OCI using MySQL HeatWave, the MySQL Database Service in Oracle Cloud Infrastructure:

• Using MySQL Database Service for WordPress
• Deploying WordPress on OCI with MySQL Database Service: the easy way !
• Deploy WordPress on OCI using MDS – updated version
• Deploy WordPress on OCI with MySQL Database Service using Read Replicas
• …

Let’s continue our journey of deploying the MySQL Database System on OCI with Terraform.
This time we will see how we can use a backup (see [1] and [2]) as a source (initial data) for a new instance.

Within the oci_mysql_mysql_db_system it’s possible to define a source detailing how to provision the initial data of the db system.

Let’s deploy a new MySQL Database Instance using a manual backup we made earlier:

We can also find the backup’s ocid using the oci cli command:

 $ oci mysql backup list …

Recently I wrote an article on how to define a backup policy for MySQL Database Service in OCI using Terraform. We saw that it was possible to define tags (defined_tags and freeform_tags) in the backup_policy section of a oci_mysql_mysql_db_system resource.

However, it seems that these tags are never used for manual or automated backups in the MySQL Database Service backup process. In the strategy implemented on OCI, the backups inherit the tags from the MySQL DB system itself.

This means that if you want to have some custom tags on your backups, you need to specify them in the MySQL Database resource like this (on line 12):

resource "oci_mysql_mysql_db_system" "MDSinstance" {
    admin_password = var.admin_password
    admin_username = …

Let’s continue the discovery of the MySQL Database Resource when deploying on Oracle Cloud Infrastructure using Terraform.

Last week, we saw how to create custom configurations and define user variables. Today we will see how we can define a backup policy and a maintenance window.

Backup Policy

In the oci_mysql_mysql_db_system resource, we will add a new section called backup_policy like this:

backup_policy {
       is_enabled        = "true"
       retention_in_days = "3"
       window_start_time = "01:00-00:00"
       freeform_tags = {"backup_defined_by"="Terraform"}
       pitr_policy {
            is_enabled = "true"
       }
}

This part of code (you can see in a working Terraform architecture sample), enables backup, sets the retention days to 3. It also defines the starting time …

With Terraform OCI provider 4.90.0 (released August 24th, 2022), we have added the possibility to specify the value of editable configuration variables directly from Terraform.

These variables must be defined in a resource of type oci_mysql_mysql_configuration like this:

resource "oci_mysql_mysql_configuration" "mds_mysql_configuration" {
        #Required
        compartment_id = var.compartment_ocid
    shape_name   = var.mysql_shape

         …

Apache Airflow is an open-source workflow management platform for data engineering pipelines.

Today we will see how we can deploy very easily Apache Airflow on a Compute instance in Oracle Cloud Infrastructure (OCI) using MySQL HeatWave Database Service (MDS).

I am sharing Terraform modules you can use to deploy in your architecture:

Architectures

With the modules you can deploy architectures like these:

with a single MDS instancewith MDS High Availabilitywith HeatWave Cluster

We will use the exact same modules built into a stack for OCI’s Resource Manager. This will allow us to deploy the architecture just in few clicks.

Deployment

We open in a browser the following GitHub repository: …

In my prior blog post on Terraform, I demonstrated building the dependent infrastructure that MySQL implementations need.  Building MySQL isn’t much different, but does identify a need for a Webserver to provide configuration files for Terraform to execute on as was done in my prior MySQL on OCI post, and a Yum Repo Webserver to… Read More »