Managing databases with Cloud 66
About deploying databases
We currently support the following databases, with no need for additional configuration after deployment.
- MySQL (or Percona if configured via Manifest)
- SQLite (only in development environments)
After you have analyzed your code, ensure that your desired database type is displayed in the About your app section of the analysis results.
When we deploy a database we automatically generate the required users and passwords to allow authentication. You can find these values via your Dashboard in the detail page of any database server. They will be available as environment variables and your application will be configured to use them.
MySQL and PostgreSQL databases managed by Cloud 66 automatically have the following users created:
- a Database Application user
- a Database Admin user
- a Database Replication user (where replication is required)
The Application and Replication users always have the same password. The associated Linux users for these will differ depending on database type.
If you switch to managing your passwords manually, be sure to update all of these users whenever you change passwords. Remember that the Application and Replication users must use the same password.
Environment variables during deployment
When you set up an application on Cloud 66, we detect its database type(s) (from your code) and generate a set of variables for things like
URL. We only generate these “analyzed variables” after you have confirmed that we will be managing the database(s).
You can see a list of these variables during application creation by clicking on the Add Environment Variables button (in the yellow Review your Rails application box) . You will see the list of analyzed variables for your database(s) at the top of the panel.
For databases that we manage, we will generate all of these variables, and replace any existing variables you have in your YAML config files unless you turn the auto-replacement feature off. (You can also override the values of these variables manually, one by one, if you wish - see below)
If your application uses an externally hosted (self-managed) database, we will not generate any of the analysed variables. If your config files rely on environment variables, you will need to set these manually before you deploy, or we will not be able to connect to your database.
Setting variables manually (overriding)
To add your own values to the analyzed variables, click on the Add Environment Variables button and then click the Override link next to each of the variables you wish to update. Remember, for external databases, we will discard any variables which do not have values set manually.
Database deployment types
No database (external)
This option allows you to deploy your application without a database managed by Cloud 66, and is ideal for externally hosted databases.
You can also configure an external database via your Manifest file by specifying the
server node as
Please note that if there is no connectivity to your external database, or your external database host is not configured correctly, the deployment will fail.
This option deploys your chosen database to the same server as your web server - this is intended primarily for development, as running your database locally in production is not advised. In this case, your application database configuration will be amended to target your local database server. If you scale up your web server, these settings will also be amend automatically to reflect your database configuration.
This option will automatically create a new server for your database and configure your application accordingly.
Upgrading your database
Cloud 66 will not do in-place database upgrades, because this process may cause your application to stop working or may not be possible automatically. To upgrade your database through Cloud 66, we recommend that you create a new application (at which point Cloud 66 will deploy the newer database version).
Once the new application is created, you can migrate data from your old application to your new application.
Customize your database configuration
You can customize the database configuration on your servers using CustomConfig. CustomConfig is available for MySQL, PostgreSQL, Redis and MongoDB.
Editing and committing your database CustomConfig will perform the following steps on every database server in your application, one by one, sequentially:
- Check your template for Liquid syntax errors
- Determine the correct server configuration and prepare general variables
- Prepare custom variables for your database type (e.g. server_state)
- Compile the database configuration based on the information from the server and database type
- Upload the configuration to the server
- Restart your database
🚨 A bad database configuration might stop your database from working. Take extra care to make sure the configuration is correct.
Database customization variables
There are a number of variables available for use in your database CustomConfig. Some are general for all database types, while others are database specific.
The following variables are available to any database CustomConfig.
|server||Hash||Hash containing information about your server|
|memory||integer||Server memory size (bytes)|
|core||integer||Server core count|
The following variables are only available in the MySQL CustomConfig.
|server_state||string||Value can be stand_alone, mysql_master or mysql_slave based on your server status|
|server_id||integer||An ID used by MySQL replication to identify your server*|
*It is 0 for standalone servers, 1 for master servers and a number greater than 1 for slave servers
The following variables are only available in the PostgreSQL CustomConfig.
|server_state||string||Value can be stand_alone, pg_master or pg_slave based on your server status|
The following variables are only available in the Redis CustomConfig.
|server_state||string||Value can be stand_alone, redis_master or redis_slave based on your server status|
|master_address||string||IP address of replication master (empty string if server is stand alone or master)|
|master_port||integer||Will be 6379 when server is redis_slave , otherwise it is 0|
Migrating to an external database
If you need to migrate a database managed by Cloud 66 to an external provider, you should bear in mind the following:
- Updating your Manifest file will not be sufficient to reconfigure your application - you will need to connect your application manually to your new database servers, including authentication credentials, ideally via your app’s environment variables.
- Your existing database servers will need to be manually removed from your application after you have migrated. They will not be automatically removed or deleted.
The exact migration process will differ widely depending on both the database used, and the host to which you are migrating your data, but all of them share the following steps:
- Switch off your application (maintenance mode is useful here)
- Migrate your data to the new host
- Set up authentication credentials and connection details
- Add a firewall rule to allow your app to reach the new data host (and vice versa)
- Turn your application back on
- Delete your defunct Cloud 66 database servers