Description

Ensure that production Cloud SQL instances are configured for high availability using the REGIONAL availability type, which maintains a standby replica in a different zone within the same region and automatically fails over if the primary zone becomes unavailable.

Rationale

A Cloud SQL instance configured with ZONAL availability runs in a single zone, so a zonal outage, hardware failure, or maintenance event causes a database outage until the instance can be restarted, potentially resulting in extended downtime and data unavailability. REGIONAL (high availability) configuration maintains a synchronously replicated standby instance in a second zone and performs automatic failover, significantly reducing downtime for zonal failures and improving the resilience of production workloads.

Impact

  • Reduces downtime from zonal outages or maintenance events through automatic failover

  • Improves resilience and business continuity for production database workloads

  • Increases cost due to the standby replica, which should be weighed against the availability requirements of the workload

Default Value

By default, new Cloud SQL instances may be created with ZONAL availability depending on the tier and settings chosen; REGIONAL (high availability) must be explicitly selected.

Pre-Requisites

  • IAM permissions to view and edit Cloud SQL instances (e.g., Cloud SQL Admin)

  • Awareness of the additional cost associated with the standby replica

Test Plan

  1. Sign in to the Google Cloud Console at https://console.cloud.google.com.

  2. Select the relevant project.

  3. Navigate to Cloud SQL and select the instance to review.

  4. Open the Overview or Configuration section.

  5. Verify the Availability type / High availability field shows Multiple zones (REGIONAL) rather than Single zone (ZONAL).

  6. If a production instance is configured as ZONAL, follow the implementation steps.

Implementation Steps

  1. Sign in to the Google Cloud Console at https://console.cloud.google.com.

  2. Select the relevant project.

  3. Navigate to Cloud SQL and select the instance to update.

  4. Select Edit.

  5. Under Connections / Availability, choose Multiple zones (Highly available).

  6. Review the estimated cost impact.

  7. Click Save to apply the configuration change.

  8. Wait for the instance to restart and confirm that a standby instance now appears in the instance overview.

Backout Plan

  1. Sign in to the Google Cloud Console at https://console.cloud.google.com.

  2. Select the relevant project.

  3. Navigate to Cloud SQL and select the instance to revert.

  4. Select Edit.

  5. Under Connections / Availability, choose Single zone.

  6. Click Save to apply the configuration change.

Reference