Introduction

RDS maintenance types include “Available” and “Required”. Since Aurora (PostgreSQL) and Neptune each had both Available and Required patches, I looked into them.

Neptune appears to share the same operational technology as RDS. (Though not everything is identical.)

https://docs.aws.amazon.com/ja_jp/neptune/latest/userguide/limits.html

> For certain management functions, Amazon Neptune uses shared operational technology with Amazon Relational Database Service (Amazon RDS).

Neptune

Aurora

About Available and Required

Required - The maintenance action will be applied to the resource and cannot be deferred.
Available - The maintenance action is available but will not be automatically applied to the resource. It can be applied manually.

DescribePendingMaintenanceActions API

Maintenance can be checked via the DescribePendingMaintenanceActions API .

[ec2-user@bastin ~]$ aws rds describe-pending-maintenance-actions
{
    "PendingMaintenanceActions": [
        {
            "PendingMaintenanceActionDetails": [
                {
                    "Action": "system-update",
                    "Description": "Upgrade to Aurora PostgreSQL 3.1.2"
                }
            ],
            "ResourceIdentifier": "arn:aws:rds:ap-northeast-1:xxxxxx:cluster:xxxxxxxpostgresv11"
        },
        {
            "PendingMaintenanceActionDetails": [
                {
                    "Action": "system-update",
                    "CurrentApplyDate": "2020-05-08T18:33:00Z",
                    "AutoAppliedAfterDate": "2020-05-08T18:33:00Z",
                    "Description": "Engine Patch Upgrade"
                }
            ],
            "ResourceIdentifier": "arn:aws:rds:ap-northeast-1:xxxxxxx:cluster:xxxxxxx-cluster"
        }
    ]
}

From the CLI, you cannot tell whether it is Available or Required just by looking at the items. For Required, AutoAppliedAfterDate and CurrentApplyDate are output.

The descriptions of each field are as follows:

Field	Description
Action	The type of pending maintenance action available for the resource: system-update, db-upgrade, hardware-maintenance, or ca-certificate-rotation.
Description	Describes the details of the maintenance action
AutoAppliedAfterDate	The date when the action will be applied during the maintenance window
CurrentApplyDate	The effective date when the pending maintenance action will be applied to the resource
ForcedApplyDate	The date when the maintenance action will be automatically applied (cannot be deferred)
OptInStatus	The type of opt-in request received for the resource: “next-maintenance”, “immediate”, “undo-opt-in”. Output when apply-pending-maintenance-action is explicitly executed.

OptInStatus is output when explicitly specified with apply-pending-maintenance-action, or by selecting “Upgrade at Next Window” or “Upgrade Now” in the management console.

[ec2-user@bastin ~]$ aws rds apply-pending-maintenance-action --resource-identifier arn:aws:rds:ap-northeast-1:xxxxxxxxxxxxxx:cluster:neptestdb-cluster --apply-action system-update --opt-in-type next-maintenance

After this, OptInStatus will be output as follows:

[ec2-user@bastin ~]$ aws rds describe-pending-maintenance-actions --resource-identifier arn:aws:rds:ap-northeast-1:xxxxxxxxxxxxxx:cluster:neptestdb-cluster
{
    "PendingMaintenanceActions": [
        {
            "PendingMaintenanceActionDetails": [
                {
                    "Action": "system-update",
                    "Description": "Engine Patch Upgrade",
                    "CurrentApplyDate": "2020-05-03T15:58:00Z",
                    "AutoAppliedAfterDate": "2020-05-03T15:58:00Z",
                    "OptInStatus": "next-maintenance"
                }
            ],
            "ResourceIdentifier": "arn:aws:rds:ap-northeast-1:xxxxxxx:cluster:xxxxxxx-cluster"
        }
    ]
}

References:

https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_PendingMaintenanceAction.html

https://docs.aws.amazon.com/cli/latest/reference/rds/apply-pending-maintenance-action.html