# Aurora MySQL 就地升级教程
<a name="AuroraMySQL.Upgrading.Tutorial"></a>

以下 Linux 示例展示了如何使用 AWS CLI 执行就地升级过程的一般步骤。

第一个示例创建了运行 Aurora MySQL 版本 2.x 的 Aurora 数据库集群。该集群包括写入器数据库实例和读取器数据库实例。`wait db-instance-available` 命令会暂停，直到写入器数据库实例可用。此时，集群做好升级准备。

```
aws rds create-db-cluster --db-cluster-identifier mynewdbcluster --engine aurora-mysql \
  --db-cluster-version 5.7.mysql_aurora.2.11.2
...
aws rds create-db-instance --db-instance-identifier mynewdbcluster-instance1 \
  --db-cluster-identifier mynewdbcluster --db-instance-class db.t4g.medium --engine aurora-mysql
...
aws rds wait db-instance-available --db-instance-identifier mynewdbcluster-instance1
```

您可以将集群升级到的 Aurora MySQL 3.x 版本取决于集群当前正在运行的 2.x 版本和集群所在的 AWS 区域。第一个命令（带 `--output text`）只显示可用的目标版本。第二个命令显示响应的完整 JSON 输出。在该响应中，您可以看到详细信息，例如您用于 `engine` 参数的 `aurora-mysql` 值。您还可以看到这样一个事实，即升级到 3.04.0 表示一次主要版本升级。

```
aws rds describe-db-clusters --db-cluster-identifier mynewdbcluster \
  --query '*[].{EngineVersion:EngineVersion}' --output text
5.7.mysql_aurora.2.11.2

aws rds describe-db-engine-versions --engine aurora-mysql --engine-version 5.7.mysql_aurora.2.11.2 \
  --query '*[].[ValidUpgradeTarget]'
...
{
    "Engine": "aurora-mysql",
    "EngineVersion": "8.0.mysql_aurora.3.04.0",
    "Description": "Aurora MySQL 3.04.0 (compatible with MySQL 8.0.28)",
    "AutoUpgrade": false,
    "IsMajorVersionUpgrade": true,
    "SupportedEngineModes": [
        "provisioned"
    ],
    "SupportsParallelQuery": true,
    "SupportsGlobalDatabases": true,
    "SupportsBabelfish": false,
    "SupportsIntegrations": false
},
...
```

此示例表示，如果您输入的目标版本号不是集群的有效升级目标，Aurora 不会执行升级。Aurora 也不会执行主要版本升级，除非您包含 `--allow-major-version-upgrade` 参数。这样一来，您就不能意外执行有可能需要大量测试和更改应用程序代码的升级。

```
aws rds modify-db-cluster --db-cluster-identifier mynewdbcluster \
  --engine-version 5.7.mysql_aurora.2.09.2 --apply-immediately
An error occurred (InvalidParameterCombination) when calling the ModifyDBCluster operation: Cannot find upgrade target from 5.7.mysql_aurora.2.11.2 with requested version 5.7.mysql_aurora.2.09.2.

aws rds modify-db-cluster --db-cluster-identifier mynewdbcluster \
  --engine-version 8.0.mysql_aurora.3.04.0 --region us-east-1 --apply-immediately
An error occurred (InvalidParameterCombination) when calling the ModifyDBCluster operation: The AllowMajorVersionUpgrade flag must be present when upgrading to a new major version.

aws rds modify-db-cluster --db-cluster-identifier mynewdbcluster \
  --engine-version 8.0.mysql_aurora.3.04.0 --apply-immediately --allow-major-version-upgrade
{
  "DBClusterIdentifier": "mynewdbcluster",
  "Status": "available",
  "Engine": "aurora-mysql",
  "EngineVersion": "5.7.mysql_aurora.2.11.2"
}
```

 集群和关联数据库实例的状态需要一段时间才能更改为 `upgrading`。集群和数据库实例的版本号仅在升级完成后才会更改。同样，您可以使用 `wait db-instance-available` 命令让写入器数据库实例等到升级完成后再继续。

```
aws rds describe-db-clusters --db-cluster-identifier mynewdbcluster \
  --query '*[].[Status,EngineVersion]' --output text
upgrading 5.7.mysql_aurora.2.11.2

aws rds describe-db-instances --db-instance-identifier mynewdbcluster-instance1 \
  --query '*[].{DBInstanceIdentifier:DBInstanceIdentifier,DBInstanceStatus:DBInstanceStatus} | [0]'
{
    "DBInstanceIdentifier": "mynewdbcluster-instance1",
    "DBInstanceStatus": "upgrading"
}

aws rds wait db-instance-available --db-instance-identifier mynewdbcluster-instance1
```

 此时，集群的版本号与为升级指定的版本号匹配。

```
aws rds describe-db-clusters --db-cluster-identifier mynewdbcluster \
  --query '*[].[EngineVersion]' --output text

8.0.mysql_aurora.3.04.0
```

前面的示例通过指定 `--apply-immediately` 参数进行了立即升级。为了让升级在集群预计不繁忙的方便之时进行，您可以指定 `--no-apply-immediately` 参数。这样做可以在集群的下一个维护时段内启动升级。维护时段定义了可以启动维护操作的时间段。在维护时段内，长时间运行的操作可能无法完成。因此，即使您预计升级可能需要很长时间，也不需要定义更大的维护时段。

以下示例升级最初运行 Aurora MySQL 版本 2.11.2 的集群。在 `describe-db-engine-versions` 输出中，`False` 和 `True` 值表示 `IsMajorVersionUpgrade` 属性。您可以从版本 2.11.2 升级到一些其他 2.\$1 版本。这些升级不被视为主要版本升级，因此不需要就地升级。就地升级仅适用于升级到列表中显示的 3.\$1 版本。

```
aws rds describe-db-clusters --db-cluster-identifier mynewdbcluster \
  --query '*[].{EngineVersion:EngineVersion}' --output text
5.7.mysql_aurora.2.11.2

aws rds describe-db-engine-versions --engine aurora-mysql --engine-version 5.7.mysql_aurora.2.10.2 \
  --query '*[].[ValidUpgradeTarget]|[0][0]|[*].[EngineVersion,IsMajorVersionUpgrade]' --output text

5.7.mysql_aurora.2.11.3 False
5.7.mysql_aurora.2.11.4 False
5.7.mysql_aurora.2.11.5 False
5.7.mysql_aurora.2.11.6 False
5.7.mysql_aurora.2.12.0 False
5.7.mysql_aurora.2.12.1 False
5.7.mysql_aurora.2.12.2 False
5.7.mysql_aurora.2.12.3 False
8.0.mysql_aurora.3.04.0 True
8.0.mysql_aurora.3.04.1 True
8.0.mysql_aurora.3.04.2 True
8.0.mysql_aurora.3.04.3 True
8.0.mysql_aurora.3.05.2 True
8.0.mysql_aurora.3.06.0 True
8.0.mysql_aurora.3.06.1 True
8.0.mysql_aurora.3.07.1 True

aws rds modify-db-cluster --db-cluster-identifier mynewdbcluster \
  --engine-version 8.0.mysql_aurora.3.04.0 --no-apply-immediately --allow-major-version-upgrade
...
```

如果在没有指定的维护时段的情况下创建集群，Aurora 会随机选择一周中的一天。在这种情况下，`modify-db-cluster` 命令将在星期一提交。因此，我们将维护时段更改为星期二早上。所有时间都以 UTC 时区表示。`tue:10:00-tue:10:30` 时段对应于太平洋时间凌晨 2:00-2:30。维护时段的更改会立即生效。

```
aws rds describe-db-clusters --db-cluster-identifier mynewdbcluster --query '*[].[PreferredMaintenanceWindow]'
[
    [
        "sat:08:20-sat:08:50"
    ]
]

aws rds modify-db-cluster --db-cluster-identifier mynewdbcluster --preferred-maintenance-window tue:10:00-tue:10:30"
aws rds describe-db-clusters --db-cluster-identifier mynewdbcluster --query '*[].[PreferredMaintenanceWindow]'
[
    [
        "tue:10:00-tue:10:30"
    ]
]
```

以下示例说明如何获取升级所生成的事件的报告。`--duration` 参数表示检索事件信息的分钟数。系统需要此参数，因为默认情况下，`describe-events` 仅返回最后一个小时的事件。

```
aws rds describe-events --source-type db-cluster --source-identifier mynewdbcluster --duration 20160
{
    "Events": [
        {
            "SourceIdentifier": "mynewdbcluster",
            "SourceType": "db-cluster",
            "Message": "DB cluster created",
            "EventCategories": [
                "creation"
            ],
            "Date": "2022-11-17T01:24:11.093000+00:00",
            "SourceArn": "arn:aws:rds:us-east-1:123456789012:cluster:mynewdbcluster"
        },
        {
            "SourceIdentifier": "mynewdbcluster",
            "SourceType": "db-cluster",
            "Message": "Upgrade in progress: Performing online pre-upgrade checks.",
            "EventCategories": [
                "maintenance"
            ],
            "Date": "2022-11-18T22:57:08.450000+00:00",
            "SourceArn": "arn:aws:rds:us-east-1:123456789012:cluster:mynewdbcluster"
        },
        {
            "SourceIdentifier": "mynewdbcluster",
            "SourceType": "db-cluster",
            "Message": "Upgrade in progress: Performing offline pre-upgrade checks.",
            "EventCategories": [
                "maintenance"
            ],
            "Date": "2022-11-18T22:57:59.519000+00:00",
            "SourceArn": "arn:aws:rds:us-east-1:123456789012:cluster:mynewdbcluster"
        },
        {
            "SourceIdentifier": "mynewdbcluster",
            "SourceType": "db-cluster",
            "Message": "Upgrade in progress: Creating pre-upgrade snapshot [preupgrade-mynewdbcluster-5-7-mysql-aurora-2-10-2-to-8-0-mysql-aurora-3-02-0-2022-11-18-22-55].",
            "EventCategories": [
                "maintenance"
            ],
            "Date": "2022-11-18T23:00:22.318000+00:00",
            "SourceArn": "arn:aws:rds:us-east-1:123456789012:cluster:mynewdbcluster"
        },
        {
            "SourceIdentifier": "mynewdbcluster",
            "SourceType": "db-cluster",
            "Message": "Upgrade in progress: Cloning volume.",
            "EventCategories": [
                "maintenance"
            ],
            "Date": "2022-11-18T23:01:45.428000+00:00",
            "SourceArn": "arn:aws:rds:us-east-1:123456789012:cluster:mynewdbcluster"
        },
        {
            "SourceIdentifier": "mynewdbcluster",
            "SourceType": "db-cluster",
            "Message": "Upgrade in progress: Purging undo records for old row versions. Records remaining: 164",
            "EventCategories": [
                "maintenance"
            ],
            "Date": "2022-11-18T23:02:25.141000+00:00",
            "SourceArn": "arn:aws:rds:us-east-1:123456789012:cluster:mynewdbcluster"
        },
        {
            "SourceIdentifier": "mynewdbcluster",
            "SourceType": "db-cluster",
            "Message": "Upgrade in progress: Purging undo records for old row versions. Records remaining: 164",
            "EventCategories": [
                "maintenance"
            ],
            "Date": "2022-11-18T23:06:23.036000+00:00",
            "SourceArn": "arn:aws:rds:us-east-1:123456789012:cluster:mynewdbcluster"
        },
        {
            "SourceIdentifier": "mynewdbcluster",
            "SourceType": "db-cluster",
            "Message": "Upgrade in progress: Upgrading database objects.",
            "EventCategories": [
                "maintenance"
            ],
            "Date": "2022-11-18T23:06:48.208000+00:00",
            "SourceArn": "arn:aws:rds:us-east-1:123456789012:cluster:mynewdbcluster"
        },
        {
            "SourceIdentifier": "mynewdbcluster",
            "SourceType": "db-cluster",
            "Message": "Database cluster major version has been upgraded",
            "EventCategories": [
                "maintenance"
            ],
            "Date": "2022-11-18T23:10:28.999000+00:00",
            "SourceArn": "arn:aws:rds:us-east-1:123456789012:cluster:mynewdbcluster"
        }
    ]
}
```