本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。

# AWS CLI Amazon Aurora 自訂端點的範例
<a name="Aurora.Endpoint.Tutorial"></a>

下列教學課程使用 Unix shell 語法 AWS CLI 的範例，示範如何定義具有數個「小型」資料庫執行個體和數個「大型」資料庫執行個體的叢集，並建立自訂端點以連線至每組資料庫執行個體。若要在自己的系統上執行類似的命令，您應該充分熟悉使用 Aurora 叢集和 AWS CLI 用量的基本概念，為區域、子網路群組和 VPC 安全群組等參數提供自己的值。

此範例示範初始設定步驟：建立 Aurora 叢集和新增資料庫執行個體至叢集。這是異質叢集，表示不是所有資料庫執行個體都有相同的容量。大多數執行個體使用 AWS 執行個體類別 `db.r4.4xlarge`，但最後兩個資料庫執行個體使用 `db.r4.16xlarge`。這些範例 `create-db-instance` 命令中的每個會將其輸出列印至畫面，並將 JSON 的副本儲存在檔案中，供後續檢查。

```
aws rds create-db-cluster --db-cluster-identifier custom-endpoint-demo --engine aurora-mysql \
     --engine-version 8.0.mysql_aurora.3.04.0 --master-username $MASTER_USER --manage-master-user-password \
     --db-subnet-group-name $SUBNET_GROUP  --vpc-security-group-ids $VPC_SECURITY_GROUP \
     --region $REGION

for i in 01 02 03 04 05 06 07 08
do
  aws rds create-db-instance --db-instance-identifier custom-endpoint-demo-${i} \
     --engine aurora --db-cluster-identifier custom-endpoint-demo --db-instance-class db.r4.4xlarge \
     --region $REGION \
     | tee custom-endpoint-demo-${i}.json
done

for i in 09 10
do
  aws rds create-db-instance --db-instance-identifier custom-endpoint-demo-${i} \
     --engine aurora --db-cluster-identifier custom-endpoint-demo --db-instance-class db.r4.16xlarge \
     --region $REGION \
     | tee custom-endpoint-demo-${i}.json
done
```

較大的執行個體保留供專業類型的報告查詢使用。為了讓它們不可能被提升為主要執行個體，下列範例會將其提升層變更至最低優先順序。此範例會指定 `--manage-master-user-password` 選項來產生主要使用者密碼，並在 Secrets Manager 中管理該密碼。如需詳細資訊，請參閱[使用 Amazon Aurora 和 進行密碼管理 AWS Secrets Manager](rds-secrets-manager.md)。或者，您可以使用 `--master-password` 選項，自行指定和管理密碼。

```
for i in 09 10
do
  aws rds modify-db-instance --db-instance-identifier custom-endpoint-demo-${i} \
    --region $REGION --promotion-tier 15
done
```

假設您只要對最資源密集的查詢使用兩個「較大的」執行個體。若要這樣做，您可以先建立自訂唯讀端點。然後，您可以新增成員的靜態列表，以便端點僅連線到這些資料庫執行個體。這些執行個體已處於最低的提升層級，使它們兩個都不可能被提升為主要執行個體。如果已將它們其中之一提升為主要執行個體，將會變得無法透過此端點連線，因為我們指定的是 `READER` 類型而非 `ANY` 類型。

下列範例示範建立和修改端點命令，而範例 JSON 輸出顯示自訂端點的初始和修改的狀態。

```
$ aws rds create-db-cluster-endpoint --region $REGION \
    --db-cluster-identifier custom-endpoint-demo \
    --db-cluster-endpoint-identifier big-instances --endpoint-type reader
{
    "EndpointType": "CUSTOM",
    "Endpoint": "big-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com",
    "DBClusterEndpointIdentifier": "big-instances",
    "DBClusterIdentifier": "custom-endpoint-demo",
    "StaticMembers": [],
    "DBClusterEndpointResourceIdentifier": "cluster-endpoint-W7PE3TLLFNSHXQKFU6J6NV5FHU",
    "ExcludedMembers": [],
    "CustomEndpointType": "READER",
    "Status": "creating",
    "DBClusterEndpointArn": "arn:aws:rds:ca-central-1:111122223333:cluster-endpoint:big-instances"
}

$ aws rds modify-db-cluster-endpoint --db-cluster-endpoint-identifier big-instances \
    --static-members custom-endpoint-demo-09 custom-endpoint-demo-10 --region $REGION
{
    "EndpointType": "CUSTOM",
    "ExcludedMembers": [],
    "DBClusterEndpointIdentifier": "big-instances",
    "DBClusterEndpointResourceIdentifier": "cluster-endpoint-W7PE3TLLFNSHXQKFU6J6NV5FHU",
    "CustomEndpointType": "READER",
    "DBClusterEndpointArn": "arn:aws:rds:ca-central-1:111122223333:cluster-endpoint:big-instances",
    "StaticMembers": [
        "custom-endpoint-demo-10",
        "custom-endpoint-demo-09"
    ],
    "Status": "modifying",
    "Endpoint": "big-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com",
    "DBClusterIdentifier": "custom-endpoint-demo"
}
```

叢集的預設 `READER` 端點可以連線至小型或大型資料庫執行個體，使得當叢集變得忙碌時，要預測查詢效能和可擴展性變得不切實際。若要在資料庫執行個體集之間清楚劃分工作負載，您可以忽略預設的 `READER` 端點，並建立連線至所有其他資料庫執行個體的第二個自訂端點。以下範例會透過建立自訂端點，然後新增排除清單來執行此動作。您之後新增至叢集的任何資料庫執行個體，將會自動新增至此端點。`ANY` 類型表示此端點與總共八個執行個體相關聯：一個主要執行個體和另外七個 Aurora 複本。如果範例使用 `READER` 類型，則自訂端點只會與七個 Aurora 複本相關聯。

```
$ aws rds create-db-cluster-endpoint --region $REGION --db-cluster-identifier custom-endpoint-demo \
    --db-cluster-endpoint-identifier small-instances --endpoint-type any
{
    "Status": "creating",
    "DBClusterEndpointIdentifier": "small-instances",
    "CustomEndpointType": "ANY",
    "EndpointType": "CUSTOM",
    "Endpoint": "small-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com",
    "StaticMembers": [],
    "ExcludedMembers": [],
    "DBClusterIdentifier": "custom-endpoint-demo",
    "DBClusterEndpointArn": "arn:aws:rds:ca-central-1:111122223333:cluster-endpoint:small-instances",
    "DBClusterEndpointResourceIdentifier": "cluster-endpoint-6RDDXQOC3AKKZT2PRD7ST37BMY"
}

$ aws rds modify-db-cluster-endpoint --db-cluster-endpoint-identifier small-instances \
    --excluded-members custom-endpoint-demo-09 custom-endpoint-demo-10 --region $REGION
{
    "DBClusterEndpointIdentifier": "small-instances",
    "DBClusterEndpointArn": "arn:aws:rds:ca-central-1:c7tj4example:cluster-endpoint:small-instances",
    "DBClusterEndpointResourceIdentifier": "cluster-endpoint-6RDDXQOC3AKKZT2PRD7ST37BMY",
    "CustomEndpointType": "ANY",
    "Endpoint": "small-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com",
    "EndpointType": "CUSTOM",
    "ExcludedMembers": [
        "custom-endpoint-demo-09",
        "custom-endpoint-demo-10"
    ],
    "StaticMembers": [],
    "DBClusterIdentifier": "custom-endpoint-demo",
    "Status": "modifying"
}
```

以下範例會檢查此叢集的端點狀態。叢集仍有其原始叢集端點，其 `EndPointType` 為 `WRITER`，您仍將它用於管理、ETL 和其他寫入操作。它仍會有其原始 `READER` 端點，但您不會使用它，因為對它的每個連線都可能會被導向至「小型」或「大型」資料庫執行個體。自訂端點讓此行為能被預測，以保證連線使用其中一個「小型」或「大型」資料庫執行個體 (根據您指定的端點)。

```
$ aws rds describe-db-cluster-endpoints --region $REGION
{
    "DBClusterEndpoints": [
        {
            "EndpointType": "WRITER",
            "Endpoint": "custom-endpoint-demo.cluster-c7tj4example.ca-central-1.rds.amazonaws.com",
            "Status": "available",
            "DBClusterIdentifier": "custom-endpoint-demo"
        },
        {
            "EndpointType": "READER",
            "Endpoint": "custom-endpoint-demo.cluster-ro-c7tj4example.ca-central-1.rds.amazonaws.com",
            "Status": "available",
            "DBClusterIdentifier": "custom-endpoint-demo"
        },
        {
            "Endpoint": "small-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com",
            "CustomEndpointType": "ANY",
            "DBClusterEndpointArn": "arn:aws:rds:ca-central-1:111122223333:cluster-endpoint:small-instances",
            "ExcludedMembers": [
                "custom-endpoint-demo-09",
                "custom-endpoint-demo-10"
            ],
            "DBClusterEndpointResourceIdentifier": "cluster-endpoint-6RDDXQOC3AKKZT2PRD7ST37BMY",
            "DBClusterIdentifier": "custom-endpoint-demo",
            "StaticMembers": [],
            "EndpointType": "CUSTOM",
            "DBClusterEndpointIdentifier": "small-instances",
            "Status": "modifying"
        },
        {
            "Endpoint": "big-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com",
            "CustomEndpointType": "READER",
            "DBClusterEndpointArn": "arn:aws:rds:ca-central-1:111122223333:cluster-endpoint:big-instances",
            "ExcludedMembers": [],
            "DBClusterEndpointResourceIdentifier": "cluster-endpoint-W7PE3TLLFNSHXQKFU6J6NV5FHU",
            "DBClusterIdentifier": "custom-endpoint-demo",
            "StaticMembers": [
                "custom-endpoint-demo-10",
                "custom-endpoint-demo-09"
            ],
            "EndpointType": "CUSTOM",
            "DBClusterEndpointIdentifier": "big-instances",
            "Status": "available"
        }
    ]
}
```

最後的範例示範對自訂端點的後續資料庫連線如何連線至 Aurora 叢集中的各種資料庫執行個體。`small-instances` 端點一律會連線至 `db.r4.4xlarge` 資料庫執行個體，它是此叢集中編號較低的主機。

```
$ mysql -h small-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com -u $MYUSER -p
mysql> select @@aurora_server_id;
+-------------------------+
| @@aurora_server_id      |
+-------------------------+
| custom-endpoint-demo-02 |
+-------------------------+

$ mysql -h small-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com -u $MYUSER -p
mysql> select @@aurora_server_id;
+-------------------------+
| @@aurora_server_id      |
+-------------------------+
| custom-endpoint-demo-07 |
+-------------------------+

$ mysql -h small-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com -u $MYUSER -p
mysql> select @@aurora_server_id;
+-------------------------+
| @@aurora_server_id      |
+-------------------------+
| custom-endpoint-demo-01 |
+-------------------------+
```

`big-instances` 端點一律會連線至 `db.r4.16xlarge` 資料庫執行個體，它是此叢集中編號最高的兩個主機。

```
$ mysql -h big-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com -u $MYUSER -p
mysql> select @@aurora_server_id;
+-------------------------+
| @@aurora_server_id      |
+-------------------------+
| custom-endpoint-demo-10 |
+-------------------------+

$ mysql -h big-instances.cluster-custom-c7tj4example.ca-central-1.rds.amazonaws.com -u $MYUSER -p
mysql> select @@aurora_server_id;
+-------------------------+
| @@aurora_server_id      |
+-------------------------+
| custom-endpoint-demo-09 |
+-------------------------+
```