AWS PostgreSQL `找不到極光的版本 X`

Question

類似於Error creating DB Instance: InvalidParameterCombination: Cannot find version 5.6.10a for aurora-mysql but for Postgres，原因不同。

* error creating RDS Cluster (mycompany-pulumi-aurora-cluster) Instance: InvalidParameterCombination: Cannot find version 12.6 for aurora
    status code: 400, request id: someid

但 12.6 對該區域的 Aurora PostgreSQL 有效：

$ aws rds describe-db-engine-versions --engine aurora-postgresql --query '*[].[EngineVersion]' --output text --region us-east-2
9.6.3
9.6.6
9.6.8
9.6.9
9.6.11
9.6.12
9.6.16
9.6.17
9.6.18
9.6.19
9.6.21
10.4
10.5
10.6
10.7
10.11
10.12
10.13
10.14
10.14
10.16
11.4
11.6
11.7
11.8
11.9
11.11
12.4
12.6

Answer 1

有兩個同時導致此錯誤的原因：

1. Aurora 版本受實例類型限制

2. 您需要為每個集群實例（以及集群本身）指定engineVersion 。

結果代碼（我使用的是 Pulumi，但相同的邏輯適用於 Terraform、原始 CloudFormation 等）。

const rdsCluster = new aws.rds.Cluster("default", {
  clusterIdentifier: config.database.clusterName,
  engine: "aurora-postgresql",
  // Restricted based on https://docs.amazonaws.cn/en_us/AmazonRDS/latest/AuroraUserGuide/Concepts.DBInstanceClass.html#Concepts.DBInstanceClass.SupportAurora
  engineVersion: "12.7",
  databaseName: config.database.name,
  masterUsername: config.database.username,
  masterPassword: config.database.password,
  dbSubnetGroupName: rdsSubnetGroup.name,
  storageEncrypted: true,
});

// https://www.pulumi.com/docs/reference/pkg/aws/rds/clusterinstance/#engineversion_nodejs
const clusterInstances: Array<aws.rds.ClusterInstance> = [];
for (let range = 0; range < config.database.instanceCount; range++) {
  clusterInstances.push(
    new aws.rds.ClusterInstance(`clusterInstances-${range}`, {
      identifier: `aurora-cluster-demo-${range}`,
      clusterIdentifier: rdsCluster.id,
      instanceClass: config.database.instanceType,
      // Engine must be specified otherwise AWS will give a misleading error about DB versions not being available.
      // https://github.com/hashicorp/terraform-provider-aws/issues/2419#issuecomment-347060274
      engine: "aurora-postgresql",
      engineVersion: "12.7",
    })
  );
}