cloudpack大阪の佐々木です。

RDSの認証をIAMでできるという話です。
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/UsingWithRDS.IAMDBAuth.html

基本的な設定はこちらを参照
http://qiita.com/Pampus/items/18b45330b990927652fd

認証に必要なTokenをaws-cliで取得できるようになってました。

aws-cliをアップデートします。

$ sudo pip install -U awscli
$ aws --version
aws-cli/1.11.81 Python/2.7.12 Linux/4.9.17-8.31.amzn1.x86_64 botocore/1.5.44

aws rds generate-db-auth-token コマンドが使えるようになっています。

NAME
       generate-db-auth-token -

DESCRIPTION
       Generates an auth token used to connect to a db with IAM credentials.

SYNOPSIS
            generate-db-auth-token
          --hostname <value>
          --port <value>
          --username <value>

OPTIONS
       --hostname (string) The hostname of the database to connect to.

       --port (integer) The port number the database is listening on.

       --username (string) The username to log in as.

実行するとトークンが発行されます。

$ aws rds generate-db-auth-token --hostname test.xxxxxxxxxx.ap-northeast-1.rds.amazonaws.com --port 3306 --username testuser --region ap-northeast-1
test.xxxxxxxxxx.ap-northeast-1.rds.amazonaws.com:3306/?Action=connect&DBUser=testuser&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Expires=900&X-Amz-Date=20170427T134947Z&X-Amz-SignedHeaders=host&X-Amz-Security-Token=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx&X-Amz-Credential=xxxxxxxxxxxxxxxxxxxxxx2Faws4_request&X-Amz-Signature=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

これをパスワードにして接続します。

$ mysql -u testuser -h test.xxxxxxxxxxxx.ap-northeast-1.rds.amazonaws.com -p`aws rds generate-db-auth-token --hostname test.xxxxxxxxxxxx.ap-northeast-1.rds.amazonaws.com --port 3306 --username testuser --region ap-northeast-1` --ssl-ca=rds-combined-ca-bundle.pem

ERROR 2059 (HY000): Authentication plugin 'mysql_clear_password' cannot be loaded: plugin not enabled

んん？

--enable-cleartext-plugin ってのがいるらしいです。
https://dev.mysql.com/doc/refman/5.6/ja/cleartext-authentication-plugin.html

$ mysql -u testuser -h test.xxxxxxxxxxx.ap-northeast-1.rds.amazonaws.com -p`aws rds generate-db-auth-token --hostname test.xxxxxxxxxx.ap-northeast-1.rds.amazonaws.com --port 3306 --username testuser --region ap-northeast-1` --ssl-ca=rds-combined-ca-bundle.pem --enable-cleartext-plugin

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