CloudWatch agent credentials preference - Amazon CloudWatch

CloudWatch agent credentials preference

This section outlines the credentials provider chain that the CloudWatch agent uses to obtain credentials when communicating with other AWS services and APIs. The ordering is as follows. The preferences listed in numbers two through five of the following list are the same preference order as defined in the AWS SDK. For more information, see Specifying Credentials in the SDK documentation.

  1. Shared config and credentials files as defined in the CloudWatch agent’s common-config.toml file. For more information, see (Optional) Modify the common configuration for proxy or Region information.

  2. AWS SDK environment variables

    Important

    On Linux, if you run the CloudWatch agent using the amazon-cloudwatch-agent-ctl script, the script starts the agent as a systemd service. In this case, environment variables such as HOME, AWS_ACCESS_KEY_ID, and AWS_SECRET_ACCESS_KEY are not accessible by the agent.

  3. Shared configuration and credentials files found in $HOME/%USERPROFILE%

    Note

    The CloudWatch agent looks for .aws/credentials in $HOME for Linux and MacOS and looks in %USERPROFILE% for Windows. Unlike the AWS SDK, the CloudWatch agent does not have fallback methods to determine the home directory if the environment variables are inaccessible. This difference in behavior is to maintain backwards compatibility with earlier implementations of the AWS SDK.

    Furthermore, unlike with the shared credentials found in common-config.toml, if the AWS SDK-derived shared credentials expire and are rotated, the renewed credentials are not automatically picked up by the CloudWatch agent and require a restart of the agent to do so.

  4. An AWS Identity and Access Management role for tasks if an application is present that uses an Amazon Elastic Container Service task definition or a RunTask API operation.

  5. An instance profile attached to an Amazon EC2 instance.

As a best practice, we recommend that you specify credentials in the following order when you use the CloudWatch agent.

  1. Use IAM roles for tasks if your application uses an Amazon Elastic Container Service task definition or a RunTask API operation.

  2. Use IAM roles if your application runs on an Amazon EC2 instance.

  3. Use the CloudWatch agent common-config.toml file to specify the credentials file. This credentials file is the same one used by other AWS SDKs and the AWS CLI. If you’re already using a shared credentials file, you can also use it for this purpose. If you provide it by using the CloudWatch agent’s common-config.toml file, you ensure that the agent will consume rotated credentials when they expire and get replaced without requiring you to restart the agent.

  4. Use environment variables. Setting environment variables is useful if you’re doing development work on a computer other than an Amazon EC2 instance.

Note

If you send telemetry to a different account as explained in Sending metrics, logs, and traces to a different account, the CloudWatch agent uses the credentials provider chain described in this section to obtain the initial set of credentials. It then uses those credentials when assuming the IAM role specified by role_arn in the CloudWatch agent configuration file.