How do you manage multiple (nearly identical) ECS Task Definitions?

Create separate task definitions for each distinct purpose - one for your Rails application, one for backups/jobs, etc. This allows you to scale each independently.

Use environment variables or a configuration file to store common configuration that is shared across tasks, like database credentials. Then each task definition only specifies what is unique for that purpose.

Consider using a sidecar container pattern - have your tasks pull a common "sidecar" container image that runs scripts/jobs via environment variables or configuration passed to the task. This avoids duplicating the application image.

For communication between tasks, use AWS services like SQS queues or SNS topics rather than trying to connect containers directly. The sidecar container could listen to SQS and trigger scripts as needed.

Automate task definition updates using a tool like the AWS Copilot CLI. It can manage common configuration and make updates/rollouts easier across multiple definitions.

Refer to the AWS documentation on best practices for structuring task definitions and service configurations for guidance on common patterns and approaches.