Reference
App Parameters

Setting Parameters

App parameters configure specific behaviors at the application level. Parameters can be set using the following command:

$ convox apps params set ParameterName=Value

When a Rack update adds new app parameters, they become available for each app after its next deployment.

Available Parameters

Set to false to disable automatic minor version upgrades for any database resources in this app. Defaults to true.

Set to Yes to enable Circuit Breaker deployments in ECS. This allows failing deployments to roll back faster. However, if a deployment requires the Rack to scale up, it may trip the Circuit Breaker prematurely. Best used when sufficient capacity is available.

This parameter controls whether ECS containers operate with a read-only root filesystem, enhancing security by preventing modifications to critical system files.

| Default value | No | | Allowed values | Yes, No |

  • Yes: Activates read-only mode, restricting write operations to the root filesystem. Applications must use external storage or explicitly writable paths.
  • No (default): Containers have standard write access to the root filesystem.

Potential Breaking Change:
Enabling this parameter may disrupt applications that write to the root filesystem. Ensure your application is compatible before enabling it. Use external storage solutions or designated writable paths to prevent unexpected failures.

Set to Yes to run all services for this application in Fargate.
Set to Spot to run all services in Fargate Spot.

Set to Yes to run all timers for this application in Fargate.
Set to Spot to run all timers in Fargate Spot.

Specify the ARN of a custom IAM policy to attach to the Service’s Task Role at runtime.
If the service has the Policies parameter set, this will not apply at the service level.

When autoscaling is enabled, this parameter controls whether manually set desired counts are ignored in favor of autoscaler-managed scaling.

| Default value | No | | Allowed values | Yes, No |

If set to Yes, any manually set service counts using convox scale will be ignored, and the autoscaler will dynamically manage the service count based on the targets defined in convox.yml.
Additionally, during deployments, the active instance count at the time of deployment will be used as the new desired count, ensuring the autoscaler fully controls scaling behavior without manual overrides.

For more details on how this parameter interacts with scaling, see Scaling.

Set to No to disable internal domain names at convox.site and .convox from routing to this application.
Use this parameter if you are running out of available rules on your load balancer.

Sets the routing algorithm used for the services within the application.
Defaults to round_robin. Can also be set to least_outstanding_requests.

Specifies the GRPC codes that healthy targets must use when responding to a GRPC health check.

| Default value | 12 | | Allowed values | 0-99 |

You can specify multiple values (e.g., 12,13) or a range (e.g., 10-99).

Specifies the HTTP codes that healthy targets must return when responding to an HTTP health check.

| Default value | 200-399,401 | | Allowed values | 200-499 |

You can specify multiple values (e.g., 200,202) or a range (e.g., 200-299).

Defines how long logs should be retained.

| Default value | 7 days |

Setting this to a high/unlimited value may affect the performance of convox logs.
For long-term log storage, consider using syslog.

Set to No to allow the app to listen on HTTP rather than automatically redirecting all HTTP requests to HTTPS.

Sets the ramp-up period during which a newly deployed service gradually receives an increasing share of traffic.

| Default value | 0 seconds (disabled) | | Allowed values | 30-900 seconds |

Once the duration expires, the full share of traffic will be directed to the new service.

Set to Yes to propagate ECS tags to the task level.