rvn-ecs-worker · Latest version: 0.3.3
Dependencies and consumers
Every dependency input can be specified manually to reference existing external infrastructure rather than a Ravion module.Readme
Background worker ECS service for running private container workloads without exposed ports.Overview
The ECS Worker module creates an ECS service for background jobs, queue consumers, event processors, and other private workloads in an existing Ravion ECS cluster. It uses the same ECS service Terraform module as ECS Web Server, but does not create or attach a load balancer target group and does not expose a primary container port. Terraform source: flightcontrolhq/modules/compute/ecs_serviceUse cases
Networking
Workers do not expose a primary app port and are not registered with an Application Load Balancer. Run in private subnets is enabled by default so tasks stay private while using NAT or equivalent egress for outbound dependencies. Sidecars may still define port mappings for task-local agents, proxies, or helper containers. Those sidecar ports are not exposed through a load balancer by this module.Build and deployment
Workers support Dockerfile, Railpack, and Pull from image registry deployments. Deployments update the ECS service task definition with the selected image, generated container definition, logs, runtime environment variables, secrets, IAM roles, volumes, sidecars, and selected capacity provider settings. For Railpack builds, you can optionally pin the Railpack version and override install, build, and start commands. For Fargate and Fargate Spot, App ephemeral storage uses the AWS default of 20 GiB unless you increase it to 21-200 GiB. For image registry deployments, use Start command to override the image default CMD when the worker process uses a different command.Persistent storage
Enable the EFS file system setting, select a Ravion EFS module, and set the EFS mount path. Ravion adds the task volume, mounts it into the worker container, attaches the file system’s client security group to the service so NFS traffic is allowed, and mounts through the file system’s access point when one is enabled. Sidecars mount the same file system through their Mount points setting withefs as the source volume.
EFS volumes work with Fargate and EC2 Linux tasks and keep data across task replacement. Transit encryption is enabled by default. Enable EFS IAM authorization to authorize file system access with the task role; the task role must allow elasticfilesystem:ClientMount, plus elasticfilesystem:ClientWrite or elasticfilesystem:ClientRootAccess as needed.
Autoscaling
Autoscaling is enabled by default with CPU and memory target tracking. Use custom metric scaling policies for queue depth, lag, backlog, or other workload-specific metrics that better represent worker demand. When autoscaling is disabled, Desired tasks controls how many worker tasks the ECS service keeps running.Configuration
Design decisions
- The module intentionally creates an ECS service without load balancer attachment or primary container port mappings.
- Sidecar port mappings are allowed for task-local communication, agents, and proxies.
- Desired count uses the autoscaling minimum when autoscaling is enabled and the Desired tasks input when autoscaling is disabled.
- Advanced Terraform variables exist for exceptional lower-level overrides. Prefer the typed Ravion fields whenever possible.
Learn more
Inputs reference
All inputs forrvn-ecs-worker version 0.3.3. Use the name shown for each field as the input key in module config.
ECS cluster
$ref:rvn-ecs-cluster
required
ECS cluster.
- Immutable after creation
Worker service
string
required
Service name. Name for the ECS worker service and related resources.
- Default:
<<project.given_id>>-<<environment.given_id>>-<<module.given_id>> - Immutable after creation
- Pattern:
^[A-Za-z0-9][A-Za-z0-9_-]{0,254}$— Use 1-255 letters, numbers, underscores, or hyphens, starting with a letter or number.
boolean
Run in private subnets. Recommended. Requires a NAT gateway or equivalent for internet access and keeps worker tasks off public subnets.
- Default:
true
Build config
string
required
Build source.
- Default:
dockerfile - Allowed values:
dockerfile(Dockerfile),railpack(Railpack),image_registry(Pull from image registry)
gitrepo
required
Git repository. Repository containing the application source for Dockerfile or Railpack builds.
- Shown when:
{"build_source":["dockerfile","railpack"]}
string
Source base path. Repository-relative source and build root.
- Default:
. - Shown when:
{"build_source":["dockerfile","railpack"]}
string
required
Image repository. Image repository without a tag or digest, such as
nginx, ghcr.io/org/app, or 123456789012.dkr.ecr.us-east-1.amazonaws.com/app.- Shown when:
{"build_source":"image_registry"}
string
Registry credentials secret ARN. Secrets Manager secret ARN for private registries such as GHCR or Docker Hub. The secret must use the ECS repository credentials JSON format. Not needed for public images or normal same-account ECR.
- Shown when:
{"build_source":"image_registry"}
string_array
Start command. Optional command arguments that override the image default command. For shell behavior, use
/bin/sh, -lc, and your command string as separate arguments.- Default:
[] - Shown when:
{"build_source":"image_registry"}
Docker
string
Dockerfile path. Path to the Dockerfile to use for the build, relative to the repository root or configured source base path.
- Shown when:
{"build_source":"dockerfile"}
string
Docker build context path. Directory to use as the Docker build context, relative to the repository root or configured source base path.
- Shown when:
{"build_source":"dockerfile"}
Railpack
string
Railpack version. Optional Railpack version to use for the build. Leave blank to use the Ravion default.
- Pattern:
^(|latest|v?[0-9]+\.[0-9]+\.[0-9]+(?:[-+][0-9A-Za-z.-]+)?)$— Leave blank, use latest, a semantic version like 0.29.0, or a v-prefixed version like v0.29.0. - Shown when:
{"build_source":"railpack"}
string
Install command. Optional dependency installation command. Leave blank to use Railpack detection.
- Shown when:
{"build_source":"railpack"}
string
Build command. Optional application build command. Leave blank to use Railpack detection.
- Shown when:
{"build_source":"railpack"}
string
Start command.
- Shown when:
{"build_source":"railpack"}
Container resources
string
required
Capacity provider. Choose the primary capacity provider. Most services should use only one provider.
- Default:
fargate - Allowed values:
fargate(Fargate),fargate_spot(Fargate spot),ec2(EC2)
boolean
Also use Fargate. Add Fargate to the capacity provider strategy in addition to the primary provider.
- Default:
false - Shown when:
{"capacity_provider":{"not":"fargate"}}
boolean
Also use Fargate spot. Add lower-cost interruptible Fargate spot capacity in addition to the primary provider.
- Default:
false - Shown when:
{"capacity_provider":{"not":"fargate_spot"}}
boolean
Also use EC2. Add EC2 capacity from the selected cluster in addition to the primary provider.
- Default:
false - Shown when:
{"capacity_provider":{"not":"ec2"}}
compound
required
App size. CPU and memory for Fargate tasks. Prices are estimated from AWS Fargate pricing for the selected region, architecture, and capacity provider.
- Default:
{"memory_gb":4,"vcpu":2} - Shown when:
{"capacity_provider":["fargate","fargate_spot"]}
number
App ephemeral storage (GiB). Optional ephemeral storage size for each Fargate app task, from 21 to 200 GiB. Leave blank to use the AWS default of 20 GiB.
- Min:
21 - Max:
200 - Shown when:
{"capacity_provider":["fargate","fargate_spot"]}
string
required
App vCPU. vCPU reserved for each app task on EC2 capacity. Leave at least 0.25 vCPU unreserved on each EC2 instance for the ECS agent and system processes.
- Default:
1.5 - Pattern:
^(?:0|[1-9][0-9]*)(?:\.[0-9]+)?$— Enter a vCPU value, such as 0.5, 1, or 2. - Shown when:
{"capacity_provider":"ec2"}
string
required
App memory in GB. Memory reserved for each app task on EC2 capacity. Leave at least 0.5 GB unreserved on each EC2 instance for the ECS agent and system processes.
- Default:
3.5 - Pattern:
^(?:0|[1-9][0-9]*)(?:\.[0-9]+)?$— Enter a memory value in GB, such as 0.5, 1, or 4. - Shown when:
{"capacity_provider":"ec2"}
string
CPU architecture. Use x86_64 for broad compatibility; use ARM64 for lower cost when your image and dependencies support it.
- Default:
X86_64 - Allowed values:
X86_64(x86_64 - widest compatibility),ARM64(ARM64 - lower cost)
boolean
ECS exec. Enable ECS Exec for interactive debugging in running containers. Leave off by default for tighter access control; turn on when operators need shell/debug access through AWS Systems Manager.
- Default:
false
Autoscaling
boolean
Autoscaling.
- Default:
true
number
Minimum tasks. Recommend at least 2 for production.
- Default:
1 - Min:
0 - Shown when:
{"auto_scaling_enabled":true}
number
Maximum tasks.
- Default:
3 - Min:
1 - Shown when:
{"auto_scaling_enabled":true}
number
Desired tasks. Number of tasks to keep running when autoscaling is disabled.
- Default:
1 - Min:
1 - Shown when:
{"auto_scaling_enabled":false}
number
CPU target (%).
- Default:
70 - Min:
1 - Max:
100 - Shown when:
{"auto_scaling_enabled":true}
number
Memory target (%). Target average memory utilization for memory-based autoscaling. Leave blank to disable memory autoscaling.
- Default:
80 - Min:
1 - Max:
100 - Shown when:
{"auto_scaling_enabled":true}
number
Scale-in cooldown (secs). Time after a scale-in activity before another scale-in can happen. AWS defaults ECS target tracking cooldowns to 300 secs; start here for production and tune if needed.
- Default:
300 - Min:
0 - Shown when:
{"auto_scaling_enabled":true}
number
Scale-out cooldown (secs). Time after a scale-out activity before another scale-out can happen. AWS defaults ECS target tracking cooldowns to 300 secs; start here for production and tune if needed.
- Default:
300 - Min:
0 - Shown when:
{"auto_scaling_enabled":true}
boolean
Scale in. Allow autoscaling to reduce task count automatically.
- Default:
true - Shown when:
{"auto_scaling_enabled":true}
object_array
Scheduled scaling actions. Optional Application Auto Scaling scheduled actions for the ECS service desired count. Each action sets a recurring, one-time, or rate-based schedule and may update the minimum capacity, maximum capacity, or both.
- Default:
[] - Shown when:
{"auto_scaling_enabled":true}
object_array
Custom metric scaling policies. Additional target tracking scaling policies using custom CloudWatch metrics. Each policy must use a metric that changes proportionally with ECS service capacity.
- Default:
[] - Shown when:
{"auto_scaling_enabled":true}
Environment variables
object
Build environment variables. Environment variables available during builds. Values can be plain strings or references loaded from Parameter Store or Secrets Manager.
boolean
Inject environment variables in Dockerfile. Pass build environment variables into Dockerfile builds as build arguments.
- Default:
false - Shown when:
{"build_source":"dockerfile"}
array
Runtime environment variables. Runtime environment variables passed to the worker container.
array
Runtime secrets. Secrets injected into the ECS task at runtime as an array of {name, value_from} objects. value_from can be an SSM parameter or Secrets Manager ARN.
Pre and post deploy
boolean
Run pre-deploy command. Run a one-off ECS task before updating the ECS service.
- Default:
false
string_array
required
Pre-deploy command. Command arguments to run before updating the ECS service. For shell behavior, use
/bin/sh, -lc, and your command string as separate arguments.- Default:
[] - Shown when:
{"pre_deploy_enabled":true}
array
Pre-deploy environment variables. Additional environment variables for the pre-deploy task. Runtime environment variables and secrets are already inherited from the app container.
- Default:
[] - Shown when:
{"pre_deploy_enabled":true}
number
Pre-deploy CPU units. Optional CPU units for the pre-deploy task. Leave blank to use the app task CPU setting.
- Min:
1 - Shown when:
{"pre_deploy_enabled":true}
number
Pre-deploy memory (MiB). Optional memory in MiB for the pre-deploy task. Leave blank to use the app task memory setting.
- Min:
1 - Shown when:
{"pre_deploy_enabled":true}
number
Pre-deploy ephemeral storage (GiB). Optional ephemeral storage size for the pre-deploy task. Leave blank to use the task definition default.
- Min:
21 - Max:
200 - Shown when:
{"pre_deploy_enabled":true}
number
Pre-deploy timeout (secs). Maximum time to wait for the pre-deploy task to finish.
- Default:
1800 - Min:
1 - Shown when:
{"pre_deploy_enabled":true}
boolean
Run post-deploy command. Run a one-off ECS task after the ECS service deployment succeeds.
- Default:
false
string_array
required
Post-deploy command. Command arguments to run after the ECS service deployment succeeds. For shell behavior, use
/bin/sh, -lc, and your command string as separate arguments.- Default:
[] - Shown when:
{"post_deploy_enabled":true}
array
Post-deploy environment variables. Additional environment variables for the post-deploy task. Runtime environment variables and secrets are already inherited from the app container.
- Default:
[] - Shown when:
{"post_deploy_enabled":true}
number
Post-deploy CPU units. Optional CPU units for the post-deploy task. Leave blank to use the app task CPU setting.
- Min:
1 - Shown when:
{"post_deploy_enabled":true}
number
Post-deploy memory (MiB). Optional memory in MiB for the post-deploy task. Leave blank to use the app task memory setting.
- Min:
1 - Shown when:
{"post_deploy_enabled":true}
number
Post-deploy ephemeral storage (GiB). Optional ephemeral storage size for the post-deploy task. Leave blank to use the task definition default.
- Min:
21 - Max:
200 - Shown when:
{"post_deploy_enabled":true}
number
Post-deploy timeout (secs). Maximum time to wait for the post-deploy task to finish.
- Default:
1800 - Min:
1 - Shown when:
{"post_deploy_enabled":true}
Logging
boolean
FireLens log routing. Routes the app container logs through a Fluent Bit sidecar. CloudWatch output stays enabled by default so Ravion runtime logs continue to work.
- Default:
false
string
required
FireLens image. Container image for the Fluent Bit log router sidecar.
- Default:
public.ecr.aws/aws-observability/aws-for-fluent-bit:stable - Shown when:
{"firelens_enabled":true}
text
Additional Fluent Bit config. Optional Fluent Bit config appended after the generated [SERVICE] block. Add [OUTPUT] blocks here for destinations such as Datadog, Splunk, Firehose, OpenSearch, or S3.
- Shown when:
{"firelens_enabled":true}
boolean
Keep CloudWatch output enabled. Recommended. Sends FireLens-routed app logs to the service CloudWatch log group so Ravion runtime logs continue to work. Disable only if all app logs should go exclusively to external destinations.
- Default:
true - Shown when:
{"firelens_enabled":true}
boolean
Add ECS log metadata. Adds ECS cluster, task, and container metadata to FireLens log records.
- Default:
true - Shown when:
{"firelens_enabled":true}
array
FireLens environment variables. Environment variables passed to the log router sidecar. Use these for non-secret destination options.
- Default:
[] - Shown when:
{"firelens_enabled":true}
array
FireLens secrets. Secrets injected into the log router sidecar as an array of {name, value_from} objects. Use these for API keys or tokens stored in SSM Parameter Store or Secrets Manager.
- Default:
[] - Shown when:
{"firelens_enabled":true}
IAM roles and policies
string
Execution role ARN override. Optional existing ECS task execution role ARN. Leave blank to let the module create and manage the execution role used for pulling images and writing logs.
string
Task role ARN override. Optional existing ECS task role ARN for application AWS permissions. Leave blank to let the module create a task role and attach the policies configured below.
string_array
Task role policy ARNs. Additional managed IAM policy ARNs to attach to the generated task role. Only used when task role ARN override is blank.
- Default:
[]
object
Task role inline policies. Inline IAM policy documents keyed by policy name.
- Default:
{}
string_array
Execution role policy ARNs. Additional managed IAM policy ARNs to attach to the generated execution role. Only used when execution role ARN override is blank.
- Default:
[]
Networking and deployment
number
Minimum healthy percent. Minimum percentage of desired tasks that must stay healthy during rolling deployments. Keep 100 for zero-downtime deploys. Lower it only when the cluster does not have enough spare capacity to start replacement tasks first, since lowering it can reduce availability during deploys.
- Default:
100 - Min:
0 - Max:
200
number
Maximum percent. Maximum temporary task count during rolling deployments. Keep 200 for fast replacement capacity. Lower it when cluster capacity, IP availability, or burst cost should limit how many extra tasks ECS can start.
- Default:
200 - Min:
100 - Max:
400
string_array
Additional security groups. Additional security group IDs to attach to ECS tasks.
- Default:
[]
string_array
Allowed CIDR blocks. CIDR blocks allowed direct access to the service in addition to load balancer traffic.
- Default:
[]
object_array
Sidecars. Optional containers that run in the same ECS task as the app container. Use sidecars for agents, local proxies, lightweight workers, or helper processes that should share task networking and lifecycle with the app.
- Default:
[]
Persistent storage
boolean
EFS file system. Mount an EFS file system into the app container. The service attaches the file system’s client security group and adds the volume and mount point automatically.
- Default:
false
$ref:rvn-efs
required
EFS file system.
- Shown when:
{"efs_enabled":true}
string
required
EFS mount path. Path inside the app container where the file system is mounted.
- Default:
/mnt/efs - Pattern:
^/— Use an absolute container path. - Shown when:
{"efs_enabled":true}
boolean
EFS read only. Mount the file system as read-only inside the app container.
- Default:
false - Shown when:
{"efs_enabled":true}
boolean
EFS IAM authorization. Use the task role to authorize file system access. The task role must allow
elasticfilesystem:ClientMount, plus elasticfilesystem:ClientWrite or elasticfilesystem:ClientRootAccess as needed.- Default:
false - Shown when:
{"efs_enabled":true}
Builder config
string
required
Builder instance type. Use on-demand EC2 for predictable availability or EC2 Spot for lower cost with possible capacity delays or interruption.
- Default:
ec2 - Allowed values:
ec2(EC2),ec2-spot(EC2 spot) - Shown when:
{"build_source":["dockerfile","railpack","nixpacks"]}
string
required
Builder instance size. EC2 instance type for builds. Start with the default value, then increase or decrease it based on the resource usage report at the end of builds.
- Default:
c7a.4xlarge - Shown when:
{"build_source":["dockerfile","railpack","nixpacks"]}
string
Builder execution environment. Optional execution environment ID or given ID for builds. Defaults to the module Terraform execution environment.
- Shown when:
{"build_source":["dockerfile","railpack","nixpacks"]}
string
Builder AMI. Optional AMI ID for build runners. Leave empty to use the default runner image.
- Shown when:
{"build_source":["dockerfile","railpack","nixpacks"]}
Image registry lifecycle
boolean
Scan images on push. Ask ECR to run its basic vulnerability scan whenever a new image is pushed. Keep this on for early dependency and OS package findings; disable only if another scanner owns image scanning or duplicate findings are noisy.
- Default:
true - Shown when:
{"build_source":["dockerfile","railpack","nixpacks"]}
boolean
Force delete image repository. Allow the ECR repository to be deleted even when it contains images. Use with care.
- Default:
false - Shown when:
{"build_source":["dockerfile","railpack","nixpacks"]}
Misc
boolean
Force new deployment. Force ECS to start a new deployment when applying service configuration, even if the task definition did not change.
- Default:
true
keyvalue
Tags. A map of tags to assign to all resources. Default tags are
Owner, ProjectGivenId, EnvironmentGivenId, ModuleGivenId, ModuleIdTerraform settings
string
OpenTofu version override. Override the environment’s default version for this module
string
Ravion Terraform workspace name. Override Terraform state backend workspace name. Defaults to project + environment + module given ids.
- Immutable after creation
object
Advanced Terraform variables. Optional raw Terraform variable overrides for advanced module inputs or one-off overrides. Values here override the generated variables above.
- Default:
{}