Configuration

The Fast Autoscaler can be configured using environment variables to customize its behavior.

Environment Variables

Variable	Description	Default
ECS_CLUSTER	ECS cluster name	(required)
SERVICE_NAME	ECS service name	(required)
SQS_QUEUE_URL	URL of the SQS queue to monitor	(required)
MIN_TASKS	Minimum number of tasks	10
MAX_TASKS	Maximum number of tasks	300
SCALE_UP_THRESHOLD	Queue size threshold for scaling up	100.0
SCALE_DOWN_THRESHOLD	Queue size threshold for scaling down	99.0
SCALE_OUT_COOLDOWN	Cooldown period for scaling out (seconds)	120
SCALE_IN_COOLDOWN	Cooldown period for scaling in (seconds)	120
SCALING_STEP_COUNT	Step count for scaling operations	5
TASKS_PER_MESSAGE	Task-to-message ratio for scaling calculations	0.01
MAX_SCALE_DOWN_FACTOR	Maximum scale down percentage	0.99
USE_COMBINED_MESSAGES	Include in-flight messages in scaling decisions	False
S3_CONFIG_BUCKET	S3 bucket for state storage	tf-configuration-bucket-test
LOG_LEVEL	Logging level	INFO

Configuration Examples

Basic Configuration

# Required variables
ECS_CLUSTER=production-cluster
SERVICE_NAME=worker-service
SQS_QUEUE_URL=https://sqs.us-east-1.amazonaws.com/123456789012/worker-queue

# Optional tuning
MIN_TASKS=5
MAX_TASKS=100
SCALE_UP_THRESHOLD=50
SCALE_DOWN_THRESHOLD=10

Advanced Configuration

# Required variables
ECS_CLUSTER=production-cluster
SERVICE_NAME=worker-service
SQS_QUEUE_URL=https://sqs.us-east-1.amazonaws.com/123456789012/worker-queue

# Task constraints
MIN_TASKS=5
MAX_TASKS=100

# Scaling behavior
SCALE_UP_THRESHOLD=50
SCALE_DOWN_THRESHOLD=10
TASKS_PER_MESSAGE=0.025
MAX_SCALE_DOWN_FACTOR=0.8

# Cooldown periods
SCALE_OUT_COOLDOWN=60
SCALE_IN_COOLDOWN=300

# Use combined (visible + in-flight) messages for scaling decisions
USE_COMBINED_MESSAGES=True