Source Code

AWS ECS Monitor

Production health monitoring and log analysis for AWS ECS services.

What It Does

Health Checks: HTTP probes against your domain, ECS service status (desired vs running), ALB target group health, SSL certificate expiry
Log Analysis: Pulls CloudWatch logs, categorizes errors (panics, fatals, OOM, timeouts, 5xx), detects container restarts, filters health check noise
Auto-Diagnosis: Reads health status and automatically investigates failing services via log analysis

Prerequisites

aws CLI configured with appropriate IAM permissions:
- ecs:ListServices, ecs:DescribeServices
- elasticloadbalancing:DescribeTargetGroups, elasticloadbalancing:DescribeTargetHealth
- logs:FilterLogEvents, logs:DescribeLogGroups
curl for HTTP health checks
python3 for JSON processing and log analysis
openssl for SSL certificate checks (optional)

Configuration

All configuration is via environment variables:

Variable	Required	Default	Description
`ECS_CLUSTER`	Yes	—	ECS cluster name
`ECS_REGION`	No	`us-east-1`	AWS region
`ECS_DOMAIN`	No	—	Domain for HTTP/SSL checks (skip if unset)
`ECS_SERVICES`	No	auto-detect	Comma-separated service names to monitor
`ECS_HEALTH_STATE`	No	`./data/ecs-health.json`	Path to write health state JSON
`ECS_HEALTH_OUTDIR`	No	`./data/`	Output directory for logs and alerts
`ECS_LOG_PATTERN`	No	`/ecs/{service}`	CloudWatch log group pattern (`{service}` is replaced)
`ECS_HTTP_ENDPOINTS`	No	—	Comma-separated `name=url` pairs for HTTP probes

Directories Written

ECS_HEALTH_STATE (default: ./data/ecs-health.json) — Health state JSON file
ECS_HEALTH_OUTDIR (default: ./data/) — Output directory for logs, alerts, and analysis reports

Scripts

`scripts/ecs-health.sh` — Health Monitor

# Full check
ECS_CLUSTER=my-cluster ECS_DOMAIN=example.com ./scripts/ecs-health.sh

# JSON output only
ECS_CLUSTER=my-cluster ./scripts/ecs-health.sh --json

# Quiet mode (no alerts, just status file)
ECS_CLUSTER=my-cluster ./scripts/ecs-health.sh --quiet

Exit codes: 0 = healthy, 1 = unhealthy/degraded, 2 = script error

`scripts/cloudwatch-logs.sh` — Log Analyzer

# Pull raw logs from a service
ECS_CLUSTER=my-cluster ./scripts/cloudwatch-logs.sh pull my-api --minutes 30

# Show errors across all services
ECS_CLUSTER=my-cluster ./scripts/cloudwatch-logs.sh errors all --minutes 120

# Deep analysis with error categorization
ECS_CLUSTER=my-cluster ./scripts/cloudwatch-logs.sh diagnose --minutes 60

# Detect container restarts
ECS_CLUSTER=my-cluster ./scripts/cloudwatch-logs.sh restarts my-api

# Auto-diagnose from health state file
ECS_CLUSTER=my-cluster ./scripts/cloudwatch-logs.sh auto-diagnose

# Summary across all services
ECS_CLUSTER=my-cluster ./scripts/cloudwatch-logs.sh summary --minutes 120

Options: --minutes N (default: 60), --json, --limit N (default: 200), --verbose

Auto-Detection

When ECS_SERVICES is not set, both scripts auto-detect services from the cluster:

aws ecs list-services --cluster $ECS_CLUSTER

Log groups are resolved by pattern (default /ecs/{service}). Override with ECS_LOG_PATTERN:

# If your log groups are /ecs/prod/my-api, /ecs/prod/my-frontend, etc.
ECS_LOG_PATTERN="/ecs/prod/{service}" ECS_CLUSTER=my-cluster ./scripts/cloudwatch-logs.sh diagnose

Integration

The health monitor can trigger the log analyzer for auto-diagnosis when issues are detected. Set ECS_HEALTH_OUTDIR to a shared directory and run both scripts together:

export ECS_CLUSTER=my-cluster
export ECS_DOMAIN=example.com
export ECS_HEALTH_OUTDIR=./data

# Run health check (auto-triggers log analysis on failure)
./scripts/ecs-health.sh

# Or run log analysis independently
./scripts/cloudwatch-logs.sh auto-diagnose --minutes 30

Error Categories

The log analyzer classifies errors into:

panic — Go panics
fatal — Fatal errors
oom — Out of memory
timeout — Connection/request timeouts
connection_error — Connection refused/reset
http_5xx — HTTP 500-level responses
python_traceback — Python tracebacks
exception — Generic exceptions
auth_error — Permission/authorization failures
structured_error — JSON-structured error logs
error — Generic ERROR-level messages

Health check noise (GET/HEAD /health from ALB) is automatically filtered from error counts and HTTP status distribution.

aws-ecs-monitor