ln-774-healthcheck-setup
Type: L3 Worker
Category: 7XX Project Bootstrap
Configures health check endpoints for Kubernetes probes and monitoring.
Overview
| Aspect |
Details |
| Input |
Context Store from ln-770 |
| Output |
Health check endpoints and Kubernetes probe configuration |
| Stacks |
.NET (AspNetCore.Diagnostics.HealthChecks), Python (FastAPI routes) |
Phase 1: Receive Context + Identify Dependencies
Accept Context Store and scan for dependencies to monitor.
Required Context:
STACK: .NET or PythonPROJECT_ROOT: Project directory path
Idempotency Check:
- .NET: Grep for
AddHealthChecks or MapHealthChecks
- Python: Grep for
/health route
- If found: Return
{ "status": "skipped" }
Dependency Detection:
| Dependency |
.NET Detection |
Python Detection |
| PostgreSQL |
Npgsql in csproj |
psycopg2 or asyncpg in requirements |
| MySQL |
MySql.Data in csproj |
mysql-connector-python in requirements |
| Redis |
StackExchange.Redis in csproj |
redis in requirements |
| RabbitMQ |
RabbitMQ.Client in csproj |
pika or aio-pika in requirements |
| MongoDB |
MongoDB.Driver in csproj |
pymongo in requirements |
Phase 2: Design Health Check Strategy
Define three types of health endpoints per Kubernetes best practices.
Endpoint Types
| Endpoint |
Probe Type |
Purpose |
Checks |
/health/live |
Liveness |
Is app alive? |
App responds (no dependency checks) |
/health/ready |
Readiness |
Can app serve traffic? |
All dependencies healthy |
/health/startup |
Startup (K8s 1.16+) |
Is app initialized? |
Initial warmup complete |
When Each Probe Fails
| Probe |
Failure Action |
Kubernetes Behavior |
| Liveness |
Container restart |
kubelet restarts container |
| Readiness |
Remove from service |
Traffic stopped, no restart |
| Startup |
Delay other probes |
Liveness/Readiness paused |
Phase 3: Research Health Check Patterns
Use MCP tools for current documentation.
For .NET:
MCP ref: "ASP.NET Core health checks Kubernetes probes"
Context7: /dotnet/aspnetcore
For Python:
MCP ref: "FastAPI health check endpoint Kubernetes"
Context7: /tiangolo/fastapi
Key Patterns to Research:
- Database health checks (connection pool)
- Redis connectivity check
- Custom health check implementation
- Health check response writer customization
Phase 4: Configure Kubernetes Probes
Determine probe timing based on application characteristics.
Probe Configuration
| Parameter |
Liveness |
Readiness |
Startup |
initialDelaySeconds |
10 |
5 |
0 |
periodSeconds |
10 |
5 |
5 |
timeoutSeconds |
5 |
3 |
3 |
failureThreshold |
3 |
3 |
30 |
successThreshold |
1 |
1 |
1 |
Startup Probe Calculation:
Max startup time = initialDelaySeconds + (periodSeconds × failureThreshold)
Default: 0 + (5 × 30) = 150 seconds
Phase 5: Generate Implementation
.NET Output Files
| File |
Purpose |
Extensions/HealthCheckExtensions.cs |
Health check registration |
HealthChecks/StartupHealthCheck.cs |
Custom startup check |
Generation Process:
- Use MCP ref for current ASP.NET Core health checks API
- Generate HealthCheckExtensions with:
- AddHealthChecks registration
- Database health check (if detected)
- Redis health check (if detected)
- Custom StartupHealthCheck
- Configure three endpoints with proper tags
Packages to Add:
AspNetCore.HealthChecks.NpgSql (if PostgreSQL)AspNetCore.HealthChecks.Redis (if Redis)AspNetCore.HealthChecks.MySql (if MySQL)
Registration Code:
builder.Services.AddHealthCheckServices(builder.Configuration);
app.MapHealthCheckEndpoints();
Python Output Files
| File |
Purpose |
routes/health.py |
Health check router |
services/health_checker.py |
Dependency health checks |
Generation Process:
- Use MCP ref for FastAPI health patterns
- Generate health router with:
- /health/live endpoint (simple)
- /health/ready endpoint (with dependency checks)
- /health/startup endpoint
- Generate health_checker service for dependency verification
Registration Code:
from routes.health import health_router
app.include_router(health_router)
Kubernetes Manifest Snippet
Generate for inclusion in deployment.yaml:
livenessProbe:
httpGet:
path: /health/live
port: 5000
initialDelaySeconds: 10
periodSeconds: 10
timeoutSeconds: 5
failureThreshold: 3
readinessProbe:
httpGet:
path: /health/ready
port: 5000
initialDelaySeconds: 5
periodSeconds: 5
timeoutSeconds: 3
failureThreshold: 3
startupProbe:
httpGet:
path: /health/startup
port: 5000
periodSeconds: 5
failureThreshold: 30
Phase 6: Validate
Validation Steps:
-
Syntax check:
- .NET:
dotnet build --no-restore
- Python:
python -m py_compile routes/health.py
-
Endpoint test:
curl http://localhost:5000/health/live
curl http://localhost:5000/health/ready
curl http://localhost:5000/health/startup
-
Verify response format:
{
"status": "Healthy",
"checks": {
"database": { "status": "Healthy", "duration": "00:00:00.0234" },
"redis": { "status": "Healthy", "duration": "00:00:00.0012" }
},
"totalDuration": "00:00:00.0250"
}
-
Dependency failure test:
- Stop database
- Verify
/health/ready returns 503
- Verify
/health/live still returns 200
Return to Coordinator
{
"status": "success",
"files_created": [
"Extensions/HealthCheckExtensions.cs",
"HealthChecks/StartupHealthCheck.cs"
],
"packages_added": [
"AspNetCore.HealthChecks.NpgSql"
],
"registration_code": "builder.Services.AddHealthCheckServices(configuration);",
"message": "Configured health checks with liveness, readiness, and startup probes"
}
Reference Links
Critical Rules
- Three separate endpoints —
/health/live, /health/ready, /health/startup per Kubernetes best practices
- Liveness must not check dependencies — only confirms app is alive (avoids cascade restarts)
- Readiness checks all dependencies — DB, Redis, RabbitMQ connectivity verified
- Auto-detect dependencies from project files — scan csproj/requirements for known packages
- Idempotent — if
AddHealthChecks/MapHealthChecks or /health route exists, return status: "skipped"
Definition of Done
Version: 2.0.0
Last Updated: 2026-01-10
