Docker Health Check Configuration Checker
Analyze Docker health check configuration for PHP stacks and dependent services.
Health Check Patterns by Service
1. PHP-FPM
# Using php-fpm-healthcheck script (recommended)
HEALTHCHECK --interval=10s --timeout=3s --start-period=10s --retries=3 \
CMD php-fpm-healthcheck || exit 1
# Using cgi-fcgi (requires libfcgi)
HEALTHCHECK --interval=10s --timeout=3s --start-period=10s --retries=3 \
CMD cgi-fcgi -bind -connect 127.0.0.1:9000 /ping || exit 1
; Required PHP-FPM pool config
ping.path = /ping
ping.response = pong
pm.status_path = /status
2. Nginx
HEALTHCHECK --interval=10s --timeout=3s --start-period=5s --retries=3 \
CMD curl -f http://localhost/health || exit 1
# Or wget for minimal images
HEALTHCHECK --interval=10s --timeout=3s --start-period=5s --retries=3 \
CMD wget --spider --quiet http://localhost/health || exit 1
3. MySQL
services:
mysql:
healthcheck:
test: ["CMD", "mysqladmin", "ping", "-h", "localhost", "-u", "root", "-p${MYSQL_ROOT_PASSWORD}"]
interval: 10s
timeout: 5s
retries: 5
start_period: 30s
4. PostgreSQL
services:
postgres:
healthcheck:
test: ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER} -d ${POSTGRES_DB}"]
interval: 10s
timeout: 5s
retries: 5
start_period: 30s
5. Redis
services:
redis:
healthcheck:
test: ["CMD", "redis-cli", "ping"]
interval: 10s
timeout: 3s
retries: 3
start_period: 5s
6. RabbitMQ
services:
rabbitmq:
healthcheck:
test: ["CMD-SHELL", "rabbitmq-diagnostics check_running && rabbitmq-diagnostics check_local_alarms"]
interval: 15s
timeout: 10s
retries: 5
start_period: 30s
Recommended Parameters
| Service | interval | timeout | start_period | retries |
|---|
| PHP-FPM | 10s | 3s | 10s | 3 |
| Nginx | 10s | 3s | 5s | 3 |
| MySQL | 10s | 5s | 30s | 5 |
| PostgreSQL | 10s | 5s | 30s | 5 |
| Redis | 10s | 3s | 5s | 3 |
| RabbitMQ | 15s | 10s | 30s | 5 |
Improper Health Check Detection
# BAD: Too frequent (overhead)
HEALTHCHECK --interval=1s --timeout=1s --retries=1 CMD curl localhost
# BAD: No start_period (fails during init)
HEALTHCHECK --interval=5s --timeout=3s --retries=3 CMD pg_isready
# BAD: Checking external dependency
HEALTHCHECK CMD curl -f https://api.external.com/health
# BAD: Too slow detection (interval*retries > 5min)
HEALTHCHECK --interval=60s --timeout=30s --retries=10 CMD curl localhost
Grep Patterns
Grep: "HEALTHCHECK" --glob "**/Dockerfile*"
Grep: "healthcheck:" --glob "**/docker-compose*.yml"
Grep: "depends_on:" --glob "**/docker-compose*.yml"
Grep: "ping\\.path|pm\\.status_path" --glob "**/*.conf"
Severity Classification
| Issue | Severity | Impact |
|---|
| No health check for any service | Critical | No failure detection |
| PHP-FPM without health check | Critical | Dead workers undetected |
| Database without health check | Major | App starts before DB ready |
| No start_period for databases | Major | False unhealthy during init |
| Checking external dependency | Major | External outage cascades |
| depends_on without condition | Major | Startup race condition |
| Interval too low (< 5s) | Minor | Unnecessary overhead |
| Interval too high (> 60s) | Minor | Slow failure detection |
| timeout >= interval | Minor | Overlapping checks |
Output Format
### Health Check Issue: [Description]
**Severity:** Critical/Major/Minor
**Service:** [service name]
**File:** `docker-compose.yml:line` or `Dockerfile:line`
**Issue:**
[Description of missing or misconfigured health check]
**Recommended:**
```yaml
healthcheck:
test: ["CMD-SHELL", "..."]
interval: 10s
timeout: 3s
start_period: 10s
retries: 3
Parameters:
| Param | Current | Recommended | Reason |
|---|
| interval | N/A | 10s | Standard frequency |
| timeout | N/A | 3s | Fast failure detection |
| start_period | N/A | 10s | Allow initialization |
| retries | N/A | 3 | Prevent flapping |
