PHP数据容器化与Kubernetes部署

PHP数据容器化与Kubernetes部署

容器化和Kubernetes是现代应用部署的标准方式。PHP应用容器化后可以在K8s上弹性运行。今天说说PHP应用的容器化和K8s部署最佳实践。

PHP的Docker镜像构建需要注意几个要点。使用多阶段构建减小镜像体积，配置OPcache提升性能，调整PHP-FPM参数。

```dockerfile
# 多阶段构建
FROM composer:latest AS composer
COPY composer.json composer.lock /app/
RUN composer install --no-dev --optimize-autoloader --no-interaction

FROM php:8.2-fpm-alpine AS base

# 安装扩展
RUN docker-php-ext-install pdo_mysql mbstring opcache

# 配置OPcache
RUN docker-php-ext-configure opcache --enable-opcache
COPY opcache.ini /usr/local/etc/php/conf.d/opcache.ini

# 复制应用代码
COPY --from=composer /app/vendor /var/www/html/vendor
COPY . /var/www/html

WORKDIR /var/www/html
RUN chown -R www-data:www-data storage bootstrap/cache

FROM base AS production
COPY .env.production .env
RUN php artisan optimize
EXPOSE 9000
```

PHP应用的健康检查和就绪探针：

```php
// healthz.php - 存活检查
header('Content-Type: application/json');

$healthy = true;
$checks = [];

// 检查PHP-FPM
$checks['php'] = true;

// 检查数据库
try {
$pdo = new PDO('mysql:host=localhost;dbname=test', 'root', '');
$pdo->query('SELECT 1');
$checks['database'] = true;
} catch (\Exception $e) {
$checks['database'] = false;
$healthy = false;
}

// 检查Redis
try {
$redis = new Redis();
$redis->connect('redis-service', 6379);
$checks['redis'] = true;
} catch (\Exception $e) {
$checks['redis'] = false;
}

$status = $healthy ? 200 : 503;
http_response_code($status);

echo json_encode([
'status' => $healthy ? 'healthy' : 'unhealthy',
'checks' => $checks,
'timestamp' => date('c'),
]);
?>

// readyz.php - 就绪检查（检查服务是否准备好接收流量）
header('Content-Type: application/json');

$ready = true;
$checks = [];

try {
$pdo = new PDO('mysql:host=localhost;dbname=test', 'root', '');
$stmt = $pdo->query("SELECT COUNT(*) FROM migration");
$checks['migrations'] = true;
} catch (\Exception $e) {
$checks['migrations'] = false;
$ready = false;
}

// 检查缓存预热
$cacheWarmed = file_exists('/tmp/cache_warmed');
$checks['cache'] = $cacheWarmed;

if (!$cacheWarmed) {
$ready = false;
}

$status = $ready ? 200 : 503;
http_response_code($status);

echo json_encode([
'ready' => $ready,
'checks' => $checks,
'timestamp' => date('c'),
]);
?>
```

Kubernetes部署配置：

```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: php-app
labels:
app: php-app
spec:
replicas: 3
selector:
matchLabels:
app: php-app
template:
metadata:
labels:
app: php-app
spec:
containers:
- name: php-fpm
image: registry.example.com/php-app:latest
ports:
- containerPort: 9000
env:
- name: APP_ENV
value: "production"
- name: DB_HOST
valueFrom:
configMapKeyRef:
name: app-config
key: db_host
- name: DB_PASSWORD
valueFrom:
secretKeyRef:
name: app-secret
key: db_password
resources:
requests:
memory: "128Mi"
cpu: "100m"
limits:
memory: "256Mi"
cpu: "500m"
livenessProbe:
httpGet:
path: /healthz
port: 8080
initialDelaySeconds: 10
periodSeconds: 10
readinessProbe:
httpGet:
path: /readyz
port: 8080
initialDelaySeconds: 5
periodSeconds: 5
volumeMounts:
- name: storage
mountPath: /var/www/html/storage
volumes:
- name: storage
persistentVolumeClaim:
claimName: php-storage
---
apiVersion: v1
kind: Service
metadata:
name: php-app
spec:
selector:
app: php-app
ports:
- port: 80
targetPort: 9000
type: ClusterIP
---
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
name: php-app-hpa
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: php-app
minReplicas: 2
maxReplicas: 10
metrics:
- type: Resource
resource:
name: cpu
target:
type: Utilization
averageUtilization: 70
- type: Resource
resource:
name: memory
target:
type: Utilization
averageUtilization: 80
```

容器化部署的PHP应用需要考虑几个问题。Session不能在本地文件存储，要使用Redis外置存储。日志要输出到stdout，由容器运行时收集。文件上传要使用对象存储，不能存储在容器本地。环境配置通过环境变量注入，不同环境使用不同的配置。

Kubernetes为PHP应用提供了弹性伸缩、服务发现、配置管理等基础设施。PHP-FPM进程模型与Kubernetes的Pod管理方式配合良好，每个Pod运行一个PHP-FPM进程，通过Service暴露服务。HPA根据CPU和内存使用率自动调整Pod数量。