Kubernetes Nginx container cannot access php-fpm container

Question

I have created 2 Kubernetes deployments for nginx and php-fpm laravel containers. But for some reason, the traffic from nginx doesn't seem to reach the php-fpm container successfully and produces the following error

172.18.0.1 - - [18/Jul/2022:16:51:10 +0000] "GET / HTTP/1.1" 404 555 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36"

This is my deployment file

apiVersion: v1
kind: ConfigMap
metadata:
  name: web-server-config
  namespace: dev-api
data:
  nginx.conf: |
    server {
        li sten 80;
        index index.php index.html;
        error_log  /var/log/nginx/error.log;
        access_log /var/log/nginx/access.log;
        root /var/www/html/public;

        location ~ .php$ {
            try_files $uri =404;
            fastcgi_split_path_info ^(.+.php)(/.+)$;

            fastcgi_pass api-web-svc:9000;
            fastcgi_index index.php;
            include fastcgi_params;
            fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
            fastcgi_param PATH_INFO $fastcgi_path_info;
        }

        location / {
            try_files $uri $uri/ /index.php?$query_string;
                gzip_static on;
        }
    }
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: php-config
  namespace: dev-api
data:
  laravel.ini: |
    upload_max_filesize: 80M
    post_max_size: 80M
---
apiVersion: v1
kind: Secret
metadata:
  name: api-web-secret
  namespace: dev-api
type: Opaque
data:
 ...
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-web
  namespace: dev-api
spec:
  selector:
    matchLabels:
      app: api-web
  replicas: 1
  template:
    metadata:
      labels:
        app: api-web
    spec:
      containers:
      - name: api-web
        image: XXX.dkr.ecr.us-east-1.amazonaws.com/api-web:0.9.4-alpha
        volumeMounts:
         - name: php-config
           mountPath: /usr/local/etc/php/conf.d/laravel.ini
         - name: env-config
           mountPath: /var/www/html/.env
        ports:
        - containerPort: 9000
      volumes:
        - name: php-config
          configMap:
            name: php-config
        - name: env-config
          secret:
            secretName: api-web-secret
      imagePullSecrets:
      - name: regcred  
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  namespace: dev-api
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:alpine
        volumeMounts:
         - name: web-server-config
           mountPath: /etc/nginx/conf.d/
        ports:
        - containerPort: 80
      volumes:
        - name: web-server-config
          configMap:
            name: web-server-config 
---
apiVersion: v1
kind: Service
metadata:
  name:  web-server-svc
  namespace: dev-api
spec:
  type: NodePort
  selector:
    app:  nginx
  ports:
  - protocol: TCP
    port:  80
    targetPort:  80
    nodePort: 32420
---
apiVersion: v1
kind: Service
metadata:
  name:  api-web-svc
  namespace: dev-api
  labels:
    app: api-web
spec:
  type: ClusterIP
  selector:
    app:  api-web
  ports:
  - protocol: TCP
    port:  9000

namespace is declared separately. Both containers in each deployment run successfully.

k logs deployment/nginx-deployment  -n dev-api
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-list en-on-ipv6-by-default.sh
10-lis ten-on-ipv6-by-default.sh: info: /etc/nginx/conf.d/default.conf is not a file or does not exist
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2022/07/18 16:18:50 [notice] 1#1: using the "epoll" event method
2022/07/18 16:18:50 [notice] 1#1: nginx/1.21.6
2022/07/18 16:18:50 [notice] 1#1: built by gcc 10.3.1 20211027 (Alpine 10.3.1_git20211027) 
2022/07/18 16:18:50 [notice] 1#1: OS: Linux 5.4.0-109-generic
2022/07/18 16:18:50 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2022/07/18 16:18:50 [notice] 1#1: start worker processes
2022/07/18 16:18:50 [notice] 1#1: start worker process 21
2022/07/18 16:18:50 [notice] 1#1: start worker process 22
2022/07/18 16:18:50 [notice] 1#1: start worker process 23
2022/07/18 16:18:50 [notice] 1#1: start worker process 24
2022/07/18 16:18:50 [notice] 1#1: start worker process 25
2022/07/18 16:18:50 [notice] 1#1: start worker process 26
2022/07/18 16:18:50 [notice] 1#1: start worker process 27
2022/07/18 16:18:50 [notice] 1#1: start worker process 28

k logs deployment/api-web -n dev-api
[18-Jul-2022 16:18:51] NOTICE: [pool www] 'user' directive is ignored when FPM is not running as root
[18-Jul-2022 16:18:51] NOTICE: [pool www] 'user' directive is ignored when FPM is not running as root
[18-Jul-2022 16:18:51] NOTICE: [pool www] 'group' directive is ignored when FPM is not running as root
[18-Jul-2022 16:18:51] NOTICE: [pool www] 'group' directive is ignored when FPM is not running as root
[18-Jul-2022 16:18:51] NOTICE: fpm is running, pid 1
[18-Jul-2022 16:18:51] NOTICE: ready to handle connections

The Dockerfile used to generate the image api-web:0.9.4-alpha in the deployment is as follows

FROM php:7.2-fpm

# Copy composer.lock and composer.json
COPY composer.lock composer.json /var/www/html/

# Set working directory
WORKDIR /var/www/html

# Install dependencies
RUN apt-get update && apt-get install -y 
    build-essential 
    libpng-dev 
    libjpeg62-turbo-dev 
    libfreetype6-dev 
    locales 
    zip 
    jpegoptim optipng pngquant gifsicle 
    vim 
    unzip 
    git 
    curl 
    nodejs 
    npm

# Clear cache
RUN apt-get cle an && rm -rf /var/lib/apt/lists/*

# Install extensions
RUN docker-php-ext-install pdo_mysql mbstring zip exif pcntl
RUN docker-php-ext-configure gd --with-gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ --with-png-dir=/usr/include/
RUN docker-php-ext-install gd

# Install composer
RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer

# Add user for laravel application
RUN groupadd -g 1000 www
RUN useradd -u 1000 -ms /bin/bash -g www www

# Copy existing application directory contents
COPY . /var/www/html/

# Copy existing application directory permissions
COPY --chown=www:www . /var/www/html/

# Change current user to www
USER www

## Run composer dependencies
RUN composer update
RUN composer install

# Expose port 9000 and start php-fpm server
EXPOSE 9000
CMD ["php-fpm"]

This Dockerfile also runs fine without any problems.

docker-compose

files using this image will also work fine. Any ideas why traffic from the

nginx-deployment

container cannot reach the api-web php-fpm container with the error

172.18.0.1 - - [18/Jul/2022:16:51:10 +0000] "GET / HTTP/1.1" 404 555 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36"

Answer 1

As far as I know, both Pods or at least containers need the same source files. If nginx doesn't know that this php file exists, it can't forward the request to the php-fpm container.

I'm talking about containers, but I don't recommend splitting nginx and php-fpm into separate pods. I'm more likely to launch these containers as a unit, in a Pod with the same source. Unless you have some kind of cron job or batch job.