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Hi, I am Vladimir Smagin, SysAdmin and

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Laravel applications scaling inside Kubernetes

№ 11122 В разделе Sysadmin от November 3rd, 2020,
В подшивках: Kubernetes, Linux, PHP, Redis

I ran into the problem of scaling a Laravel application today. It scales well, but this is hampered by the session management plugin that stores data in files. If you do not share sessions between Pods after scaling the browser will show error 419, page expired.

First of all, I needed to create a Redis cluster that would store the sessions. You can do it however you want, I used the redis-operator which I wrote. For best results, I added balancing via haproxy and turned off persistent storage.

$ k get po -l instance=sessions-store
NAME                                       READY   STATUS    RESTARTS   AGE
sessions-store-haproxy-59b45854f4-48sfp    2/2     Running   0          5h16m
sessions-store-redis-0                     1/1     Running   0          5h16m
sessions-store-redis-1                     1/1     Running   0          5h15m
sessions-store-redis-2                     1/1     Running   0          5h15m
sessions-store-sentinel-586f47d744-4kgqx   1/1     Running   0          5h16m
sessions-store-sentinel-586f47d744-cfwng   1/1     Running   0          5h16m
sessions-store-sentinel-586f47d744-fd254   1/1     Running   0          5h16m

After that, you need to create a connection to the new Redis cluster in config/database.php.

    'redis' => [

        'client' => env('REDIS_CLIENT', 'phpredis'),
        ...
        'sessions' => [
            'host' => env('SESSION_REDIS_HOST', '127.0.0.1'),
            'password' => env('SESSION_REDIS_PASSWORD', null),
            'port' => env('SESSION_REDIS_PORT', 6379),
            'database' => 0,
        ],

    ],

Now you need to apply a patch that will allow you to take the necessary connection parameters from the ENV in config/session.php.

    'driver' => env('SESSION_DRIVER', 'file'),
    'connection' => env('SESSION_CONNECTION', null),

Don’t forget about the php library for working with Redis in Dockerfile.

RUN apt-get install php7.3-redis

Also you can add additional support to php.ini if some additional non-laravel scripts used:

RUN sed -i 's/session.save_handler = files/session.save_handler = redis/g' /etc/php/7.3/fpm/php.ini
RUN sed -i 's/;session.save_path = "\/var\/lib\/php\/sessions"/session.save_path = "tcp:\/\/sessions-store-haproxy:6379"/g' /etc/php/7.3/fpm/php.ini

Now provide all the necessary environment variables to Pod and you can start deploying.

  SESSION_DRIVER: redis
  SESSION_CONNECTION: sessions
  SESSION_REDIS_HOST: "sessions-store-haproxy"
  SESSION_REDIS_PASSWORD: ""
  SESSION_REDIS_PORT: 6379