Laravel + predis + Redis cluster - MOVED / no connection to 127.0.0.1:6379

Question

I have a laravel (5.3) app with redis used for sessions (using predis). Everything works as long as I use a single redis node (using default approach from config/databas

Answer 1

Related: Laravel + Redis Cache via SSL?

To which I've answered here: https://stackoverflow.com/a/48876398/663058

Relevant details below:

If you have clustering and TLS then you'll need a the following config (tested with AWS Elasticache):

'redis' => [
        'client' => 'predis',
        'cluster' => env('REDIS_CLUSTER', false),

        // Note! for single redis nodes, the default is defined here.
        // keeping it here for clusters will actually prevent the cluster config
        // from being used, it'll assume single node only.
        //'default' => [
        //    ...
        //],

        // #pro-tip, you can use the Cluster config even for single instances!
        'clusters' => [
            'default' => [
                [
                    'scheme'   => env('REDIS_SCHEME', 'tcp'),
                    'host'     => env('REDIS_HOST', 'localhost'),
                    'password' => env('REDIS_PASSWORD', null),
                    'port'     => env('REDIS_PORT', 6379),
                    'database' => env('REDIS_DATABASE', 0),
                ],
            ],
            'options' => [ // Clustering specific options
                'cluster' => 'redis', // This tells Redis Client lib to follow redirects (from cluster)
            ]
        ],
        'options' => [
            'parameters' => [ // Parameters provide defaults for the Connection Factory
                'password' => env('REDIS_PASSWORD', null), // Redirects need PW for the other nodes
                'scheme'   => env('REDIS_SCHEME', 'tcp'),  // Redirects also must match scheme
            ],
            'ssl'    => ['verify_peer' => false], // Since we dont have TLS cert to verify
        ]
    ]

Explaining the above:

• 'client' => 'predis': This specifies the PHP Library Redis driver to use (predis).
• 'cluster' => 'redis': This tells Predis to assume server-side clustering. Which just means "follow redirects" (e.g. -MOVED responses). When running with a cluster, a node will respond with a -MOVED to the node that you must ask for a specific key.
  • If you don't have this enabled with Redis Clusters, Laravel will throw a -MOVED exception 1/n times, n being the number of nodes in Redis cluster (it'll get lucky and ask the right node every once in awhile)
• 'clusters' => [...]: Specifies a list of nodes, but setting just a 'default' and pointing it to the AWS 'Configuration endpoint' will let it find any/all other nodes dynamically (recommended for Elasticache, because you don't know when nodes are comin' or goin').
• 'options': For Laravel, can be specified at the top-level, cluster-level, and node option. (they get combined in Illuminate before being passed off to Predis)
• 'parameters': These 'override' the default connection settings/assumptions that Predis uses for new connections. Since we set them explicitly for the 'default' connection, these aren't used. But for a cluster setup, they are critical. A 'master' node may send back a redirect (-MOVED) and unless the parameters are set for password and scheme it'll assume defaults, and that new connection to the new node will fail.