Document updated on Mar 27, 2025

Redis connection pools for stateful functionality

KrakenD’s architecture allows developers to define all Redis connections in a single redis namespace, so you can reuse the definitions in other components across the configuration.

You can configure both connection pools and clusters. Whether you use one option or both, each pool and cluster is identified by a unique name that must not clash (make sure of it), which is then referenced by the components requiring a connection. This approach eliminates the need to repeatedly specify Redis connection details in every component configuration.

For example, a configuration that defines 2 connection pools and 1 cluster could be:

{
  "$schema": "https://www.krakend.io/schema/v2.9/krakend.json",
  "version": 3,
  "extra_config": {
    "redis": {
      "connection_pools": [
        {
          "name": "shared_redis_pool",
          "address": "192.168.1.45:6379"
        },
        {
          "name": "ratelimit_counters",
          "address": "192.168.1.52:6379",
          "db": 2
        }
      ],
      "clusters": [
        {
          "name": "shared_redis_cluster",
          "addresses": ["192.168.1.90:6379", "192.168.1.91:6379"]
        }
      ]
    }
  }
}

The block above creates two Redis connection pools named shared_redis_pool and ratelimit_counters, and it also creates a connection set to a Redis Cluster shared_redis_cluster that utilizes internally two different addresses. These names are how other components (like the Redis-based service rate limit) can select which one to use.

Configuration of Redis connection pools

Different pools can connect to different redis instances, or to the same instances but with different parameters. The configuration allows you to declare extra options to fine tune how the pool should behave: secure connection, retries, etc ..

Best practices to select those parameters will depend on the components that will use the pool.

The full list of options is explained below.

Configuration of Redis clusters

The configuration of Redis cluster is identical to connection pools, except that the addresses field is an array, that the db is not available, and a new field max_redirects is added.

A simple configuration would look like this:

{
  "$schema": "https://www.krakend.io/schema/v2.9/krakend.json",
  "version": 3,
  "extra_config": {
    "redis": {
      "clusters": [
        {
          "name": "shared_redis_cluster",
          "addresses": ["192.168.1.45:6379", "192.168.1.52:6379"]
        }
      ]
    }
  }
}

The full list of options is:

Best practices for Redis connection management

While the library sets defaults for all the options (except the address and the name), you might want to tweak several of the parameters available. Generally speaking, the additional parameters are not needed. A few things to have in mind when configuring pools and clusters:

• Set realistic timeouts and limits: Use appropriate values for timeouts and connection limits to prevent overloading Redis and ensure smooth operations during peak traffic.
• Don’t disable monitoring: Let OpenTelemetry to track metrics and traces, helping you identify and address potential bottlenecks. Add the Redis Grafana dashboard for greater visibility.
• Align pools with functionality: Use separate pools for different functionalities to isolate workloads and ensure predictable performance.