docs redis: add info on secdist for redis cluster

6c3c928029d0ab5fd428a535ed3edc10f45047dd

redis/include/userver/storages/redis/component.hpp

@@ -75,14 +75,14 @@ namespace components {
 ///    # yaml
 ///    redis:
 ///        groups:
-///          - config_name: taxi-tmp
-///            db: taxi-tmp
-///            sharding_strategy: "RedisCluster"
-///          - config_name: taxi-tmp-pubsub
-///            db: taxi-tmp-pubsub
+///          - config_name: cats
+///            db: hello_service_cats_catalogue
+///            sharding_strategy: RedisCluster
+///          - config_name: dogs
+///            db: hello_service_dogs_catalogue
 ///        subscribe_groups:
-///          - config_name: taxi-tmp-pubsub
-///            db: taxi-tmp-pubsub
+///          - config_name: food
+///            db: hello_service_pet_food_orders
 ///        thread_pools:
 ///            redis_thread_pool_size: 8
 ///            sentinel_thread_pool_size: 1
@@ -108,6 +108,20 @@ namespace components {
 ///   }
 /// }
 /// @endcode
+///
+/// ## Cluster Redis setup
+///
+/// Redis cluster is the new recommended way of setting up Redis servers
+/// with improved stability.
+///
+/// To start, set `sharding_strategy: RedisCluster` in the static config
+/// as shown above.
+///
+/// Secdist configuration is simplified:
+///
+/// 1. `"shards"` field is ignored, you can specify an empty array there;
+/// 2. `"sentinels"` field should contain some of the cluster nodes. They are
+///    only used for topology discovery; it is not necessary to list all nodes.
 
 // clang-format on
 class Redis : public LoggableComponentBase {

scripts/docs/en/userver/tutorial/redis_service.md

@@ -151,13 +151,15 @@ implemented using the testsuite. To do that you have to:
 * Prepare the pytest by importing the pytest_userver.plugins.redis plugin:
   @snippet samples/redis_service/tests/conftest.py redis setup
 
-* Add the Redis settings info to the service environment variable:
+* Add the Redis Secdist settings info to the service environment variable:
   @snippet samples/redis_service/tests/conftest.py service_env
   The @ref pytest_userver.plugins.service_client.auto_client_deps "auto_client_deps"
   fixture already knows about the redis_store fixture, so there's no need to override
   the @ref pytest_userver.plugins.service_client.extra_client_deps "extra_client_deps"
   fixture.
 
+  For details on Redis Secdist format, see @ref components::Redis.
+
 * Write the test:
   @snippet samples/redis_service/tests/test_redis.py  Functional test