+++ title = "Redis Streams (supports Redis Cluster)" availability = "v2.1+" maintainer = "Community" description = "Redis Streams scaler with support for Redis Cluster topology" go_file = "redis_streams_scaler" +++ ### Trigger Specification Redis 5.0 introduced [Redis Streams](https://redis.io/topics/streams-intro) which is an append-only log data structure. One of its features includes [`Consumer Groups`](https://redis.io/topics/streams-intro#consumer-groups), that allows a group of clients to co-operate consuming a different portion of the same stream of messages. This specification describes the `redis-cluster-streams` trigger that scales based on the *Pending Entries List* (see [`XPENDING`](https://redis.io/commands/xpending)) for a specific Consumer Group of a Redis Stream and supports Redis Cluster topology. ```yaml triggers: - type: redis-cluster-streams metadata: addresses: localhost:6379 # Required if hosts and ports are not provided. Format - comma separated list of host:port hosts: localhost # Comma separated lists of hosts. Required if address is not provided ports: "6379" # Comma separated lists of ports. Required if addresses are not provided and hosts has been provided. passwordFromEnv: REDIS_PASSWORD # optional (can also use authenticationRef) stream: my-stream # Required - name of the Redis Stream consumerGroup: my-consumer-group # Required - name of consumer group associated with Redis Stream pendingEntriesCount: "10" # Required - number of entries in the Pending Entries List for the specified consumer group in the Redis Stream enableTLS: "false" # optional # Alternatively, you can use existing environment variables to read configuration from: # See details in "Parameter list" section addressesFromEnv: REDIS_ADDRESSES # Optional. You can use this instead of `addresses` parameter hostsFromEnv: REDIS_HOSTS # Optional. You can use this instead of `hosts` parameter portsFromEnv: REDIS_PORTS # Optional. You can use this instead of `ports` parameter ``` **Parameter list:** - `addresses` - Comma separated list of hosts and ports of Redis Cluster nodes in the format `host:port` for example `node1:6379, node2:6379, node3:6379`. > As an alternative to the `addresses` field, the user can specify `hosts` and `ports` parameters. - `hosts` - Comma separated list of hosts of Redis Cluster nodes. > It is not required if `addresses` has been provided. - `ports`: Comma separated list of ports for corresponding hosts of Redis Cluster nodes. > It is only to be used along with the `hosts`/`hostsFromEnv` attribute and not required if `addresses` has been provided. - `passwordFromEnv` - Name of the environment variable your deployment uses to get the Redis password. (Optional) - `stream` - Name of the Redis Stream. - `consumerGroup` - Name of the Consumer group associated with Redis Stream. - `pendingEntriesCount` - Threshold for the number of `Pending Entries List`. This is the average target value to scale the workload. (Default: `5`, Optional) - `enableTLS` - Allow a connection to Redis using tls. (Values: `true`, `false`, Default: `false`, Optional) > ⚠️ **WARNING:** In this version, `enableTLS: true` automatically skips the certificate verification which is insecure. Use v2.9 or above to properly verify the server certificate. Some parameters could be provided using environmental variables, instead of setting them directly in metadata. Here is a list of parameters you can use to retrieve values from environment variables: - `addressesFromEnv` - The hosts and corresponding ports of Redis Cluster nodes, similar to `addresses`, but reads it from an environment variable on the scale target. Name of the environment variable your deployment uses to get the URLs of Redis Cluster nodes. The resolved hosts should follow a format like `node1:6379, node2:6379, node3:6379 ...`. - `hostsFromEnv` - The hosts of the Redis Cluster nodes, similar to `hosts`, but reads it from an environment variable on the scale target. - `portsFromEnv` - The corresponding ports for the hosts of Redis Cluster nodes, similar to `ports`, but reads it from an environment variable on the scale target. ### Authentication Parameters The scaler supports two modes of authentication: **Password Authentication:** - `password` - Redis password to authenticate with. #### Using password authentication Use the `password` field in the `metadata` to specify the name of an environment variable that your deployment uses to get the Redis password. This is usually resolved from a `Secret V1` or a `ConfigMap V1` collections. `env` and `envFrom` are both supported. Here is an example: ```yaml apiVersion: keda.sh/v1alpha1 kind: ScaledObject metadata: name: redis-streams-scaledobject namespace: default spec: scaleTargetRef: name: redis-streams-consumer pollingInterval: 15 cooldownPeriod: 200 maxReplicaCount: 25 minReplicaCount: 1 triggers: - type: redis-cluster-streams metadata: addressesFromEnv: REDIS_ADDRESSES passwordFromEnv: REDIS_PASSWORD # name of the environment variable in the Deployment stream: my-stream consumerGroup: consumer-group-1 pendingEntriesCount: "10" ``` #### Using `TriggerAuthentication` You can use `TriggerAuthentication` CRD to configure the authentication. For example: ```yaml apiVersion: v1 kind: Secret metadata: name: redis-streams-password type: Opaque data: redis_password: --- apiVersion: keda.sh/v1alpha1 kind: TriggerAuthentication metadata: name: keda-redis-stream-triggerauth spec: secretTargetRef: - parameter: password name: redis-streams-password # name of the Secret key: redis_password # name of the key in the Secret --- apiVersion: keda.sh/v1alpha1 kind: ScaledObject metadata: name: redis-streams-scaledobject namespace: default spec: scaleTargetRef: name: redis-streams-consumer pollingInterval: 15 cooldownPeriod: 200 maxReplicaCount: 25 minReplicaCount: 1 triggers: - type: redis-cluster-streams metadata: address: node1:6379, node2:6379, node3:6379 stream: my-stream consumerGroup: consumer-group-1 pendingEntriesCount: "10" authenticationRef: name: keda-redis-stream-triggerauth # name of the TriggerAuthentication resource ```