Trigger Specification
Redis 5.0 introduced Redis Streams which is an append-only log data structure.
One of its features includes 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-streams
trigger that scales based on the Pending Entries List (see XPENDING
) for a specific Consumer Group of a Redis Stream.
triggers:
- type: redis-streams
metadata:
address: localhost:6379 # Required if host and port are not provided. Format - host:port
host: localhost # Required if address is not provided
port: "6379" # Required if address is not provided and host 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
databaseIndex: "0" # optional
# Alternatively, you can use existing environment variables to read configuration from:
# See details in "Parameter list" section
addressFromEnv: REDIS_ADDRESS # Optional. You can use this instead of `address` parameter
hostFromEnv: REDIS_HOST # Optional. You can use this instead of `host` parameter
portFromEnv: REDIS_PORT # Optional. You can use this instead of `port` parameter
Parameter list:
address
: The host and port of the Redis server in the formathost:port
, for examplemy-redis:6379
As an alternative to the
address
field, the user can specifyhost
andport
parameters.
host
: The host of the Redis server
It is not required if
address
has been provided
port
: The port of the Redis server
It is only to be used along with the
host
/hostFromEnv
attribute and not required ifaddress
has been provided
passwordFromEnv
(optional): Name of the environment variable your deployment uses to get the Redis password.stream
: Name of the Redis StreamconsumerGroup
: Name of the Consumer group associated with Redis StreampendingEntriesCount
: Threshold for the number ofPending Entries List
. This is the average target value to scale the workload. Defaults to5
databaseIndex
: The Redis database index. Defaults to0
if not specifiedenableTLS
: Set this totrue
if TLS connection to Redis is required. Defaults tofalse
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:
addressFromEnv
: The host and port of the Redis server, similar toaddress
, but reads it from an environment variable on the scale target. Name of the environment variable your deployment uses to get the Redis server URL. The resolved host should follow a format likemy-redis:6379
.hostFromEnv
: The host of the Redis server, similar tohost
, but reads it from an environment variable on the scale target.portFromEnv
: The port of the Redis server, similar toport
, but reads it from an environment variable on the scale target.
Authentication Parameters
The scaler supports two modes of authentication:
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:
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-streams
metadata:
addressFromEnv: REDIS_HOST
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:
apiVersion: v1
kind: Secret
metadata:
name: redis-streams-password
type: Opaque
data:
redis_password: <encoded 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-streams
metadata:
address: localhost:6379
stream: my-stream
consumerGroup: consumer-group-1
pendingEntriesCount: "10"
authenticationRef:
name: keda-redis-stream-triggerauth # name of the TriggerAuthentication resource