Concepts — Redis

Architecture

Redis on Hikube is a managed service based on the Spotahome Redis Operator. Each instance deployed via the Redis resource creates a master-replica cluster with Redis Sentinel for automatic failover.

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Terminology

Term	Description
Redis	Kubernetes resource (apps.cozystack.io/v1alpha1) representing a managed Redis cluster.
Master	Primary instance that accepts reads and writes.
Replica	Read-only instance, synchronized from the master.
Sentinel	Monitoring process that detects master failures and orchestrates automatic failover.
Spotahome Redis Operator	Kubernetes operator that manages the deployment and lifecycle of Redis clusters.
authEnabled	Enables password authentication (requirepass).
resourcesPreset	Predefined resource profile (nano to 2xlarge).

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High availability with Sentinel

Redis Sentinel ensures high availability by:

1. Continuously monitoring the master and replicas
2. Detecting master failure by consensus (quorum among Sentinels)
3. Automatically promoting a replica to become the new master
4. Reconfiguring the other replicas to follow the new master

tip

Configure replicas: 3 minimum to guarantee Sentinel quorum and enable automatic failover.

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Persistence

Redis on Hikube supports persistent storage:

Parameter	Description
size	Persistent volume size (e.g., 10Gi)
storageClass	local (performance) or replicated (high availability)

Redis data is written to disk via native Redis mechanisms (RDB/AOF), ensuring durability even in case of restart.

warning

For production, always use storageClass: replicated to protect data against node failure.

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Authentication

Redis supports optional authentication:

• authEnabled: true — a password is generated and stored in the Secret <instance>-credentials
• authEnabled: false — passwordless access (avoid in production)

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Resource presets

Preset	CPU	Memory
nano	250m	128Mi
micro	500m	256Mi
small	1	512Mi
medium	1	1Gi
large	2	2Gi
xlarge	4	4Gi
2xlarge	8	8Gi

warning

If the resources field (explicit CPU/memory) is set, resourcesPreset is ignored.

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Limits and quotas

Parameter	Value
Max replicas	Depending on tenant quota
Storage size (size)	Variable (in Gi)
Redis databases	Single database (db 0 by default)

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Further reading

• Overview: service presentation
• API Reference: all parameters of the Redis resource