FAQ — Redis
How does Redis Sentinel work on Hikube?
Redis on Hikube is deployed with a Redis Sentinel architecture for high availability:
- Redis Sentinel monitors the Redis instances and performs an automatic switchover (failover) if the master fails.
- A quorum of sentinels decides on the failover. Three sentinels are always deployed, whatever the number of Redis replicas: switchover works from 2 replicas.
- Sentinels count against the project quotas (CPU and memory, at the size of the cluster's preset).
- The address in the Host field follows the master: after a switchover, it automatically points to the new master, with no change of address.
In production, choose at least 3 replicas at creation: this number cannot be changed afterwards.
Which presets are available?
The Preset sets the CPU and memory of each node. Presets are the virtual machine sizes of the u1, s1 and m1 series: a preset has the same resources as the VM of the same name. The list displayed by the wizard is authoritative:
| Preset | CPU | Memory |
|---|---|---|
u1.medium | 1 | 4Gi |
u1.large | 2 | 8Gi |
u1.xlarge | 4 | 16Gi |
u1.2xlarge | 8 | 32Gi |
u1.4xlarge | 16 | 64Gi |
u1.8xlarge | 32 | 128Gi |
s1.small | 1 | 2Gi |
s1.medium | 2 | 4Gi |
s1.large | 4 | 8Gi |
s1.xlarge | 8 | 16Gi |
s1.2xlarge | 16 | 32Gi |
s1.4xlarge | 32 | 64Gi |
m1.large | 2 | 16Gi |
m1.xlarge | 4 | 32Gi |
m1.2xlarge | 8 | 64Gi |
m1.4xlarge | 16 | 128Gi |
m1.8xlarge | 32 | 256Gi |
It can be changed after creation from Edit.
Does Redis persist data?
Yes. Each node has a persistent volume (Volume size (GB)) to which Redis writes its data through its native mechanisms. The data survives restarts.
What is the "Enable authentication" option for?
When enabled (the default), it protects the cluster with an automatically generated password, displayed only once at creation together with the default user. This password is required for every connection.
Always keep authentication enabled, especially if the public network is enabled.
I lost the password. How can I recover it?
It cannot be read back. Generate a new one from the Security section of the cluster page (Rotate password). See Renew the password.
How do I scale Redis?
- Vertically: change the Preset and the Volume size (GB) via Edit. See Change resources.
- Horizontally: the number of replicas is set at creation. To change it, contact support.
How do I connect to Redis?
With the public network enabled, use the address in the Host field (Connection section of the cluster page) on port 6379:
REDISCLI_AUTH='<password>' redis-cli -h <host> -p 6379 ping
Without the public network, the instance remains reachable from the project's VMs and Kubernetes clusters through an internal address, which the console does not display. Contact support to obtain it.
Can I create several Redis users (ACL)?
No, the console does not offer Redis user management: access relies on a cluster-wide password.