Storage¶

Limitador limits counters are stored in a backend storage. This is In contrast to the storage of the limits themselves, which are always stored in ephemeral memory. Limitador's operator supports several storage configurations:

In-Memory: ephemeral and cannot be shared
Redis: Persistent (depending on the redis storage configuration) and can be shared
Redis Cached: Persistent (depending on the redis storage configuration) and can be shared
Disk: Persistent (depending on the underlying disk persistence capabilities) and cannot be shared

In-Memory¶

Counters are held in Limitador (ephemeral)

In-Memory is the default option defined by the Limitador's Operator.

apiVersion: limitador.kuadrant.io/v1alpha1
kind: Limitador
metadata:
  name: limitador-sample
spec:
  storage: null

For any of those, one should store the URL of the Redis service, inside a K8s opaque Secret.

apiVersion: v1
kind: Secret
metadata:
  name: redisconfig
stringData:
  URL: redis://127.0.0.1/a # Redis URL of its running instance
type: Opaque

Redis¶

Uses Redis to store counters.

Selected when spec.storage.redis is not null.

apiVersion: limitador.kuadrant.io/v1alpha1
kind: Limitador
metadata:
  name: limitador-sample
spec:
  storage:
    redis:
      configSecretRef: # The secret reference storing the URL for Redis
        name: redisconfig

The URL of the Redis service is provided inside a K8s opaque Secret. The secret is required to be in the same namespace as the Limitador CR.

apiVersion: v1
kind: Secret
metadata:
  name: redisconfig
stringData:
  URL: redis://127.0.0.1/a # Redis URL of its running instance
type: Opaque

Note: Limitador's Operator will only read the URL field of the secret.

Redis Cached¶

Uses Redis to store counters, with an in-memory cache.

Selected when spec.storage.redis-cached is not null.

apiVersion: limitador.kuadrant.io/v1alpha1
kind: Limitador
metadata:
  name: limitador-sample
spec:
  storage:
    redis-cached:
      configSecretRef: # The secret reference storing the URL for Redis
        name: redisconfig

The URL of the Redis service is provided inside a K8s opaque Secret. The secret is required to be in the same namespace as the Limitador CR.

apiVersion: v1
kind: Secret
metadata:
  name: redisconfig
stringData:
  URL: redis://127.0.0.1/a # Redis URL of its running instance
type: Opaque

Note: Limitador's Operator will only read the URL field of the secret.

Additionally, caching options can be specified in the spec.storage.redis-cached.options field.

Options¶

Option	Description
`ttl`	TTL for cached counters in milliseconds [default: 5000]
`ratio`	Ratio to apply to the TTL from Redis on cached counters [default: 10]
`flush-period`	Flushing period for counters in milliseconds [default: 1000]
`max-cached`	Maximum amount of counters cached [default: 10000]

For example:

apiVersion: limitador.kuadrant.io/v1alpha1
kind: Limitador
metadata:
  name: limitador-sample
spec:
  storage:
    redis-cached:
      configSecretRef: # The secret reference storing the URL for Redis
        name: redisconfig
      options: # Every option is optional
        ttl: 1000
        max-cached: 5000

Disk¶

Counters are held on disk (persistent). Kubernetes Persistent Volumes will be used to store counters.

Selected when spec.storage.disk is not null.

apiVersion: limitador.kuadrant.io/v1alpha1
kind: Limitador
metadata:
  name: limitador-sample
spec:
  storage:
    disk: {}

Additionally, disk options can be specified in the spec.storage.disk.persistentVolumeClaim and spec.storage.disk.optimize fields.

Persistent Volume Claim Options¶

spec.storage.disk.persistentVolumeClaim field is an object with the following fields.

Field	Description
`storageClassName`	StorageClass of the storage offered by cluster administrators [default: default storage class of the cluster]
`resources`	The minimum resources the volume should have. Resources will not take any effect when VolumeName is provided. This parameter is not updateable when the underlying PV is not resizable. [default: 1Gi]
`volumeName`	The binding reference to the existing PersistentVolume backing this claim [default: null]

Example:

apiVersion: limitador.kuadrant.io/v1alpha1
kind: Limitador
metadata:
  name: limitador-sample
spec:
  storage:
    disk:
      persistentVolumeClaim:
        storageClassName: "customClass"
        resources:
          requests: 2Gi

Optimize¶

Defines the valid optimization option of the disk persistence type.

spec.storage.disk.optimize field is a string type with the following valid values:

Option	Description
`throughput`	Optimizes for higher throughput. Default
`disk`	Optimizes for disk usage

Example:

apiVersion: limitador.kuadrant.io/v1alpha1
kind: Limitador
metadata:
  name: limitador-sample
spec:
  storage:
    disk:
      optimize: disk