Redis cache limit

Redis cache limit fault limits the amount of memory used by a Redis cache. The original limit is restored after the chaos duration.

Use cases

Determines the resilience of Redis-dependant applications on frequent cache misses that occur due to a low cache size.

note

• This fault can be executed on Ubuntu 16 or higher, Debian 10 or higher, CentOS 7 or higher, RHEL 7 or higher, Fedora 30 or higher, and openSUSE LEAP 15.4 or higher.
• The linux-chaos-infrastructure systemd service should be in an active state, and the infrastructure should be in CONNECTED state.

Fault permissions

The fault uses the root Linux user and root user group.

Redis authentication

note

If your Redis server doesn't require authentication, you may directly provide the address tunable. Refer here.

The following authentication and connection details reside on the same machine where the chaos infrastructure is executed. These details are provided in the /etc/linux-chaos-infrastructure/redis.env file in the following format:

ADDRESS="127.0.0.1:6379"
PASSWORD=XXXXXXXX
TLS_AUTH_CERT="/path/to/tls-cert"

tip

• ADDRESS is a mandatory field. You can also include PASSWORD and TLS_AUTH_CERT fields. You need them only if you have configured your Redis database to facilitate authentication.

ENV name	Description	Example
ADDRESS	Location where the Redis server is running.	redis-server.com
PASSWORD	Password to connect to the Redis database.	password
TLS_AUTH_CERT	File path to the location where the TLS certificate is stored.	/path/to/file

Optional tunables

Tunable	Description	Notes
address	The address of the Redis server.	If a password or certificate is also required alongside the address, please use the secret file approach.
maxMemory	The percentage of existing Redis maxMemory or an absolute amount (in MB, KB, GB) that should be used by Redis.	Default: 50 %. For more information, go to maximum memory.
duration	Duration through which chaos is injected into the target resource. Should be provided in [numeric-hours]h[numeric-minutes]m[numeric-seconds]s format.	Default: 30s. Examples: 1m25s, 1h3m2s, 1h3s. For more information, go to duration.
rampTime	Period to wait before and after injecting chaos. Should be provided in [numeric-hours]h[numeric-minutes]m[numeric-seconds]s format.	Default: 0s. Examples: 1m25s, 1h3m2s, 1h3s. For more information, go to ramp time.

Maximum memory

The maxMemory input variable indicates the percentage of Redis cache memory or absolute memory used by Redis to limit during the chaos duration. Its default value is 50 %.

The following YAML snippet illustrates the use of this input variable:

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: redis-cache-limit
  labels:
    name: cache-limit
spec:
  redisChaos/inputs:
    duration: "30s"
    maxMemory: "50%"
    rampTime: ""