Redis cache expire

Redis cache expire expires a given key (or all keys) for a specific duration. Due to this, you won't be able to access the key/s associated with the cache during chaos.

Use cases

• Determines the resilience of Redis-dependant application when a key expires on a Linux machine.

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

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
key	The key to expire in the Redis cache.	For empty value, all the keys are expired. For more information, go to key.
expiration	The duration after which the key expires.	Default: 0. For more information, go to expiration.
database	Redis database where the key exists.	Default: 0. For more information, go to database.
expiryOption	The options for expiring a Redis key. Refer here for more information.	Supports one of: NX, XX, GT and LT. For more information, go to expiry option.
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.

Key

The key input variable indicates the key to be expired from the Redis cache.

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

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: redis-cache-expire
  labels:
    name: cache-expire
spec:
  redisChaos/inputs:
    duration: 30s
    expiration: ""
    key: "KeyName"
    database: 1
    expiryOption: ""
    rampTime: ""

Expiration

The expiration input value describes the duration after which the key expires.

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

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: redis-cache-expire
  labels:
    name: cache-expire
spec:
  redisChaos/inputs:
    duration: 30s
    expiration: 30s
    key: ""
    database: 1
    expiryOption: ""
    rampTime: ""

Expiry option

The expiryOption input variable provides options to expire a Redis key. It supports NX, XX, GT and LT. Go to expire command for more information.

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

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: redis-cache-expire
  labels:
    name: cache-expire
spec:
  redisChaos/inputs:
    duration: 30s
    expiration: "5s"
    key: ""
    database: 1
    expiryOption: "GT"
    rampTime: ""

Database

The database input variable is represented as an integer. Its default value is 0.

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

apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: redis-cache-expire
  labels:
    name: cache-expire
spec:
  redisChaos/inputs:
    duration: 30s
    expiration: ""
    key: ""
    database: 1
    expiryOption: ""
    rampTime: ""