Simulate time faults

You can use this experiment type to simulate a time offset scenario. This document describes how to create a TimeChaos experiment.

note

TimeChaos only affects the PID 1 process in the PID namespace of the container, and child processes of the PID 1. For example, the process started by kubectl exec does not be affected.

Option	Short	Description	Default value	Required
--time-offset	None	It specifies the length of time offset.	None	Yes
--clock-id	None	It specifies the ID of clock that will be offset. See the clock_gettime documentation for details.	CLOCK_REALTIME	No
--container	-c	It specifies a container name for fault injection.	None	No

Simulate fault injections by kbcli

This experiment configuration shifts the time of the processes in the specified Pod forward by 5 seconds. Once this time fault is injected into the Pod, a failure occurs to this Pod and this Pod restarts.

kbcli fault time --time-offset=-5s

Simulate fault injections by YAML file

This section introduces the YAML configuration file examples. You can also refer to the Chaos Mesh official docs for details.

1. Write the experiment configuration to the time.yaml file.

   In the following example, Chaos Mesh injects a time fault to shift the time of the processes in the specified Pod forward by 5 seconds. Once this time fault is injected into the Pod, a failure occurs to this Pod and this Pod restarts.

   apiVersion: chaos-mesh.org/v1alpha1
   kind: TimeChaos
   metadata:
     creationTimestamp: null
     generateName: time-chaos-
     namespace: default
   spec:
     duration: 10s
     mode: all
     selector:
       namespaces:
       - default
     timeOffset: -5s

2. Run kubectl to start an experiment.

   kubectl apply -f ./time.yaml

Field description

The fields in the YAML configuration file are described in the following table:

Parameter	Type	Note	Default value	Required
timeOffset	string	It specifies the length of time offset.	None	Yes
clockIds	[]string	It specifies the ID of clock that will be offset. See the clock_gettime documentation for details.	["CLOCK_REALTIME"]	No
mode	string	It specifies the mode of an experiment. The mode options include one (selecting a random Pod), all (selecting all eligible Pods), fixed (selecting a specified number of eligible Pods), fixed-percent (selecting a specified percentage of Pods from the eligible Pods), and random-max-percent (selecting the maximum percentage of Pods from the eligible Pods).	None	Yes
value	string	It provides parameters for the mode configuration, depending on mode. For example, when mode is set to fixed-percent, value specifies the percentage of Pods.	None	No
containerNames	[]string	It specifies the name of the container into which the fault is injected.	None	No
selector	struct	It specifies the target Pod.	None	Yes