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Linux time chaos

Linux time chaos injects chaos to change the time of the Linux machine.

Linux time chaos

Use cases​

  • Induces time chaos to change the system time on the target Linux machines.
  • Determines the resiliency of the underlying application components when subjected to a change in the system time.
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.

Optional tunables​

Tunable Description Notes
offset Time offset to increment or decrement the system time. Should be provided in (+/-)[numeric-hours]h[numeric-minutes]m[numeric-seconds]s format. For example: +24h, -13h12m, -3h12m16s
disableNTP Set it to disable the NTP server. Defaults to true
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
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

Offset​

The offset input variable increments and decrements the system time using time offset. It is specified in (+/-)[numeric-hours]h[numeric-minutes]m[numeric-seconds]s format.

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

# time offset
apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: linux-time-chaos
  labels:
    name: time-chaos
spec:
  timeChaos/inputs:
    offset: '+1h30m'

DisableNTP​

The disableNTP input variable prevents the fault from disabling the NTP server.

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

# disable the ntp server
apiVersion: litmuchaos.io/v1alpha1
kind: LinuxFault
metadata:
  name: linux-time-chaos
  labels:
    name: time-chaos
spec:
  timeChaos/inputs:
    disableNTP: 'true'