Simulate Time Faults

This document describes how to use Chaosd to simulate a time offset scenario. You can create experiments either in command-line mode or service mode.

Create experiments using command-line mode

This section describes how to create time fault experiments using commands.

Before creating an experiment, you can run the following command to check the options of time faults:

chaosd attack clock -h

The result is as follows:

$ chaosd attack clock -h

clock skew

Usage:
  chaosd attack clock attack [flags]

Flags:
  -c, --clock-ids-slice string   The identifier of the particular clock on which to act.More clock description in linux kernel can be found in man page of clock_getres, clock_gettime, clock_settime.Muti clock ids should be split with "," (default "CLOCK_REALTIME")
  -h, --help                     help for clock
  -p, --pid int                  Pid of target program.
  -t, --time-offset string       Specifies the length of time offset.

Global Flags:
      --log-level string   the log level of chaosd, the value can be 'debug', 'info', 'warn' and 'error'
      --uid string         the experiment ID

Quick Example

Prepare test program:

cat > time.c << EOF
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <sys/types.h>

int main() {
    printf("PID : %ld\n", (long)getpid());
    struct  timespec ts;
    for(;;) {
        clock_gettime(CLOCK_REALTIME, &ts);
        printf("Time : %lld.%.9ld\n", (long long)ts.tv_sec, ts.tv_nsec);
        sleep(10);
    }
}
EOF

gcc -o get_time ./time.c

Then execute get_time and try to attack it. The following is an example:

chaosd attack clock -p $PID -t 11s

Configurations of simulating time faults

Parameter	Type	Note	Default value	Required	Example
timeOffset	string	Specifies the length of time offset.	None	Yes	-5m
clockIds	[]string	Specifies the ID of clock that will be offset. See the clock_gettime documentation for details.	["CLOCK_REALTIME"]	No	["CLOCK_REALTIME", "CLOCK_MONOTONIC"]
pid	string	The identifier of the process.	None	Yes	1

Create experiments using service mode

(ongoing update)