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Run an Experiment with Docker

ChaosIQ Docker image

ChaosIQ have made the chaosiq/chaostoolkit Docker image available on docker hub, you can download it with:

docker pull chaosiq/chaostoolkit

This will make the image available in your own Docker environment.

Run an Experiment on the ChaosIQ Docker image

The ChaosIQ Docker image uses /home/svc as its working directory, we will use this to pass experiments to the docker image and to share the chaostoolkit.log and the journal.json files with the host. In your working directory create a subdirectory /ctk. You will then be able to execute and experiment with the following command:

docker run  -e "ENDPOINT_URL=" \
-v `pwd`/ctk:/home/svc chaosiq/chaostoolkit run  \
The experiment used is an experiment from the open source Experiment Catalog, its a useful resource to get you started with your own experiments. The experiment we are using simply probes a URL and expects a 200 success response code, the full experiment can be seen in Catalog Url Responds Experiment.

The experiment depends on an environment variable ENDPOINT_URL, this is setup with the -e command line argument in the docker run command.

We are also using the -v option to mount a shared volume between our local ./ctk subdirectory and the /home/svc directory on the Docker guest.

We then specify the image we are going to run and provide some command line arguments, in the above case we use the command run and provide a URL to the experiment.

The output from the above command is:

[2020-03-25 09:26:14 INFO] Validating the experiment's syntax
[2020-03-25 09:26:14 INFO] Experiment looks valid
[2020-03-25 09:26:14 INFO] Running experiment: Checks the hypothesis that a URL responds with a 200 status
[2020-03-25 09:26:14 INFO] Steady state hypothesis: Application is normal
[2020-03-25 09:26:14 INFO] Probe: application-must-respond-normally
[2020-03-25 09:26:17 INFO] Steady state hypothesis is met!
[2020-03-25 09:26:17 INFO] Action: dummy step
[2020-03-25 09:26:17 INFO] Steady state hypothesis: Application is normal
[2020-03-25 09:26:17 INFO] Probe: application-must-respond-normally
[2020-03-25 09:26:20 INFO] Steady state hypothesis is met!
[2020-03-25 09:26:20 INFO] Let's rollback...
[2020-03-25 09:26:20 INFO] No declared rollbacks, let's move on.
[2020-03-25 09:26:20 INFO] Experiment ended with status: completed

After running docker run command we can check the ./ctk subdirectory and we will find the chaostoolkit.log and the journal.json file.

Using a local Experiment file

We can also use a local experiment file with this approach. In the ./ctk subdirectory create an experiment.json and paste in a copy of the Url Responds Experiment and save the file. Then run:

docker run  -e "ENDPOINT_URL=" \
  -v `pwd`/ctk:/home/svc chaosiq/chaostoolkit  run experiment.json

You will get the same output show above and an updated chaostoolkit.log and a new journal.json in the ./ctk folder.