crashy-mccrashface

A simple app that will use up resources and eventually crash in order to make interesting monitoring graphs.

The purpose is to demo the ability of the platform

• to restart when the application crashes
• horizontal scaling
• gather and graph data such as
  • memory usage
  • cpu usage
  • log collection
  • http requests

Seeing webstats

The property management.metrics.web.server.auto-time-requests is enabled, so if you hit some pages, then if you go to a url like http://localhost:8080/actuator/metrics/http.server.requests you can see the available tags. You can filter to a given url like http://localhost:8080/actuator/metrics/http.server.requests?tag=uri:/load

You can also filter to a given status code like http://localhost:8080/actuator/metrics/http.server.requests?tag=status:404

Note: building container images with spring boot or the native image needs a newer OS than redhat 7 See buildpacks/pack#439 for similar issues.

Building and Running

Building it yourself.

You can build it yourself using the regular maven commands. See the maven.yml for examples used for the github actions.

Container image

You can run the image that is build by the github actions and pushed to docker hub. docker run --rm -p8080:8080 --cpus=".5" --memory="400m" sellersj/crashy-mccrashface

Liveness and Readiness Probes

It depends on the name of your deployment, but assuming it is called crashy-mccrashface and the actuator are running on the standard port the following commands can be run.

oc set probe deployment/crashy-mccrashface --startup --get-url=http://localhost:8080/actuator/health/readiness --initial-delay-seconds=2 --failure-threshold=60 --period-seconds=2 --timeout-seconds=2
oc set probe deployment/crashy-mccrashface --readiness --get-url=http://localhost:8080/actuator/health/readiness --initial-delay-seconds=30 --period-seconds=5 --timeout-seconds=5
oc set probe deployment/crashy-mccrashface --liveness --get-url=http://localhost:8080/actuator/health/liveness --initial-delay-seconds=45 --period-seconds=5 --timeout-seconds=5

Can clear the probes

oc set probe deployment/crashy-mccrashface --remove --startup --readiness --liveness

References https://www.mankier.com/1/oc-set-probe https://spring.io/blog/2020/03/25/liveness-and-readiness-probes-with-spring-boot

Set resource limits

oc set resources deployment crashy-mccrashface --limits=cpu=500m,memory=600Mi --requests=cpu=100m,memory=400Mi

BuildConfig and Webhooks

If using a openshift BuildConfig to build this, when using webhooks you will need to specify the ref for the branch to be main. By default it will be master, but even if the webhook request is delivered correctly it will not trigger a build since the master branch no longer exists.

Building a native image

You will need the spring release repos and plugin repos set in your settings.xml or maven proxy Run mvn spring-boot:build-image -P native