Providing multiple health check URLs for kubernetes probes

Question

I am using container Probes to check the health of the application running inside the container within kubernetes pod. For now my example pod config looks like,

"spec":{
   "containers":[
      {
        "image":"tomcat",
        "name":"tomcat",
        "livenessProbe":{
           "httpGet":{
              "port": 80
            },
            "initialDelaySeconds": 15,
            "periodSeconds": 10
        }
      }
   ]
}

In my case, I need to monitor two ports for the same container. 80 and 443. But I am unable to find a method to provide both the ports for same container in the config file. Is there an alternate way of doing this?

I tried HEALTHCHECK docker command while creating the docker image. But even if the container is unhealthy, pod description doesn't give those details. I just states that the container is in running phase. — Sujai Sivasamy, Apr 11 '17 at 08:46

Giancarlo Rubio · Answer 1 · 2017-04-12T09:09:13.460

2

It's not possible, try to encapsulate the health check inside your application

Ex: http://localhost:80/health_check?full => (proxy to) => http://localhost:443/health_check?full

can be help you https://github.com/kubernetes/kubernetes/issues/37218

edited Apr 12 '17 at 09:09

answered Apr 11 '17 at 07:49

Giancarlo Rubio

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I cannot touch my application. Need to do it from the outer level. I am looking for some other solution. – Sujai Sivasamy Apr 11 '17 at 08:28

score 2 · Accepted Answer · answered Aug 16 '18 at 08:22

2

If you have curl / wget on the container you could just run a container exec healthcheck, and do something like curl localhost:80 && curl localhost:443.

answered Aug 16 '18 at 08:22

Chris Stryczynski

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This is what it looks like: https://raw.githubusercontent.com/kubernetes/website/master/content/en/examples/pods/probe/exec-liveness.yaml – Tillerino Jul 24 '20 at 10:34

score 1 · Answer 3 · answered Sep 19 '18 at 18:26

This would be a very useful feature but that is missing. As others mentioned earlier you can use a script for health check instead of httpget and check both urls in that script.
One another option is to create a sidecar health container to monitor both urls of the main container and take action.

Providing multiple health check URLs for kubernetes probes

3 Answers3