K
Q

Knowing the replica count in Kubernetes

4/1/2020

I'm wondering for a batch distributed job I need to run. Is there a way in K8S if I use a Job/Stateful Set or whatever, a way for the pod itself(via ENV var or whatever) to know its 1 of X pods run for this job?

I need to chunk up some data and have each process fetch the stuff it needs.

--

I guess the statefulset hostname setting is one way of doing it. Is there a better option?

-- Tom Barber
kubernetes

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2 Answers

4/1/2020

You could write some infrastructure as code using Ansible that will perform the following tasks in order:

  1. kubectl create -f jobs.yml
  2. kubectl wait --for=condition=complete job/job1
  3. kubectl wait --for=condition=complete job/job2
  4. kubectl wait --for=condition=complete job/job3
  5. kubectl create -f pod.yml

kubectl wait can be used in situations like this to halt progress until an action has been performed. In this case, a job has completed its run.

Here is a similar question that someone asked on StackOverflow before.

-- TJ Zimmerman
Source: StackOverflow
4/1/2020

This is planned but not yet implemented that I know of. You probably want to look into higher order layers like Argo Workflows or Airflow instead for now.

-- coderanger
Source: StackOverflow