CODEWITHSUNDEEP
kubernetes
Raz Buchnik
Raz Buchnik

Reputation: 8411

How to send traffic to only one Pod in a Deployment?

I want to create a Deployment with 3 Pods, but that only one of them receives traffic. If this Pod goes down, then the ClusterIP Service should route new requests to one of the remaining Pods (which act like a backup Pods for availability only) and it will act as the new "Primary".

How can it be achieved?

Upvotes: 0

Views: 824

Answers (1)

Justin Pierce
Justin Pierce

Reputation: 252

You can modify your pod definition to contain a leader election sidecar container and achieve this with a readiness probe.

Only the leader in the group of pods will return a valid status for the readiness probe port. A kubernetes service resource will only route requests to pods that are reporting ready.

When one pod terminates, another leader election will take place, the selected pod's readiness will activate, and the service will begin routing traffic to the newly elected leader.

Example probe definition (container checking whether it is leader).

readinessProbe:
  exec:
    command:
    - /bin/sh
    - -c
    - curl -v --silent http://localhost:4040/ 2>&1 | grep $HOSTNAME

Upvotes: 3

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