Is there a way to get the replica count at runtime within a pod that belongs to a StatefulSet? I have verified that the following answer https://stackoverflow.com/a/54306021/5514015 gives you the hostname of the pod, which includes the pod ordinal number, at runtime, but I would also like to know the number of replicas configured in the StatefulSet. Is this possible to determine?
1 Answers
Unfortunately, the number of replicas is not available through the Downward API. But in a StatefulSet, as you say, it is common to need this number.
Proposed ways to get the number:
- Implement this within your app so that they coordinate, and perhaps can find out it through ordinal identities.
- Alternatively let your app communicate with the Kubernetes API Server using e.g. client-go, but this ties your application to Kubernetes.
For reliability, you might want to design your app in a way so that it can work (at least for some time) without the Kubernetes control-plane being available, so I would recommend to implement this without the Kubernetes API e.g. the first solution above.
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