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While a reassignment is in progress, the number of replicas for a partition being reassigned temporarily increases beyond the replication factor. Once all new replicas are in the ISR, the old replicas are removed and the number of replicas again matches the replication factor. Until that point, however, the partition is treated as under-replicated both from the perspective of metrics and from the topic command utility. This is misleading because the partitions may satisfy the required replication factor throughout the reassignment. This has two major drawbacks:
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makes it difficult to use URPs for alerting, for example, because they are expected during a reassignment.
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Furthermore, this can obscure actual replication problems while a reassignment is in progress
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. This
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In this KIP, we propose KIP proposes to distinguish the URPs caused by reassignment.
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