TLDR Tech / Data
Zero Downtime Upgrade: Yelp's Cassandra 4.x Upgrade Story
Yelp upgraded over 1,000 Cassandra nodes from version 3.11 to 4.1 across multiple clusters with zero downtime using a careful rolling upgrade strategy with Kubernetes init containers, automated pre-flight/flight/post-flight stages, version-specific images, and strict monitoring during the mixed-version period. The upgrade delivered 21-60% latency improvements overall, faster streaming, better observability, new guardrails, and preparation for Cassandra 5.
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