• Avoiding Zombie Cluster Members When Upgrading to etcd v3.6 This article is a mirror of an original that was recently published to the official etcd blog. • Always upgrade to etcd v3.5.26 or later before moving to v3.6. • This ensures your cluster is automatically repaired, and avoids zombie members. • Issue summary Recently, the etcd community addressed an issue that may appear when users upgrade from v3.5 to v3.6. • This bug can cause the cluster to report “zombie members”, which are etcd nodes that were removed from the database cluster some time ago, and are re-appearing and joining database consensus. • The etcd cluster is then inoperable until these zombie members are removed.
Article Summaries:
- Summary
The etcd team has released a fix for a bug that can cause “zombie” members-nodes that were removed but re‑appear-when upgrading from v3.5 to v3.6. The issue stems from inconsistencies between the legacy v2store and the newer v3store, which can surface after certain operations such as snapshot restores or using the --unsafe-no-sync flag. To avoid cluster failure, users must first upgrade to etcd v3.5.26 (or later), which automatically synchronizes the stores, verify all members are healthy, and then proceed to v3.6. No safe workaround exists for those unable to reach v3.5.26, so upgrading to v3.6 should be delayed until that version is available.
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