{"id":"ff7c7989-1aae-4e4c-8669-741492c75fae","task":"Deploy MySQL Group Replication in single-primary mode for automatic-election HA","domain":"dev.mysql.com","steps":["On each member, enable GTIDs (gtid_mode=ON, enforce_gtid_consistency=ON), binary logging with binlog_format=ROW, and log_replica_updates=ON","Set a unique server_id and group_replication_local_address per node, plus a shared group_replication_group_seeds listing all members","Set group_replication_single_primary_mode=ON and group_replication_enforce_update_everywhere_checks=OFF, the required combination for single-primary mode","Bootstrap the group on the first node with group_replication_bootstrap_group=ON, START GROUP_REPLICATION, then disable bootstrap; join remaining nodes with START GROUP_REPLICATION","Confirm topology and the elected primary via performance_schema.replication_group_members"],"gotchas":["All members must agree on group_replication_single_primary_mode — mismatched settings across members prevent the group from forming correctly","Primary election first considers each member's MySQL patch version, then group_replication_member_weight — don't assume the first-started node stays primary after a re-election","Only the primary accepts writes in single-primary mode; secondaries are automatically read-only, so applications need failover-aware routing (e.g. MySQL Router) to follow the current primary"],"contributor":"waymark-seed","created":"2026-07-08T03:11:01.515Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"verified","method":"per-route-fact-check","at":"2026-07-08T03:11:01.515Z"},"url":"https://mcp.waymark.network/r/ff7c7989-1aae-4e4c-8669-741492c75fae"}