---
id: "bug-1462"
status: "fixed"
status_updated: "2026-09-24"
status_note: ""
component: "controller"
severity: "unknown"
timestamp: "2026-07-23T03:04:50.000Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 1
files: ["src/controller/ha.c"]
tags: ["ha", "config-replication", "late-joiner", "committed_config_tag", "raft-promotion", "auto-detected"]
related: ["bug-1060"]
legacy: true
---

# bug-1462: ctrl-3 conf/ empty after HA failover deploy at /tmp/xce-ha-deploy -- config never replicated, but…

## Description
ctrl-3 conf/ empty after HA failover deploy at /tmp/xce-ha-deploy -- config never replicated, but WAL/jobs replicated fine

## Environment
_Not recorded (migrated from buglog.json)._

## Reproduction
_Not recorded (migrated from buglog.json)._

## Root cause
Post-election baseline for ha->committed_config_tag (raft_cb_become_leader, ha.c:1279, set to safe_tag from ha_compute_safe_committed_lsn, ha.c:744-802) is computed as the MAJORITY-SAFE FLOOR across granted voters' self-reported tags (median of sorted tags, same conservative math used for WAL safe_committed_lsn). On a cluster where no admin config push has ever happened live (deploy-ha.sh places cluster.bin on disk pre-boot, not via a live push), every peer voter reports tag=0 except the newly-elected primary itself (self_tag=nonzero, e.g. 860cfd4f59ef9381) -- so the majority-floor computation picks 0, even though the primary demonstrably has a real, valid, currently-loaded config. This 0-floor is CORRECT for WAL LSN safety (a leader must not assume unacknowledged entries are durable) but WRONG for config_tag: a node's own actively-loaded config is not speculative the way an unacknowledged WAL entry is.

Effect: the ONLY path that successfully pushes config after promotion is the one-shot, promotion-instant fan-out (ha.c:1583-1602) to vote endpoints still connected AT THAT EXACT MOMENT (ectx->votes[i].ep != NULL) -- it correctly bypasses committed_config_tag and reads myconf->config_version_tag directly. Any standby that is NOT connected at that instant (a late joiner reconnecting seconds later via on_standby_connected, or any future reconnect/ restart for the rest of the term) relies entirely on the ONGOING heartbeat-driven decision loop (ha_dispatch_repl_action_for_standby -> ha_evaluate_repl_action, ha.c:3633-3663 / 3194-3199: 'if standby_tag < committed_tag -> HA_REPL_PUSH_CONFIG'). Since committed_config_tag is permanently floored at 0 for the rest of the term (nothing advances it except a live admin xceadmin config push via config_commit_change -> push_config_to_standbys, config_repl.c:1524/1556-1558, which never happens in a normal deploy-ha.sh-deployed cluster), standby_tag(0) < committed_tag(0) is false forever -> HA_REPL_PUSH_CONFIG never fires for that standby. Meanwhile WAL/job replication is unaffected since it correctly tracks committed_lsn (a genuinely-advancing value, set from real job commits), not the broken config_tag floor -- exactly matching the observed symptom (jobs replicate, config does not).

Reproduced live: /tmp/xce-ha-deploy, peers ctrl-1=9901/ctrl-2=9902/ctrl-3=9903 (src/build.dbg/controller/xce_controller). ctrl-1 promoted primary at term=2 via PreVote failover (ha_compute_safe_committed_lsn logged safe_committed_lsn=0 safe_config_tag=0 'from 2 granted voters'). ctrl-2 (already-connected vote ep[0]) received handle_repl_config_push 45ms after promotion (one-shot path). ctrl-3 connected 3s later as 'late-joiner standby peer[2]' (ha.c on_standby_connected), got WAL-caught-up correctly (ha_process_standby_state: standby[2] converged: config_tag=0 applied_lsn=1 committed_tag=0 committed_lsn=1) but NEVER received a config push -- ctrl-1's full log has zero further push_config/repl_config lines after promotion, and ctrl-3's log stays stuck at 'CTRL_STANDBY -- waiting for primary to connect and push config'. ctrl-3/conf/ is empty on disk (no cluster.bin.*, no current pointer) while ctrl-1/ctrl-2 both have cluster.bin.860cfd4f59ef + current.

## Fix
FIXED 2026-07-23. Implemented candidate direction (a): added ha_promotion_config_tag_floor(safe_tag, self_tag) (ha.h/ha.c, declared beside ha_promotion_truncate_floor) returning safe_tag > self_tag ? safe_tag : self_tag -- mirrors bug-1060's WAL-truncation clamp pattern but for config_tag instead of LSN. raft_cb_become_leader (ha.c ~1279) now clamps committed_config_tag to this floor instead of the raw majority-safe tag, so a newly-elected primary's own actively-loaded config tag is never dropped back to a stale majority-of-zero baseline. RED test added: test_promotion_config_tag_never_drops_below_own_loaded_config (testsuite/test_ha_election.c), covers the exact bug-1462 repro (safe_tag=0, self_tag=0x860cfd4f59ef9381 -> floor=self_tag), the equal case, safe_tag-above-self_tag case, and fresh-boot (0,0)->0. Unit suite green 977/977, zero regressions. Live regression: 20-round sequential soak (xce-test-ha, ~/tmp/xce-ha-soak-seq) PASS -- 63 jobs, zero job loss, all 3 nodes (ctrl-1/ctrl-2/ctrl-3) cycled through leadership across 20 promotions, 9m00.8s wall-clock. 20-round chaotic (overlapping-kill) soak (~/tmp/xce-ha-soak-chaos) also PASS -- VERDICT mode=chaotic rounds=20 jobs=57 committed_divergence=0 committed_job_loss=0 excluded_bug854_discovery=8 excluded_bug924_fdatasync=0 result=PASS (the 8 excluded bug-854 hits are client primary-discovery misses during overlapping-kill windows, not server-side loss). Confirms the fix holds under both normal and double-fault-within-reconvergence-window failover.

## Verification
_Not recorded (migrated from buglog.json)._

## References
- Related: bug-1060