wiki(ingest): vds-kzntsv network-stack mismatch RCA + ifupdown anti-pattern

Incident 2026-05-28 ~05:45–13:52 MSK на vds-kzntsv. ~2.5ч активного outage
+ ~5.5ч на эфемерной статике до окончательного fix хостером.

Revised RCA: наш netplan+systemd-networkd конфликтовал с provider's expected
ifupdown stack. Их start/ipadd procedure ожидает чистый ifupdown и не может
auto-recover когда networkd «держит» eth0. 8 дней работало потому что
networkd сам тянул DHCP. Когда что-то на стороне Rusonyx разорвало
DHCP-binding — auto-recovery не сработала.

Fix: systemctl mask netplan + systemd-networkd* (на running system без stop —
IP и SSH сохранились), Rusonyx ребутнул VM и положил чистый
/etc/network/interfaces.d/ifcfg-eth0 через свой start/ipadd. Netmask /18,
gw 89.253.192.1, чистый ifupdown.

Wiki:
- NEW concepts/vds-kzntsv-dhcp-outage-2026-05-28 — full RCA + recovery
  runbook (эфемерная статика + permanent-fix via ifupdown) + diagnostic
  dot-graph + revised lessons-learned + anti-pattern
- NEW sources/vds-kzntsv-incident-2026-05-28 — timeline 05:25 backup OK →
  08:43 statics → 13:52 final reset; provider's ifcfg-eth0 content; ticket
  text reference
- UPDATE entities/vds-kzntsv — mask /18, ifupdown stack, kernel cmdline
  net.ifnames=0 объясняет eth0 naming, hypervisor hw80, pass-store путь,
  Known issues §
- UPDATE concepts/rusonyx-vps-onboarding-quirks — quirk #9 переписан про
  /18 layout + canonical ifcfg, quirk #10 NEW про ifupdown vs netplan
  stack choice + bootstrap mask commands
- UPDATE index.md + log.md

Tasks:
- STATUS header: incident RESOLVED summary
- NEXT_SESSION: следующая сессия — cleanup netplan-artifacts (optional),
  registry GC (~20G pending), board-viewer-build unhealthy разбор

Memory (out-of-repo): vds-kzntsv-rusonyx-network-recovery переписан с
revised RCA — canonical bootstrap step «mask netplan/networkd» для всех
Rusonyx Ubuntu VDS.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.wiki/index.md

@@ -42,6 +42,7 @@ Catalog of all wiki pages. One line per page, organized by type. Updated on ever
 - [traefik-on-windows-docker-desktop](concepts/traefik-on-windows-docker-desktop.md) — Traefik на Windows Docker Desktop — нюансы
 - [traefik-tcp-passthrough-vs-starttls](concepts/traefik-tcp-passthrough-vs-starttls.md) — Traefik TCP passthrough vs STARTTLS-protocols
 - [vbox-windows-stability-tuning](concepts/vbox-windows-stability-tuning.md) — VirtualBox + Windows-гость — нюансы стабильности cross-hypervisor миграции
+- [vds-kzntsv-dhcp-outage-2026-05-28](concepts/vds-kzntsv-dhcp-outage-2026-05-28.md) — DHCP outage 2026-05-28 на vds-kzntsv — диагностика + recovery runbook (link UP но без IPv4 → статика + тикет хостеру)
 - [verdaccio-prune-semantics](concepts/verdaccio-prune-semantics.md) — Verdaccio prune semantics — proxied vs locally-published
 - [wd40efax-smr-cascade](concepts/wd40efax-smr-cascade.md) — WD40EFAX SMR Cascade — root cause NAS failure 2026-05-18
 - [windows-server-2025-core-bootstrap](concepts/windows-server-2025-core-bootstrap.md) — Win Server 2025 Core (RUVDS) — bootstrap для IIS-хоста: default-blockers + transfer-методов матрица
@@ -58,3 +59,4 @@ Catalog of all wiki pages. One line per page, organized by type. Updated on ever
 - [books-vds-backup-daily-kreknin-2026-05-25](sources/books-vds-backup-daily-kreknin-2026-05-25.md) — books VDS daily backup → kreknin pipeline standup 2026-05-25 (ES file-snapshot repo + DB dumps + curl SMTP)
 - [ruvds-backup-daily-kreknin-2026-05-24](sources/ruvds-backup-daily-kreknin-2026-05-24.md) — RUVDS daily backup → kreknin pipeline standup 2026-05-24 (rclone+SFTP, SYSTEM task)
 - [vds-kzntsv-bootstrap-2026-05-20](sources/vds-kzntsv-bootstrap-2026-05-20.md) — VDS bootstrap session 2026-05-20 chronology
+- [vds-kzntsv-incident-2026-05-28](sources/vds-kzntsv-incident-2026-05-28.md) — DHCP outage incident session 2026-05-28 — chronology + ticket text