F5 GTM/DNS Architecture

BIG-IP 17.5.1
Failover Simulation DC Active — DR Standby
F5 BIG-IP 17.5.1 — 172.16.28.28LTM + DNS/GTM Modules
DC_Lab — Primary SiteVLAN 2026 • 172.16.26.0/24
DR_Lab — Standby SiteVLAN 2025 • 172.16.25.0/24
Client / DNS Resolver
dig @172.16.28.28 *.swongpai-gtm.rhdemo.local
DNS Listener
172.16.28.28:53 • UDP
Wide IP (Type A)
*.swongpai-gtm.rhdemo.local
GTM Pool — POOL_GTM_OCP_APPS
LB: global-availability (Active-Standby)
mon_gtm_https_ocp
HTTPS :443 • 10s/31s
VS_OCP_HCP_LAB
172.16.26.150:443
Order 0 • Primary
VS_OCP_HCP2_LAB
172.16.25.220:443
Order 1 • Standby
POOL_OCP_HCP_ING
least-connections • mon: https_443
POOL_OCP_HCP2_ING
round-robin • mon: https_443
bmwrk02-01
172.16.26.151
UP
bmwrk02-02
172.16.26.152
DOWN
bmwrk02-03
172.16.26.153
DOWN
bmwrk-dr-01
172.16.25.231
UP
bmwrk-dr-02
172.16.25.232
DISABLED
bmwrk-dr-03
172.16.25.233
DOWN
OpenShift HCP Cluster • apps.hcp.rhdemo.local
OpenShift HCP2 Cluster • apps.hcp2.rhdemo.local
DNS Response: 172.16.26.150 (DC)
Active traffic path
Standby path
Health monitor
Healthy
Down
Standby
ⓘ Active-Standby Failover: DNS queries resolve to DC VIP (172.16.26.150) while healthy. If DC VS fails health check, GTM automatically returns DR VIP (172.16.25.220). Toggle the switch above to simulate.