Reduce hosts plugin refresh interval

Update the AKS LocalDNS hosts setup systemd timer to refresh every 10 seconds instead of every 15 minutes. Tighten timer accuracy to 1 second so the shorter cadence is honored.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: 2 people

parts/linux/cloud-init/artifacts/aks-localdns-hosts-setup.timer

@@ -4,13 +4,12 @@ Description=Run AKS LocalDNS hosts setup periodically
 [Timer]
 # Run immediately on boot
 OnBootSec=0
-# Refresh every 15 minutes. AKS critical FQDN IPs can change due to load balancer
-# rotation, Traffic Manager failover, or regional DNS updates. 15 minutes balances
-# freshness against unnecessary DNS traffic — stale IPs would cause the hosts plugin
-# to serve unreachable addresses until the next refresh.
-OnUnitActiveSec=15min
+# Refresh every 10 seconds. AKS critical FQDN IPs can change due to load balancer
+# rotation, Traffic Manager failover, or regional DNS updates. Frequent refreshes
+# keep stale IPs from causing the hosts plugin to serve unreachable addresses for long.
+OnUnitActiveSec=10s
 # Timer accuracy (how much systemd can delay)
-AccuracySec=1min
+AccuracySec=1s
 
 [Install]
 WantedBy=timers.target