docs: add DNS ADR

docs/ADR/004-DNS.md

@@ -52,7 +52,31 @@ Implement sytemd-resolved on all cluster member and add a DNS redirection
 
 need to modify annsible system role for systemd-resolved activation and consul role for configure redirection
 
-## 003 migrate recurson in cluster
+## 003 migrate authority DNS from NAS to cluster
+
+### Status
+
+Study
+
+### Context
+
+we have curently three authority domain on NAS:
+
+- ducamps.win
+- ducamps.eu
+- lan.ducamps.eu
+
+we could migrate authority DNS in cluster
+ducamps.win and ducamps.eu are only use for application access so no dependence with cluster build
+need to study cluster build dependance for lan.ducamps.eu
+need keepalive IP and check if no conflict if store on same machine than pihole
+DNS authority will dependant to storage (less problematic than recursor)
+
+### Decision
+
+### Consequences
+
+## 004 migrate recurson in cluster
 
 ### Status
 
@@ -69,7 +93,7 @@ advantage:
 agains:
 
 - this job need a keepalive IP like pihole
-- loss recursor if lost nomad cluster
+- *loss recursor if lost nomad cluster*
 
 ### Decision