feat(mgmt): DHCP server + web UI on the isolated mgmt VLAN

Makerspace experiment: plug into ether8 and get a 192.168.88.x lease, reach the
admin at http://192.168.88.1 (web UI re-enabled) / WinBox / SSH. Login still
required; default admin stays disabled. mamba keeps static .2 (outside the pool).
New flags switch_web_enabled + switch_mgmt_dhcp_enabled/pool/network (off by
default). Verified: www HTTP 200, lease handed out + bound, run-twice idempotent.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backups/crs310-maker/export.rsc

@@ -1,4 +1,4 @@
-# 2025-09-11 10:03:39 by RouterOS 7.19.6
+# 2025-09-11 10:21:40 by RouterOS 7.19.6
 # software id = 73S3-5F2W
 #
 # model = CRS310-8G+2S+
@@ -8,6 +8,8 @@ add admin-mac=D0:EA:11:24:F4:AA auto-mac=no comment=defconf name=bridge \
     vlan-filtering=yes
 /interface vlan
 add interface=bridge name=vlan-mgmt vlan-id=99
+/ip pool
+add name=mgmt-pool ranges=192.168.88.10-192.168.88.254
 /interface bridge port
 add bridge=bridge comment=defconf interface=ether1 pvid=30
 add bridge=bridge comment=defconf interface=ether2 pvid=30
@@ -25,10 +27,13 @@ add bridge=bridge untagged="ether1,ether2,ether3,ether4,ether5,ether6,ether7,s\
 add bridge=bridge tagged=bridge untagged=ether8 vlan-ids=99
 /ip address
 add address=192.168.88.1/24 interface=vlan-mgmt network=192.168.88.0
+/ip dhcp-server
+add address-pool=mgmt-pool interface=vlan-mgmt lease-time=1h name=mgmt-dhcp
+/ip dhcp-server network
+add address=192.168.88.0/24 gateway=192.168.88.1
 /ip service
 set ftp disabled=yes
 set telnet disabled=yes
-set www disabled=yes
 set api disabled=yes
 set api-ssl disabled=yes
 /system identity

host_vars/crs310-maker.yml

@@ -27,6 +27,20 @@ switch_mgmt_gateway: ""        # isolated mgmt -> no default route
 switch_dns_servers: ""         # no DNS on an isolated mgmt plane
 switch_ntp_enabled: false      # no internet on mgmt -> NTP would only error
 
+# Makerspace experiment: make the mgmt port low-friction. Serve DHCP on the mgmt VLAN
+# and enable the web UI so anyone plugging into ether8 can reach the admin (still a
+# login; default `admin` stays disabled). mamba keeps its static .2 (outside the pool).
+switch_web_enabled: true
+switch_disabled_services:      # same as the role default but WITHOUT www (web UI on)
+  - telnet
+  - ftp
+  - www-ssl
+  - api
+  - api-ssl
+switch_mgmt_dhcp_enabled: true
+switch_mgmt_dhcp_pool: "192.168.88.10-192.168.88.254"
+switch_mgmt_dhcp_network: "192.168.88.0/24"
+
 switch_admin_user: "sjat"
 
 # ----- VLANs + per-port map (all untagged access; no trunks) -----

roles/makerfloss.mikrotik_switch/defaults/main.yml

@@ -17,6 +17,12 @@ switch_disabled_services:
   - api
   - api-ssl
 switch_ssh_port: 22
+switch_web_enabled: false                # enable the WWW (HTTP) admin UI
+
+# Optional DHCP server on the management VLAN (convenience; login still required).
+switch_mgmt_dhcp_enabled: false
+switch_mgmt_dhcp_pool: ""                # e.g. "192.168.88.10-192.168.88.254"
+switch_mgmt_dhcp_network: ""             # e.g. "192.168.88.0/24"
 
 # ----- Users -----
 switch_admin_user: "sjat"

roles/makerfloss.mikrotik_switch/tasks/identity.yml

@@ -43,3 +43,10 @@
     commands:
       - /ip/service/set ssh disabled=no port={{ switch_ssh_port }}
   changed_when: false
+
+- name: Enable the WWW (HTTP) admin UI
+  community.routeros.command:
+    commands:
+      - /ip/service/set www disabled=no
+  when: switch_web_enabled | bool
+  changed_when: false

roles/makerfloss.mikrotik_switch/tasks/vlans.yml

@@ -101,6 +101,39 @@
         interface="vlan-mgmt" }
   changed_when: false
 
+# Optional DHCP server on the isolated mgmt VLAN: plug into the mgmt port and get an
+# address automatically (login to the switch is still required). Guards by name; the
+# network entry guards on "no networks yet" because RouterOS find-by-address does not
+# match prefix values (see the legacy-bridge-IP note above).
+- name: Create the management DHCP address pool
+  community.routeros.command:
+    commands:
+      - >-
+        :if ([:len [/ip/pool/find name="mgmt-pool"]] = 0)
+        do={ /ip/pool/add name="mgmt-pool" ranges="{{ switch_mgmt_dhcp_pool }}" }
+  when: switch_mgmt_dhcp_enabled | bool
+  changed_when: false
+
+- name: Create the management DHCP server on vlan-mgmt
+  community.routeros.command:
+    commands:
+      - >-
+        :if ([:len [/ip/dhcp-server/find name="mgmt-dhcp"]] = 0)
+        do={ /ip/dhcp-server/add name="mgmt-dhcp" interface="vlan-mgmt"
+        address-pool="mgmt-pool" lease-time=1h disabled=no }
+  when: switch_mgmt_dhcp_enabled | bool
+  changed_when: false
+
+- name: Define the management DHCP network
+  community.routeros.command:
+    commands:
+      - >-
+        :if ([:len [/ip/dhcp-server/network/find]] = 0)
+        do={ /ip/dhcp-server/network/add address="{{ switch_mgmt_dhcp_network }}"
+        gateway="{{ switch_mgmt_address.split('/')[0] }}" }
+  when: switch_mgmt_dhcp_enabled | bool
+  changed_when: false
+
 - name: Set the default gateway route
   community.routeros.command:
     commands: