From 78d0936f9dc88cc6bcf9ff807102170f9c16aeb1 Mon Sep 17 00:00:00 2001
From: Matt Birkholz <matt@birchwood-abbey.net>
Date: Mon, 2 Sep 2024 17:16:47 -0600
Subject: [PATCH] Add a Systemd dependency for the isc-dhcp-server.service.

This old daemon is still started by the SysV init compatibility layer?
It would occasionally start and find no IP address for the wifi
interface.
---
 README.org                     | 19 ++++++++++++++++++-
 roles_t/gate/handlers/main.yml |  5 +++++
 roles_t/gate/tasks/main.yml    |  9 +++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/README.org b/README.org
index 04555f7..7a0e635 100644
--- a/README.org
+++ b/README.org
@@ -4938,7 +4938,10 @@ If physically moved or rebooted for some other reason, the above
 command would not be necessary.
 
 Installation and configuration of the DHCP daemon follows.  Note that
-the daemon listens /only/ on the Gate-WiFi network interface.
+the daemon listens /only/ on the Gate-WiFi network interface.  Also
+note the drop-in ~Requires~ dependency, without which the DHCP server
+intermittently fails, finding the ~wifi~ interface has no IPv4
+addresses (or perhaps finding no ~wifi~ interface at all?).
 
 #+CAPTION: [[file:roles_t/gate/tasks/main.yml][=roles_t/gate/tasks/main.yml=]]
 #+BEGIN_SRC conf :tangle roles_t/gate/tasks/main.yml
@@ -4955,6 +4958,15 @@ the daemon listens /only/ on the Gate-WiFi network interface.
     regexp: ^INTERFACESv4=
   notify: Restart DHCP server.
 
+- name: Configure DHCP server dependence on interface.
+  become: yes
+  copy:
+    content: |
+      [Unit]
+      Requires=network-online.target
+    dest: /etc/systemd/system/isc-dhcp-server.service.d/depend.conf
+  notify: Reload Systemd.
+
 - name: Configure DHCP for WiFiAP service.
   become: yes
   copy:
@@ -4993,6 +5005,11 @@ the daemon listens /only/ on the Gate-WiFi network interface.
   systemd:
     service: isc-dhcp-server
     state: restarted
+
+- name: Reload Systemd.
+  become: yes
+  systemd:
+    daemon-reload: yes
 #+END_SRC
 
 ** Install Server Certificate
diff --git a/roles_t/gate/handlers/main.yml b/roles_t/gate/handlers/main.yml
index 9121860..a65da25 100644
--- a/roles_t/gate/handlers/main.yml
+++ b/roles_t/gate/handlers/main.yml
@@ -9,6 +9,11 @@
     service: isc-dhcp-server
     state: restarted
 
+- name: Reload Systemd.
+  become: yes
+  systemd:
+    daemon-reload: yes
+
 - name: Restart OpenVPN.
   become: yes
   systemd:
diff --git a/roles_t/gate/tasks/main.yml b/roles_t/gate/tasks/main.yml
index d9cf678..66bf06d 100644
--- a/roles_t/gate/tasks/main.yml
+++ b/roles_t/gate/tasks/main.yml
@@ -112,6 +112,15 @@
     regexp: ^INTERFACESv4=
   notify: Restart DHCP server.
 
+- name: Configure DHCP server dependence on interface.
+  become: yes
+  copy:
+    content: |
+      [Unit]
+      Requires=network-online.target
+    dest: /etc/systemd/system/isc-dhcp-server.service.d/depend.conf
+  notify: Reload Systemd.
+
 - name: Configure DHCP for WiFiAP service.
   become: yes
   copy:
-- 
2.25.1