From d6e71353dd826f1cc2933ccb14acef2b9922fb96 Mon Sep 17 00:00:00 2001
From: Jeremy Lecour <jlecour@evolix.fr>
Date: Fri, 14 Sep 2018 14:53:38 +0200
Subject: [PATCH] Add a role to switch from networkd to ifconfig

---
 CHANGELOG.md                                 |  1 +
 networkd-to-ifconfig/README.md               |  9 ++++
 networkd-to-ifconfig/meta/main.yml           | 19 +++++++
 networkd-to-ifconfig/tasks/main.yml          | 54 ++++++++++++++++++++
 networkd-to-ifconfig/templates/interfaces.j2 | 17 ++++++
 5 files changed, 100 insertions(+)
 create mode 100644 networkd-to-ifconfig/README.md
 create mode 100644 networkd-to-ifconfig/meta/main.yml
 create mode 100644 networkd-to-ifconfig/tasks/main.yml
 create mode 100644 networkd-to-ifconfig/templates/interfaces.j2

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3ceda4a2..7b6ff07f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ The **patch** part changes incrementally at each release.
 * evolinux-base: better shell history
 * evolinux-users: add user to /etc/aliases
 * mysql: add a variable to prevent mysql from restarting
+* networkd-to-ifconfig: add a role to switch from networkd to ifconfig
 * webapps/evoadmin-web: add users to /etc/aliases
 
 ### Changed
diff --git a/networkd-to-ifconfig/README.md b/networkd-to-ifconfig/README.md
new file mode 100644
index 00000000..dfcadf4b
--- /dev/null
+++ b/networkd-to-ifconfig/README.md
@@ -0,0 +1,9 @@
+# networkd-to-ifconfig
+
+Switch back from systemd "networkd" to plain old /etc/network/interfaces.
+
+The role does nothing if an /etc/network/interfaces file is present.
+
+You should always double-check if everything seems OK, then reboot.
+
+Caveat: a public IPv4 and a public IPv6 are expected.
diff --git a/networkd-to-ifconfig/meta/main.yml b/networkd-to-ifconfig/meta/main.yml
new file mode 100644
index 00000000..e5cd8119
--- /dev/null
+++ b/networkd-to-ifconfig/meta/main.yml
@@ -0,0 +1,19 @@
+galaxy_info:
+  author: Evolix
+  description: Switch back from systemd "networkd" to plain old /etc/network/interfaces.
+
+  issue_tracker_url: https://forge.evolix.org/projects/ansible-roles/issues
+
+  license: GPLv2
+
+  min_ansible_version: 2.2
+
+  platforms:
+  - name: Debian
+    versions:
+    - stretch
+
+dependencies: []
+  # List your role dependencies here, one per line.
+  # Be sure to remove the '[]' above if you add dependencies
+  # to this list.
diff --git a/networkd-to-ifconfig/tasks/main.yml b/networkd-to-ifconfig/tasks/main.yml
new file mode 100644
index 00000000..02ef0c53
--- /dev/null
+++ b/networkd-to-ifconfig/tasks/main.yml
@@ -0,0 +1,54 @@
+---
+
+- name: Check state of /etc/network/interfaces
+  stat:
+    path: /etc/network/interfaces
+  register: interfaces_file
+
+- debug:
+    msg: A /etc/network/interfaces file already exists, nothing is done.
+  when: interfaces_file.stat.exists
+
+- block:
+  - name: "Parse addresses"
+    shell: "grep Address= /etc/systemd/network/50-default.network | cut -d'=' -f2"
+    register: network_address_grep
+    check_mode: no
+    
+  - name: "Parse gateways"
+    shell: "grep Gateway= /etc/systemd/network/50-default.network | cut -d'=' -f2"
+    register: network_gateway_grep
+    check_mode: no
+
+  - name: Prepare variables
+    set_fact:
+      eni_interface_name: "{{ ansible_default_ipv4.interface }}"
+      eni_ipv4_address: "{{ network_address_grep.stdout_lines | ipv4 | first }}"
+      eni_ipv4_gateway: "{{ network_gateway_grep.stdout_lines | ipv4 | first }}"
+      eni_ipv6_address: "{{ network_address_grep.stdout_lines | ipv6 | first }}"
+      eni_ipv6_gateway: "{{ network_gateway_grep.stdout_lines | ipv6 | first }}"
+
+  - name: "A new /etc/network/interfaces is generated"
+    template:
+      src: interfaces.j2
+      dest: /etc/network/interfaces
+      mode: "0644"
+      owner: root
+      group: root
+
+  - name: "Systemd 'networkd' unit is stopped and disabled"
+    systemd:
+      name: systemd-networkd.service
+      enabled: False
+      state: stopped
+
+  - name: "Systemd 'networking' unit is restarted (it often results in error)"
+    systemd:
+      name: networking
+      enabled: True
+      state: restarted
+    ignore_errors: True
+  
+  - debug:
+      msg: You should verify your configuration, then reboot the server.
+  when: not interfaces_file.stat.exists
diff --git a/networkd-to-ifconfig/templates/interfaces.j2 b/networkd-to-ifconfig/templates/interfaces.j2
new file mode 100644
index 00000000..f1030430
--- /dev/null
+++ b/networkd-to-ifconfig/templates/interfaces.j2
@@ -0,0 +1,17 @@
+# This file describes the network interfaces available on your system
+# and how to activate them. For more information, see interfaces(5).
+
+# The loopback network interface
+iface lo inet loopback
+
+# The primary network interface
+auto {{ eni_interface_name }}
+iface {{ eni_interface_name }} inet static
+  address {{ eni_ipv4_address }}
+  gateway {{ eni_ipv4_gateway }}
+
+iface {{ eni_interface_name }} inet6 static
+  address {{ eni_ipv6_address }}
+  gateway {{ eni_ipv6_gateway }}
+  post-up /sbin/ip -6 route add {{ eni_ipv6_gateway }} dev {{ eni_interface_name }}
+  post-up /sbin/ip -6 route add default via IPV6