From ddf6e6ff041cb553a7d51737c082ce242ba6bd71 Mon Sep 17 00:00:00 2001
From: Slash <daniele.baracchi@gmail.com>
Date: Sun, 29 May 2016 12:18:09 +0200
Subject: [PATCH] Auto-updating guest VM DNS config via bind-mount.

---
 roles/lxc_guest/tasks/main.yaml          | 6 ++++++
 roles/lxc_guest/templates/config.j2      | 4 +++-
 roles/lxc_guest/templates/resolv.conf.j2 | 1 +
 3 files changed, 10 insertions(+), 1 deletion(-)
 create mode 100644 roles/lxc_guest/templates/resolv.conf.j2

diff --git a/roles/lxc_guest/tasks/main.yaml b/roles/lxc_guest/tasks/main.yaml
index ae2753d..8d25193 100644
--- a/roles/lxc_guest/tasks/main.yaml
+++ b/roles/lxc_guest/tasks/main.yaml
@@ -21,6 +21,9 @@
           state: stopped
     - name: deploy container config
       template: src=config.j2 dest="/var/lib/lxc/{{ vm_name }}/config"
+    - name: update container DNS configuration
+      template: src=resolv.conf.j2 dest="/var/lib/lxc/{{ vm_name }}/resolv.conf"
+      register: container_config_update
     - name: start container
       lxc_container:
           name: "{{ vm_name }}"
@@ -31,6 +34,9 @@
     - name: update container config
       template: src=config.j2 dest="/var/lib/lxc/{{ vm_name }}/config"
       register: container_config_update
+    - name: update container DNS configuration
+      template: src=resolv.conf.j2 dest="/var/lib/lxc/{{ vm_name }}/resolv.conf"
+      register: container_config_update
     - name: restart container
       lxc_container:
           name: "{{ vm_name }}"
diff --git a/roles/lxc_guest/templates/config.j2 b/roles/lxc_guest/templates/config.j2
index 6b2fc20..e051aab 100644
--- a/roles/lxc_guest/templates/config.j2
+++ b/roles/lxc_guest/templates/config.j2
@@ -6,10 +6,12 @@ lxc.rootfs = /dev/{{ inventory_hostname }}vg/vm_{{ vm_name }}
 lxc.tty = 4
 lxc.arch = amd64
 
+lxc.mount.entry = /var/lib/lxc/{{ vm_name }}/resolv.conf etc/resolv.conf none ro,bind,create=file
+
 lxc.network.type = veth
 lxc.network.flags = up
 lxc.network.link = br0
 lxc.network.name = eth0
-lxc.network.ipv4 = {{ hostvars[vm_name]['ansible_host'] }}/24
+lxc.network.ipv4 = {{ hostvars[vm_name]['ansible_host'] }}/16
 lxc.network.ipv4.gateway = {{ hostvars[ext_gateway]['ansible_host'] }}
 lxc.start.auto = {% if auto_start %}1{% else %}0{% endif %}
diff --git a/roles/lxc_guest/templates/resolv.conf.j2 b/roles/lxc_guest/templates/resolv.conf.j2
new file mode 100644
index 0000000..32b139c
--- /dev/null
+++ b/roles/lxc_guest/templates/resolv.conf.j2
@@ -0,0 +1 @@
+nameserver {{ hostvars[ext_gateway]['ansible_host'] }}