Enhance configurability of LXC net interfaces

Add the ability to append pre-up, post-up, pre-down, and post-down script
entries to the container_networks dict that are dropped along with the OSA
default configurations when templating the container's interface config files.

The keys preup, postup, predown, and postdown will be appended to the OSA
lxc_container_default_{pre,post}{up/down} lists when dropping the interface
config.

Change-Id: Idf15ec17bac03b55638fb8d862e5445093677f23

defaults/main.yml

@@ -74,6 +74,14 @@ lxc_container_fs_type: ext4
 # using the directory backing.
 lxc_container_vg_name: lxc
 
+# Scripts allowing the configuration of pre/post-up/down scripts in Ubuntu
+# interface files. These are merged with per-interface scripts defined in the
+# container_networks dict
+lxc_container_default_preup: []
+lxc_container_default_postup: []
+lxc_container_default_predown: []
+lxc_container_default_postdown: []
+
 lxc_container_default_mtu: "1500"
 
 lxc_container_domain: "openstack.local"
@@ -110,4 +118,3 @@ lxc_container_network_veth_pair: "{{ inventory_hostname[-8:].replace('-', '').re
 
 # Enable fixed mac address generation for an lxc container
 lxc_container_fixed_mac: false
-

releasenotes/notes/lxc-interface-scripts-78e9021cf2ed0c97.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - In the lxc_container_create role, the keys ``preup``, ``postup``,
+    ``predown``, and ``postdown`` are now supported in the
+    ``container_networks`` dict for Ubuntu systems. This allows operators to
+    configure custom scripts to be run by Ubuntu's ifupdown system when network
+    interface states are changed.

templates/debian-interface.cfg.j2

@@ -10,10 +10,6 @@ iface {{ item.value.interface }} inet static
     gateway {{ item.value.gateway }}
 {% endif %}
     mtu {{ item.value.mtu|default(lxc_container_default_mtu) }}
-    # needed to enable gratuitous arps on interface events
-    post-up sysctl -w net.ipv4.conf.$IFACE.arp_notify=1
-    # needed to force an interface event (setting mac to what it already is)
-    post-up ip link set $IFACE address $(cat /sys/class/net/$IFACE/address)
 {% if item.value.static_routes is defined %}
 {% for route in item.value.static_routes %}
     post-up ip route add {{ route['cidr'] }} via {{ route['gateway'] }} || true
@@ -22,4 +18,16 @@ iface {{ item.value.interface }} inet static
 {% else %}
 iface {{ item.value.interface }} inet manual
 {% endif %}
-### end generated network for [ {{ item.value.interface }} ] ###
+{% for item in item.value.preup | default([]) | union(lxc_container_default_preup) %}
+    pre-up {{ item }}
+{% endfor %}
+{% for item in item.value.postup | default([]) | union(lxc_container_default_postup) %}
+    post-up {{ item }}
+{% endfor %}
+{% for item in item.value.predown | default([]) | union(lxc_container_default_predown) %}
+    pre-down {{ item }}
+{% endfor %}
+{% for item in item.value.postdown | default([]) | union(lxc_container_default_postdown) %}
+    post-down {{ item }}
+{% endfor %}
+### end generated network for [ {{ item.value.interface }} ] ###

vars/ubuntu-16.04.yml

@@ -29,3 +29,9 @@ lxc_container_map:
   distro: ubuntu
   arch: "{{ lxc_architecture_mapping.get( hostvars[physical_host]['ansible_architecture'] | lower ) }}"
   release: xenial
+
+lxc_container_default_postup:
+  # needed to enable gratuitous arps on interface events
+  - "sysctl -w net.ipv4.conf.$IFACE.arp_notify=1"
+  # needed to force an interface event (setting mac to what it already is)
+  - "ip link set $IFACE address $(cat /sys/class/net/$IFACE/address)"