Initial hotplug support (#936)

Adds a udev script which will invoke a hotplug hook script on all net
add events. The script will write some udev arguments to a systemd FIFO
socket (to ensure we have only instance of cloud-init running at a
time), which is then read by a new service that calls a new 'cloud-init
devel hotplug-hook' command to handle the new event.

This hotplug-hook command will:
- Fetch the pickled datsource
- Verify that the hotplug event is supported/enabled
- Update the metadata for the datasource
- Ensure the hotplugged device exists within the datasource
- Apply the config change on the datasource metadata
- Bring up the new interface (or apply global network configuration)
- Save the updated metadata back to the pickle cache

Also scattered in some unrelated typing where helpful

1 files changed, 7 insertions, 0 deletions

diff --git a/packages/redhat/cloud-init.spec.in b/packages/redhat/cloud-init.spec.in
index 16138012..b930709b 100644
--- a/packages/redhat/cloud-init.spec.in
+++ b/packages/redhat/cloud-init.spec.in
@@ -119,6 +119,12 @@ version_pys=$(cd "$RPM_BUILD_ROOT" && find . -name version.py -type f)
 ( cd "$RPM_BUILD_ROOT" &&
   sed -i "s,@@PACKAGED_VERSION@@,%{version}-%{release}," $version_pys )
 
+# patch hotplug /usr/libexec script path
+hotplug_file=$(cd "$RPM_BUILD_ROOT" && find . -name 10-cloud-init-hook-hotplug.rules -type f)
+
+( cd "$RPM_BUILD_ROOT" &&
+  sed -i "s,/usr/lib,%{_libexecdir}," $hotplug_file )
+
 %clean
 rm -rf $RPM_BUILD_ROOT
 
@@ -172,6 +178,7 @@ fi
 %files
 
 /lib/udev/rules.d/66-azure-ephemeral.rules
+/lib/udev/rules.d/10-cloud-init-hook-hotplug.rules
 
 %if "%{init_system}" == "systemd"
 /usr/lib/systemd/system-generators/cloud-init-generator