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Diffstat (limited to 'doc/sources/azure/README.rst')
| -rw-r--r-- | doc/sources/azure/README.rst | 32 |
1 files changed, 28 insertions, 4 deletions
diff --git a/doc/sources/azure/README.rst b/doc/sources/azure/README.rst index 8239d1fa..48f3cc7a 100644 --- a/doc/sources/azure/README.rst +++ b/doc/sources/azure/README.rst @@ -9,10 +9,34 @@ Azure Platform The azure cloud-platform provides initial data to an instance via an attached CD formated in UDF. That CD contains a 'ovf-env.xml' file that provides some information. Additional information is obtained via interaction with the -"endpoint". The ip address of the endpoint is advertised to the instance -inside of dhcp option 245. On ubuntu, that can be seen in -/var/lib/dhcp/dhclient.eth0.leases as a colon delimited hex value (example: -``option unknown-245 64:41:60:82;`` is 100.65.96.130) +"endpoint". + +To find the endpoint, we now leverage the dhcp client's ability to log its +known values on exit. The endpoint server is special DHCP option 245. +Depending on your networking stack, this can be done +by calling a script in /etc/dhcp/dhclient-exit-hooks or a file in +/etc/NetworkManager/dispatcher.d. Both of these call a sub-command +'dhclient_hook' of cloud-init itself. This sub-command will write the client +information in json format to /run/cloud-init/dhclient.hook/<interface>.json. + +In order for cloud-init to leverage this method to find the endpoint, the +cloud.cfg file must contain: + +datasource: + Azure: + set_hostname: False + agent_command: __builtin__ + +If those files are not available, the fallback is to check the leases file +for the endpoint server (again option 245). + +You can define the path to the lease file with the 'dhclient_lease' configuration +value under system_info: and paths:. For example: + + dhclient_lease: /var/lib/dhcp/dhclient.eth0.leases + +If no configuration value is provided, the dhclient_lease value will fallback to +/var/lib/dhcp/dhclient.eth0.leases. walinuxagent ------------ |