[Planetlab-devel] 2.6.17

[Mark Huang]

Kevin Atkinson wrote:
>> You can and should edit the main configuration file to change values; 
>> and most people who are not performing customization en masse, 
>> shouldn't have to know about the support for configuration templates.
> 
> But, won't the cause problems when new variables are introduced when 
> performing an upgrade, like from RC1 to RC2 which you pointed out?

The common case is someone installing MyPLC, making some changes to 
/etc/planetlab/plc_config.xml, then upgrading to a new version. Their changes 
will be preserved, and any new values in /etc/planetlab/default_config.xml will 
also get merged in.

I believe that the problem doesn't lie with what you actually did (copying in 
their old plc_config.xml file), which should be supported. It lies with an 
optimization that I made to reduce the number of times that 
/etc/planetlab/plc_config.xml is regenerated. If /etc/planetlab/plc_config.xml 
has a newer timestamp than /etc/planetlab/default_config.xml and 
/etc/planetlab/configs/*, then it's not regenerated and new defaults won't be 
merged in. This will be the case if you, say, copy in your old plc_config.xml 
file after installing or upgrading but before starting things up.

If you touch /etc/planetlab/default_config.xml, then restart MyPLC, do things 
fix themselves? If so, then I will remove the optimization if all of MyPLC is 
being brought up or down.

--Mark