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hi Peter,<br><br>
very nice to hear your appreciation about operational stability during upgrades !<br><br>
You ask about personal preferences, so here is my strictly personal preference:<br>
- I hate defaults, when they are not visible : to my preference, all possible parameters should be listed in config files, with their default value commented or explicitly assigned; this way I know what parameters exist, and by seeing their default values I can appreciate how to use them ; this dates from my stone-age era of learning programming via declarative languages as Pascal (no surprises, all is declared and visible)<br>
- so if an upgraded software suite has new parameters, or no longer supports old parameters, I can easily run a 'diff' between old and new config files to see the differences in parameters (their existence, as well as their values)<br><br>
Therefor, to me the option is always highly preferred to have a upgrade install its new config files, backing-out my old config files (renaming, obviously), and then telling me explicitly what diffs its finds between the new and old config files so that I assess manually each and every parameter change.<br><br>
-> new defaults<br>
-> new config will work with the new software<br>
-> all new params are visible<br>
-> I assess each and every parameter change<br><br>
Curious to hear about other people's working preferences !<br><br>
cheers, and keep up this good work with ThinLinc !<br>
Rob<br><br>
Citeren Peter Astrand <<a href="mailto:astrand@cendio.se">astrand@cendio.se</a>>:</p>
<blockquote style="border-left:2px solid blue;margin-left:2px;padding-left:12px;" type="cite">
Hi. We are thinking about improving the configuration handling during a ThinLinc upgrade, and wants to share our thoughts with you, in order to get some feedback.<br><br>
As you probably know, ThinLinc uses the "Hiveconf" configuration system, where parameter/value pairs are stored in an abstract folder-like namespace. In practice, parameters are stored in text files below /opt/thinlinc/etc/conf.d/. These files are marked as configuration files, in order to get some special attention by the package managers (RPM/DPKG). What happens during upgrade depends on if the file has been changed in the updated package and/or on disk. In most cases, the package manager can determine what to do. Only one case is problematic: If a particular file is changed both in the updated package and on disk (by the admin). When this happens, the package manager will install the new file from the updated package, and save the edited file in .rpmsave or .dpkg-old. (See <a href="http://www-uxsup.csx.cam.ac.uk/~jw35/docs/rpm_config.html" target="_blank">http://www-uxsup.csx.cam.ac.uk/~jw35/docs/rpm_config.html</a> and <a href="https://raphaelhertzog.com/2010/09/21/debian-conffile-configuration-file-managed-by-dpkg/" target="_blank">https://raphaelhertzog.com/2010/09/21/debian-conffile-configuration-file-managed-by-dpkg/</a> for details).<br><br>
Currently, the ThinLinc installer will not allow you to proceed with running "tl-setup" directly after an upgrade (regardless of whether any .rpmsave or .dpkg-old files were actually created), but instead advise you to check for such files and review them to make sure your system is correctly configured. You need to review the differences between the old and the new files, and add relevant statements from the old files to the new files, before proceeding with tl-setup. Depending on how much has changed, this task can range from very simple to mindboggling. It is possible to simply rename the saved files to .hconf and continue using the old files as-is, but there are a few problems with this approach as well (see below).<br><br>
We want to improve this situation, and perhaps provides 2-3 different options in tl-setup, but wants to get your feedback about which options to include, and perhaps if any of these should be marked as default. There are different pros and cons with all options. This includes:<br><br>
* If the existing configuration is preserved or not. If not, the administrator has to change all relevant parameters again, using the Web interface, tl-config, or edit the .hconf files manually.<br><br>
* If the configuration is guaranteed to work good with the new version. Although unlikely, it is possible that the old configuration does not work with the new version. For example, a certain parameter value is perhaps longer be supported.<br><br>
* If default values are taken from the new or old ThinLinc version. When we are changing a default value, you as a customer might either prefer the old or new value, depending on many things. Computer code cannot determine what is "best".<br><br>
* If comments and file structure (such as the order of parameters, or even the file name) is preserved or not. In some cases, you might want to stay as close to the shipped configuration files as possible. This makes is easier to use tools such as "diff" to compare changes. In other cases, the configuration files might have a custom structure, many customer specific comments etc.<br><br>
* If new parameters are available visible in the configuration files or not.<br><br><br>
The different options we are discussing now are:<br><br>
1) Use the "new" files from the updated packages. This is how it works today, if you do not do anything between running install-server and tl-setup. This option has the following properties:<br><br>
Preserves existing configuration?: NO<br>
Conf. guaranteed to work with new version? YES<br>
Default values?: NEW<br>
Comments and file structure?: NEW<br>
New parameters visible?: YES<br><br><br>
2) Use the "old" files. The .rpmsave/.dpkg-old files are simply renamed into place.<br><br>
Preserves existing configuration?: YES<br>
Conf. guaranteed to work with new version? NO<br>
Default values?: OLD<br>
Comments and file structure?: OLD<br>
New parameters visible?: NO<br><br><br>
3) Base the configuration on the new files, but import values from the old file. I have written a tool that basically loops over the parameters in all .rpmsave/.dpkg-old and "imports" the parameter values into the active configuration (which is based on the new files). This means that the perceived configuration (say, for end users) is the same as before the upgrade.<br><br>
Preserves existing configuration?: YES<br>
Conf. guaranteed to work with new version? NO<br>
Default values?: OLD<br>
Comments and file structure?: NEW<br>
New parameters visible?: YES<br><br><br>
I'm personally quite fond of solution 3 (migrate), so my initial idea was to have that as the default option in tl-setup, but also make it possible to opt out for such a migration, which means solution 1 (new files) instead (since that is what the package manager gives you). It would also be possible to get solution 2 (old files) by exiting tl-setup and, say, manually renaming files.<br><br>
However, we are considering other alternatives as well. This includes but is not limited to: not having any default, providing an option for solution 2 (old files) as well etc. Or perhaps the current implementation is sufficient?<br><br>
Since it's somewhat difficult to describe all this in text, I'm attaching a screenshot of what it could look like.<br><br>
What do you think? Any feedback is appreciated.<br><br>
Regards, ---<br>
Peter Astrand ThinLinc Chief Developer<br>
Cendio AB <a href="https://cendio.com" target="_blank">https://cendio.com</a><br>
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