Hello, TL;DR: Some ideas to improve the context packages. We need your feedback and help with them!
I have recently moved the context packages source files from the main repository to a new one [1]. I think this will make easier to contribute to it and have out of band releases that addresses problems and supports more distributions. There are some changes that we have been thinking about for some time and I think now is a good time to let you know them and maybe work on them before 4.8. Interface names and ifconfig ============================ Right now the network configuration scripts rely on ifconfig and the assumption that the interfaces are called eth<n>. With recent distributions it no longer works (for example CentOS 7 or Fedora 20). ifconfig is deprecated (or has a different output than older versions) and there is also the Predictable Network Interface Names [2]. This means that a new system is needed to get information from the interfaces and cope with the new naming scheme. To get information about the interfaces we can start using "ip" command or use some other method you my know. Whatever we use we have to move from "ifconfig". For naming I would like to continue to use the context generated so it is backwards compatible, that is ETH0_IP, etc. My idea is to associate the variables with the correct interface by looking up its MAC address. The context generated has a ETH0_MAC with the MAC address that OpenNebula gave to the interface, this way we can check which interface has it. It may give problems with multiple interfaces with the same MAC but I don't think this is a common case in OpenNebula VMs. Interface IP from MAC address ============================= You may know that by default OpenNebula generates the MAC address using a prefix and the IP address assigned to it (PREFIX+IP). This is nice as we could use the MAC address to set ebtables filters and such. It was also used to configure the network when the contextualization file was not present. I believe we should drop this system from the context packages: * context configures more things than just network * the method adds complexity to the network configuration scripts * it gives a false working state belief (gateway is not the one I'd configured) I'm not sure if someone is still using this system. Maybe a better way is to just disable it by default but I think it is better to take out the code [3]. Init system =========== The context packages use the old SysV system to start. It worked more or less fine but we are already having problems with some distributions that just don't run it properly or at the right time and it seems that everyone is moving to systemd. Maybe a new set of start scripts should be tailored for each distro (and sometimes version). Separate distribution scripts ============================= The source for the context packages was made with the idea of reusing the scripts that go inside it as much as possible. There is a a "base" directory with the common files for all the packages and "base_rpm" and "base_deb" to put the specific files for RedHat and Debian based packages. I still think we should share as much as possible but maybe some more separation is needed to support more distros. Post-install actions and dependencies ===================================== In the current version the post-install scripts do these actions: * delete udev rules for network and cdrom * delete network configuration * add the vmcontext init script to startup There may be other actions that could be interesting to do automatically to prepare the image, for example disabling NetworkManager or deleting the root password. Also some dependencies can be added to the context package. For example it could be nice to install acpid daemons so the VM shutsdown and reboots. If you reached this far I'm sure you are interested in the context packages :). We would like to tell us what do you think about these ideas and give us some others that could be nice to do. This is also a call for help with the packages. If you think you can give ideas, help with some developments or test the packages in new distributions you are more than welcome. I think that for 4.8 we really need to change the use of "ifconfig" to "ip" or some other system and at least I am going to open an issue in the repository about it. If someone has some ideas or working code for this it would be great. Maybe we can have a broad discussion here and move the technical things to the repository tickets but we wanted to hear what do you think about all of this. Cheers [1] https://github.com/OpenNebula/addon-context-linux [2] http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/ [3] https://github.com/OpenNebula/addon-context-linux/blob/master/base_rpm/etc/one-context.d/00-network#L37 -- Javier Fontán Muiños Developer OpenNebula - Flexible Enterprise Cloud Made Simple www.OpenNebula.org | @OpenNebula | github.com/jfontan _______________________________________________ Dev mailing list Dev@lists.opennebula.org http://lists.opennebula.org/listinfo.cgi/dev-opennebula.org
