Jeremias Blendin <jeremias@xxxxxxxxxxx> writes: > Thank you for the detailed answer! > > See also my comments below: > > 2015-03-20 21:10 GMT+01:00 Eric W. Biederman <ebiederm@xxxxxxxxxxxx>: >> Jeremias Blendin <jeremias@xxxxxxxxxxx> writes: >> >>> Hi, >>> >>> I hope this is the right list to post this question. >> >> This list and netdev are the right lists. It is one of those >> overlapping topics. >> >> Right now I find applications dealing with multiple network namespaces >> interesting as the APIs are a little rough and it is time to knock off >> some of the rough edges. >> >>> Currently, we are using a patched version of bwm-ng to poll statistics >>> of network interfaces. Some of these interfaces are located inside >>> network namespaces, unfortunately we have found no way to poll all >>> interfaces from all netspaces at once, without making our client >>> application process traverse through all the available network >>> namespaces (one result is this patch for bwm-ng: >>> https://github.com/jgjl/bwm-ng/tree/lxns). >>> Is there a more efficient way (for example by using netlink directly) >>> to get a complete list of the statistics of all network interfaces >>> existing in the kernel e.g. tagged by their netns? >> >> Not at this point. Although we have ids that are now possible of that >> tagging. At this point you need to have a separate socket for each >> network namespace. > ok >> >> All network devices in all network namespaces is not going to ever >> happen as that makes nested containers and migration impossible. All >> network devices in an interesting subset of network namespaces is a very >> reasonable request. > That would indeed be very helpful. I (and numerous other people) use > the Mininet network emulator (mininet.org) for research purposes. In > this context a centralized and efficient way to poll at least a subset > of namespaces would be very helpful. For reading network statistics I am not convinced that having just one socket instead of having several sockets provides any real world benefits. >> >>> Any pointers are appreciated :) >> >> I would look at iproute2. Looking at the description of your code you > Yes, we are currently investigating the use of pyroute2, which is a > iproute implementation in Python. My point is specifically that in iproute2 there is ip/ipnetns.c that uses and in so using demonstrates how to use some of the more advanced features of network namespaces. So it is a good place to see how some of the network namespace features are being used. >> don't even pick up on the names that have been assigned to network >> namespaces. So I don't think you are up to speed on everything that is >> going on there. > In this specific context of Mininet all required information is > already in the network interface name, so there is no need to get the > namespace name. My point was doing the equivalent of "ip netns show" could be much simpler and a more straighforward default than passing a sequence of pids. > Nonetheless I would like to get more up to speed, the > question is what is the best way to do so? There seems to be a lot of > information on network namespaces scattered in the man pages, the > Linux kernel documentation files and lwn. Is there a better place to > stay updated on this topic? It all depends on how much time you have to invest. I try and keep the documentation up to date as I implement things but sometimes that does not work out. The sources of iproute2 the kernel are always up to date but not necessarily the easiest to read through. Eric _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
