On Thu, Feb 21, 2019 at 11:55:11PM -0800, si-wei liu wrote: > > > On 2/21/2019 11:00 PM, Samudrala, Sridhar wrote: > > > > > > On 2/21/2019 7:33 PM, si-wei liu wrote: > > > > > > > > > On 2/21/2019 5:39 PM, Michael S. Tsirkin wrote: > > > > On Thu, Feb 21, 2019 at 05:14:44PM -0800, Siwei Liu wrote: > > > > > Sorry for replying to this ancient thread. There was some remaining > > > > > issue that I don't think the initial net_failover patch got addressed > > > > > cleanly, see: > > > > > > > > > > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1815268 > > > > > > > > > > The renaming of 'eth0' to 'ens4' fails because the udev userspace was > > > > > not specifically writtten for such kernel automatic enslavement. > > > > > Specifically, if it is a bond or team, the slave would typically get > > > > > renamed *before* virtual device gets created, that's what udev can > > > > > control (without getting netdev opened early by the other part of > > > > > kernel) and other userspace components for e.g. initramfs, > > > > > init-scripts can coordinate well in between. The in-kernel > > > > > auto-enslavement of net_failover breaks this userspace convention, > > > > > which don't provides a solution if user care about consistent naming > > > > > on the slave netdevs specifically. > > > > > > > > > > Previously this issue had been specifically called out when IFF_HIDDEN > > > > > and the 1-netdev was proposed, but no one gives out a solution to this > > > > > problem ever since. Please share your mind how to proceed and solve > > > > > this userspace issue if netdev does not welcome a 1-netdev model. > > > > Above says: > > > > > > > > there's no motivation in the systemd/udevd community at > > > > this point to refactor the rename logic and make it work well with > > > > 3-netdev. > > > > > > > > What would the fix be? Skip slave devices? > > > > > > > There's nothing user can get if just skipping slave devices - the > > > name is still unchanged and unpredictable e.g. eth0, or eth1 the > > > next reboot, while the rest may conform to the naming scheme (ens3 > > > and such). There's no way one can fix this in userspace alone - when > > > the failover is created the enslaved netdev was opened by the kernel > > > earlier than the userspace is made aware of, and there's no > > > negotiation protocol for kernel to know when userspace has done > > > initial renaming of the interface. I would expect netdev list should > > > at least provide the direction in general for how this can be > > > solved... I was just wondering what did you mean when you said "refactor the rename logic and make it work well with 3-netdev" - was there a proposal udev rejected? Anyway, can we write a time diagram for what happens in which order that leads to failure? That would help look for triggers that we can tie into, or add new ones. > > > > > Is there an issue if slave device names are not predictable? The user/admin scripts are expected > > to only work with the master failover device. > Where does this expectation come from? > > Admin users may have ethtool or tc configurations that need to deal with > predictable interface name. Third-party app which was built upon specifying > certain interface name can't be modified to chase dynamic names. > > Specifically, we have pre-canned image that uses ethtool to fine tune VF > offload settings post boot for specific workload. Those images won't work > well if the name is constantly changing just after couple rounds of live > migration. It should be possible to specify the ethtool configuration on the master and have it automatically propagated to the slave. BTW this is something we should look at IMHO. > > Moreover, you were suggesting hiding the lower slave devices anyway. There was some discussion > > about moving them to a hidden network namespace so that they are not visible from the default namespace. > > I looked into this sometime back, but did not find the right kernel api to create a network namespace within > > kernel. If so, we could use this mechanism to simulate a 1-netdev model. > Yes, that's one possible implementation (IMHO the key is to make 1-netdev > model as much transparent to a real NIC as possible, while a hidden netns is > just the vehicle). However, I recall there was resistance around this > discussion that even the concept of hiding itself is a taboo for Linux > netdev. I would like to summon potential alternatives before concluding > 1-netdev is the only solution too soon. > > Thanks, > -Siwei Your scripts would not work at all then, right? > > > > > -Siwei > > > > > > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
