On Wed, Aug 17, 2022 at 03:49:08PM +0300, Andrey Zhadchenko wrote: > Hi! > > CRIU currently do not support checkpoint/restore of OVS configurations, but > there was several requests for it. For example, > https://github.com/lxc/lxc/issues/2909
Ah right, I remember that. :) > > The main problem is ifindexes of newly created interfaces. We realy need to > preserve them after restore. Current openvswitch API does not allow to > specify ifindex. Most of the time we can just create an interface via > generic netlink requests and plug it into ovs but datapaths (generally any > OVS_VPORT_TYPE_INTERNAL) can only be created via openvswitch requests which > do not support selecting ifindex. > > This patch allows to do so. > For new datapaths I decided to use dp_infindex in header as infindex > because it control ifindex for other requests too. > For internal vports I reused OVS_VPORT_ATTR_IFINDEX. > > The only concern I have is that previously dp_ifindex was not used for > OVS_DP_VMD_NEW requests and some software may not set it to zero. However > we have been running this patch at Virtuozzo for 2 years and have not > encountered this problem. Not sure if it is worth to add new > ovs_datapath_attr instead. > > > As a broader solution, another generic approach is possible: modify > __dev_change_net_namespace() to allow changing ifindexes within the same > netns. Yet we will still need to ignore NETIF_F_NETNS_LOCAL and I am not > sure that all its users are ready for ifindex change. I think that might become confusing. We already have issues - even with the tracking infrastucture - to keep track of ifindex changes when a network device is moved between network namespaces multiple times. So I'd rather not make it possible to change the ifindex at will within the same network namespace though I understand the appeal for CRIU. > This will be indeed better for CRIU so we won't need to change every SDN > module to be able to checkpoint/restore it. And probably avoid some bloat. > What do you think of this? > > Andrey Zhadchenko (1): > openvswitch: allow specifying ifindex of new interfaces > > include/uapi/linux/openvswitch.h | 4 ++++ > net/openvswitch/datapath.c | 16 ++++++++++++++-- > net/openvswitch/vport-internal_dev.c | 1 + > net/openvswitch/vport.h | 2 ++ > 4 files changed, 21 insertions(+), 2 deletions(-) > > -- > 2.31.1 > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
