Having thought this again, I'd rather merge the patch I proposed in my previous email (I'd need tests and propose a formal patch after your feedback) but in the long term I think it'd make sense to also implement some sort of aging to the MAC_Binding entries so that they eventually expire, especially for entries that come from external networks.
On Fri, Nov 16, 2018 at 6:41 PM Daniel Alvarez Sanchez <dalva...@redhat.com> wrote: > > On Sat, Nov 10, 2018 at 12:21 AM Ben Pfaff <b...@ovn.org> wrote: > > > > On Mon, Oct 29, 2018 at 05:21:13PM +0530, Numan Siddique wrote: > > > On Mon, Oct 29, 2018 at 5:00 PM Daniel Alvarez Sanchez < > dalva...@redhat.com> > > > wrote: > > > > > > > Hi, > > > > > > > > After digging further. The problem seems to be reduced to reusing an > > > > old gateway IP address for a dnat_and_snat entry. > > > > When a gateway port is bound to a chassis, its entry will show up in > > > > the MAC_Binding table (at least when that Logical Switch is connected > > > > to more than one Logical Router). After deleting the Logical Router > > > > and all its ports, this entry will remain there. If a new Logical > > > > Router is created and a Floating IP (dnat_and_snat) is assigned to a > > > > VM with the old gw IP address, it will become unreachable. > > > > > > > > A workaround now from networking-ovn (OpenStack integration) is to > > > > delete MAC_Binding entries for that IP address upon a FIP creation. I > > > > think that this however should be done from OVN, what do you folks > > > > think? > > > > > > > > > > > Agree. Since the MAC_Binding table row is created by ovn-controller, it > > > should > > > be handled properly within OVN. > > > > I see that this has been sitting here for a while. The solution seems > > reasonable to me. Are either of you working on it? > > I started working on it. I came up with a solution (see patch below) which > works but I wanted to give you a bit more of context and get your feedback: > > > ^ localnet > | > +---+---+ > | | > +------+ pub +------+ > | | | | > | +-------+ | > | 172.24.4.0/24 | > | | > 172.24.4.220 | | 172.24.4.221 > +---+---+ +---+---+ > | | | | > | LR0 | | LR1 | > | | | | > +---+---+ +---+---+ > 10.0.0.254 | | 20.0.0.254 > | | > +---+---+ +---+---+ > | | | | > 10.0.0.0/24 | SW0 | | SW1 | 20.0.0.0/24 > | | | | > +---+---+ +---+---+ > | | > | | > +---+---+ +---+---+ > | | | | > | VM0 | | VM1 | > | | | | > +-------+ +-------+ > 10.0.0.10 20.0.0.10 > 172.24.4.100 172.24.4.200 > > > When I ping VM1 floating IP from the external network, a new entry for > 172.24.4.221 in the LR0 datapath appears in the MAC_Binding table: > > _uuid : 85e30e87-3c59-423e-8681-ec4cfd9205f9 > datapath : ac5984b9-0fea-485f-84d4-031bdeced29b > ip : "172.24.4.221" > logical_port : "lrp02" > mac : "00:00:02:01:02:04" > > > Now, if LR1 gets removed and the old gateway IP (172.24.4.221) is reused > for VM2 FIP with different MAC and new gateway IP is created (for example > 172.24.4.222 00:00:02:01:02:99), VM2 FIP becomes unreachable from VM1 > until the old MAC_Binding entry gets deleted as pinging 172.24.4.221 will > use the wrong address ("00:00:02:01:02:04"). > > With the patch below, removing LR1 results in deleting all MAC_Binding > entries for every datapath where '172.24.4.221' appears in the 'ip' column > so the problem goes away. > > Another solution would be implementing some kind of 'aging' for > MAC_Binding entries but perhaps it's more complex. > Looking forward for your comments :) > > > diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c > index 58bef7d..a86733e 100644 > --- a/ovn/northd/ovn-northd.c > +++ b/ovn/northd/ovn-northd.c > @@ -2324,6 +2324,18 @@ cleanup_mac_bindings(struct northd_context *ctx, > struct hmap *ports) > } > } > > +static void > +delete_mac_binding_by_ip(struct northd_context *ctx, const char *ip) > +{ > + const struct sbrec_mac_binding *b, *n; > + SBREC_MAC_BINDING_FOR_EACH_SAFE (b, n, ctx->ovnsb_idl) { > + if (strstr(ip, b->ip)) { > + sbrec_mac_binding_delete(b); > + } > + } > +} > + > + > /* Updates the southbound Port_Binding table so that it contains the > logical > * switch ports specified by the northbound database. > * > @@ -2383,6 +2395,15 @@ build_ports(struct northd_context *ctx, > /* Delete southbound records without northbound matches. */ > LIST_FOR_EACH_SAFE(op, next, list, &sb_only) { > ovs_list_remove(&op->list); > + > + /* Delete all MAC_Binding entries which match the IP addresses of > the > + * deleted logical router port (ie. port with a peer). */ > + const char *peer = smap_get(&op->sb->options, "peer"); > + if (peer) { > + for (int i = 0; i < op->sb->n_mac; i++) { > + delete_mac_binding_by_ip(ctx, op->sb->mac[i]); > + } > + } > sbrec_port_binding_delete(op->sb); > ovn_port_destroy(ports, op); > } >
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