[ovs-dev] [PATCH v2 ovn 0/3] Forwarding group to load balance l2 traffic with liveness detection
numans at ovn.org
Thu Jan 16 15:34:31 UTC 2020
On Sat, Jan 11, 2020 at 6:11 AM Manoj Sharma <manoj.sharma at nutanix.com>
> A forwarding group is an aggregation of logical switch ports of a
> logical switch to load balance traffic across the ports. It also detects
> the liveness if the logical switch ports are realized as OVN tunnel ports
> on the physical topology.
> In the below logical topology diagram, the logical switch has two ports
> connected to chassis / external routers R1 and R2. The logical router needs
> to send traffic to an external network that is connected through R1 and R2.
> +----------+ R1 | *****
> / +----+ ** **
> +----------+ +--------------+ / lsp1 * *
> | Logical | | Logical |/ * External *
> | Router +--------+ switch X * Network *
> | | | |\ * *
> +----------+ +--------------+ \ lsp2 * *
> ^ \ +----+ ** **
> | +----------+ R2 | *****
> | +----+
> fwd_group -> (lsp1, lsp2)
> In the absence of forwarding group, the logical router will have unicast
> route to point to either R1 or R2. In case of R1 or R2 going down, it will
> require control plane's intervention to update the route to point to proper
> With forwarding group, a virtual IP (VIP) and virtual MAC (VMAC) address
> are configured on the forwarding group. The logical router points to the
> forwarding group's VIP as the nexthop for hosts behind R1 and R2.
> [root at fwd-group]# ovn-nbctl fwd-group-add fwd ls1 VIP_1 VMAC_1 lsp1 lsp2
> [root at fwd-group]# ovn-nbctl fwd-group-list
> UUID FWD_GROUP VIP VMAC CHILD_PORTS
> UUID_1 fwd VIP_1 VMAC_1 lsp1 lsp2
> [root at fwd-group]# ovn-nbctl lr-route-list lr1
> IPv4 Routes
> external_host_prefix/prefix_len VIP_1 dst-ip
> The logical switch will install an ARP responder rule to reply with VMAC
> as the MAC address for ARP requests for VIP. It will also install a MAC
> lookup rule for VMAC with action to load balance across the logical switch
> ports of the forwarding group.
> Datapath: "ls1" Pipeline: ingress
> table=10(ls_in_arp_rsp ), priority=50 , match=(arp.tpa == VIP_1 &&
> arp.op == 1), action=(eth.dst = eth.src; eth.src = VMAC_1; arp.op = 2;
> /* ARP reply */ arp.tha = arp.sha; arp.sha = VMAC_1; arp.tpa = arp.spa;
> arp.spa = VIP; outport = inport; flags.loopback = 1; output;)
> table=13(ls_in_l2_lkup ), priority=50 , match=(eth.dst == VMAC_1),
> In the physical topology, OVN managed hypervisors are connected to R1 and
> R2 through overlay tunnels. The logical flow's "fwd_group" action mentioned
> above, gets translated to openflow group type "select" with one bucket for
> each logical switch port.
> cookie=0x0, duration=16.869s, table=29, n_packets=4, n_bytes=392,
> priority=111,metadata=0x9,dl_dst=VMAC_1 actions=group:1
> bucket=actions=load:0x2->NXM_NX_REG15[0..15], resubmit(,32),
> where 0x2 and 0x3 are port tunnel keys of lsp1 and lsp2.
> The openflow group type "select" with selection method "dp_hash" load
> balances traffic based on source and destination Ethernet address, VLAN ID,
> Ethernet type, IPv4/v6 source and destination address and protocol, and for
> TCP and SCTP only, the source and destination ports.
> To detect path failure between OVN managed hypervisors and (R1, R2), BFD is
> enabled on the tunnel interfaces. The openflow group is modified to include
> watch_port for liveness detection of a port.
> Where 31 and 32 are ovs port numbers for the tunnel interfaces connecting
> to R1 and R2.
> If the BFD forwarding status is down for any of the tunnels, the
> corresponding bucket will not be selected for packet forwarding.
Thanks for the explanation in the previous message.
Regarding the commit message, I think I was not clear.
Can you please include the above description (with the ascii diagram) in
message of patch 2 of this series ?
I think you can drop patch 3 and instead include the test cases added to
ovn-nbctl.at into patch 1
and the rest in patch 2.
I have some comments about the series which I will reply separately.
> Manoj Sharma (3):
> Schema changes for adding forwarding_group table and new ovn-nbctl
> Changes to add flow in the logical switch as well as in the ovn
> Unit tests for forwarding group
> controller/lflow.c | 20 ++++
> controller/physical.c | 13 +++
> controller/physical.h | 4 +
> include/ovn/actions.h | 19 +++-
> lib/actions.c | 122 ++++++++++++++++++++++
> northd/ovn-northd.c | 63 ++++++++++++
> ovn-nb.ovsschema | 18 +++-
> ovn-nb.xml | 35 +++++++
> tests/ovn-nbctl.at | 37 +++++++
> tests/ovn.at | 124 +++++++++++++++++++++++
> utilities/ovn-nbctl.8.xml | 37 +++++++
> utilities/ovn-nbctl.c | 253
> utilities/ovn-trace.c | 3 +
> 13 files changed, 745 insertions(+), 3 deletions(-)
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