Hey, Felix! We found a backwards compatibility issue in your code. I'd
appreciate it if you could take a look at the patch.
On 07.10.2025 17:27, Alexandra Rukomoinikova wrote:
> Restore inter-AZ connectivity during OVN upgrades by allowing
> legacy routes (without lr-id) from different availability zones
> to be learned. Previously, updated nodes skipped all routes
> without lr-id, breaking connectivity to non-upgraded AZs.
>
> The fix checks availability zone for legacy routes instead of
> skipping them entirely, maintaining backward compatibility.
>
> Fixes: b1f8d726390e ("ovn-ic: support learning routes in same AZ")
> Signed-off-by: Alexandra Rukomoinikova <[email protected]>
> Tested-by: Evgeniy Kovalev <[email protected]>
> ---
> ic/ovn-ic.c | 17 ++++++++++-------
> tests/ovn-ic.at | 51 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 61 insertions(+), 7 deletions(-)
>
> diff --git a/ic/ovn-ic.c b/ic/ovn-ic.c
> index fa4a6b118..f989f91cc 100644
> --- a/ic/ovn-ic.c
> +++ b/ic/ovn-ic.c
> @@ -1702,15 +1702,18 @@ sync_learned_routes(struct ic_context *ctx,
>
> ICSBREC_ROUTE_FOR_EACH_EQUAL (isb_route, isb_route_key,
> ctx->icsbrec_route_by_ts) {
> + /* Filters ISSB routes, skipping those that either belong to
> + * current logical router or are legacy routes from the current
> + * availability zone (withoud lr-id).
> + */
> const char *lr_id = smap_get(&isb_route->external_ids, "lr-id");
> - if (lr_id == NULL) {
> - continue;
> - }
> struct uuid lr_uuid;
> - if (!uuid_from_string(&lr_uuid, lr_id)) {
> - continue;
> - }
> - if (uuid_equals(&ic_lr->lr->header_.uuid, &lr_uuid)) {
> + if (lr_id) {
> + if (!uuid_from_string(&lr_uuid, lr_id)
> + || uuid_equals(&ic_lr->lr->header_.uuid, &lr_uuid)) {
> + continue;
> + }
> + } else if (isb_route->availability_zone == ctx->runned_az) {
> continue;
> }
>
> diff --git a/tests/ovn-ic.at b/tests/ovn-ic.at
> index 74ea3bad2..d2c2d70ed 100644
> --- a/tests/ovn-ic.at
> +++ b/tests/ovn-ic.at
> @@ -4047,3 +4047,54 @@ OVN_CLEANUP_IC([az1], [az2], [az3])
> AT_CLEANUP
> ])
>
> +AT_BANNER([Learning routes backward compatibility])
> +OVN_FOR_EACH_NORTHD([
> +AT_SETUP([ovn-ic -- Backward compatibility of learning routes in the same
> AZ])
> +
> +ovn_init_ic_db
> +ovn_start az1
> +
> +# Enable route learning at AZ level
> +check ovn-nbctl set nb_global . options:ic-route-learn=true
> +# Enable route advertising at AZ level
> +check ovn-nbctl set nb_global . options:ic-route-adv=true
> +
> +# Create a fake availability zone to announce a route from.
> +# This route will not have an lr-id in its external_ids, simulating
> +# the behavior of the legacy code. The system is expected to
> +# learn this route to maintain backward compatibility.
> +ovn-ic-sbctl create Availability_Zone name=fake_az
> +fake_az_uuid=$(fetch_column ic-sb:availability-zone _uuid name="fake_az")
> +ovn-ic-sbctl create Gateway name=fake_az_gw availability_zone=$fake_az_uuid \
> + encap=@encap -- --id=@encap create encap type=geneve ip="192.168.0.2"
> +
> +check ovn-ic-nbctl ts-add ts1
> +check ovn-ic-nbctl ts-add ts2
> +
> +check ovn-nbctl lr-add lr1
> +check ovn-nbctl lrp-add lr1 lrp-lr1-ts1 aa:aa:aa:aa:aa:02 169.254.100.1/24
> +check ovn-nbctl lsp-add ts1 lsp-ts1-lr1 -- \
> + lsp-set-addresses lsp-ts1-lr1 router -- \
> + lsp-set-type lsp-ts1-lr1 router -- \
> + lsp-set-options lsp-ts1-lr1 router-port=lrp-lr1-ts1
> +
> +# Check ISB
> +check_row_count ic-sb:Datapath_Binding 1 transit_switch=ts1
> +check_row_count ic-sb:Datapath_Binding 1 transit_switch=ts2
> +
> +ovn-ic-sbctl create Route availability_zone=$fake_az_uuid
> ip_prefix="172.31.0.0/24" nexthop="169.254.100.2" origin=connected
> transit_switch=ts1
> +
> +AT_CHECK([ovn-ic-sbctl find Route nexthop="169.254.100.2" | grep
> external_ids], [0], [dnl
> +external_ids : {}
> +])
> +
> +AT_CHECK([ovn-nbctl lr-route-list lr1], [0], [dnl
> +IPv4 Routes
> +Route Table <main>:
> + 172.31.0.0/24 169.254.100.2 dst-ip (learned)
> +])
> +
> +OVN_CLEANUP_IC([az1])
> +AT_CLEANUP
> +])
> +
--
regards,
Alexandra.
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