Description of problem:

In our enhancements docs we make several references about configuring skipHostSNAT, however it looks we are not implementing it, since looking at the code we have this field commented and in fact the CRD doesn't mentioned it.

https://github.com/openshift/ovn-kubernetes/blob/87e64b772528470577795c4f82a09e5cb253491a/go-controller/pkg/crd/adminpolicybasedroute/v1/types.go#L79

So far okay, but on the same documentation we mentioned that the default is to be set to false, so I assume SNATs will be configured as always whether we use AdminPolicyBasedExternalRoute. The problem is that doesn't seem the case and when we create the AdminPolicyBasedExternalRoute SNATs are not created and even when we delete the CR the SNATs will continute missing creating issues on what the normal routing from the pod is expected to happen and all egress connections hung until they timeout. The only solution is to delete the pod and force its restart.

Configuring APBER:

apiVersion: v1
items:

• apiVersion: k8s.ovn.org/v1
    kind: AdminPolicyBasedExternalRoute
    metadata:
      creationTimestamp: "2025-02-26T14:09:35Z"
      generation: 1
      name: additional-network-hop-policy
      resourceVersion: "444741"
      uid: 7abbf06d-c6be-42eb-a135-2f33493da500
    spec:
      from:
        namespaceSelector:
          matchLabels:
            kubernetes.io/metadata.name: cluster-network-tests
      nextHops:
        static:
        - bfdEnabled: false
          ip: 172.23.184.1
    status:
      lastTransitionTime: "2025-02-26T14:09:35Z"
      messages:
      - 'ocp415-vmw-vcstf-worker-0-n8f4r: configured external gateway IPs: 172.23.184.1'
      - 'ocp415-vmw-vcstf-master-0: configured external gateway IPs: 172.23.184.1'
      - 'ocp415-vmw-vcstf-worker-0-dmq4m: configured external gateway IPs: 172.23.184.1'
      - 'ocp415-vmw-vcstf-master-1: configured external gateway IPs: 172.23.184.1'
      - 'ocp415-vmw-vcstf-worker-0-6f7dd: configured external gateway IPs: 172.23.184.1'
      - 'ocp415-vmw-vcstf-master-2: configured external gateway IPs: 172.23.184.1'
      status: Success
  kind: List
  metadata:
    resourceVersion: ""

Pod running:

NAME                                    READY   STATUS    RESTARTS   AGE   IP            NODE                              NOMINATED NODE   READINESS GATES
net-tools-simplehttp-85d8444d56-r2nff   1/1     Running   0          52m   100.94.10.4   ocp415-vmw-vcstf-worker-0-6f7dd   <none>           <none>

The OVN DBs:

[root@ocp415-vmw-vcstf-worker-0-6f7dd ~]# ovn-sbctl lflow-list GR_ocp415-vmw-vcstf-worker-0-6f7dd | grep 100.94.10.4
  table=7 (lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && ip4 && ip4.dst == 172.25.74.139 && tcp && tcp.dst == 9180), action=(flags.force_snat_for_lb = 1; ct_lb_mark(backends=100.94.10.4:9180; force_snat)
  table=13(lr_in_ip_routing   ), priority=96   , match=(ip4.src == 100.94.10.4/32), action=(ip.ttl--; reg8[0..15] = 0; reg0 = 172.23.184.1; reg1 = 172.23.181.82; eth.src = 00:50:56:88:7a:9b; outport = "rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd"; flags.loopback = 1; next

[root@ocp415-vmw-vcstf-worker-0-6f7dd ~]# ovn-nbctl lr-route-list GR_ocp415-vmw-vcstf-worker-0-6f7dd
IPv4 Routes
Route Table <main>:
              100.94.10.4              172.23.184.1 src-ip rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd ecmp-symmetric-reply
         169.254.169.0/29             169.254.169.4 dst-ip rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd
            100.94.0.0/16                100.64.0.1 dst-ip
                0.0.0.0/0              172.23.180.1 dst-ip rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd

IPv6 Routes
Route Table <main>:
               fd69::/125                   fd69::4 dst-ip rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd
                fd02::/48                   fd98::1 dst-ip
                     ::/0 fe80::1afd:74ff:fe71:1fdb dst-ip rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd

[root@ocp415-vmw-vcstf-worker-0-6f7dd ~]# ovn-nbctl lr-nat-list GR_ocp415-vmw-vcstf-worker-0-6f7dd
TYPE             GATEWAY_PORT          EXTERNAL_IP        EXTERNAL_PORT    LOGICAL_IP          EXTERNAL_MAC         LOGICAL_PORT
snat                                   172.23.181.82                       100.64.0.7
snat                                   172.23.181.82                       100.94.10.35
snat                                   172.23.181.82                       100.94.10.3
snat                                   172.23.181.82                       100.94.10.38
snat                                   172.23.181.82                       100.94.10.22
snat                                   172.23.181.82                       100.94.10.39
snat                                   fdca:5d7b:fdda:                     fd98::7
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::26
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::16
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::27
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::3
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::23

After deleting the APBER:

$ oc delete adminpolicybasedexternalroutes.k8s.ovn.org  additional-network-hop-policy
adminpolicybasedexternalroute.k8s.ovn.org "additional-network-hop-policy" deleted

Nothing changes in the DBs:

[root@ocp415-vmw-vcstf-worker-0-6f7dd ~]# ovn-nbctl lr-nat-list GR_ocp415-vmw-vcstf-worker-0-6f7dd
TYPE             GATEWAY_PORT          EXTERNAL_IP        EXTERNAL_PORT    LOGICAL_IP          EXTERNAL_MAC         LOGICAL_PORT
snat                                   172.23.181.82                       100.64.0.7
snat                                   172.23.181.82                       100.94.10.35
snat                                   172.23.181.82                       100.94.10.3
snat                                   172.23.181.82                       100.94.10.38
snat                                   172.23.181.82                       100.94.10.22
snat                                   172.23.181.82                       100.94.10.39
snat                                   fdca:5d7b:fdda:                     fd98::7
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::26
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::16
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::27
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::3
snat                                   fdca:5d7b:fdda:                     fd02:0:0:6::23
[root@ocp415-vmw-vcstf-worker-0-6f7dd ~]# ovn-nbctl lr-route-list GR_ocp415-vmw-vcstf-worker-0-6f7dd
IPv4 Routes
Route Table <main>:
         169.254.169.0/29             169.254.169.4 dst-ip rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd
            100.94.0.0/16                100.64.0.1 dst-ip
                0.0.0.0/0              172.23.180.1 dst-ip rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd

IPv6 Routes
Route Table <main>:
               fd69::/125                   fd69::4 dst-ip rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd
                fd02::/48                   fd98::1 dst-ip
                     ::/0 fe80::1afd:74ff:fe71:1fdb dst-ip rtoe-GR_ocp415-vmw-vcstf-worker-0-6f7dd

[root@ocp415-vmw-vcstf-worker-0-6f7dd ~]# ovn-sbctl lflow-list GR_ocp415-vmw-vcstf-worker-0-6f7dd | grep 100.94.10.4
  table=7 (lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && ip4 && ip4.dst == 172.25.74.139 && tcp && tcp.dst == 9180), action=(flags.force_snat_for_lb = 1; ct_lb_mark(backends=100.94.10.4:9180; force_snat)

This will cause egress connections from the pod to fail until its restarted.

Version-Release number of selected component (if applicable):

Tested on OCP 4.16 but assume this will happen all the way back to 4.14

How reproducible:

Always

Steps to Reproduce:

1. Deploy a project and some deployment

2. Configure a simple AdminPolicyBasedExternalRoute 

3. Check the OVN DBs

4. Delete the AdminPolicyBasedExternalRoute and test a few egress connections and check the OVN DBs

5. Delete the pod and re-test connections and check the OVN DBs.

Actual results:

Expected results:

Additional info:

Please fill in the following template while reporting a bug and provide as much relevant information as possible. Doing so will give us the best chance to find a prompt resolution.

Affected Platforms:

Is it an

1. internal CI failure
2. customer issue / SD
3. internal RedHat testing failure

If it is an internal RedHat testing failure:

• Please share a kubeconfig or creds to a live cluster for the assignee to debug/troubleshoot along with reproducer steps (specially if it's a telco use case like ICNI, secondary bridges or BM+kubevirt).

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• When did the failure start happening? Please provide the UTC timestamp of the networking outage window from a sample failure run
• If it's a connectivity issue,
• What is the srcNode, srcIP and srcNamespace and srcPodName?
• What is the dstNode, dstIP and dstNamespace and dstPodName?
• What is the traffic path? (examples: pod2pod? pod2external?, pod2svc? pod2Node? etc)

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  • If it is a connectivity issue:
    • What is the srcNode, srcNamespace, srcPodName and srcPodIP?
    • What is the dstNode, dstNamespace, dstPodName and dstPodIP?
    • What is the traffic path? (examples: pod2pod? pod2external?, pod2svc? pod2Node? etc)
    • Please provide the UTC timestamp networking outage window from must-gather
    • Please provide tcpdump pcaps taken during the outage filtered based on the above provided src/dst IPs
  • If it is not a connectivity issue:
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