Example route advertisements setup - Advanced networking | Networking

Sample route advertisements setup

As a cluster administrator, you can configure the following example route advertisements setup for your cluster. This configuration is intended as a sample that demonstrates how to configure route advertisements.

Sample route advertisements setup

As a cluster administrator, you can enable Border Gateway Protocol (BGP) routing support for your cluster. This configuration is intended as a sample that demonstrates how to configure route advertisements. The configuration uses route reflection rather than a full mesh setup.

BGP routing is supported only on bare-metal infrastructure.

Prerequisites

You installed the OpenShift CLI (oc).
You are logged in to the cluster as a user with cluster-admin privileges.
The cluster is installed on bare-metal infrastructure.
You have a bare-metal system with access to the cluster where you plan to run the FRR daemon container.

Procedure

Confirm that the RouteAdvertisements feature gate is enabled by running the following command:
```
$ oc get featuregate -oyaml | grep -i routeadvertisement
```
Example output
```
      - name: RouteAdvertisements
```

Configure the Cluster Network Operator (CNO) by running the following command:

$ oc patch Network.operator.openshift.io cluster --type=merge \
  -p='
    {"spec":{
      "additionalRoutingCapabilities": {
        "providers": ["FRR"]},
        "defaultNetwork":{"ovnKubernetesConfig"{
          "routeAdvertisements":"Enabled"
          }}}}'

It might take a few minutes for the CNO to restart all nodes.

Get the IP addresses of the nodes by running the following command:

$ oc get node -owide

Example output

NAME                                       STATUS   ROLES                  AGE   VERSION   INTERNAL-IP      EXTERNAL-IP   OS-IMAGE                                                KERNEL-VERSION                 CONTAINER-RUNTIME
master-0                                   Ready    control-plane,master   27h   v1.31.3   192.168.111.20   <none>        Red Hat Enterprise Linux CoreOS 418.94.202501062026-0   5.14.0-427.50.1.el9_4.x86_64   cri-o://1.31.4-2.rhaos4.18.git33d7598.el9
master-1                                   Ready    control-plane,master   27h   v1.31.3   192.168.111.21   <none>        Red Hat Enterprise Linux CoreOS 418.94.202501062026-0   5.14.0-427.50.1.el9_4.x86_64   cri-o://1.31.4-2.rhaos4.18.git33d7598.el9
master-2                                   Ready    control-plane,master   27h   v1.31.3   192.168.111.22   <none>        Red Hat Enterprise Linux CoreOS 418.94.202501062026-0   5.14.0-427.50.1.el9_4.x86_64   cri-o://1.31.4-2.rhaos4.18.git33d7598.el9
worker-0                                   Ready    worker                 27h   v1.31.3   192.168.111.23   <none>        Red Hat Enterprise Linux CoreOS 418.94.202501062026-0   5.14.0-427.50.1.el9_4.x86_64   cri-o://1.31.4-2.rhaos4.18.git33d7598.el9
worker-1                                   Ready    worker                 27h   v1.31.3   192.168.111.24   <none>        Red Hat Enterprise Linux CoreOS 418.94.202501062026-0   5.14.0-427.50.1.el9_4.x86_64   cri-o://1.31.4-2.rhaos4.18.git33d7598.el9
worker-2                                   Ready    worker                 27h   v1.31.3   192.168.111.25   <none>        Red Hat Enterprise Linux CoreOS 418.94.202501062026-0   5.14.0-427.50.1.el9_4.x86_64   cri-o://1.31.4-2.rhaos4.18.git33d7598.el9

Get the default pod network of each node by running the following command:

$ oc get node <node_name> -o=jsonpath={.metadata.annotations.k8s\\.ovn\\.org/node-subnets}

Example output

{"default":["10.129.0.0/23"],"ns1.udn-network-primary-layer3":["10.150.6.0/24"]}

On the bare-metal hypervisor, get the IP address for the external FRR container to use by running the following command:

$ ip -j -d route get <a cluster node's IP> | jq -r '.[] | .dev' | xargs ip -d -j address show | jq -r '.[] | .addr_info[0].local'

Create a frr.conf file for FRR that includes each node’s IP address, as shown in the following example:

Example frr.conf configuration file

router bgp 64512
 no bgp default ipv4-unicast
 no bgp default ipv6-unicast
 no bgp network import-check
 neighbor 192.168.111.20 remote-as 64512
 neighbor 192.168.111.20 route-reflector-client
 neighbor 192.168.111.21 remote-as 64512
 neighbor 192.168.111.21 route-reflector-client
 neighbor 192.168.111.22 remote-as 64512
 neighbor 192.168.111.22 route-reflector-client
 neighbor 192.168.111.40 remote-as 64512
 neighbor 192.168.111.40 route-reflector-client
 neighbor 192.168.111.47 remote-as 64512
 neighbor 192.168.111.47 route-reflector-client
 neighbor 192.168.111.23 remote-as 64512
 neighbor 192.168.111.23 route-reflector-client
 neighbor 192.168.111.24 remote-as 64512
 neighbor 192.168.111.24 route-reflector-client
 neighbor 192.168.111.25 remote-as 64512
 neighbor 192.168.111.25 route-reflector-client
 address-family ipv4 unicast
  network 192.168.1.0/24
  network 192.169.1.1/32
 exit-address-family
 address-family ipv4 unicast
  neighbor 192.168.111.20 activate
  neighbor 192.168.111.20 next-hop-self
  neighbor 192.168.111.21 activate
  neighbor 192.168.111.21 next-hop-self
  neighbor 192.168.111.22 activate
  neighbor 192.168.111.22 next-hop-self
  neighbor 192.168.111.40 activate
  neighbor 192.168.111.40 next-hop-self
  neighbor 192.168.111.47 activate
  neighbor 192.168.111.47 next-hop-self
  neighbor 192.168.111.23 activate
  neighbor 192.168.111.23 next-hop-self
  neighbor 192.168.111.24 activate
  neighbor 192.168.111.24 next-hop-self
  neighbor 192.168.111.25 activate
  neighbor 192.168.111.25 next-hop-self
 exit-address-family
 neighbor  remote-as 64512
 neighbor  route-reflector-client
 address-family ipv6 unicast
  network 2001:db8::/128
 exit-address-family
 address-family ipv6 unicast
  neighbor  activate
  neighbor  next-hop-self
 exit-address-family

Create a file named daemons that includes the following content:

Example daemons configuration file

# This file tells the frr package which daemons to start.
#
# Sample configurations for these daemons can be found in
# /usr/share/doc/frr/examples/.
#
# ATTENTION:
#
# When activating a daemon for the first time, a config file, even if it is
# empty, has to be present *and* be owned by the user and group "frr", else
# the daemon will not be started by /etc/init.d/frr. The permissions should
# be u=rw,g=r,o=.
# When using "vtysh" such a config file is also needed. It should be owned by
# group "frrvty" and set to ug=rw,o= though. Check /etc/pam.d/frr, too.
#
# The watchfrr and zebra daemons are always started.
#
bgpd=yes
ospfd=no
ospf6d=no
ripd=no
ripngd=no
isisd=no
pimd=no
ldpd=no
nhrpd=no
eigrpd=no
babeld=no
sharpd=no
pbrd=no
bfdd=yes
fabricd=no
vrrpd=no

#
# If this option is set the /etc/init.d/frr script automatically loads
# the config via "vtysh -b" when the servers are started.
# Check /etc/pam.d/frr if you intend to use "vtysh"!
#
vtysh_enable=yes
zebra_options="  -A 127.0.0.1 -s 90000000"
bgpd_options="   -A 127.0.0.1"
ospfd_options="  -A 127.0.0.1"
ospf6d_options=" -A ::1"
ripd_options="   -A 127.0.0.1"
ripngd_options=" -A ::1"
isisd_options="  -A 127.0.0.1"
pimd_options="   -A 127.0.0.1"
ldpd_options="   -A 127.0.0.1"
nhrpd_options="  -A 127.0.0.1"
eigrpd_options=" -A 127.0.0.1"
babeld_options=" -A 127.0.0.1"
sharpd_options=" -A 127.0.0.1"
pbrd_options="   -A 127.0.0.1"
staticd_options="-A 127.0.0.1"
bfdd_options="   -A 127.0.0.1"
fabricd_options="-A 127.0.0.1"
vrrpd_options="  -A 127.0.0.1"

# configuration profile
#
#frr_profile="traditional"
#frr_profile="datacenter"

#
# This is the maximum number of FD's that will be available.
# Upon startup this is read by the control files and ulimit
# is called. Uncomment and use a reasonable value for your
# setup if you are expecting a large number of peers in
# say BGP.
#MAX_FDS=1024

# The list of daemons to watch is automatically generated by the init script.
#watchfrr_options=""

# for debugging purposes, you can specify a "wrap" command to start instead
# of starting the daemon directly, e.g. to use valgrind on ospfd:
#   ospfd_wrap="/usr/bin/valgrind"
# or you can use "all_wrap" for all daemons, e.g. to use perf record:
#   all_wrap="/usr/bin/perf record --call-graph -"
# the normal daemon command is added to this at the end.

Save both the frr.conf and daemons files in the same directory, such as /tmp/frr.

Create an external FRR container by running the following command:

$ sudo podman run -d --privileged --network host --rm --ulimit core=-1 --name frr --volume /tmp/frr:/etc/frr quay.io/frrouting/frr:9.1.0

Create the following FRRConfiguration and RouteAdvertisements configurations:

Create a receive_all.yaml file that includes the following content:

Example receive_all.yaml configuration file

apiVersion: frrk8s.metallb.io/v1beta1
kind: FRRConfiguration
metadata:
  name: receive-all
  namespace: openshift-frr-k8s
spec:
  bgp:
    routers:
    - asn: 64512
      neighbors:
      - address: 192.168.111.1
        asn: 64512
        toReceive:
          allowed:
            mode: all

Create a ra.yaml file that includes the following content:

Example ra.yaml configuration file

apiVersion: k8s.ovn.org/v1
kind: RouteAdvertisements
metadata:
  name: default
spec:
  nodeSelector: {}
  frrConfigurationSelector: {}
  networkSelectors:
  - networkSelectionType: DefaultNetwork
  advertisements:
  - "PodNetwork"
  - "EgressIP"

Apply the receive_all.yaml and ra.yaml files by running the following command:
```
$ for f in receive_all.yaml ra.yaml; do oc apply -f $f; done
```

Verification

Verify that the configurations were applied:

Verify that the FRRConfiguration configurations were created by running the following command:

$ oc get frrconfiguration -A

Example output

NAMESPACE           NAME                   AGE
openshift-frr-k8s   ovnk-generated-6lmfb   4h47m
openshift-frr-k8s   ovnk-generated-bhmnm   4h47m
openshift-frr-k8s   ovnk-generated-d2rf5   4h47m
openshift-frr-k8s   ovnk-generated-f958l   4h47m
openshift-frr-k8s   ovnk-generated-gmsmw   4h47m
openshift-frr-k8s   ovnk-generated-kmnqg   4h47m
openshift-frr-k8s   ovnk-generated-wpvgb   4h47m
openshift-frr-k8s   ovnk-generated-xq7v6   4h47m
openshift-frr-k8s   receive-all            4h47m

Verify that the RouteAdvertisements configurations were created by running the following command:
```
$ oc get ra -A
```
Example output
```
NAME      STATUS
default   Accepted
```

Get the external FRR container ID by running the following command:

$ sudo podman ps | grep frr

Example output

22cfc713890e  quay.io/frrouting/frr:9.1.0              /usr/lib/frr/dock...  5 hours ago   Up 5 hours ago               frr

Use the container ID that you obtained in the previous step to check the BGP neighbor and routes in the external FRR container’s vtysh session. Run the following command:

$ sudo podman exec -it <container_id> vtysh -c "show ip bgp"

Example output

BGP table version is 10, local router ID is 192.168.111.1, vrf id 0
Default local pref 100, local AS 64512
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

    Network          Next Hop            Metric LocPrf Weight Path
 *>i10.128.0.0/23    192.168.111.22           0    100      0 i
 *>i10.128.2.0/23    192.168.111.23           0    100      0 i
 *>i10.129.0.0/23    192.168.111.20           0    100      0 i
 *>i10.129.2.0/23    192.168.111.24           0    100      0 i
 *>i10.130.0.0/23    192.168.111.21           0    100      0 i
 *>i10.130.2.0/23    192.168.111.40           0    100      0 i
 *>i10.131.0.0/23    192.168.111.25           0    100      0 i
 *>i10.131.2.0/23    192.168.111.47           0    100      0 i
 *> 192.168.1.0/24   0.0.0.0                  0         32768 i
 *> 192.169.1.1/32   0.0.0.0                  0         32768 i

Find the frr-k8s pod for each cluster node by running the following command:

$ oc -n openshift-frr-k8s get pod -owide

Example output

NAME                                      READY   STATUS    RESTARTS   AGE   IP               NODE                                       NOMINATED NODE   READINESS GATES
frr-k8s-86wmq                             6/6     Running   0          25h   192.168.111.20   master-0                                   <none>           <none>
frr-k8s-h2wl6                             6/6     Running   0          25h   192.168.111.21   master-1                                   <none>           <none>
frr-k8s-jlbgs                             6/6     Running   0          25h   192.168.111.40   node1.example.com   <none>           <none>
frr-k8s-qc6l5                             6/6     Running   0          25h   192.168.111.25   worker-2                                   <none>           <none>
frr-k8s-qtxdc                             6/6     Running   0          25h   192.168.111.47   node2.example.com   <none>           <none>
frr-k8s-s5bxh                             6/6     Running   0          25h   192.168.111.24   worker-1                                   <none>           <none>
frr-k8s-szgj9                             6/6     Running   0          25h   192.168.111.22   master-2                                   <none>           <none>
frr-k8s-webhook-server-6cd8b8d769-kmctw   1/1     Running   0          25h   10.131.2.9       node3.example.com   <none>           <none>
frr-k8s-zwmgh                             6/6     Running   0          25h   192.168.111.23   worker-0                                   <none>           <none>

From the OKD cluster, check BGP routes on the cluster node’s frr-k8s pod in the FRR container by running the following command:
```
$ oc -n openshift-frr-k8s -c frr rsh frr-k8s-86wmq
```

Check the IP routes from the cluster node by running the following command:

sh-5.1# vtysh

Example output

Hello, this is FRRouting (version 8.5.3).
Copyright 1996-2005 Kunihiro Ishiguro, et al.

Check the IP routes by running the following command:

worker-2# show ip bgp

Example output

BGP table version is 10, local router ID is 192.168.111.25, vrf id 0
Default local pref 100, local AS 64512
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

    Network          Next Hop            Metric LocPrf Weight Path
 *>i10.128.0.0/23    192.168.111.22           0    100      0 i
 *>i10.128.2.0/23    192.168.111.23           0    100      0 i
 *>i10.129.0.0/23    192.168.111.20           0    100      0 i
 *>i10.129.2.0/23    192.168.111.24           0    100      0 i
 *>i10.130.0.0/23    192.168.111.21           0    100      0 i
 *>i10.130.2.0/23    192.168.111.40           0    100      0 i
 *> 10.131.0.0/23    0.0.0.0                  0         32768 i
 *>i10.131.2.0/23    192.168.111.47           0    100      0 i
 *>i192.168.1.0/24   192.168.111.1            0    100      0 i
 *>i192.169.1.1/32   192.168.111.1            0    100      0 i

Displayed  10 routes and 10 total paths

From the OKD cluster, debug the node by running the following command:

$ oc debug node/<node_name>

Example output

Temporary namespace openshift-debug-lbtgh is created for debugging node...
Starting pod/worker-2-debug-zrg4v ...
To use host binaries, run `chroot /host`
Pod IP: 192.168.111.25
If you don't see a command prompt, try pressing enter.

Confirm that the BGP routes are being advertised by running the following command:

sh-5.1# ip route show | grep bgp

Example output

10.128.0.0/23 nhid 268 via 192.168.111.22 dev br-ex proto bgp metric 20
10.128.2.0/23 nhid 259 via 192.168.111.23 dev br-ex proto bgp metric 20
10.129.0.0/23 nhid 260 via 192.168.111.20 dev br-ex proto bgp metric 20
10.129.2.0/23 nhid 261 via 192.168.111.24 dev br-ex proto bgp metric 20
10.130.0.0/23 nhid 266 via 192.168.111.21 dev br-ex proto bgp metric 20
10.130.2.0/23 nhid 262 via 192.168.111.40 dev br-ex proto bgp metric 20
10.131.2.0/23 nhid 263 via 192.168.111.47 dev br-ex proto bgp metric 20
192.168.1.0/24 nhid 264 via 192.168.111.1 dev br-ex proto bgp metric 20
192.169.1.1 nhid 264 via 192.168.111.1 dev br-ex proto bgp metric 20