/32 maintenance mode

frr.conf.R0

int net0
  ipv6 nd ra-interval 3
  no ipv6 nd suppress-ra
!

int net1
  ipv6 nd ra-interval 3
  no ipv6 nd suppress-ra
!

router bgp 65000
  bgp router-id 10.255.0.1
  bgp bestpath as-path multipath-relax
  neighbor PEER peer-group
  neighbor PEER remote-as external
  neighbor PEER bfd 4 400 400
  neighbor net1 interface peer-group PEER
  neighbor net2 interface peer-group PEER
  neighbor net3 interface peer-group PEER
  !
  address-family ipv4 unicast
    redistribute connected
  exit-address-family
!

frr.conf.R1

int net0
  ipv6 nd ra-interval 3
  no ipv6 nd suppress-ra
!

int net1
  ipv6 nd ra-interval 3
  no ipv6 nd suppress-ra
!

router bgp 65001
  bgp router-id 10.255.0.2
  bgp bestpath as-path multipath-relax
  neighbor PEER peer-group
  neighbor PEER remote-as external
  neighbor PEER bfd 4 400 400
  neighbor net0 interface peer-group PEER
  !
  address-family ipv4 unicast
    neighbor PEER route-map LB_OUT out
    network 1.1.1.1/32
    network 2.2.2.2/32
    network 3.3.3.3/32
    network 4.4.4.4/32
  exit-address-family
!

route-map LB_OUT permit 5
  match ip address prefix-list lbvip_maint
  # no set as-path prependで、as-path-prependの設定を解除できる
  set as-path prepend 65001 65001 65001 65001
!

route-map LB_OUT permit 10
  match ip address prefix-list lbvip
!

ip prefix-list lbvip permit 1.1.1.1/32
ip prefix-list lbvip permit 2.2.2.2/32
ip prefix-list lbvip permit 3.3.3.3/32
ip prefix-list lbvip permit 4.4.4.4/32

ip prefix-list lbvip_maint permit 1.1.1.1/32
ip prefix-list lbvip_maint permit 2.2.2.2/32
!

frr.conf.R2

int net0
  ipv6 nd ra-interval 3
  no ipv6 nd suppress-ra
!

int net1
  ipv6 nd ra-interval 3
  no ipv6 nd suppress-ra
!

router bgp 65001
  bgp router-id 10.255.0.3
  bgp bestpath as-path multipath-relax
  neighbor PEER peer-group
  neighbor PEER remote-as external
  neighbor PEER bfd 4 400 400
  neighbor net0 interface peer-group PEER
  !
  address-family ipv4 unicast
    neighbor PEER route-map LB_OUT out
    network 1.1.1.1/32
    network 2.2.2.2/32
    network 3.3.3.3/32
    network 4.4.4.4/32
  exit-address-family
!

route-map LB_OUT permit 5
  match ip address prefix-list lbvip_maint
  # no set as-path prependで、as-path-prependの設定を解除できる
  set as-path prepend 65001 65001 65001 65001
!

route-map LB_OUT permit 10
  match ip address prefix-list lbvip
!

ip prefix-list lbvip permit 1.1.1.1/32
ip prefix-list lbvip permit 2.2.2.2/32
ip prefix-list lbvip permit 3.3.3.3/32
ip prefix-list lbvip permit 4.4.4.4/32

ip prefix-list lbvip_maint permit 1.1.1.1/32
ip prefix-list lbvip_maint permit 2.2.2.2/32
!

frr.conf.R3

int net0
  ipv6 nd ra-interval 3
  no ipv6 nd suppress-ra
!

int net1
  ipv6 nd ra-interval 3
  no ipv6 nd suppress-ra
!

router bgp 65001
  bgp router-id 10.255.0.4
  bgp bestpath as-path multipath-relax
  neighbor PEER peer-group
  neighbor PEER remote-as external
  neighbor PEER bfd 4 400 400
  neighbor net0 interface peer-group PEER
  !
  address-family ipv4 unicast
    neighbor PEER route-map LB_OUT out
    network 1.1.1.1/32
    network 2.2.2.2/32
    network 3.3.3.3/32
    network 4.4.4.4/32
  exit-address-family
!

route-map LB_OUT permit 5
  match ip address prefix-list lbvip_maint
  # no set as-path prependで、as-path-prependの設定を解除できる
  set as-path prepend 65001 65001 65001 65001
!

route-map LB_OUT permit 10
  match ip address prefix-list lbvip
!

ip prefix-list lbvip permit 1.1.1.1/32
ip prefix-list lbvip permit 2.2.2.2/32
ip prefix-list lbvip permit 3.3.3.3/32
ip prefix-list lbvip permit 4.4.4.4/32

ip prefix-list lbvip_maint permit 1.1.1.1/32
ip prefix-list lbvip_maint permit 2.2.2.2/32
!

tinet.conf

postinit:
  - cmds:
    - cmd: docker cp frr.conf.R0 R0:/etc/frr/frr.conf
    - cmd: docker cp frr.conf.R1 R1:/etc/frr/frr.conf
    - cmd: docker cp frr.conf.R2 R2:/etc/frr/frr.conf
    - cmd: docker cp frr.conf.R3 R3:/etc/frr/frr.conf
    - cmd: docker exec R0 /usr/lib/frr/frr start
    - cmd: docker exec R1 /usr/lib/frr/frr start
    - cmd: docker exec R2 /usr/lib/frr/frr start
    - cmd: docker exec R3 /usr/lib/frr/frr start

nodes:
  - name: S0
    image: slankdev/frr
    interfaces:
      - { name: net0, type: direct, args: R0#net0 }

  - name: R0
    image: slankdev/frr
    sysctls:
      - sysctl: net.ipv4.ip_forward=1
      - sysctl: net.ipv4.conf.all.rp_filter=0
      - sysctl: net.ipv4.conf.lo.rp_filter=0
      - sysctl: net.ipv6.conf.all.disable_ipv6=0
      - sysctl: net.ipv6.conf.all.forwarding=1
      - sysctl: net.ipv6.conf.all.forwarding=1
      - sysctl: net.ipv4.fib_multipath_hash_policy=1
    interfaces:
      - { name: net0, type: direct, args: S0#net0 }
      - { name: net1, type: direct, args: R1#net0 }
      - { name: net2, type: direct, args: R2#net0 }
      - { name: net3, type: direct, args: R3#net0 }

  - name: R1
    image: slankdev/frr
    sysctls:
      - sysctl: net.ipv4.ip_forward=1
      - sysctl: net.ipv4.conf.all.rp_filter=0
      - sysctl: net.ipv4.conf.lo.rp_filter=0
      - sysctl: net.ipv6.conf.all.disable_ipv6=0
      - sysctl: net.ipv6.conf.all.forwarding=1
      - sysctl: net.ipv6.conf.all.forwarding=1
      - sysctl: net.ipv4.fib_multipath_hash_policy=1
    interfaces:
      - { name: net0, type: direct, args: R0#net1 }
      - { name: net1, type: direct, args: S1#net0 }
  - name: S1
    image: slankdev/frr
    interfaces:
      - { name: net0, type: direct, args: R1#net1 }

  - name: R2
    image: slankdev/frr
    sysctls:
      - sysctl: net.ipv4.ip_forward=1
      - sysctl: net.ipv4.conf.all.rp_filter=0
      - sysctl: net.ipv4.conf.lo.rp_filter=0
      - sysctl: net.ipv6.conf.all.disable_ipv6=0
      - sysctl: net.ipv6.conf.all.forwarding=1
      - sysctl: net.ipv6.conf.all.forwarding=1
      - sysctl: net.ipv4.fib_multipath_hash_policy=1
    interfaces:
      - { name: net0, type: direct, args: R0#net2 }
      - { name: net1, type: direct, args: S2#net0 }
  - name: S2
    image: slankdev/frr
    interfaces:
      - { name: net0, type: direct, args: R2#net1 }

  - name: R3
    image: slankdev/frr
    sysctls:
      - sysctl: net.ipv4.ip_forward=1
      - sysctl: net.ipv4.conf.all.rp_filter=0
      - sysctl: net.ipv4.conf.lo.rp_filter=0
      - sysctl: net.ipv6.conf.all.disable_ipv6=0
      - sysctl: net.ipv6.conf.all.forwarding=1
      - sysctl: net.ipv6.conf.all.forwarding=1
      - sysctl: net.ipv4.fib_multipath_hash_policy=1
    interfaces:
      - { name: net0, type: direct, args: R0#net3 }
      - { name: net1, type: direct, args: S3#net0 }
  - name: S3
    image: slankdev/frr
    interfaces:
      - { name: net0, type: direct, args: R3#net1 }

node_configs:
  - name: S0
    cmds:
      - cmd: ip addr add 10.1.0.2/24 dev net0
      - cmd: ip route replace default via 10.1.0.1
  - name: R0
    cmds:
      - cmd: ip addr add 10.255.0.1/32 dev lo
      - cmd: ip addr add 10.0.0.1/24 dev net0
      - cmd: ip addr add 10.1.0.10/24 dev net1
      - cmd: ip addr add 10.1.0.20/24 dev net2
      - cmd: ip addr add 10.1.0.30/24 dev net3

  - name: R1
    cmds:
      - cmd: ip addr add 10.255.0.2/32 dev lo
      - cmd: ip addr add 10.0.0.11/24 dev net0
      - cmd: ip addr add 192.168.0.1/24 dev net1
      # VIP
      - cmd: ip addr add 1.1.1.1/32 dev lo
      - cmd: ip addr add 2.2.2.2/32 dev lo
      - cmd: ip addr add 3.3.3.3/32 dev lo
      - cmd: ip addr add 4.4.4.4/32 dev lo
      - cmd: ip route replace default via 10.0.0.1
  - name: S1
    cmds:
      - cmd: ip addr add 192.168.0.2/24 dev net0
      - cmd: ip route replace default via 192.168.0.1
      - cmd: sh -c "echo S1 > index.html"
      - cmd: nohup python3 -m http.server 80 &

  - name: R2
    cmds:
      - cmd: ip addr add 10.255.0.3/32 dev lo
      - cmd: ip addr add 10.0.0.21/24 dev net0
      - cmd: ip addr add 192.168.0.1/24 dev net1
      # VIP
      - cmd: ip addr add 1.1.1.1/32 dev lo
      - cmd: ip addr add 2.2.2.2/32 dev lo
      - cmd: ip addr add 3.3.3.3/32 dev lo
      - cmd: ip addr add 4.4.4.4/32 dev lo
      - cmd: ip route replace default via 10.0.0.1
  - name: S2
    cmds:
      - cmd: ip addr add 192.168.0.2/24 dev net0
      - cmd: ip route replace default via 192.168.0.1
      - cmd: sh -c "echo S2 > index.html"
      - cmd: nohup python3 -m http.server 80 &

  - name: R3
    cmds:
      - cmd: ip addr add 10.255.0.4/32 dev lo
      - cmd: ip addr add 10.0.0.31/24 dev net0
      - cmd: ip addr add 192.168.0.1/24 dev net1
      # VIP
      - cmd: ip addr add 1.1.1.1/32 dev lo
      - cmd: ip addr add 2.2.2.2/32 dev lo
      - cmd: ip addr add 3.3.3.3/32 dev lo
      - cmd: ip addr add 4.4.4.4/32 dev lo
      - cmd: ip route replace default via 10.0.0.1
  - name: S3
    cmds:
      - cmd: ip addr add 192.168.0.2/24 dev net0
      - cmd: ip route replace default via 192.168.0.1
      - cmd: sh -c "echo S3 > index.html"
      - cmd: nohup python3 -m http.server 80 &