Devstack : how to access instances by there floating IPs from a no-openstack computer ?

asked 2018-09-20 09:56:54 -0600

Hi Openstack community, :)

I got a networking issue with my "all-in-one" Openstack.

My Setup is :

  - 1 node "Openstack" installed in "all-in-one" with devstack : IP ens3 :, and a "br-ex" bridge
  - 1 node "debug": IP ens3: 
  - 1 Instance "ubuntu" : Floatting IP :, local IP:

"Openstack" and "debug" are on the same network.

I used Devstack to install Openstack with "default" settings.

My openstack is working well and i can access my instances from my Openstack "all-in-one" Node by using their floatting IPs.

My instance "ubuntu" can access the node "debug" and "internet". In fact, my instance "ubuntu" can access all what i want :)

Therefore, my node "debug" can't access my instance "ubuntu"...

IP_Fowarding is activated on node "Openstack"

My routes on node "debug" are :

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         UG    0      0        0 ens3        *        U     0      0        0 ens3   UG    0      0        0 ens3

I used Tshark to follow the traffic and i noticed that my ping do that :

"debug" -> "ens3 openstack" -> "br-ex openstack" -> "instance ubuntu" -> "br-ex openstack" -> "ens3 openstack" -> "fail"

Under are the dumps off all my interfaces :

"ens3 - debug" (no reply) :

 1.045048378 →   ICMP 98 Echo (ping) request  id=0x0515, seq=1577/10502, ttl=64

"ens3 - openstack" (i got reply):

1.661209325 →   ICMP 98 Echo (ping) request  id=0x0515, seq=1691/39686, ttl=64
9 1.661740772 →     ICMP 98 Echo (ping) reply    id=0x0515, seq=1691/39686, ttl=62

"br-ex - openstack" (i got reply):

1.007990472 →   ICMP 98 Echo (ping) request  id=0x0515, seq=1767/59142, ttl=63
4 1.008212533 →     ICMP 98 Echo (ping) reply    id=0x0515, seq=1767/59142, ttl=63

"ens3 - from my Instance ubuntu" (i got reply):

0.000000000 →   ICMP 98 Echo (ping) request  id=0x0515, seq=1841/12551, ttl=62
2 0.000034847 →     ICMP 98 Echo (ping) reply    id=0x0515, seq=1841/12551, ttl=64

Does someone has any idea of that is happening ?

Thx for help,

Have a good day :)

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