Floating IP addresses

Binero cloud provides two ways to use public IP addresses , using directly attached IP addresses or Floating IP addresses.

Directly attached IP addresses is a public IP addresses assigned directly on the port of an instances. This means that when list the IP address in your operating system you would see the public IP address assigned to the network interface.

When using a floating IP, the result would instead be the IP from the subnet that you assigned to the instance.

The floating IP is then diverted to and from the instance through the router that performs NAT.

Floating IP addresses are, as the name implies, not tied to a single instance but mapped to a port (which has an IP from a subnet).

They are floating in the sense that you can move them between instances with zero configuration required on the instance.

A floating IP is local to and owned by the project, even if its not actively used on any instance it’s still allocated to you.

Using a floating IP makes the IP address portable within the platform and if you have third party dependencies such as using the IP address in remote firewall configurations it’s the preferred way to use public IP addressing as you keep the floating IP until you delete the allocation.

Floating IP addresses require a router as its the router that does the mapping. On a technical level the router uses NAT in both directions:

  • Incoming traffic from the internet would be a destination NAT (DNAT) to the subnet IP from the floating.

  • Outgoing traffic to the internet would be a source NAT (SNAT) to appear as if originating from the floating IP.

Key differences to directly attached IP addresses

  • A floating IP is not visible (or indeed configured) on an instance. This means any application that use a floating IP, will have to work with NAT (which the majority of applications do).

  • A floating IP uses a router where directly attached IP addresses does not giving a small performance penalty that is negligible and insignificant.

  • Some features in the platform require floating IP addresses and will not work with directly attached IP addresses such as the load balancer service.

Setting up a floating IP

You assign floating IP addresses to instances (and in particular, to a subnet IP on an instance). Depending on what tool used, you might need to add floating IP addresses to the project first.

Important

When assigning a new floating IP, make sure you assign one from the same availability zone that the instance or service you want to use it on.

Note

A floating IP is a service and a incurs a cost per IP address allocated to your project. If you have floating IP addresses no longer used, make sure to remove them to release the IP back to the pool.

Note

If you have many internal IP addresses on an instance, you need to assign the floating IP to the internal IP of the port that is the default route for the instance. If you are unsure, assign the floating IP and if it does not work, remove it and try another internal IP.

Adding floating IP addresses using the cloud management portal

To assign a floating IP to an instance by using the Cloud management portal

  • Press Network and then Floating IPs in the sidebar menu.

  • Verify that you have a free floating IP. It should say Down under the IP.

  • If not, assign a new IP by clicking the + (plus) symbol in the lower right corner.

    • Under Choice of network, select a network from the same availability zone as the instance you want to assign the IP to.

    • Optionally give the IP a description.

    • Press Create.

    • Press Compute and then Instances in the sidebar menu.

  • Press the instance that you want to add a floating IP to.

  • Press the more icon (looks like three small dots) in the top right.

  • Press Add floating IP.

  • Select your new (or old, if you had one already) IP under fixed IPs.

  • Under Available ports, select the internal IP to map the floating IP to.

  • Press Associate IP.

  • Your IP should now be visible under the Networking tab. Remember that you might need to add security groups to the instance if you cannot reach it.

Adding floating IP addresses using OpenStack Horizon

To assign a floating IP to an instance by using the OpenStack Horizon

  • Under Project, click Network and then Floating IPs in the sidebar menu.

  • Verify that you have a free floating IP. It should say - under the column mapped fixed IP address.

  • If not, assign a new IP by clicking the + (plus) symbol in the lower right corner.

    • Press Allocate IP to project in the top right corner.

    • Under Pool, select a network from the same availability zone as the instance you want to assign the IP to.

    • Optionally give the IP a description.

    • Press Allocate IP.

  • Under Project, click Compute and then Instances in the sidebar menu.

  • In the dropdown menu to the far right of the line corresponding to the instance you want to add the floating IP to, press Associate floating IP.

  • Select your new (or old, if you had one already) IP under IP Address.

  • Under Ports to be associated, select the internal IP to map the floating IP to.

  • Press Associate

  • Your IP should now be visible under the IP address column. Remember that you might need to add security groups to the instance if you cannot reach it.

Adding a floating IP using OpenStack terminal client

To assign a floating IP to an instance by using the OpenStack Terminal Client

  • Run this command: openstack floating ip list

  • If there is an IP that says none under the fixed IP address column then that’s available.

    • We recommend also figuring out if the floating IP is from the right availability zone, you can do this by running openstack network show [ID] where ID is the UUID from the Floating Network column in the previous command. Its important that you use a floating IP from the same availability zone.

  • If there was no available IP, assign one to the project:

    • Run this command: openstack network list --external. Note the name of the network that is in the availability zone that you want to use the floating IP (for example europe-se-1-1a-net0).

    • Run this command: openstack floating ip create [NETWORK NAME], replacing [NETWORK NAME] with the name of the network from the previous step.

  • Run this command: openstack floating ip list, note the new IP address.

  • Run this command: openstack server list, note the name of the instance you want to assign the floating IP to.

  • Run this command: openstack server show [NAME], replacing [NAME] with the name of the server from previous step. Note which address from the addresses field you want to connect the floating IP to.

  • Run this command: openstack server add floating ip --fixed-ip-address [INTERNAL IP] [INSTANCE NAME] [FLOATING IP], replacing [INTERNAL IP] with the instances IP from the previous step, [INSTANCE NAME] with the name of the instance and [FLOATING IP] with whichever floating IP you added as per earlier step.

  • Your IP should now be visible under the addresses field when running the command openstack server show [NAME]. Remember that you might need to add security groups to the instance if you cannot reach it.

See also