Floating IPs¶

There are two main ways to use public IP-space (globally accessible IP-space) in Binero cloud, directly attached IPs and Floating-ips. Directly attached IPs are assigned directly on the instances network interface (port). This means that when you run for instance ip addr show or ipconfig /all inside an instance operating system, you would (with a directly attached IP) see the public IP assigned on the interface. When using a floating IP, the result would instead be the ip from the private subnet that you assigned to the instance. The floating IP is then redirected (by using DNAT or SNAT) to and from the instance using the router.

Floating IPs are, as the name implies, not tied to a single instance but mapped to another IP (usually an IP that comes from a private subnet). They are “floating” in the sense that they are easily movable between instances as zero configuration is needed in the actual instance. A floating IP is local to a project and is owned by the project, even if its not actively used on an instance. This is because a public IP-address could have various dependencies (in firewalls, etc) on the internet and users normally want to keep their IPs. Using a floating IP makes the IP concept portable (within the platform).

Floating IPs require a router as its the router that does the mapping. On a technical level, NAT is used and its used in both directions:

Incoming traffic from the internt would be destination NAT:ed (DNAT:ed) to the private subnet IP from the floating.
Outgoing traffic to the internet would be source NAT:ed (SNAT:ed) to appear as if originating from the floating IP.

Note

Floating IPs are only meant to be used to reach the internet (or, potentially when using more then a single project, or namespace - a floating IP would provide access between them). This is a big benefit as easier to manage internal traffic, even if its routed, if it always originates from its true IP.

Key differences to directly attached IPs¶

A floating IP is not visible (or indeed configured) on an instance. This means any application that is to use a floating IP, will have to work with NAT (which the vast amount of applications do).
Since a router is used and translation to VXLAN happens earlier than in the case of directly attached IPs, a floating IP would have a small performance penalty. This is very insignificant.
Some features in the platform require floating IPs and will not work with directly attached IPs.

Setting up a floating IP¶

Floating IPs are assigned to instances (and in particular, to a private subnet IP on an instance). Depending on what tool is used, floating IPs may need to be allocated 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 product. There is a (small) cost associated with allocating the IP (as no one else can then use it) to your project. If you have floating IPs that you no longer need, make sure to de-allocate them back to the pool.

Note

If you have several internal IPs on an instance, you need to assign the floating IP to the internal IP that has the default route. If you are unsure, just try and if the floating IP does not work, remove it and try another internal IP.

Adding floating IPs using the cloud management portal¶

To assign a floating IP to an instance using the Cloud management portal, follow these steps:

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 “+” 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 IPs using OpenStack Horizon¶

To assign a floating IP to an instance using the OpenStack Horizon, follow these steps:

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 “+” 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 drop-down 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 using the OpenStack terminal client, follow these steps:

Run this command: openstack floating ip list
If there is an IP that says “none” under the “fixed ip address” column then thats available. We recommend also figuring out if the floating IP is from the right availability zone, this can be done 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 instance “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 that was assigned.
Run this commadn: 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.