You want to assign an OpenStack Instance a floating IP address from your public network?. When an virtual instance is created in OpenStack, it is automatically assigned a fixed IP in the network to which it is assigned . This IP address is permanently associated with the instance until the instance is terminated.
OpenStack also gives you an option to use floating IP address created from external network’s subnet. A “floating IP” is an IP address that can be dynamically added to a running virtual instance. The floating IP association can be modified at any time regardless of the state of the instance in question.
Here is the process you’ll use to create a floating IP Address in OpenStack and assign it to an instance.
Step 1: Create an Instance on private network
First create a Virtual instance from OpenStack horizon dashboard or CLI in a private network.
I have two networks – public and private. The instance will be created on the private subnet.
$ openstack network list
+--------------------------------------+---------+--------------------------------------+
| ID | Name | Subnets |
+--------------------------------------+---------+--------------------------------------+
| b94431cb-08cf-42ea-be61-55f5cf459276 | private | 57601b99-ea64-41a8-a927-fbd591ae3f2b |
| f7ccac3b-73eb-49bf-a4ec-af750216b819 | public | 7536e4a8-6aa8-45dc-aed6-1a98afcf416d |
+--------------------------------------+---------+--------------------------------------+
$ openstack subnet list
+--------------------------------------+----------------+--------------------------------------+----------------+
| ID | Name | Network | Subnet |
+--------------------------------------+----------------+--------------------------------------+----------------+
| 57601b99-ea64-41a8-a927-fbd591ae3f2b | private_subnet | b94431cb-08cf-42ea-be61-55f5cf459276 | 10.10.1.0/24 |
| 7536e4a8-6aa8-45dc-aed6-1a98afcf416d | public_subnet | f7ccac3b-73eb-49bf-a4ec-af750216b819 | 96.220.99.8/29 |
+--------------------------------------+----------------+--------------------------------------+----------------+I’ll create an Instance called testfloating from Ubuntu 22.04 template.
openstack server create \
--image Ubuntu-22 \
--key-name jmutai \
--flavor m1.small \
--security-group 7fffea2a-b756-473a-a13a-219dd0f1913a \
--network private \
testfloatingVM creation can be done from your OpenStack Dashboard.
After creation, confirm the server is running.
$ openstack server show testfloating
+-------------------------------------+----------------------------------------------------------+
| Field | Value |
+-------------------------------------+----------------------------------------------------------+
| OS-DCF:diskConfig | MANUAL |
| OS-EXT-AZ:availability_zone | nova |
| OS-EXT-SRV-ATTR:host | server1.computingforgeeks.com |
| OS-EXT-SRV-ATTR:hypervisor_hostname | server1.computingforgeeks.com |
| OS-EXT-SRV-ATTR:instance_name | instance-0000002e |
| OS-EXT-STS:power_state | Running |
| OS-EXT-STS:task_state | None |
| OS-EXT-STS:vm_state | active |
| OS-SRV-USG:launched_at | 2019-09-22T07:13:40.000000 |
| OS-SRV-USG:terminated_at | None |
| accessIPv4 | |
| accessIPv6 | |
| addresses | private=10.10.1.185 |
| config_drive | |
| created | 2019-09-22T07:13:35Z |
| flavor | m1.small (1) |
| hostId | da0a05ef20a03e97f301563551bab9b669ef04adbce232d941519946 |
| id | a731e48d-d3b5-4fcf-8fc7-f8f280b51b44 |
| image | Ubuntu-18 (7bd462ad-cc11-4d89-8b85-9aab0cfe114b) |
| key_name | jmutai |
| name | testfloating |
| progress | 0 |
| project_id | 06bcc3c56ab1489282b65681e782d7f6 |
| properties | |
| security_groups | name='default' |
| status | ACTIVE |
| updated | 2019-09-22T07:13:40Z |
| user_id | 336acbb7421f47f8be4891eabf0c9cc8 |
| volumes_attached | |
+-------------------------------------+----------------------------------------------------------+
Step 2: Reserve a floating IP address from external network pool.
You need to reserve a floating IP address from external network subnet pool. This can be done from the web dashboard or CLI.
From CLI:
openstack floating ip create --project admin --subnet public_subnet publicWhere:
- admin is the Owner’s project. Created floating IP will be available for association in this project.
- public_subnet is the name of the subnet on which you want to create the floating IP.
- public is the name of the network to allocate floating IP from.
See all options by typing:
$ openstack floating ip create --helpFrom Dashboard:
Log in to the dashboard as a user that has the Member role. The navigate to:
Project > Network > Floating IPs
Click on the “ALLOCATE IP TO PROJECT” button. On the new window, select a Pool, provide description and click on “ALLOCATE IP“.
Step 3: Associate the reserved floating IP address with the instance.
Once the floating IP address is reserved, we can associate it with an instance.
From CLI:
$ openstack floating ip list
$ openstack server list
$ openstack server add floating ip From dashboard:
Option 1: Project > Network > Floating IPs > Select IP > Associate
Pick a floating IP, an instance and a port to associate.
Option 2: Project > Compute > Instances
Under actions, select “ASSOCIATE FLOATING IP”
Select an IP address and click “ASSOCIATE”.
Disassociate a floating IP Address
To disassociate IP address, use either of below methods:
CLI:
$ openstack server remove floating ip Dashboard:
- Project > Network > Floating IPs > DISASSOCIATE
- Project > Compute > Instances > Actions > DISASSOCIATE FLOATING IP
That’s all on how to associate a floating IP address to an instance running on OpenStack.
