Manage IP addresses
Each instance can have a private, or fixed, IP address and a
public, or floating, one.
Private IP addresses are used for communication between
instances, and public ones are used for communication with the
outside world.
When you launch an instance, it is automatically assigned a
private IP address that stays the same until you explicitly
terminate the instance. Rebooting an instance has no effect on
the private IP address.
A pool of floating IPs, configured by the cloud operator, is
available in OpenStack Compute.
You can allocate a certain number of these to a project: The
maximum number of floating IP addresses per project is defined
by the quota.
You can add a floating IP address from this set to an
instance of the project. Floating IP addresses can be
dynamically disassociated and associated with other instances
of the same project at any time.
Before you can assign a floating IP address to an instance,
you first must allocate floating IPs to a project. After
floating IP addresses have been allocated to the current
project, you can assign them to running instances.
You can assign a floating IP address to one instance at a
time.
List floating IP address information
To list all floating IP addresses:
$ nova floating-ip-bulk-list
+------------+---------------+---------------+--------+-----------+
| project_id | address | instance_uuid | pool | interface |
+------------+---------------+---------------+--------+-----------+
| None | 172.24.4.225 | None | public | eth0 |
| None | 172.24.4.226 | None | public | eth0 |
| None | 172.24.4.227 | None | public | eth0 |
| None | 172.24.4.228 | None | public | eth0 |
| None | 172.24.4.229 | None | public | eth0 |
| None | 172.24.4.230 | None | public | eth0 |
| None | 172.24.4.231 | None | public | eth0 |
| None | 172.24.4.232 | None | public | eth0 |
| None | 172.24.4.233 | None | public | eth0 |
| None | 172.24.4.234 | None | public | eth0 |
| None | 172.24.4.235 | None | public | eth0 |
| None | 172.24.4.236 | None | public | eth0 |
| None | 172.24.4.237 | None | public | eth0 |
| None | 172.24.4.238 | None | public | eth0 |
| None | 192.168.253.1 | None | test | eth0 |
| None | 192.168.253.2 | None | test | eth0 |
| None | 192.168.253.3 | None | test | eth0 |
| None | 192.168.253.4 | None | test | eth0 |
| None | 192.168.253.5 | None | test | eth0 |
| None | 192.168.253.6 | None | test | eth0 |
+------------+---------------+---------------+--------+-----------+
To list all pools that provide floating IP
addresses:
$ nova floating-ip-pool-list
+--------+
| name |
+--------+
| public |
| test |
+--------+
Assign floating IP addresses
You can assign floating IP addresses to a project or an
instance.
Allocate a floating IP address to the current
project. If more than one IP address pool is
available, you can specify the pool from which to
allocate the IP address. This example specifies
the public pool:
$ nova floating-ip-create public
+--------------+-------------+----------+--------+
| Ip | Instance Id | Fixed Ip | Pool |
+--------------+-------------+----------+--------+
| 172.24.4.225 | None | None | public |
+--------------+-------------+----------+--------+
To release a floating IP address from the
current project:
$ nova floating-ip-delete FLOATING_IP
The IP address is returned to the pool of IP
addresses that are available for all projects. If
an IP address is assigned to a running instance,
it is disassociated from the instance.
To associate an IP address with an instance, at
least one floating IP address must be allocated to
the current project.
To assign a floating IP address to an
instance:
$ nova add-floating-ip INSTANCE_NAME_OR_ID FLOATING_IP
After you assign the IP address and configure
security group rules for the instance, the
instance is publicly available at the floating IP
address.
To remove a floating IP address from an
instance, specify the same arguments that
you used to assign the IP address:
$ nova remove-floating-ip INSTANCE_NAME_OR_ID FLOATING_IP