Manage IP addresses
Each instance has a private, fixed IP address and can also have a public, or floating,
address. Private IP addresses are used for communication between instances, and public
addresses are used for communication with networks outside the cloud, including the
Internet.
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 IP addresses, configured by the cloud administrator, is available in
OpenStack Compute. The project quota defines the maximum number of floating IP addresses
that you can allocate to the project. After you allocate a floating IP address to a project,
you can:
Associate the floating IP address with an instance of the project. Only one
floating IP address can be allocated to an instance at any given time.
Disassociate a floating IP address from an instance in the project.
Delete a floating IP from the project; deleting a floating IP automatically
deletes that IP's associations.
Use the nova floating-ip-* commands to manage floating IP
addresses.
List floating IP address information
To list all pools that provide floating IP addresses, run:
$ nova floating-ip-pool-list
+--------+
| name |
+--------+
| public |
| test |
+--------+
If this list is empty, the cloud administrator must configure a pool of floating IP
addresses.
To list all floating IP addresses that are allocated to the current project, run:
$ nova floating-ip-list
+--------------+--------------------------------------+----------+--------+
| Ip | Instance Id | Fixed Ip | Pool |
+--------------+--------------------------------------+----------+--------+
| 172.24.4.225 | 4a60ff6a-7a3c-49d7-9515-86ae501044c6 | 10.0.0.2 | public |
| 172.24.4.226 | None | None | public |
+--------------+--------------------------------------+----------+--------+
For each floating IP address that is allocated to the current project, the
command outputs the floating IP address, the ID for the instance to which the
floating IP address is assigned, the associated fixed IP address, and the pool
from which the floating IP address was allocated.
Associate floating IP addresses
You can assign a floating IP address to a project and to an instance.
Run the following command to allocate a floating IP address to the current
project. By default, the floating IP address is allocated from the
public pool. The command outputs the allocated IP
address.
$ nova floating-ip-create
+--------------+-------------+----------+--------+
| Ip | Instance Id | Fixed Ip | Pool |
+--------------+-------------+----------+--------+
| 172.24.4.225 | None | None | public |
+--------------+-------------+----------+--------+
If more than one IP address pool is available, you can specify the pool from which to allocate
the IP address, using the pool's name. For example, to allocate a floating
IP address from the test pool, run:
$ nova floating-ip-create test
List all project instances with which a floating IP address could be
associated:
$ nova list
+--------------------------------------+------+---------+------------+-------------+------------------+
| ID | Name | Status | Task State | Power State | Networks |
+--------------------------------------+------+---------+------------+-------------+------------------+
| d5c854f9-d3e5-4fce-94d9-3d9f9f8f2987 | VM1 | ACTIVE | - | Running | private=10.0.0.3 |
| 42290b01-0968-4313-831f-3b489a63433f | VM2 | SHUTOFF | - | Shutdown | private=10.0.0.4 |
+--------------------------------------+------+---------+------------+-------------+------------------+
Associate an IP address with an instance in the project, as follows:
$ nova floating-ip-associate INSTANCE_NAME_OR_ID FLOATING_IP_ADDRESS
For example:
$ nova floating-ip-associate VM1 172.24.4.225
Notice that the instance is now associated with two IP addresses:
$ nova list
+--------------------------------------+------+---------+------------+-------------+--------------------------------+
| ID | Name | Status | Task State | Power State | Networks |
+--------------------------------------+------+---------+------------+-------------+--------------------------------+
| d5c854f9-d3e5-4fce-94d9-3d9f9f8f2987 | VM1 | ACTIVE | - | Running | private=10.0.0.3, 172.24.4.225 |
| 42290b01-0968-4313-831f-3b489a63433f | VM2 | SHUTOFF | - | Shutdown | private=10.0.0.4 |
+--------------------------------------+------+---------+------------+-------------+--------------------------------+
After you associate the IP address and configure security group rules for the instance, the instance is
publicly available at the floating IP address.
If an instance is connected to multiple networks, you can associate a floating IP
address with a specific fixed IP address using the optional
--fixed-address parameter:
$ nova floating-ip-associate --fixed-address FIXED_IP_ADDRESS INSTANCE_NAME_OR_ID FLOATING_IP_ADDRESS
Disassociate floating IP addresses
Release a floating IP address from an instance, as follows:
$ nova floating-ip-disassociate INSTANCE_NAME_OR_ID FLOATING_IP_ADDRESS
Release the floating IP address from the current project, as follows:
$ nova floating-ip-delete FLOATING_IP_ADDRESS
The IP address is returned to the pool of IP addresses that is available for
all projects. If the IP address is still associated with a running instance, it
is automatically disassociated from that instance.