Unable to connect VM to a specific subnet

[Yair Fried]

VM can only connected (on creation or later) to a network and not to a specific subnet on that network.
Same goes for port - you cannot create a port on a specific subnet in a network.

This is inconsistent with router-interface-add which targets a specific subnet instead of network.

It also greatly limits the user's ability to manage VMs in his own network

port and VM creation should allow user to target a specific subnet.

[Eugene Nikanorov (enikanorov)]

On the neutron side - it is possible. You need to specify "fixed_ip" for the port.
Fixed ip is a list of {ip_address, subnet_id} dicts. Ip address for fixed_ip may be omitted and then subnet_id will be used to allocate ip address from the appropriate subnet.

[Yair Fried (yfried)]

Didn't know about using "fixed ip" to choose subnet. I still think the API/CLI should support subnet name/id same as choosing network.
We are using objects by name, then it should be possible to keep referring them the same way

[Yair Fried (yfried)]

name = name/id

[Yair Fried (yfried)]

OK, so I see the port thing was, indeed, invalid.
Nova doesn't accept the same syntax.
You could work around it by creating the port first and then attaching the VM to the port, but that seems like a bad practice

[Thang Pham (thang-pham)]

There is already a blueprint for this: https://blueprints.launchpad.net/nova/+spec/selecting-subnet-when-creating-vm

[Markus Zoeller (markus_z) (mzoeller)]

This wishlist bug has been open a year without any activity. I'm going to move it to "Opinion / Wishlist", which is an easily-obtainable queue of older requests that have come on.

In case you want to work on that, consider writing a blueprints [1] and spec [2]. I'll recommend to read [3] if not yet done. The effort to implement the requested feature is then driven only by the blueprint (and spec).

References:
[1] https://blueprints.launchpad.net/nova/
[2] https://github.com/openstack/nova-specs
[3] https://wiki.openstack.org/wiki/Blueprints