Discussion: Child prefix listing in container prefixes

[Zanthras]

An improvement that I found helpful was changing the behavior of a prefix of type container set to the global vrf, to show child prefixes from all vrf's. While this makes alot of sense for my environment, I'm not sure how applicable or useful that would be to others. Anyone have thoughts on it?

[malaiam]

Hey!

I just hit this one too. I think this makes sense for all environments where VRF use is prevalent. Maybe not so useful in a DC environment, but for infrastructure / customer address management is definitely needed. I just did some tests on http://netbox-demo01.packetlife.net/ipam/prefixes/ and I found it a bit confusing at start until I figured how it works.

If the current behavior is preferred by some, maybe a knob toggling between the two could be implemented. I think this would be useful also on the main prefixes page, to show prefixes from all VRFs until a VRF is selected via the filters on the side.

Another thing is that in the current behavior, the IP addresses are listed from all VRFs even if child prefixes are not - this is a bit inconsistent.

Thanks,
Marius

[jeremystretch]

IMO viewing a specific prefix instils some context around what you want to see. It may or may not make sense to display child prefixes from other VRFs, depending on your particular environment.

As an alternative, I suggest searching by parent prefix to show all children regardless of VRF. For example, if I want to find all children of 192.0.2.0/24, I can go to the prefixes list, enter "192.0.2.0/24" in the "search within" field, and check "expand hierarchy" at the bottom. This will return a hierarchy showing all children.

Another thing is that in the current behavior, the IP addresses are listed from all VRFs even if child prefixes are not - this is a bit inconsistent.

Opened #397 for this.

[Zanthras]

I agree that a specific prefix + vrf does indicate you want to see specific information. I think the more concise summary of my request is a way to say vrf "all" for a prefix. That way its up to the end user to determine where it is or isnt the correct use case.

[malaiam]

I still think all child prefixes, from all VRFs, should be shown, especially if the current prefix is in the global and not in a specific VRF.

Let's say that I have a prefix that is an "allocation" for some purpose - e.g. infrastructure, so it will have some child prefixes. And those child prefixes will belong to different VRFs, e.g. some in management, some in voice, etc. Then I want to go the parent prefix and make another assigment, doesn't matter in which VRF. How do I do that in a quick way so I don't make duplicate assignments?

[jeremystretch]

It seems like it might make sense to show all children (regardless of VRF) only for prefixes which are in the global table. Does that make sense?

[malaiam]

It does and it would probably work OK for me in most cases, but I don't see why limit it to the global VRF, besides principles. Corner cases might still allow for unwanted duplicate assignment, if the parent prefix is not in the global for some reason. I still believe displaying child prefixes from all VRFs, based on a global user setting if wanted, is a less error prone approach.
Just argumenting for a better IPAM here, otherwise I think you did a very good job so far!

[jeremystretch]

I don't see why limit it to the global VRF

Suppose you use 192.168.0.0/16 for each customer within their own VRF. You don't want customer A's 192.168.0.0/16 showing children in customer B's VRF. Doing so would defeat the purpose of using a VRF.

[malaiam]

Yes, that's a valid example, so a way to see only the specific VRF prefixes should exist.

But I still think limiting for just the global to see all child prefixes, without any option for the user to change that, would open for unwanted behavior - one case is the corner case example above, when a parent prefix might be in a VRF by mistake, and another could be that some customer's IP plan overlaps with some global prefix, and hence the user seeing customer prefixes when he/she doesn't want to.

I still think the best is to allow the user to chose what he wants to see. Maybe the "knob" idea is not the best in this case. What I think the behavior should be is that in the main prefix list all prefixes should be shown (not just global) if the "All" VRF is chosen in the drop-down on the side, and probably a similar drop-down should be shown on the prefix specific page, with the current VRF selected by default if you want to.

[DanSheps]

Just to add onto this, Global VRF would be where I would see this being used the most, but not always. Would this be something that you could add a toggle onto the individual global VRF to either contain all child prefixes regardless of VRF or not to.

[jeremystretch]

9f3647c tweaks the prefix display to now include children from all VRFs if the parent is in the global table.