How do drivers decide the ethX name?

[shettyg]

Currently it is expected that driver.CreateEndpoint() returns back the sandbox.info structure that needs to include ip, gateway, veth_inside and veth_outside information. (Where veth_inside is "The name that will be assigned to the interface once moved inside a network namespace.")

As I see it, the driver cannot return back that information because it does not know how many other endpoints will be added to the container in question. What is the thought process of the designers here?

[mrjana]

@shettyg Was busy integrating libnetwork with docker hence the delay in answering some of your earlier questions. Getting back to this question, the interface SrcName, DstName being present as part of the return value of the CreateEndpoint is an artifact of an earlier design where endpoint was a local resource and a container joined it during CreateEndpoint. With the goal of Endpoint being a service abstraction and hence a universal resource, it makes no more sense to keep interface names as part of information returned during CreateEndpoint. The IP addresses still will remain as part of CreateEndpont info. But expect a few adjustments in what needs to be returned during endpoint create and join which will hopefully clarify all these questions. I will probably push a PR tomorrow to fix this. Please take a look and comment.

[tomdee]

@mrjana Any update on this? This sounds like quite a significant change to the API. If you're not ready to push code for it, could you at least update the design doc (on a branch)?

[mrjana]

@tomdee I am getting back to working on this. Our first priority was to settle down the libnetwork northbound apis so that we can get it integrated with docker core for which we have a PR in progress. It should probably not be that much of a change in driver API other than only IP addresses required to be returned during CreateEndpoint and everything else during Join. I will try to push a PR today and update the doc. If not I will try to see if we can send a doc update PR.

[tomdee]

@mrjana Thanks for the quick response. That all sounds good.

[squaremo]

Is this (or rather, the analogous problem with Join) addressed by #193, which changed the meaning of DstName to be a prefix to which libnetwork appends an index?

[mrjana]

@squaremo Yes, and I think we should close this issue