Add default nodename for chef-client

[scott2449]

Defaulting on nodename which seems more graceful and in-line with other provisioners. Also clarifying knife docs. RFC.

See #1520, #1295, #1100, and probably some others 😀

[scott2449]

@sethvargo @erjohnso @rickard-von-essen RFC

[sethvargo]

Seems reasonable to me. Although it would be nice to add some "user" information to the node name, like packer-<username>-<uuid>. This way, if I am looking in my Chef Sever and I see packer-sethvargo-1312-42-24-44, I know exactly who created it and can ask if it is still being used.

[scott2449]

@sethvargo Agreed. Do you know of a place in the code that I can easily get to that info currently? I thought about using the FQDN as well but that info is only known chef server side. This might be a bit easier because it's in the local chef config.

[sethvargo]

@scott2449 you could probably just use client_name:

if nodeName == "" {
    nodeName = fmt.Sprintf("packer-%s-%s", p.config.ClientName uuid.TimeOrderedUUID())
}

That being said, I don't know if that's actually a required field.

[scott2449]

@sethvargo Do you mean ValidationClientName? That can be shard by multiple builds (cookbooks). After looking a bit more I still do see anything we could use to make it more unique with running commands on the node (target machine) and parsing the results. At least with packer- we can find and remove any ones are aren't caught by a knife delete. I mean since we just use these to build and image I don't think there is a use case where you want to keep the node entry on the chef server.

[scott2449]

@mitchellh thoughts?

[sethvargo]

Thanks!