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[OpenStack Infra <1693265@xxxxxxxxxxxxxxxxxx>]

Reviewed:  https://review.openstack.org/467699
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=4b333b989dfc778a8b61db4a1b8552e988a10471
Submitter: Jenkins
Branch:    master

commit 4b333b989dfc778a8b61db4a1b8552e988a10471
Author: Lars Kellogg-Stedman <lars@xxxxxxxxxx>
Date:   Wed May 24 12:40:13 2017 -0400

    provide interface-scoped nameserver information
    
    DNS nameserver information is subnet-specific, but nova provides this
    information globally, which makes it impossible for system
    configuration tools to place the nameserver information in the right
    place (e.g., in interface configuration files).  This commit modifies
    nova to *also* provide the DNS information per-subnet, where it can be
    accessed by tools that want to configure the system properly.
    
    Change-Id: I003a25b0d60cb6cd16c3ee1ad1a43910825622be
    Closes-bug: #1693265


** Changed in: nova
       Status: In Progress => Fix Released

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https://bugs.launchpad.net/bugs/1693265

Title:
  network_data.json should provide interface-scoped nameserver
  information

Status in OpenStack Compute (nova):
  Fix Released

Bug description:
  Nova currently provides nameserver information in network_data.json as
  a globally-scoped "services" key.  E.g., from
  https://specs.openstack.org/openstack/nova-
  specs/specs/liberty/implemented/metadata-service-network-info.html
  #rest-api-impact:

    {
    "links": [...],
    "networks": [...],
    "services": [
        {
            "type": "dns",
            "address": "8.8.8.8"
        },
        {
            "type": "dns",
            "address": "8.8.4.4"
        }
      ]
    }

  This is problematic because nameserver information is actually
  provided to OpenStack *per-subnet*, and nameservers that are reachable
  via one subnet may not be reachable from others.  This is true outside
  of OpenStack as well, and is generally handled by providing nameserver
  information in interface configuration files (such as /etc/sysconfig
  /network-scripts/ifcfg-eth0 on RHEL and derivatives).

  Unfortunately, because Nova does not provide interface-scoped
  nameserver information, it is not possible to correctly configure a
  server from this information.  Depending on how /etc/resolv.conf is
  populated, this can result in name resolution delays or failures if
  some system interfaces are brought down.

  While it may be too late to remove the global nameserver information,
  we should *also* provide interface-scoped nameserver information in
  the "networks" dictionary, something like:

    "networks": [
      {
        "network_id": "100dc63c-e8f8-46d1-a99f-6da4aca171b1",
        "type": "ipv4",
        "netmask": "255.255.255.0",
        "link": "tap14c7fd7d-81",
        "routes": [
          {
            "netmask": "0.0.0.0",
            "network": "0.0.0.0",
            "gateway": "10.9.8.1"
          }
        ],
        "ip_address": "10.9.8.2",
        "id": "network1",
        "services": [
          {
            "type": "dns",
            "address": "10.9.8.1"
          }
        ]
      }
    ]

  This would allow system configuration tools to correctly configure
  interface-scoped nameserver information.

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