Shared create on list keys?

[grundler]

We ran into an issue with two different services stepping on each-others' toes when writing BGP config to a Nexus device.  Service A touches the device first, initially populating the BGP config on the router, and then Service B comes along later and adds some additional peers.  The device config in CDB looks like the following:

```

<config>
  <router xmlns="http://tail-f.com/ned/cisco-nx">
    <bgp refcounter="2" backpointer="[ /ncs:services/svcA /ncs:services/svcB ]">
    <id>65001</id>

     ...

    <neighbor refcounter="1" backpointer="[ /ncs:services/svcA]" >
      <id>1.2.3.4</id>
    </neighbor>
    <neighbor refcounter="1" backpointer="[ /ncs:services/svcB ]" >
      <id>4.5.6.7</id>
    </neighbor>

```

What is confusing me is that the refcounter and backpointers indicate that both services have 'ownership' of the data in the /devices tree like I expected to see, but after deploying service B, service A goes out of sync.  If I do a re-deploy dry-run, service A wipes out the changes that were created by service B.  Can someone clue me in on what I'm missing?

[snovello]

We should see the template for this service. My guess is you don’t have the default tags=’merge’ behavior. That would behave as you are expecting.

[grundler]

My understanding is that 'merge' is the default behavior if no tag is used:

Here is the template applied by Service A:

      <router xmlns="http://tail-f.com/ned/cisco-nx">

        <ospf>
          <id>CORE</id>
          <bfd/>
          <router-id>{$loopback0}</router-id>
        </ospf>

        <bgp>
          <id>{/evpn-overlay/as-number}</id>
          <log-neighbor-changes/>
          <template>
            <peer>
              <name>{/name}-PEERS</name>
              <update-source>loopback0</update-source>
              <address-family>
                <proto>l2vpn</proto>
                <type>evpn</type>
                <route-reflector-client/>
                <send-community>
                  <attr>extended</attr>
                </send-community>
              </address-family>
              <remote-as>{/evpn-overlay/as-number}</remote-as>
            </peer>
          </template>
          <?foreach {/evpn-overlay/leaf/name}?>
          <neighbor>
            <id>{deref(current())/../loopback-ipv4-address}</id>
            <description>{current()}</description>
            <inherit>
              <peer>{/name}-PEERS</peer>
            </inherit>
          </neighbor>
          <?end?>
        </bgp>
      </router>

Here is the template for Service B:

    <device>
      <name>{/downstream/device}</name>
      <config>
        <router xmlns="http://tail-f.com/ned/cisco-nx">
          <bgp>
            <id>{$peer-asn}</id>
            <neighbor>
              <id>{$core-ip}</id>
              <inner-remote-as>
                <remote-as>{$core-asn}</remote-as>
              </inner-remote-as>
              <description>{/upstream/device}</description>
              <inherit>
                <peer>{$remote-peer-group}</peer>
              </inherit>
            </neighbor>
          </bgp>
        </router>
      </config>
    </device>