[Kea-users] Multiple Subnets on same VLAN

[Simon]

Kris Emsoff <kris at ucs.net> wrote:

> We have a lingering issue that we are trying to work through and seem to be at a standstill each time we try and resolve our issue.
>  
> The issue is solely with VLAN’s that have more than 1 subnet.
>  
> We have tried adding into “Shared Networks” which solves the issue with one single VLAN, the issue is we have multiple VLAN’s that use more than one subnet.  When adding an additional VLAN and subnet to the “shared network” category we start getting IP issues with handouts and trying to handout from subnets that are not part of that node. I have tried using the relay function as well and have not managed to find a work around. 
>  
> All of our other VLAN’s with a single subnet are functioning as intended
>  
> Below is a snip of the configuration.  With the other nodes commented out this performs as expected.  But when I comment them back in we start seeing issues. 
>  
> Should we scrap the shared networks and move them back to individual networks and just add the relay to each? Or am I missing something here?
>  
> Any help would be appreciated
>  
>  
>         "shared-networks": [
>           {
>             "name": "SharedPop",
>             "relay": { "ip-addresses": ["X.X.X.1"] },
>           "subnet4": [
> //            {
> //                // VLAN 1116 -  Node
> //                "subnet": "X.X.X.0/22",
> //                "pools": [ { "pool": "X.X.X.4 - X.X.X.254" } ],
> //                "option-data": [ { "name": "routers", "data": "X.X.X.1" } ],
> //                "client-class": "HA_dhcp-1"
> //            },
> //            {
> //                // VLAN 1116 - Node 2nd Subnet
> //                "subnet": "X.X.X.0/23",
> //                "pools": [ { "pool": "X.X.X.4 – X.X.X.254" } ],
> //                "option-data": [ { "name": "routers", "data": "X.X.X.1" } ],
> //                "client-class": "HA_dhcp-1"
> //            },
> //            {
> //                // VLAN 1204 -  Node
> //                "subnet": "X.X.X.0/23",
> //                "pools": [ { "pool": "X.X.X.4 - X.X.X.254" } ],
> //                "option-data": [ { "name": "routers", "data": "X.X.X.1" } ],
> //                "client-class": "HA_dhcp-1"
> //            },
> //            {
> //                // VLAN 1204 -  2nd Subnet
> //                "subnet": "X.X.X.0/23",
> //                "pools": [ { "pool": "X.X.X.4 – X.X.X.254" } ],
> //                "option-data": [ { "name": "routers", "data": "X.X.X.1" } ],
> //                "client-class": "HA_dhcp-1"
> //            },
>             {
>                 // VLAN 1113 -  Node
>                 "subnet": "X.X.X.0/24",
>                 "pools": [ { "pool": "X.X.X.4 – X.X.X.254" } ],
>                 "option-data": [ { "name": "routers", "data": "X.X.X.1" } ],
>                 "client-class": "HA_dhcp-1"
>             },
>             {
>                 // VLAN 1113 - Node 2nd Subnet
>                 "subnet": "X.X.X.0/24",
>                 "pools": [ { "pool": "X.X.X.4 – X.X.X.254" } ],
>                 "option-data": [ { "name": "routers", "data": "X.X.X.1" } ],
>                 "client-class": "HA_dhcp-1"
>             }
>            ]
>          }
>        ],
> 

Bear in mind that I’m a long time dhcpd user, and not used Kea yet ...


Looking at the documentation, it isn’t very clear. However I infer that the correct syntax is along the lines of :

"shared-networks": [ <list of shared networks> ], where <list of shared networks> is {declaration for shared subnet1}, {declaration for shared subnet1}, ..., {declaration for shared subnetn}

So :
"shared-networks": [
  {
    “name”: “sharednet1”,
    ...
    “subnet4”: [
      <subnet declarations for shared network>
    ]
  }
  {
    “name”: “sharednet2”,
    ...
    “subnet4”: [
      <subnet declarations for shared network>
    ]
  }
]

I.e., there’s a separate declaration for each shared network (or, in your case, for each VLAN). While you have one declaration for a single shared network which is not correct as the subnets are spread across a number of VLANs.


Simon