Subnet Operations

Subnet definitions provide the necessary information for DHCP IP Address lease assignments, and allows Machines to be enrolled/discovered by a DRP Endpoint. For any Layer 2 subnet/network that you wish to install Machines from, you must also specify a Subnet definition for. In some environments, a Subnet definition may not be needed to allow Machines to be discovered.

Cloning a Subnet

It might be necessary to create a new subnet from an existing one. To do this, do the following:

drpcli subnets show eth0 | jq -r > new_subnet.json
# edit the new_subnet.json file with the new information
drpcli subnets create -< new_subnet.json

Creating a new Subnet

A new subnet can be created from a JSON specification. It is necessary to use all the following JSON keys to successfully create a new Subnet that can be immediately used to manage machines -- the rest of the keys will be autofilled with reasonable defaults.

echo '
{
  "Name": "local_subnet",
  "Subnet": "10.10.16.10/24",
  "ActiveStart": "10.10.16.100",
  "ActiveEnd": "10.10.16.254",
  "ActiveLeaseTime": 60,
  "Enabled": true,
  "ReservedLeaseTime": 7200,
  "Strategy": "MAC",
  "Options": [
    { "Code": 3, "Value": "10.10.16.1", "Description": "Default Gateway" },
    { "Code": 6, "Value": "8.8.8.8", "Description": "DNS Servers" },
    { "Code": 15, "Value": "example.com", "Description": "Domain Name" }
  ]
} ' > /tmp/local_subnet.json

drpcli subnets create -< /tmp/local_subnet.json

Note that the "Description" is purely cosmetic and not used - however, it can be safely specified as it'll be ignored ( it's added here for the readers reference). You must provide the minimum DHCP Options as specified above. You can find a complete set of DHCP Options at:

<https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml>

For complete documentation and information you can find the DHCP Options officially documented in RFC2132

Updating a Subnet

From time to time, you may need to modify an existing Subnet definition. Depending on your changes, you have a couple of options.

Set the NTP Server pool via DHCP Option 42 for subnet "local_subnet"

drpcli subnets set local_subnet option 42 to "0.pool.ntp.org"

Set the DHCP IP assignment from the following pick list for subnet "local_subnet". See pickers for a detailed description of the available Picker types

drpcli subnets pickers local_subnet hint,nextFree,mostExpired

Set the nextserver for PXE operation for subnet "local_subnet"

drpcli subnets nextserver local_subnet 10.16.167.10

Set the subnet DHCP range of IP addresses for subnet "local_subnet"

drpcli subnets range local_subnet 192.168.45.100 192.168.45.255

Set Active lease to 60 mins, and reserved lease to 7200 mins for subnet "local_subnet"

drpcli subnets leasetimes local_subnet 60 7200

Update a subnet to set it to disabled (do not discover, and do not provision on this subnet, for subnet "local_subnet"

drpcli subnets update local_subnet '{ "Enabled": false }'

Update a subnet with the contents of the specified JSON file, for subnet "local_subnet"

drpcli subnets update local_subnet -< update-local_subnet.json

Deleting a Subnet

To remove a Subnet and subsequently cease PXE provisioning operations for that Subnet, perform the following:

drpcli subnets destroy local_subnet

List and Show Subnets

Viewing configuration for all subnets can be done with the list command as follows:

drpcli subnets list

To show an individual subnet, you will need the subnet name. To show just the subnet names, you can use jq to filter the output, as follows:

drpcli subnets list | jq '.[].Name'

Once you have determined which subnet you'd like to show specific information for, you can do so with the following command:

# show the YAML formatted output for 'local_subnet' subnet
drpcli subnets show local_subnet --format=yaml