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:

Bash

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.

Bash

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:

Bash

drpcli subnets destroy local_subnet

List and Show Subnets¶

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

Bash

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:

Bash

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:

Bash

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