DHCP

This example demonstrates how to deploy DHCP servers inside the SEED Emulator and how to configure hosts to obtain their IP addresses through DHCP.

The example starts from the B00_mini_internet topology, then adds DHCP service to two stub ASes:

• AS151 has DHCP server dhcp-server-01.
• AS161 has DHCP server dhcp-server-02.
• AS151 has two DHCP clients: dhcp-client-01 and dhcp-client-02.
• AS161 has two DHCP clients: dhcp-client-03 and dhcp-client-04.

The tests for this example focus only on DHCP behavior. They do not repeat B00’s mini-Internet reachability tests.

Step 1: Deploy DHCP Servers

Create the DHCP service and install two DHCP server virtual nodes:

dhcp = DHCPService()

# Default DHCP range: x.x.x.101 - x.x.x.120.
# Custom AS151 DHCP range: x.x.x.125 - x.x.x.140.
dhcp.install("dhcp-01").setIpRange(125, 140)
dhcp.install("dhcp-02")

Customize their display names for visualization:

emu.getVirtualNode("dhcp-01").setDisplayName("DHCP Server 1")
emu.getVirtualNode("dhcp-02").setDisplayName("DHCP Server 2")

Create physical hosts to run the DHCP servers:

as151 = base.getAutonomousSystem(151)
as151.createHost("dhcp-server-01").joinNetwork("net0")

as161 = base.getAutonomousSystem(161)
as161.createHost("dhcp-server-02").joinNetwork("net0")

Bind the DHCP virtual nodes to those physical hosts:

emu.addBinding(Binding("dhcp-01", filter=Filter(asn=151, nodeName="dhcp-server-01")))
emu.addBinding(Binding("dhcp-02", filter=Filter(asn=161, nodeName="dhcp-server-02")))

Step 2: Create DHCP Clients

To make a host use DHCP instead of a static address, join the network with address="dhcp":

as151.createHost("dhcp-client-01").joinNetwork("net0", address="dhcp")
as151.createHost("dhcp-client-02").joinNetwork("net0", address="dhcp")

as161.createHost("dhcp-client-03").joinNetwork("net0", address="dhcp")
as161.createHost("dhcp-client-04").joinNetwork("net0", address="dhcp")

The SEED Emulator adds the DHCP client software and a startup helper script to request a lease when the container starts.

DHCP Address Ranges

The default address ranges are:

• Host static address range: .71 to .99
• DHCP address range: .101 to .120
• Router address range: .254 downward

DHCPServer.setIpRange() changes the DHCP range for the network served by that DHCP server. In this example:

• AS151 uses the custom DHCP range 10.151.0.125 to 10.151.0.140.
• AS161 uses the default DHCP range 10.161.0.101 to 10.161.0.120.

To change the entire network allocation policy, use Network.setHostIpRange(), Network.setDhcpIpRange(), and Network.setRouterIpRange().

Standard Arguments

python examples/internet/B20_dhcp/dhcp.py amd
python examples/internet/B20_dhcp/dhcp.py --platform amd --output examples/internet/B20_dhcp/output
python examples/internet/B20_dhcp/dhcp.py --dumpfile examples/internet/B20_dhcp/dhcp.bin

Supported arguments:

• amd|arm: optional legacy platform argument.
• --platform amd|arm: named platform argument.
• --output PATH: output folder for Docker compiler results.
• --dumpfile PATH: save a serialized emulator instead of compiling Docker output.
• --override / --no-override: control whether existing output is replaced.
• --skip-render: compile without calling emu.render() first.

Standardized TestRunner Lifecycle

Run the full lifecycle from the repository root:

python seedemu/testing/cli.py all examples/internet/B20_dhcp/example.yaml --artifact-dir ci-artifacts/b20-dhcp

The lifecycle can also be run step by step:

python seedemu/testing/cli.py clean examples/internet/B20_dhcp/example.yaml
python seedemu/testing/cli.py compile examples/internet/B20_dhcp/example.yaml --artifact-dir ci-artifacts/b20-dhcp
python seedemu/testing/cli.py build examples/internet/B20_dhcp/example.yaml --artifact-dir ci-artifacts/b20-dhcp
python seedemu/testing/cli.py up examples/internet/B20_dhcp/example.yaml --artifact-dir ci-artifacts/b20-dhcp
python seedemu/testing/cli.py probe examples/internet/B20_dhcp/example.yaml --artifact-dir ci-artifacts/b20-dhcp
python seedemu/testing/cli.py test examples/internet/B20_dhcp/example.yaml --artifact-dir ci-artifacts/b20-dhcp
python seedemu/testing/cli.py down examples/internet/B20_dhcp/example.yaml --artifact-dir ci-artifacts/b20-dhcp

The declarative probes check representative DHCP clients:

• An AS151 client receives an address from 10.151.0.125 to 10.151.0.140.
• An AS161 client receives an address from 10.161.0.101 to 10.161.0.120.
• DHCP clients can reach their local default routers.

The custom test_runtime.py program checks DHCP-specific deployment details:

• DHCP server containers are generated and dhcpd is running.
• AS151’s DHCP server config contains the custom range.
• AS161’s DHCP server config contains the default range.
• All four DHCP clients have the generated DHCP client helper.
• All four DHCP clients receive addresses from the expected ranges.
• All four DHCP clients install the expected default route.