Choose netplan renderer based on network config and available tools

lib/vagrant/errors.rb

@@ -468,6 +468,10 @@ module Vagrant
       error_key(:multi_vm_target_required)
     end
 
+    class NetplanNoAvailableRenderers < VagrantError
+      error_key(:netplan_no_available_renderers)
+    end
+
     class NetSSHException < VagrantError
       error_key(:net_ssh_exception)
     end

lib/vagrant/util/guest_inspection.rb

@@ -73,6 +73,14 @@ module Vagrant
           comm.test("command -v netplan")
         end
 
+        # is networkd isntalled
+        #
+        # @param [Vagrant::Plugin::V2::Communicator] comm Guest communicator
+        # @return [Boolean]
+        def networkd?(comm)
+          comm.test("command -v networkd")
+        end
+
         ## nmcli helpers
 
         # nmcli is installed

plugins/guests/debian/cap/configure_networks.rb

@@ -10,7 +10,6 @@ module VagrantPlugins
         extend Vagrant::Util::GuestInspection::Linux
 
         NETPLAN_DEFAULT_VERSION = 2
-        NETPLAN_DEFAULT_RENDERER = "networkd".freeze
         NETPLAN_DIRECTORY = "/etc/netplan".freeze
         NETWORKD_DIRECTORY = "/etc/systemd/network".freeze
 
@@ -61,12 +60,21 @@ module VagrantPlugins
           # By default, netplan expects the renderer to be systemd-networkd,
           # but if any device is managed by NetworkManager, then we use that renderer
           # ref: https://netplan.io/reference
-          renderer = NETPLAN_DEFAULT_RENDERER
-          ethernets.keys.each do |k|
-            if nm_controlled?(comm, k)
-              renderer = "NetworkManager"
-              break
+          if networkd?(comm)
+            renderer = "networkd"
+            ethernets.keys.each do |k|
+              if nm_controlled?(comm, k)
+                render = "NetworkManager"
+                if !nmcli?(comm)
+                  raise Vagrant::Errors::NetworkManagerNotInstalled, device: k
+                end
+                break
+              end
             end
+          elsif nmcli?(comm)
+            renderer = "NetworkManager"
+          else
+            raise Vagrant::Errors::NetplanNoAvailableRenderers
           end
 
           np_config = {"network" => {"version" => NETPLAN_DEFAULT_VERSION,

templates/locales/en.yml

@@ -1000,6 +1000,9 @@ en:
         the proper location.
       multi_vm_target_required: |-
         This command requires a specific VM name to target in a multi-VM environment.
+      netplan_no_available_renderers: |-
+        No renderers compatible with netplan are available on guest. Please install 
+        a compatible renderer. 
       net_ssh_exception: |-
         An error occurred in the underlying SSH library that Vagrant uses.
         The error message is shown below. In many cases, errors from this

test/unit/plugins/guests/debian/cap/configure_networks_test.rb

@@ -140,6 +140,8 @@ describe "VagrantPlugins::GuestDebian::Cap::ConfigureNetworks" do
         let(:networkd_yml) { "---\nnetwork:\n  version: 2\n  renderer: networkd\n  ethernets:\n    eth1:\n      dhcp4: true\n    eth2:\n      addresses:\n      - 33.33.33.10/16\n      gateway4: 33.33.0.1\n" }
 
         it "uses NetworkManager if detected on device" do
+          allow(cap).to receive(:networkd?).and_return(false)
+          allow(cap).to receive(:nmcli?).and_return(true)
           allow(cap).to receive(:nm_controlled?).and_return(true)
           allow(comm).to receive(:test).with("nmcli -t d show eth1").and_return(true)
           allow(comm).to receive(:test).with("nmcli -t d show eth2").and_return(true)
@@ -156,7 +158,18 @@ describe "VagrantPlugins::GuestDebian::Cap::ConfigureNetworks" do
           expect(comm.received_commands[0]).to match("netplan apply")
         end
 
+        it "raises and error if NetworkManager is detected on device but nmcli is not installed" do
+          allow(cap).to receive(:networkd?).and_return(true)
+          allow(cap).to receive(:nmcli?).and_return(false)
+          allow(cap).to receive(:nm_controlled?).and_return(true)
+          allow(comm).to receive(:test).with("nmcli -t d show eth1").and_return(true)
+          allow(comm).to receive(:test).with("nmcli -t d show eth2").and_return(true)
+
+          expect { cap.configure_networks(machine, [network_0, network_1]) }.to raise_error(Vagrant::Errors::NetworkManagerNotInstalled)
+        end
+
         it "creates and starts the networks for systemd with netplan" do
+          allow(cap).to receive(:networkd?).and_return(true)
           expect(cap).to receive(:upload_tmp_file).with(comm, networkd_yml)
             .and_return("/tmp/vagrant-network-entry.1234")