Merge pull request #11565 from soapy1/disable-host-modification

Add option to disable modification of /etc/hosts on guest

lib/vagrant/action/builtin/set_hostname.rb

@@ -10,15 +10,19 @@ module Vagrant
       class SetHostname
         def initialize(app, env)
           @app = app
+          @logger = Log4r::Logger.new("vagrant::action::builtin::set_hostname")
         end
 
         def call(env)
           @app.call(env)
 
           hostname = env[:machine].config.vm.hostname
-          if !hostname.nil?
+          allow_hosts_modification = env[:machine].config.vm.allow_hosts_modification
+          if !hostname.nil? && allow_hosts_modification
             env[:ui].info I18n.t("vagrant.actions.vm.hostname.setting")
             env[:machine].guest.capability(:change_host_name, hostname)
+          else
+            @logger.info("`allow_hosts_modification` set to false. Hosts modification has been disabled, skiping changing hostname.")
           end
         end
       end

plugins/kernel_v2/config/vm.rb

@@ -24,6 +24,7 @@ module VagrantPlugins
 
       attr_accessor :allowed_synced_folder_types
       attr_accessor :allow_fstab_modification
+      attr_accessor :allow_hosts_modification
       attr_accessor :base_mac
       attr_accessor :base_address
       attr_accessor :boot_timeout
@@ -77,6 +78,7 @@ module VagrantPlugins
         @box_extra_download_options    = UNSET_VALUE
         @box_url                       = UNSET_VALUE
         @box_version                   = UNSET_VALUE
+        @allow_hosts_modification      = UNSET_VALUE
         @clone                         = UNSET_VALUE
         @communicator                  = UNSET_VALUE
         @graceful_halt_timeout         = UNSET_VALUE
@@ -527,6 +529,7 @@ module VagrantPlugins
         @box_version = nil if @box_version == UNSET_VALUE
         @box_download_options = {} if @box_download_options == UNSET_VALUE
         @box_extra_download_options = Vagrant::Util::MapCommandOptions.map_to_command_options(@box_download_options)
+        @allow_hosts_modification = true if @allow_hosts_modification == UNSET_VALUE
         @clone = nil if @clone == UNSET_VALUE
         @communicator = nil if @communicator == UNSET_VALUE
         @graceful_halt_timeout = 60 if @graceful_halt_timeout == UNSET_VALUE
@@ -996,6 +999,12 @@ module VagrantPlugins
             option: "allow_fstab_modification", given: @allow_fstab_modification.class, required: "Boolean"
           )
         end
+        
+        if ![TrueClass, FalseClass].include?(@allow_hosts_modification.class)
+          errors["vm"] << I18n.t("vagrant.config.vm.config_type",
+            option: "allow_hosts_modification", given: @allow_hosts_modification.class, required: "Boolean"
+          )
+        end
 
         errors
       end

test/unit/plugins/kernel_v2/config/vm_test.rb

@@ -49,6 +49,20 @@ describe VagrantPlugins::Kernel_V2::VMConfig do
     assert_valid
   end
 
+  it  "validates disables_host_modification option" do
+    subject.allow_hosts_modification = true
+    subject.finalize!
+    assert_valid
+
+    subject.allow_hosts_modification = false
+    subject.finalize!
+    assert_valid
+
+    subject.allow_hosts_modification = "truthy"
+    subject.finalize!
+    assert_invalid
+  end
+
   describe "#base_mac" do
     it "defaults properly" do
       subject.finalize!

test/unit/vagrant/action/builtin/set_hostname_test.rb

@@ -0,0 +1,28 @@
+require File.expand_path("../../../../base", __FILE__)
+
+describe Vagrant::Action::Builtin::SetHostname do
+  let(:env) { { machine: machine, ui: ui } }
+  let(:app) { lambda { |env| } }
+  let(:machine) { double("machine") }
+  let(:ui) { double("ui") }
+  
+  subject { described_class.new(app, env) }
+
+  before do 
+    allow(machine).to receive_message_chain(:config, :vm, :hostname).and_return("whatever")
+    allow(machine).to receive_message_chain(:guest, :capability)
+    allow(ui).to receive(:info)
+  end
+
+  it "should change hostname if hosts modification enabled" do
+    allow(machine).to receive_message_chain(:config, :vm, :allow_hosts_modification).and_return(true)
+    expect(machine).to receive(:guest)
+    subject.call(env)
+  end
+
+  it "should not change hostname if hosts modification disabled" do
+    allow(machine).to receive_message_chain(:config, :vm, :allow_hosts_modification).and_return(false)
+    expect(machine).not_to receive(:guest)
+    subject.call(env)
+  end
+end

website/pages/docs/vagrantfile/machine_settings.mdx

@@ -21,6 +21,9 @@ machine that Vagrant manages.
   by Vagrant. Note, this may mean that folders will not be automatically mounted
   on machine reboot. Defaults to true.
 
+- `config.vm.allow_hosts_modification` (boolean) - If false, will prevent Vagrant
+  from writing to `/etc/hosts`. Defaults to true.
+
 - `config.vm.base_mac` (string) - The MAC address to be assigned to the default
   NAT interface on the guest. _Support for this option is provider dependent._