Don't allow server zone changes in pods

We auto-create a server per zone so a change should
never be necessary

app/models/miq_server.rb

@@ -38,6 +38,7 @@ class MiqServer < ApplicationRecord
   virtual_delegate :description, :to => :zone, :prefix => true, :allow_nil => true, :type => :string
 
   validate :validate_zone_not_maintenance?
+  validate :zone_unchanged_in_pods, :on => :update
 
   GUID_FILE = Rails.root.join("GUID").freeze
 
@@ -479,4 +480,12 @@ def miq_region
   def self.display_name(number = 1)
     n_('Server', 'Servers', number)
   end
+
+  private
+
+  def zone_unchanged_in_pods
+    return unless MiqEnvironment::Command.is_podified?
+
+    errors.add(:zone, N_('cannot be changed when running in containers')) if zone_id_changed?
+  end
 end # class MiqServer

spec/models/miq_server_spec.rb

@@ -420,4 +420,25 @@
       expect(s.description).to eq(s.name)
     end
   end
+
+  describe "#zone_unchanged_in_pods" do
+    it "allows zone changes when not in pods" do
+      server = FactoryBot.create(:miq_server)
+      zone = FactoryBot.create(:zone)
+
+      server.zone = zone
+      expect(server.zone_id_changed?).to be_truthy
+      expect(server.save).to be_truthy
+    end
+
+    it "prevents zone changes in pods" do
+      allow(MiqEnvironment::Command).to receive(:is_podified?).and_return(true)
+      server = FactoryBot.create(:miq_server)
+      zone = FactoryBot.create(:zone)
+
+      server.zone = zone
+      expect(server.zone_id_changed?).to be_truthy
+      expect(server.save).to be_falsey
+    end
+  end
 end