Feature: use_internal_docker_network

README.md

@@ -482,6 +482,19 @@ Examples:
     net: br3
 ```
 
+### use_internal_docker_network
+
+If you want to use kitchen-docker from within another Docker container you'll
+need to set this to true. When set to true uses port 22 as the SSH port and
+the IP of the container that chef is going to run in as the hostname so that
+you can connect to it over SSH from within another Docker container.
+
+Examples:
+
+```yaml
+  use_internal_docker_network: true
+```
+
 ## Development
 
 * Source hosted at [GitHub][repo]

lib/kitchen/driver/docker.rb

@@ -56,6 +56,7 @@ class Docker < Kitchen::Driver::Base
       default_config :public_key,    File.join(Dir.pwd, '.kitchen', 'docker_id_rsa.pub')
       default_config :build_options, nil
       default_config :run_options,   nil
+      default_config :use_internal_docker_network, false
 
       default_config :use_sudo, false
 
@@ -119,7 +120,12 @@ def create(state)
         state[:ssh_key] = config[:private_key]
         state[:image_id] = build_image(state) unless state[:image_id]
         state[:container_id] = run_container(state) unless state[:container_id]
-        state[:hostname] = remote_socket? ? socket_uri.host : 'localhost'
+        state[:hostname] = 'localhost'
+        if remote_socket?
+          state[:hostname] = socket_uri.host
+        elsif config[:use_internal_docker_network]
+          state[:hostname] = container_ip(state)
+        end
         state[:port] = container_ssh_port(state)
         if config[:wait_for_sshd]
           instance.transport.connection(state) do |conn|
@@ -376,6 +382,9 @@ def parse_container_ssh_port(output)
 
       def container_ssh_port(state)
         begin
+          if config[:use_internal_docker_network]
+            return 22
+          end
           output = docker_command("port #{state[:container_id]} 22/tcp")
           parse_container_ssh_port(output)
         rescue
@@ -384,6 +393,17 @@ def container_ssh_port(state)
         end
       end
 
+      def container_ip(state)
+        begin
+          cmd = "inspect --format '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}'"
+          cmd << " #{state[:container_id]}"
+          docker_command(cmd).strip
+        rescue
+          raise ActionFailed,
+          'Error getting internal IP of Docker container'
+        end
+      end
+
       def rm_container(state)
         container_id = state[:container_id]
         docker_command("stop -t 0 #{container_id}")