Hostname override added for AWS

* allows externalTrafficPolicy=local to work with AWS

[#157044566]

Signed-off-by: Iain Sproat <[email protected]>

jobs/kube-proxy/templates/bin/kube_proxy_ctl.erb

@@ -28,7 +28,21 @@ send_process_stderr_to_logfile() {
   exec 2>> "$LOG_DIR/$NAME.stderr.log"
 }
 
+get_hostname_override() {
+  if [[ "aws" == "$cloud_provider" ]]; then
+    # The hostname needs to be set to the instance name so the gce cloud provider can manage the instance
+    hostname_override=$(curl http://169.254.169.254/latest/meta-data/hostname)
+  else
+    hostname_override=""
+  fi
+
+  echo $hostname_override
+}
+
 start_kubernetes_proxy() {
+
+  sed -i "s|HOSTNAMEOVERRIDE|$(get_hostname_override)|g"  /var/vcap/jobs/kube-proxy/config/config.yml
+
  kube-proxy \
   <%-
     if_p('k8s-args') do |args|

jobs/kube-proxy/templates/config/config.yml.erb

@@ -1 +1,2 @@
 <% require 'yaml' %><%= p('kube-proxy-configuration').to_yaml %>
+hostnameOverride: HOSTNAMEOVERRIDE

spec/kube_proxy_ctl_spec.rb

@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+require 'rspec'
+require 'spec_helper'
+require 'fileutils'
+require 'open3'
+
+def run_get_hostname_override(rendered_contents, executable_path)
+  File.open(executable_path, 'w', 0o777) do |f|
+    f.write(rendered_contents)
+  end
+
+  # exercise bash function by first changing path for any necessary executables to our mocks
+  cmd = format('PATH=%<dirname>s:%<env_path>s /bin/bash -c "source %<exe>s && get_hostname_override"',
+               dirname: File.dirname(executable_path), env_path: ENV['PATH'], exe: executable_path)
+  # capturing stderr (ignored) prevents expected warnings from showing up in test console
+  result, = Open3.capture3(cmd)
+  result
+end
+
+describe 'kube-proxy can set hostnameOverride' do
+  let(:config_properties) do
+  {
+    'kube-proxy-configuration' => { 'mode': 'iptables' }
+  }
+  end
+  let(:rendered_template) { compiled_template('kube-proxy', 'config/config.yml', config_properties, {}) }
+
+  # Check that the config file has HOSTNAMEOVERRIDE so that start script can find
+  # and replace it at runtime
+  it 'kube-proxy config has HOSTNAMEOVERRIDE key word' do
+    expect(rendered_template).to include('HOSTNAMEOVERRIDE')
+  end
+end
+
+describe 'kube_proxy_ctl setting of hostnameOverride property' do
+  let(:test_context) do
+    mock_dir = '/tmp/kube_proxy_mock'
+    FileUtils.remove_dir(mock_dir, true)
+    FileUtils.mkdir(mock_dir)
+    kube_proxy_ctl_file = mock_dir + '/kube_proxy_ctl'
+
+    { 'mock_dir' => mock_dir, 'kube_proxy_ctl_file' => kube_proxy_ctl_file }
+  end
+  after(:each) do
+    FileUtils.remove_dir(test_context['mock_dir'], true)
+  end
+
+  describe 'when cloud-provider is AWS' do
+    it 'sets hostname_override to aws container hostname' do
+      expected_aws_hostname = 'foohost.aws.internal'
+
+      echo_mock_file = test_context['mock_dir'] + '/curl'
+      File.open(echo_mock_file, 'w', 0o777) do |f|
+        f.write("#!/bin/bash\n")
+        f.write("echo #{expected_aws_hostname}")
+      end
+
+      test_link = { 'cloud-provider' => {
+        'instances' => [],
+        'properties' => {
+          'cloud-provider' => {
+            'type' => 'aws',
+          }
+        }
+      } }
+      rendered_kube_proxy_ctl = compiled_template('kube-proxy', 'bin/kube_proxy_ctl', { 'cloud-provider' => 'aws' }, test_link)
+      result = run_get_hostname_override(rendered_kube_proxy_ctl, test_context['kube_proxy_ctl_file'])
+
+      expect(result).to include(expected_aws_hostname)
+    end
+  end
+end