Merge branch 'es_checker' of gitlab.com:gitlab-org/gitlab-ee into ee_master

CHANGELOG-EE

@@ -8,6 +8,10 @@ v 8.5.1
 
 v 8.5.0
   - Fix Elasticsearch blob results linking to the wrong reference ID (Stan Hu)
+v 8.6.0(unreleased)
+  - [Elastic] Add elastic checker to gitlab:check
+
+v 8.5.0
   - Show warning when mirror repository default branch could not be updated because it has diverged from upstream.
   - More reliable wiki indexer
   - GitLab Pages gets support for custom domain and custom certificate

lib/tasks/gitlab/check.rake

@@ -30,6 +30,7 @@ namespace :gitlab do
       check_ruby_version
       check_git_version
       check_active_users
+      check_elasticsearch if Gitlab.config.elasticsearch.enabled
 
       finished_checking "GitLab"
     end
@@ -981,4 +982,27 @@ namespace :gitlab do
       puts "No ref lock files exist".green
     end
   end
+
+  def check_elasticsearch
+    client = Elasticsearch::Client.new(host: Gitlab.config.elasticsearch.host,
+                                     port: Gitlab.config.elasticsearch.port)
+
+    print "Elasticsearch version >= 2.0? ... "
+
+    version = client.info["version"]["number"]
+
+    if version.starts_with?("2")
+      puts "yes (#{version})".green
+    else
+      puts "no".red
+    end
+
+    print "Elasticsearch has plugin delete-by-query installed? ... "
+
+    if client.cat.plugins.include?("delete-by-query")
+      puts "yes".green
+    else
+      puts "no".red
+    end
+  end
 end