Move hostname to Gitlab::Environment

config/initializers/1_settings.rb

@@ -222,7 +222,6 @@ Settings.gitlab['default_branch_protection'] ||= 2
 Settings.gitlab['default_can_create_group'] = true if Settings.gitlab['default_can_create_group'].nil?
 Settings.gitlab['host']       ||= ENV['GITLAB_HOST'] || 'localhost'
 Settings.gitlab['ssh_host']   ||= Settings.gitlab.host
-Settings.gitlab['hostname']   ||= ENV['HOSTNAME'] || Socket.gethostname
 Settings.gitlab['https']        = false if Settings.gitlab['https'].nil?
 Settings.gitlab['port']       ||= ENV['GITLAB_PORT'] || (Settings.gitlab.https ? 443 : 80)
 Settings.gitlab['relative_url_root'] ||= ENV['RAILS_RELATIVE_URL_ROOT'] || ''

lib/gitlab/environment.rb

+module Gitlab
+  module Environment
+    def self.hostname
+      @hostname ||= ENV['HOSTNAME'] || Socket.gethostname
+    end
+  end
+end

lib/gitlab/git/storage/circuit_breaker.rb

@@ -31,7 +31,7 @@ module Gitlab
           cached_circuitbreakers[storage]
         end
-        def initialize(storage, hostname = Gitlab.config.gitlab.hostname)
+        def initialize(storage, hostname = Gitlab::Environment.hostname)
           @storage = storage
           @hostname = hostname

spec/features/admin/admin_health_check_spec.rb

@@ -64,7 +64,7 @@ feature "Admin Health Check", feature: true, broken_storage: true do
     end
     it 'shows storage failure information' do
-      hostname = Gitlab.config.gitlab.hostname
+      hostname = Gitlab::Environment.hostname
       expect(page).to have_content('broken: failed storage access attempt on host:')
       expect(page).to have_content("#{hostname}: 1 of 10 failures.")

spec/lib/gitlab/git/storage/circuit_breaker_spec.rb

@@ -2,7 +2,7 @@ require 'spec_helper'
 describe Gitlab::Git::Storage::CircuitBreaker, clean_gitlab_redis_shared_state: true, broken_storage: true do
   let(:circuit_breaker) { described_class.new('default') }
-  let(:hostname) { Gitlab.config.gitlab.hostname }
+  let(:hostname) { Gitlab::Environment.hostname }
   let(:cache_key) { "storage_accessible:default:#{hostname}" }
   def value_from_redis(name)