diff --git a/Capfile b/Capfile
index 0c2b1b008..7c2f07157 100644
--- a/Capfile
+++ b/Capfile
@@ -4,6 +4,9 @@ require 'capistrano/setup'
 # Include default deployment tasks
 require 'capistrano/deploy'
 
+require "capistrano/scm/git"
+install_plugin Capistrano::SCM::Git
+
 # Include tasks from other gems included in your Gemfile
 require 'capistrano/rbenv'
 require 'capistrano/rails'
@@ -14,5 +17,3 @@ require 'new_relic/recipes'
 
 # Load custom tasks from `lib/capistrano/tasks` if you have any defined
 Dir.glob('lib/capistrano/tasks/*.rake').each { |r| import r }
-
-after "deploy:updated", "newrelic:notice_deployment"
diff --git a/config/deploy.rb b/config/deploy.rb
index f40d859a5..794578a47 100644
--- a/config/deploy.rb
+++ b/config/deploy.rb
@@ -2,8 +2,16 @@ set :stages, %w(production development staging)
 set :default_stage, "staging"
 set :application, "danbooru"
 set :repo_url,  "git://github.com/r888888888/danbooru.git"
-set :scm, :git
 set :deploy_to, "/var/www/danbooru2"
 set :rbenv_ruby, "2.5.1"
-set :linked_dirs, fetch(:linked_dirs, []).push('log', 'tmp/pids', 'tmp/cache', 'tmp/sockets', 'vendor/bundle')
+append :linked_dirs, "log", "tmp/pids", "tmp/cache", "tmp/sockets", "vendor/bundle"
 set :branch, ENV.fetch("branch", "master")
+
+# skip migrations if files in db/migrate weren't modified
+set :conditionally_migrate, true
+
+# run migrations on the primary app server
+set :migration_role, :app
+
+# how long unicorn:legacy_restart (used by deploy:rolling) waits until killing the old unicorn.
+set :unicorn_restart_sleep_time, 10
diff --git a/config/deploy/production.rb b/config/deploy/production.rb
index 697e1f9a9..62ccddb58 100644
--- a/config/deploy/production.rb
+++ b/config/deploy/production.rb
@@ -1,9 +1,11 @@
 set :user, "danbooru"
 set :rails_env, "production"
-server "kagamihara", :roles => %w(web app db), :primary => true
+set :rbenv_path, "/home/danbooru/.rbenv"
+append :linked_files, ".env.production"
+
+server "kagamihara", :roles => %w(web app), :primary => true
 server "shima", :roles => %w(web app)
 server "saitou", :roles => %w(web app)
 server "oogaki", :roles => %w(worker)
 
-set :linked_files, fetch(:linked_files, []).push(".env.production")
-set :rbenv_path, "/home/danbooru/.rbenv"
\ No newline at end of file
+after "deploy:finished", "newrelic:notice_deployment"
diff --git a/lib/capistrano/tasks/app.rake b/lib/capistrano/tasks/app.rake
new file mode 100644
index 000000000..1a0677fb9
--- /dev/null
+++ b/lib/capistrano/tasks/app.rake
@@ -0,0 +1,32 @@
+namespace :app do
+  set :rolling_deploy, false
+
+  before "deploy:migrate", "app:disable"
+  after "deploy:published", "app:enable"
+
+  task :disable do
+    if fetch(:rolling_deploy)
+      # do nothing
+    else
+      invoke "web:disable"
+      invoke "unicorn:terminate"
+    end
+  end
+
+  task :enable do
+    if fetch(:rolling_deploy)
+      invoke "unicorn:legacy_restart"
+    else
+      invoke "unicorn:start"
+      invoke "web:enable"
+    end
+  end
+end
+
+namespace :deploy do
+  desc "Deploy a rolling update without taking the site down for maintenance"
+  task :rolling do
+    set :rolling_deploy, true
+    invoke "deploy"
+  end
+end
diff --git a/lib/capistrano/tasks/unicorn.rake b/lib/capistrano/tasks/unicorn.rake
index 1c7e41f1b..d747dfb2b 100644
--- a/lib/capistrano/tasks/unicorn.rake
+++ b/lib/capistrano/tasks/unicorn.rake
@@ -1,20 +1,25 @@
+# https://bogomips.org/unicorn/SIGNALS.html
 namespace :unicorn do
   desc "Terminate unicorn processes (blocks until complete)"
   task :terminate do
     on roles(:app) do
-      execute "[[ -n $(pgrep -f unicorn) ]] && pgrep -f unicorn | xargs kill -SIGTERM"
-      sleep(5)
+      within current_path do
+        kill_unicorn("SIGQUIT")
+        sleep(10)
+        kill_unicorn("SIGTERM")
+        sleep(2)
+        kill_unicorn("SIGKILL")
+      end
     end
   end
 
-  desc "Kills unicorn processes (blocks until complete)"
-  task :kill do
-    on roles(:app) do
-      execute "[[ -n $(pgrep -f unicorn) ]] && pgrep -f unicorn | xargs kill -SIGKILL"
+  def unicorn_running?
+    test("[ -f #{fetch(:unicorn_pid)} ] && pkill --count --pidfile #{fetch(:unicorn_pid)}")
+  end
+
+  def kill_unicorn(signal)
+    if unicorn_running?
+      execute :pkill, "--signal #{signal}", "--pidfile #{fetch(:unicorn_pid)}"
     end
   end
 end
-
-after "deploy:published", "unicorn:terminate"
-after "deploy:published", "unicorn:kill"
-after "deploy:published", "unicorn:start"
diff --git a/lib/capistrano/tasks/web.rake b/lib/capistrano/tasks/web.rake
index b39eb24e8..7a4e024ad 100644
--- a/lib/capistrano/tasks/web.rake
+++ b/lib/capistrano/tasks/web.rake
@@ -19,6 +19,3 @@ namespace :web do
     end
   end
 end
-
-before "deploy:started", "web:disable"
-after "deploy:published", "web:enable"