Merge branch '22719-provide-a-new-gitlab-workhorse-install-rake-task-similar-to-gitlab-shell-install' into 'master'

New `gitlab:workhorse:install` rake task

## Why was this MR needed?

Because with this we can remove the "Ensure the gitlab-workhorse version in Install gitlab-workhorse matches the required version." step from https://gitlab.com/gitlab-org/release-tools/blob/master/doc/release-candidates.md#creating-rc1! MR is ready: gitlab-org/release-tools!57

Closes #22719

See merge request !6574

3 files changed, 222 insertions, 10 deletions

diff --git a/doc/install/installation.md b/doc/install/installation.md
index ee02d6024d9..77adb4c9f7b 100644
--- a/doc/install/installation.md
+++ b/doc/install/installation.md
@@ -175,7 +175,7 @@ We recommend using a PostgreSQL database. For MySQL check the
     ```bash
     sudo -u postgres psql -d template1 -c "CREATE USER git CREATEDB;"
     ```
-    
+
 1. Create the `pg_trgm` extension (required for GitLab 8.6+):
 
     ```bash
@@ -396,15 +396,25 @@ GitLab Shell is an SSH access and repository management software developed speci
 
 ### Install gitlab-workhorse
 
-GitLab-Workhorse uses [GNU Make](https://www.gnu.org/software/make/).
-If you are not using Linux you may have to run `gmake` instead of
-`make` below.
+GitLab-Workhorse uses [GNU Make](https://www.gnu.org/software/make/). The
+following command-line will install GitLab-Workhorse in `/home/git/gitlab-workhorse`
+which is the recommended location.
 
-    cd /home/git
-    sudo -u git -H git clone https://gitlab.com/gitlab-org/gitlab-workhorse.git
-    cd gitlab-workhorse
-    sudo -u git -H git checkout v1.0.1
-    sudo -u git -H make
+    cd /home/git/gitlab
+
+    sudo -u git -H bundle exec rake "gitlab:workhorse:install[/home/git/gitlab-workhorse]" RAILS_ENV=production
+
+You can specify a different Git repository by providing `GITLAB_WORKHORSE_REPO`:
+
+    cd /home/git/gitlab
+
+    sudo -u git -H bundle exec rake "gitlab:workhorse:install[/home/git/gitlab-workhorse]" GITLAB_WORKHORSE_REPO=https://example.com/gitlab-workhorse.git RAILS_ENV=production
+
+You can specify a different version to use by providing `GITLAB_WORKHORSE_VERSION`:
+
+    cd /home/git/gitlab
+
+    sudo -u git -H bundle exec rake "gitlab:workhorse:install[/home/git/gitlab-workhorse]" GITLAB_WORKHORSE_VERSION=0.8.1 RAILS_ENV=production
 
 ### Initialize Database and Activate Advanced Features
 
diff --git a/doc/update/8.12-to-8.13.md b/doc/update/8.12-to-8.13.md
index c0084d9d59c..8c0d3f78b55 100644
--- a/doc/update/8.12-to-8.13.md
+++ b/doc/update/8.12-to-8.13.md
@@ -166,7 +166,7 @@ See [smtp_settings.rb.sample] as an example.
 Ensure you're still up-to-date with the latest init script changes:
 
     sudo cp lib/support/init.d/gitlab /etc/init.d/gitlab
-    
+
 For Ubuntu 16.04.1 LTS:
 
     sudo systemctl daemon-reload
diff --git a/doc/update/8.14-to-8.15.md b/doc/update/8.14-to-8.15.md
new file mode 100644
index 00000000000..576b943b98c
--- /dev/null
+++ b/doc/update/8.14-to-8.15.md
@@ -0,0 +1,202 @@
+# From 8.14 to 8.15
+
+Make sure you view this update guide from the tag (version) of GitLab you would
+like to install. In most cases this should be the highest numbered production
+tag (without rc in it). You can select the tag in the version dropdown at the
+top left corner of GitLab (below the menu bar).
+
+If the highest number stable branch is unclear please check the
+[GitLab Blog](https://about.gitlab.com/blog/archives.html) for installation
+guide links by version.
+
+### 1. Stop server
+
+    sudo service gitlab stop
+
+### 2. Backup
+
+```bash
+cd /home/git/gitlab
+sudo -u git -H bundle exec rake gitlab:backup:create RAILS_ENV=production
+```
+
+### 3. Update Ruby
+
+We will continue supporting Ruby < 2.3 for the time being but we recommend you
+upgrade to Ruby 2.3 if you're running a source installation, as this is the same
+version that ships with our Omnibus package.
+
+You can check which version you are running with `ruby -v`.
+
+Download and compile Ruby:
+
+```bash
+mkdir /tmp/ruby && cd /tmp/ruby
+curl --remote-name --progress https://cache.ruby-lang.org/pub/ruby/2.3/ruby-2.3.1.tar.gz
+echo 'c39b4001f7acb4e334cb60a0f4df72d434bef711  ruby-2.3.1.tar.gz' | shasum --check - && tar xzf ruby-2.3.1.tar.gz
+cd ruby-2.3.1
+./configure --disable-install-rdoc
+make
+sudo make install
+```
+
+Install Bundler:
+
+```bash
+sudo gem install bundler --no-ri --no-rdoc
+```
+
+### 4. Get latest code
+
+```bash
+sudo -u git -H git fetch --all
+sudo -u git -H git checkout -- db/schema.rb # local changes will be restored automatically
+```
+
+For GitLab Community Edition:
+
+```bash
+sudo -u git -H git checkout 8-15-stable
+```
+
+OR
+
+For GitLab Enterprise Edition:
+
+```bash
+sudo -u git -H git checkout 8-15-stable-ee
+```
+
+### 5. Update gitlab-shell
+
+```bash
+cd /home/git/gitlab-shell
+sudo -u git -H git fetch --all --tags
+sudo -u git -H git checkout v4.0.0
+```
+
+### 6. Update gitlab-workhorse
+
+Install and compile gitlab-workhorse. This requires
+[Go 1.5](https://golang.org/dl) which should already be on your system from
+GitLab 8.1.
+
+```bash
+sudo -u git -H bundle exec rake "gitlab:workhorse:install[/home/git/gitlab-workhorse]" RAILS_ENV=production
+```
+
+### 7. Install libs, migrations, etc.
+
+```bash
+cd /home/git/gitlab
+
+# MySQL installations (note: the line below states '--without postgres')
+sudo -u git -H bundle install --without postgres development test --deployment
+
+# PostgreSQL installations (note: the line below states '--without mysql')
+sudo -u git -H bundle install --without mysql development test --deployment
+
+# Optional: clean up old gems
+sudo -u git -H bundle clean
+
+# Run database migrations
+sudo -u git -H bundle exec rake db:migrate RAILS_ENV=production
+
+# Clean up assets and cache
+sudo -u git -H bundle exec rake assets:clean assets:precompile cache:clear RAILS_ENV=production
+```
+
+### 8. Update configuration files
+
+#### New configuration options for `gitlab.yml`
+
+There are new configuration options available for [`gitlab.yml`](config/gitlab.yml.example). View them with the command below and apply them manually to your current `gitlab.yml`:
+
+```sh
+git diff origin/8-13-stable:config/gitlab.yml.example origin/8-15-stable:config/gitlab.yml.example
+```
+
+#### Git configuration
+
+Configure Git to generate packfile bitmaps (introduced in Git 2.0) on
+the GitLab server during `git gc`.
+
+```sh
+sudo -u git -H git config --global repack.writeBitmaps true
+```
+
+#### Nginx configuration
+
+Ensure you're still up-to-date with the latest NGINX configuration changes:
+
+```sh
+# For HTTPS configurations
+git diff origin/8-13-stable:lib/support/nginx/gitlab-ssl origin/8-15-stable:lib/support/nginx/gitlab-ssl
+
+# For HTTP configurations
+git diff origin/8-13-stable:lib/support/nginx/gitlab origin/8-15-stable:lib/support/nginx/gitlab
+```
+
+If you are using Apache instead of NGINX please see the updated [Apache templates].
+Also note that because Apache does not support upstreams behind Unix sockets you
+will need to let gitlab-workhorse listen on a TCP port. You can do this
+via [/etc/default/gitlab].
+
+[Apache templates]: https://gitlab.com/gitlab-org/gitlab-recipes/tree/master/web-server/apache
+[/etc/default/gitlab]: https://gitlab.com/gitlab-org/gitlab-ce/blob/8-15-stable/lib/support/init.d/gitlab.default.example#L38
+
+#### SMTP configuration
+
+If you're installing from source and use SMTP to deliver mail, you will need to add the following line
+to config/initializers/smtp_settings.rb:
+
+```ruby
+ActionMailer::Base.delivery_method = :smtp
+```
+
+See [smtp_settings.rb.sample] as an example.
+
+[smtp_settings.rb.sample]: https://gitlab.com/gitlab-org/gitlab-ce/blob/8-15-stable/config/initializers/smtp_settings.rb.sample#L13
+
+#### Init script
+
+Ensure you're still up-to-date with the latest init script changes:
+
+    sudo cp lib/support/init.d/gitlab /etc/init.d/gitlab
+
+For Ubuntu 16.04.1 LTS:
+
+    sudo systemctl daemon-reload
+
+### 9. Start application
+
+    sudo service gitlab start
+    sudo service nginx restart
+
+### 10. Check application status
+
+Check if GitLab and its environment are configured correctly:
+
+    sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production
+
+To make sure you didn't miss anything run a more thorough check:
+
+    sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production
+
+If all items are green, then congratulations, the upgrade is complete!
+
+## Things went south? Revert to previous version (8.14)
+
+### 1. Revert the code to the previous version
+
+Follow the [upgrade guide from 8.13 to 8.14](8.13-to-8.14.md), except for the
+database migration (the backup is already migrated to the previous version).
+
+### 2. Restore from the backup
+
+```bash
+cd /home/git/gitlab
+sudo -u git -H bundle exec rake gitlab:backup:restore RAILS_ENV=production
+```
+
+If you have more than one backup `*.tar` file(s) please add `BACKUP=timestamp_of_backup` to the command above.