Merge branch 'master' into 'bvl-nfs-circuitbreaker'

# Conflicts:
#   app/models/repository.rb
#   spec/models/repository_spec.rb

27 files changed, 646 insertions, 43 deletions

diff --git a/doc/articles/index.md b/doc/articles/index.md
index 9d2e5956029..558c624fe39 100644
--- a/doc/articles/index.md
+++ b/doc/articles/index.md
@@ -80,7 +80,7 @@ Install, upgrade, integrate, migrate to GitLab:
 | :------------ | :------: | --------------: |
 | [Video Tutorial: Idea to Production on Google Container Engine (GKE)](https://about.gitlab.com/2017/01/23/video-tutorial-idea-to-production-on-google-container-engine-gke/) | Tutorial | 2017/01/23 |
 | [How to Setup a GitLab Instance on Microsoft Azure](https://about.gitlab.com/2016/07/13/how-to-setup-a-gitlab-instance-on-microsoft-azure/) | Tutorial | 2016/07/13 |
-| [Get started with OpenShift Origin 3 and GitLab](https://about.gitlab.com/2016/06/28/get-started-with-openshift-origin-3-and-gitlab/) | Tutorial | 2016/06/28 |
+| [Get started with OpenShift Origin 3 and GitLab](openshift_and_gitlab/index.md) | Tutorial | 2016/06/28 |
 | [Getting started with GitLab and DigitalOcean](https://about.gitlab.com/2016/04/27/getting-started-with-gitlab-and-digitalocean/) | Tutorial | 2016/04/27 |
 
 ## Software development
diff --git a/doc/articles/openshift_and_gitlab/img/add-gitlab-to-project.png b/doc/articles/openshift_and_gitlab/img/add-gitlab-to-project.png
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diff --git a/doc/articles/openshift_and_gitlab/img/add-to-project.png b/doc/articles/openshift_and_gitlab/img/add-to-project.png
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diff --git a/doc/articles/openshift_and_gitlab/img/create-project-ui.png b/doc/articles/openshift_and_gitlab/img/create-project-ui.png
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diff --git a/doc/articles/openshift_and_gitlab/img/gitlab-logs.png b/doc/articles/openshift_and_gitlab/img/gitlab-logs.png
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+++ b/doc/articles/openshift_and_gitlab/img/gitlab-logs.png
diff --git a/doc/articles/openshift_and_gitlab/img/gitlab-overview.png b/doc/articles/openshift_and_gitlab/img/gitlab-overview.png
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diff --git a/doc/articles/openshift_and_gitlab/img/gitlab-running.png b/doc/articles/openshift_and_gitlab/img/gitlab-running.png
new file mode 100644
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+++ b/doc/articles/openshift_and_gitlab/img/gitlab-running.png
diff --git a/doc/articles/openshift_and_gitlab/img/gitlab-scale.png b/doc/articles/openshift_and_gitlab/img/gitlab-scale.png
new file mode 100644
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diff --git a/doc/articles/openshift_and_gitlab/img/gitlab-settings.png b/doc/articles/openshift_and_gitlab/img/gitlab-settings.png
new file mode 100644
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+++ b/doc/articles/openshift_and_gitlab/img/gitlab-settings.png
diff --git a/doc/articles/openshift_and_gitlab/img/no-resources.png b/doc/articles/openshift_and_gitlab/img/no-resources.png
new file mode 100644
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--- /dev/null
+++ b/doc/articles/openshift_and_gitlab/img/no-resources.png
diff --git a/doc/articles/openshift_and_gitlab/img/openshift-infra-project.png b/doc/articles/openshift_and_gitlab/img/openshift-infra-project.png
new file mode 100644
index 00000000000..8b9f85aa341
--- /dev/null
+++ b/doc/articles/openshift_and_gitlab/img/openshift-infra-project.png
diff --git a/doc/articles/openshift_and_gitlab/img/pods-overview.png b/doc/articles/openshift_and_gitlab/img/pods-overview.png
new file mode 100644
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--- /dev/null
+++ b/doc/articles/openshift_and_gitlab/img/pods-overview.png
diff --git a/doc/articles/openshift_and_gitlab/img/rc-name.png b/doc/articles/openshift_and_gitlab/img/rc-name.png
new file mode 100644
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+++ b/doc/articles/openshift_and_gitlab/img/rc-name.png
diff --git a/doc/articles/openshift_and_gitlab/img/running-pods.png b/doc/articles/openshift_and_gitlab/img/running-pods.png
new file mode 100644
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+++ b/doc/articles/openshift_and_gitlab/img/running-pods.png
diff --git a/doc/articles/openshift_and_gitlab/img/storage-volumes.png b/doc/articles/openshift_and_gitlab/img/storage-volumes.png
new file mode 100644
index 00000000000..ae1e5381faa
--- /dev/null
+++ b/doc/articles/openshift_and_gitlab/img/storage-volumes.png
diff --git a/doc/articles/openshift_and_gitlab/img/web-console.png b/doc/articles/openshift_and_gitlab/img/web-console.png
new file mode 100644
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diff --git a/doc/articles/openshift_and_gitlab/index.md b/doc/articles/openshift_and_gitlab/index.md
new file mode 100644
index 00000000000..7f76e577efa
--- /dev/null
+++ b/doc/articles/openshift_and_gitlab/index.md
@@ -0,0 +1,510 @@
+# Getting started with OpenShift Origin 3 and GitLab
+
+> **Article [Type](../../development/writing_documentation.html#types-of-technical-articles):** tutorial ||
+> **Level:** intermediary ||
+> **Author:** [Achilleas Pipinellis](https://gitlab.com/axil) ||
+> **Publication date:** 2016/06/28
+
+## Introduction
+
+[OpenShift Origin][openshift] is an open source container application
+platform created by [RedHat], based on [kubernetes] and [Docker]. That means
+you can host your own PaaS for free and almost with no hassle.
+
+In this tutorial, we will see how to deploy GitLab in OpenShift using GitLab's
+official Docker image while getting familiar with the web interface and CLI
+tools that will help us achieve our goal.
+
+---
+
+## Prerequisites
+
+OpenShift 3 is not yet deployed on RedHat's offered Online platform ([openshift.com]),
+so in order to test it, we will use an [all-in-one Virtualbox image][vm] that is
+offered by the OpenShift developers and managed by Vagrant. If you haven't done
+already, go ahead and install the following components as they are essential to
+test OpenShift easily:
+
+- [VirtualBox]
+- [Vagrant]
+- [OpenShift Client][oc] (`oc` for short)
+
+It is also important to mention that for the purposes of this tutorial, the
+latest Origin release is used:
+
+- **oc** `v1.3.0` (must be [installed][oc-gh] locally on your computer)
+- **openshift** `v1.3.0` (is pre-installed in the [VM image][vm-new])
+- **kubernetes** `v1.3.0` (is pre-installed in the [VM image][vm-new])
+
+>**Note:**
+If you intend to deploy GitLab on a production OpenShift cluster, there are some
+limitations to bare in mind. Read on the [limitations](#current-limitations)
+section for more information and follow the linked links for the relevant
+discussions.
+
+Now that you have all batteries, let's see how easy it is to test OpenShift
+on your computer.
+
+## Getting familiar with OpenShift Origin
+
+The environment we are about to use is based on CentOS 7 which comes with all
+the tools needed pre-installed: Docker, kubernetes, OpenShift, etcd.
+
+### Test OpenShift using Vagrant
+
+As of this writing, the all-in-one VM is at version 1.3, and that's
+what we will use in this tutorial.
+
+In short:
+
+1. Open a terminal and in a new directory run:
+   ```sh
+   vagrant init openshift/origin-all-in-one
+   ```
+1. This will generate a Vagrantfile based on the all-in-one VM image
+1. In the same directory where you generated the Vagrantfile
+   enter:
+
+   ```sh
+   vagrant up
+   ```
+
+This will download the VirtualBox image and fire up the VM with some preconfigured
+values as you can see in the Vagrantfile. As you may have noticed, you need
+plenty of RAM (5GB in our example), so make sure you have enough.
+
+Now that OpenShift is setup, let's see how the web console looks like.
+
+### Explore the OpenShift web console
+
+Once Vagrant finishes its thing with the VM, you will be presented with a
+message which has some important information. One of them is the IP address
+of the deployed OpenShift platform and in particular <https://10.2.2.2:8443/console/>.
+Open this link with your browser and accept the self-signed certificate in
+order to proceed.
+
+Let's login as admin with username/password `admin/admin`. This is what the
+landing page looks like:
+
+![openshift web console](img/web-console.png)
+
+You can see that a number of [projects] are already created for testing purposes.
+
+If you head over the `openshift-infra` project, a number of services with their
+respective pods are there to explore.
+
+![openshift web console](img/openshift-infra-project.png)
+
+We are not going to explore the whole interface, but if you want to learn about
+the key concepts of OpenShift, read the [core concepts reference][core] in the
+official documentation.
+
+### Explore the OpenShift CLI
+
+OpenShift Client (`oc`), is a powerful CLI tool that talks to the OpenShift API
+and performs pretty much everything you can do from the web UI and much more.
+
+Assuming you have [installed][oc] it, let's explore some of its main
+functionalities.
+
+Let's first see the version of `oc`:
+
+```sh
+$ oc version
+
+oc v1.3.0
+kubernetes v1.3.0+52492b4
+```
+
+With `oc help` you can see the top level arguments you can run with `oc` and
+interact with your cluster, kubernetes, run applications, create projects and
+much more.
+
+Let's login to the all-in-one VM and see how to achieve the same results like
+when we visited the web console earlier. The username/password for the
+administrator user is `admin/admin`. There is also a test user with username/
+password `user/user`, with limited access. Let's login as admin for the moment:
+
+```sh
+$ oc login https://10.2.2.2:8443
+
+Authentication required for https://10.2.2.2:8443 (openshift)
+Username: admin
+Password:
+Login successful.
+
+You have access to the following projects and can switch between them with 'oc project <projectname>':
+
+  * cockpit
+  * default (current)
+  * delete
+  * openshift
+  * openshift-infra
+  * sample
+
+Using project "default".
+```
+
+Switch to the `openshift-infra` project with:
+
+```sh
+oc project openshift-infra
+```
+
+And finally, see its status:
+
+```sh
+oc status
+```
+
+The last command should spit a bunch of information about the statuses of the
+pods and the services, which if you look closely is what we encountered in the
+second image when we explored the web console.
+
+You can always read more about `oc` in the [OpenShift CLI documentation][oc].
+
+### Troubleshooting the all-in-one VM
+
+Using the all-in-one VM gives you the ability to test OpenShift whenever you
+want. That means you get to play with it, shutdown the VM, and pick up where
+you left off.
+
+Sometimes though, you may encounter some issues, like OpenShift not running
+when booting up the VM. The web UI may not responding or you may see issues
+when trying to login with `oc`, like:
+
+```
+The connection to the server 10.2.2.2:8443 was refused - did you specify the right host or port?
+```
+
+In that case, the OpenShift service might not be running, so in order to fix it:
+
+1. SSH into the VM by going to the directory where the Vagrantfile is and then
+   run:
+
+   ```sh
+   vagrant ssh
+   ```
+
+1. Run `systemctl` and verify by the output that the `openshift` service is not
+   running (it will be in red color). If that's the case start the service with:
+
+   ```sh
+   sudo systemctl start openshift
+   ```
+
+1. Verify the service is up with:
+
+   ```sh
+   systemctl status openshift -l
+   ```
+
+Now you will be able to login using `oc` (like we did before) and visit the web
+console.
+
+## Deploy GitLab
+
+Now that you got a taste of what OpenShift looks like, let's deploy GitLab!
+
+### Create a new project
+
+First, we will create a new project to host our application. You can do this
+either by running the CLI client:
+
+```bash
+$ oc new-project gitlab
+```
+
+or by using the web interface:
+
+![Create a new project from the UI](img/create-project-ui.png)
+
+If you used the command line, `oc` automatically uses the new project and you
+can see its status with:
+
+```sh
+$ oc status
+
+In project gitlab on server https://10.2.2.2:8443
+
+You have no services, deployment configs, or build configs.
+Run 'oc new-app' to create an application.
+```
+
+If you visit the web console, you can now see `gitlab` listed in the projects list.
+
+The next step is to import the OpenShift template for GitLab.
+
+### Import the template
+
+The [template][templates] is basically a JSON file which describes a set of
+related object definitions to be created together, as well as a set of
+parameters for those objects.
+
+The template for GitLab resides in the Omnibus GitLab repository under the
+docker directory. Let's download it locally with `wget`:
+
+```bash
+wget https://gitlab.com/gitlab-org/omnibus-gitlab/raw/master/docker/openshift-template.json
+```
+
+And then let's import it in OpenShift:
+
+```bash
+oc create -f openshift-template.json -n openshift
+```
+
+>**Note:**
+The `-n openshift` namespace flag is a trick to make the template available to all
+projects. If you recall from when we created the `gitlab` project, `oc` switched
+to it automatically, and that can be verified by the `oc status` command. If
+you omit the namespace flag, the application will be available only to the
+current project, in our case `gitlab`. The `openshift` namespace is a global
+one that the administrators should use if they want the application to be
+available to all users.
+
+We are now ready to finally deploy GitLab!
+
+### Create a new application
+
+The next step is to use the template we previously imported. Head over to the
+`gitlab` project and hit the **Add to Project** button.
+
+![Add to project](img/add-to-project.png)
+
+This will bring you to the catalog where you can find all the pre-defined
+applications ready to deploy with the click of a button. Search for `gitlab`
+and you will see the previously imported template:
+
+![Add GitLab to project](img/add-gitlab-to-project.png)
+
+Select it, and in the following screen you will be presented with the predefined
+values used with the GitLab template:
+
+![GitLab settings](img/gitlab-settings.png)
+
+Notice at the top that there are three resources to be created with this
+template:
+
+- `gitlab-ce`
+- `gitlab-ce-redis`
+- `gitlab-ce-postgresql`
+
+While PostgreSQL and Redis are bundled in Omnibus GitLab, the template is using
+separate images as you can see from [this line][line] in the template.
+
+The predefined values have been calculated for the purposes of testing out
+GitLab in the all-in-one VM. You don't need to change anything here, hit
+**Create** to start the deployment.
+
+If you are deploying to production you will want to change the **GitLab instance
+hostname** and use greater values for the volume sizes. If you don't provide a
+password for PostgreSQL, it will be created automatically.
+
+>**Note:**
+The `gitlab.apps.10.2.2.2.xip.io` hostname that is used by default will
+resolve to the host with IP `10.2.2.2` which is the IP our VM uses. It is a
+trick to have distinct FQDNs pointing to services that are on our local network.
+Read more on how this works in <http://xip.io>.
+
+Now that we configured this, let's see how to manage and scale GitLab.
+
+## Manage and scale GitLab
+
+Setting up GitLab for the first time might take a while depending on your
+internet connection and the resources you have attached to the all-in-one VM.
+GitLab's docker image is quite big (~500MB), so you'll have to wait until
+it's downloaded and configured before you use it.
+
+### Watch while GitLab gets deployed
+
+Navigate to the `gitlab` project at **Overview**. You can notice that the
+deployment is in progress by the orange color. The Docker images are being
+downloaded and soon they will be up and running.
+
+![GitLab overview](img/gitlab-overview.png)
+
+Switch to the **Browse > Pods** and you will eventually see all 3 pods in a
+running status. Remember the 3 resources that were to be created when we first
+created the GitLab app? This is where you can see them in action.
+
+![Running pods](img/running-pods.png)
+
+You can see GitLab being reconfigured by taking look at the logs in realtime.
+Click on `gitlab-ce-2-j7ioe` (your ID will be different) and go to the **Logs**
+tab.
+
+![GitLab logs](img/gitlab-logs.png)
+
+At a point you should see a _**gitlab Reconfigured!**_ message in the logs.
+Navigate back to the **Overview** and hopefully all pods will be up and running.
+
+![GitLab running](img/gitlab-running.png)
+
+Congratulations! You can now navigate to your new shinny GitLab instance by
+visiting <http://gitlab.apps.10.2.2.2.xip.io> where you will be asked to
+change the root user password. Login using `root` as username and providing the
+password you just set, and start using GitLab!
+
+### Scale GitLab with the push of a button
+
+If you reach to a point where your GitLab instance could benefit from a boost
+of resources, you'd be happy to know that you can scale up with the push of a
+button.
+
+In the **Overview** page just click the up arrow button in the pod where
+GitLab is. The change is instant and you can see the number of [replicas] now
+running scaled to 2.
+
+![GitLab scale](img/gitlab-scale.png)
+
+Upping the GitLab pods is actually like adding new application servers to your
+cluster. You can see how that would work if you didn't use GitLab with
+OpenShift by following the [HA documentation][ha] for the application servers.
+
+Bare in mind that you may need more resources (CPU, RAM, disk space) when you
+scale up. If a pod is in pending state for too long, you can navigate to
+**Browse > Events** and see the reason and message of the state.
+
+![No resources](img/no-resources.png)
+
+### Scale GitLab using the `oc` CLI
+
+Using `oc` is super easy to scale up the replicas of a pod. You may want to
+skim through the [basic CLI operations][basic-cli] to get a taste how the CLI
+commands are used. Pay extra attention to the object types as we will use some
+of them and their abbreviated versions below.
+
+In order to scale up, we need to find out the name of the replication controller.
+Let's see how to do that using the following steps.
+
+1. Make sure you are in the `gitlab` project:
+
+   ```sh
+   oc project gitlab
+   ```
+
+1. See what services are used for this project:
+
+   ```sh
+   oc get svc
+   ```
+
+   The output will be similar to:
+
+   ```
+   NAME                   CLUSTER-IP       EXTERNAL-IP   PORT(S)         AGE
+   gitlab-ce              172.30.243.177   <none>        22/TCP,80/TCP   5d
+   gitlab-ce-postgresql   172.30.116.75    <none>        5432/TCP        5d
+   gitlab-ce-redis        172.30.105.88    <none>        6379/TCP        5d
+   ```
+
+1. We need to see the replication controllers of the `gitlab-ce` service.
+   Get a detailed view of the current ones:
+
+   ```sh
+   oc describe rc gitlab-ce
+   ```
+
+   This will return a large detailed list of the current replication controllers.
+   Search for the name of the GitLab controller, usually `gitlab-ce-1` or if
+   that failed at some point and you spawned another one, it will be named
+   `gitlab-ce-2`.
+
+1. Scale GitLab using the previous information:
+
+   ```sh
+   oc scale --replicas=2 replicationcontrollers gitlab-ce-2
+   ```
+
+1. Get the new replicas number to make sure scaling worked:
+
+   ```sh
+   oc get rc gitlab-ce-2
+   ```
+
+   which will return something like:
+
+   ```
+   NAME          DESIRED   CURRENT   AGE
+   gitlab-ce-2   2         2         5d
+   ```
+
+And that's it! We successfully scaled the replicas to 2 using the CLI.
+
+As always, you can find the name of the controller using the web console. Just
+click on the service you are interested in and you will see the details in the
+right sidebar.
+
+![Replication controller name](img/rc-name.png)
+
+### Autoscaling GitLab
+
+In case you were wondering whether there is an option to autoscale a pod based
+on the resources of your server, the answer is yes, of course there is.
+
+We will not expand on this matter, but feel free to read the documentation on
+OpenShift's website about [autoscaling].
+
+## Current limitations
+
+As stated in the [all-in-one VM][vm] page:
+
+> By default, OpenShift will not allow a container to run as root or even a
+non-random container assigned userid. Most Docker images in the Dockerhub do not
+follow this best practice and instead run as root.
+
+The all-in-one VM we are using has this security turned off so it will not
+bother us. In any case, it is something to keep in mind when deploying GitLab
+on a production cluster.
+
+In order to deploy GitLab on a production cluster, you will need to assign the
+GitLab service account  to the `anyuid` Security Context.
+
+1. Edit the Security Context:
+   ```sh
+   oc edit scc anyuid
+   ```
+
+1. Add `system:serviceaccount:<project>:gitlab-ce-user` to the `users` section.
+   If you changed the Application Name from the default the user will
+     will be `<app-name>-user` instead of `gitlab-ce-user`
+
+1. Save and exit the editor
+
+## Conclusion
+
+By now, you should have an understanding of the basic OpenShift Origin concepts
+and a sense of how things work using the web console or the CLI.
+
+GitLab was hard to install in previous versions of OpenShift,
+but now that belongs to the past. Upload a template, create a project, add an
+application and you are done. You are ready to login to your new GitLab instance.
+
+And remember that in this tutorial we just scratched the surface of what Origin
+is capable of. As always, you can refer to the detailed
+[documentation][openshift-docs] to learn more about deploying your own OpenShift
+PaaS and managing your applications with the ease of containers.
+
+[RedHat]: https://www.redhat.com/en "RedHat website"
+[openshift]: https://www.openshift.org "OpenShift Origin website"
+[vm]: https://www.openshift.org/vm/ "OpenShift All-in-one VM"
+[vm-new]: https://atlas.hashicorp.com/openshift/boxes/origin-all-in-one "Official OpenShift Vagrant box on Atlas"
+[template]: https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/docker/openshift-template.json "OpenShift template for GitLab"
+[openshift.com]: https://openshift.com "OpenShift Online"
+[kubernetes]: http://kubernetes.io/ "Kubernetes website"
+[Docker]: https://www.docker.com "Docker website"
+[oc]: https://docs.openshift.org/latest/cli_reference/get_started_cli.html "Documentation - oc CLI documentation"
+[VirtualBox]: https://www.virtualbox.org/wiki/Downloads "VirtualBox downloads"
+[Vagrant]: https://www.vagrantup.com/downloads.html "Vagrant downloads"
+[projects]: https://docs.openshift.org/latest/dev_guide/projects.html "Documentation - Projects overview"
+[core]: https://docs.openshift.org/latest/architecture/core_concepts/index.html "Documentation - Core concepts of OpenShift Origin"
+[templates]: https://docs.openshift.org/latest/architecture/core_concepts/templates.html "Documentation - OpenShift templates"
+[old-post]: https://blog.openshift.com/deploy-gitlab-openshift/ "Old post - Deploy GitLab on OpenShift"
+[line]: https://gitlab.com/gitlab-org/omnibus-gitlab/blob/658c065c8d022ce858dd63eaeeadb0b2ddc8deea/docker/openshift-template.json#L239 "GitLab - OpenShift template"
+[oc-gh]: https://github.com/openshift/origin/releases/tag/v1.3.0 "Openshift 1.3.0 release on GitHub"
+[ha]: http://docs.gitlab.com/ce/administration/high_availability/gitlab.html "Documentation - GitLab High Availability"
+[replicas]: https://docs.openshift.org/latest/architecture/core_concepts/deployments.html#replication-controllers "Documentation - Replication controller"
+[autoscaling]: https://docs.openshift.org/latest/dev_guide/pod_autoscaling.html "Documentation - Autoscale"
+[basic-cli]: https://docs.openshift.org/latest/cli_reference/basic_cli_operations.html "Documentation - Basic CLI operations"
+[openshift-docs]: https://docs.openshift.org "OpenShift documentation"
diff --git a/doc/development/background_migrations.md b/doc/development/background_migrations.md
index e67db9ff142..f83a60e49e8 100644
--- a/doc/development/background_migrations.md
+++ b/doc/development/background_migrations.md
@@ -7,6 +7,11 @@ storing data in a single JSON column the data is stored in a separate table.
 
 ## When To Use Background Migrations
 
+>**Note:**
+When adding background migrations _you must_ make sure they are announced in the
+monthly release post along with an estimate of how long it will take to complete
+the migrations.
+
 In the vast majority of cases you will want to use a regular Rails migration
 instead. Background migrations should _only_ be used when migrating _data_ in
 tables that have so many rows this process would take hours when performed in a
@@ -91,6 +96,10 @@ BackgroundMigrationWorker.perform_bulk_in(5.minutes, jobs)
 
 ## Cleaning Up
 
+>**Note:**
+Cleaning up any remaining background migrations _must_ be done in either a major
+or minor release, you _must not_ do this in a patch release.
+
 Because background migrations can take a long time you can't immediately clean
 things up after scheduling them. For example, you can't drop a column that's
 used in the migration process as this would cause jobs to fail. This means that
diff --git a/doc/development/fe_guide/style_guide_js.md b/doc/development/fe_guide/style_guide_js.md
index 149a0159680..6ade3231fac 100644
--- a/doc/development/fe_guide/style_guide_js.md
+++ b/doc/development/fe_guide/style_guide_js.md
@@ -11,7 +11,7 @@ See [our current .eslintrc][eslintrc] for specific rules and patterns.
 
 #### ESlint
 
-1. **Never** disable eslint rules unless you have a good reason.  
+1. **Never** disable eslint rules unless you have a good reason.
 You may see a lot of legacy files with `/* eslint-disable some-rule, some-other-rule */`
 at the top, but legacy files are a special case.  Any time you develop a new feature or
 refactor an existing one, you should abide by the eslint rules.
@@ -100,26 +100,44 @@ followed by any global declarations, then a blank newline prior to any imports o
     export default Foo;
   ```
 
-1. Relative paths: Unless you are writing a test, always reference other scripts using
-relative paths instead of `~`
-  * In **app/assets/javascripts**:
+1. Relative paths: when importing a module in the same directory, a child
+directory, or an immediate parent directory prefer relative paths.  When
+importing a module which is two or more levels up, prefer either `~/` or `ee/`
+.
 
-    ```javascript
-      // bad
-      import Foo from '~/foo'
+In **app/assets/javascripts/my-feature/subdir**:
 
-      // good
-      import Foo from '../foo';
-    ```
-  * In **spec/javascripts**:
+``` javascript
+// bad
+import Foo from '~/my-feature/foo';
+import Bar from '~/my-feature/subdir/bar';
+import Bin from '~/my-feature/subdir/lib/bin';
 
-    ```javascript
-      // bad
-      import Foo from '../../app/assets/javascripts/foo'
+// good
+import Foo from '../foo';
+import Bar from './bar';
+import Bin from './lib/bin';
+```
 
-      // good
-      import Foo from '~/foo';
-    ```
+In **spec/javascripts**:
+
+``` javascript
+// bad
+import Foo from '../../app/assets/javascripts/my-feature/foo';
+
+// good
+import Foo from '~/my-feature/foo';
+```
+
+When referencing an **EE component**:
+
+``` javascript
+// bad
+import Foo from '../../../../../ee/app/assets/javascripts/my-feature/ee-foo';
+
+// good
+import Foo from 'ee/my-feature/foo';
+```
 
 1. Avoid using IIFE. Although we have a lot of examples of files which wrap their
 contents in IIFEs (immediately-invoked function expressions),
@@ -465,7 +483,7 @@ A forEach will cause side effects, it will be mutating the array being iterated.
 
 #### Vue and Boostrap
 1. Tooltips: Do not rely on `has-tooltip` class name for Vue components
-  ```javascript
+  ```javascript
     // bad
     <span
       class="has-tooltip"
diff --git a/doc/development/migration_style_guide.md b/doc/development/migration_style_guide.md
index 161d2544169..9b8ab5da74e 100644
--- a/doc/development/migration_style_guide.md
+++ b/doc/development/migration_style_guide.md
@@ -35,12 +35,11 @@ Please don't depend on GitLab-specific code since it can change in future
 versions. If needed copy-paste GitLab code into the migration to make it forward
 compatible.
 
-## Commit Guidelines
+## Schema Changes
 
-Each migration **must** be added in its own commit with a descriptive commit
-message. If a commit adds a migration it _should only_ include the migration and
-any corresponding changes to `db/schema.rb`. This makes it easy to revert a
-database migration without accidentally reverting other changes.
+Migrations that make changes to the database schema (e.g. adding a column) can
+only be added in the monthly release, patch releases may only contain data
+migrations _unless_ schema changes are absolutely required to solve a problem.
 
 ## Downtime Tagging
 
@@ -224,9 +223,9 @@ add_column(:projects, :foo, :integer, default: 10, limit: 8)
 
 ## Timestamp column type
 
-By default, Rails uses the `timestamp` data type that stores timestamp data without timezone information.        
-The `timestamp` data type is used by calling either the `add_timestamps` or the `timestamps` method.       
-Also Rails converts the `:datetime` data type to the `timestamp` one.        
+By default, Rails uses the `timestamp` data type that stores timestamp data without timezone information.
+The `timestamp` data type is used by calling either the `add_timestamps` or the `timestamps` method.
+Also Rails converts the `:datetime` data type to the `timestamp` one.
 
 Example:
 
diff --git a/doc/install/installation.md b/doc/install/installation.md
index 8ded607bcab..22aedb5403e 100644
--- a/doc/install/installation.md
+++ b/doc/install/installation.md
@@ -168,8 +168,10 @@ are out of date, so we'll need to install through the following commands:
     curl --location https://deb.nodesource.com/setup_7.x | sudo bash -
     sudo apt-get install -y nodejs
 
-    # install yarn
-    curl --location https://yarnpkg.com/install.sh | bash -
+    curl --silent --show-error https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+    echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
+    sudo apt-get update
+    sudo apt-get install yarn
 
 Visit the official websites for [node](https://nodejs.org/en/download/package-manager/) and [yarn](https://yarnpkg.com/en/docs/install/) if you have any trouble with these steps.
 
diff --git a/doc/update/8.17-to-9.0.md b/doc/update/8.17-to-9.0.md
index 6308317b1f2..4d3ababaa41 100644
--- a/doc/update/8.17-to-9.0.md
+++ b/doc/update/8.17-to-9.0.md
@@ -65,7 +65,10 @@ Since 8.17, GitLab requires the use of yarn `>= v0.17.0` to manage
 JavaScript dependencies.
 
 ```bash
-curl --location https://yarnpkg.com/install.sh | bash -
+curl --silent --show-error https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
+sudo apt-get update
+sudo apt-get install yarn
 ```
 
 More information can be found on the [yarn website](https://yarnpkg.com/en/docs/install).
diff --git a/doc/update/9.0-to-9.1.md b/doc/update/9.0-to-9.1.md
index 2d597894517..2b4a7bed27f 100644
--- a/doc/update/9.0-to-9.1.md
+++ b/doc/update/9.0-to-9.1.md
@@ -65,7 +65,10 @@ Since 8.17, GitLab requires the use of yarn `>= v0.17.0` to manage
 JavaScript dependencies.
 
 ```bash
-curl --location https://yarnpkg.com/install.sh | bash -
+curl --silent --show-error https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
+sudo apt-get update
+sudo apt-get install yarn
 ```
 
 More information can be found on the [yarn website](https://yarnpkg.com/en/docs/install).
diff --git a/doc/update/9.1-to-9.2.md b/doc/update/9.1-to-9.2.md
index 225a4dcc924..f38547bba1a 100644
--- a/doc/update/9.1-to-9.2.md
+++ b/doc/update/9.1-to-9.2.md
@@ -65,7 +65,10 @@ Since 8.17, GitLab requires the use of yarn `>= v0.17.0` to manage
 JavaScript dependencies.
 
 ```bash
-curl --location https://yarnpkg.com/install.sh | bash -
+curl --silent --show-error https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
+sudo apt-get update
+sudo apt-get install yarn
 ```
 
 More information can be found on the [yarn website](https://yarnpkg.com/en/docs/install).
diff --git a/doc/update/9.2-to-9.3.md b/doc/update/9.2-to-9.3.md
index 910539acc70..373f43eb3bb 100644
--- a/doc/update/9.2-to-9.3.md
+++ b/doc/update/9.2-to-9.3.md
@@ -65,7 +65,10 @@ Since 8.17, GitLab requires the use of yarn `>= v0.17.0` to manage
 JavaScript dependencies.
 
 ```bash
-curl --location https://yarnpkg.com/install.sh | bash -
+curl --silent --show-error https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
+sudo apt-get update
+sudo apt-get install yarn
 ```
 
 More information can be found on the [yarn website](https://yarnpkg.com/en/docs/install).
diff --git a/doc/update/9.3-to-9.4.md b/doc/update/9.3-to-9.4.md
index 9540c36e7d0..b167f0737aa 100644
--- a/doc/update/9.3-to-9.4.md
+++ b/doc/update/9.3-to-9.4.md
@@ -65,7 +65,10 @@ Since 8.17, GitLab requires the use of yarn `>= v0.17.0` to manage
 JavaScript dependencies.
 
 ```bash
-curl --location https://yarnpkg.com/install.sh | bash -
+curl --silent --show-error https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
+sudo apt-get update
+sudo apt-get install yarn
 ```
 
 More information can be found on the [yarn website](https://yarnpkg.com/en/docs/install).
diff --git a/doc/update/README.md b/doc/update/README.md
index 22dbc7c750f..c98e20686e0 100644
--- a/doc/update/README.md
+++ b/doc/update/README.md
@@ -34,17 +34,67 @@ update them are in [a separate document][omnidocker].
 
 ## Upgrading without downtime
 
-Starting with GitLab 9.1.0 it's possible to upgrade to a newer major, minor, or patch version of GitLab
-without having to take your GitLab instance offline. However, for this to work
-there are the following requirements:
-
-1. You can only upgrade 1 minor release at a time. So from 9.1 to 9.2, not to 9.3.
-2. You have to be on the most recent patch release. For example, if 9.1.15 is the last
-   release of 9.1 then you can safely upgrade from that version to any 9.2.x version.
-   However, if you are running 9.1.14 you first need to upgrade to 9.1.15.
+Starting with GitLab 9.1.0 it's possible to upgrade to a newer major, minor, or
+patch version of GitLab without having to take your GitLab instance offline.
+However, for this to work there are the following requirements:
+
+1. You can only upgrade 1 minor release at a time. So from 9.1 to 9.2, not to
+   9.3.
 2. You have to use [post-deployment
    migrations](../development/post_deployment_migrations.md).
-3. You are using PostgreSQL. If you are using MySQL please look at the release post to see if downtime is required.
+3. You are using PostgreSQL. If you are using MySQL please look at the release
+   post to see if downtime is required.
+
+Most of the time you can safely upgrade from a patch release to the next minor
+release if the patch release is not the latest. For example, upgrading from
+9.1.1 to 9.2.0 should be safe even if 9.1.2 has been released. We do recommend
+you check the release posts of any releases between your current and target
+version just in case they include any migrations that may require you to upgrade
+1 release at a time.
+
+Some releases may also include so called "background migrations". These
+migrations are performed in the background by Sidekiq and are often used for
+migrating data. Background migrations are only added in the monthly releases.
+
+Certain major/minor releases may require a set of background migrations to be
+finished. To guarantee this such a release will process any remaining jobs
+before continuing the upgrading procedure. While this won't require downtime
+(if the above conditions are met) we recommend users to keep at least 1 week
+between upgrading major/minor releases, allowing the background migrations to
+finish. The time necessary to complete these migrations can be reduced by
+increasing the number of Sidekiq workers that can process jobs in the
+`background_migration` queue.
+
+As a rule of thumb, any database smaller than 10 GB won't take too much time to
+upgrade; perhaps an hour at most per minor release. Larger databases however may
+require more time, but this is highly dependent on the size of the database and
+the migrations that are being performed.
+
+### Examples
+
+To help explain this, let's look at some examples.
+
+**Example 1:** You are running a large GitLab installation using version 9.4.2,
+which is the latest patch release of 9.4. When GitLab 9.5.0 is released this
+installation can be safely upgraded to 9.5.0 without requiring downtime if the
+requirements mentioned above are met. You can also skip 9.5.0 and upgrade to
+9.5.1 once it's released, but you **can not** upgrade straight to 9.6.0; you
+_have_ to first upgrade to a 9.5.x release.
+
+**Example 2:** You are running a large GitLab installation using version 9.4.2,
+which is the latest patch release of 9.4. GitLab 9.5 includes some background
+migrations, and 10.0 will require these to be completed (processing any
+remaining jobs for you). Skipping 9.5 is not possible without downtime, and due
+to the background migrations would require potentially hours of downtime
+depending on how long it takes for the background migrations to complete. To
+work around this you will have to upgrade to 9.5.x first, then wait at least a
+week before upgrading to 10.0.
+
+**Example 3:** You use MySQL as the database for GitLab. Any upgrade to a new
+major/minor release will require downtime. If a release includes any background
+migrations this could potentially lead to hours of downtime, depending on the
+size of your database. To work around this you will have to use PostgreSQL and
+meet the other online upgrade requirements mentioned above.
 
 ## Upgrading between editions