Merge pull request #1866 from verult/faq-update

Adding header to last few questions of volume plugin faq

Author: k8s-ci-robot

sig-storage/volume-plugin-faq.md

@@ -7,7 +7,7 @@ Last Updated: 02/08/2018
 
 A *Kubernetes Volume plugin* extends the Kubernetes volume interface to support a block and/or file storage system.
 
-## In-tree vs Out-of-Tree Volume Plugins
+## In-tree vs. Out-of-Tree Volume Plugins
 
 **How do I implement a Volume plugin?**
 
@@ -18,7 +18,7 @@ There are three methods to implement a volume plugin:
 
 The Kubernetes Storage SIG, which is responsible for all volume code in the Kubernetes core repository, is no longer accepting new in-tree volume plugins. Instead, the SIG recommends storage vendors develop plugins as either FlexVolume or CSI drivers.
 
-**What is an in-tree vs out-of-tree volume plugin?**
+**What is an in-tree vs. out-of-tree volume plugin?**
 
 Before the introduction of the Container Storage Interface (CSI) and FlexVolume, all volume plugins were *in-tree* meaning they were built, linked, compiled, and shipped with the core Kubernetes binaries and extend the core Kubernetes API. This meant that adding a new storage system to Kubernetes (a volume plugin) required checking code into the core Kubernetes code repository.
 
@@ -75,6 +75,8 @@ For more information about Flex, see:
 *   FlexVolume requires root access on host machine to install FlexVolume driver files.
 *   FlexVolume drivers assume all volume mount dependencies, e.g. mount and filesystem tools, are available on the host OS. Installing these dependencies also require root access.
 
+## Working with Out-of-Tree Volume Plugin Options
+
 **Should I use CSI or FlexVolume?**
 
 The Storage SIG suggests implementing a CSI driver if possible. CSI overcomes the limitations of FlexVolume listed above, and the SIG plans to focus most of its development efforts on CSI in the long term. However, CSI is currently alpha, and will take several quarters to become GA. So if depending on alpha/beta software is a concern and you have a time constraint, implementing a FlexVolume driver may be a better option.