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Co-authored-by: Ciprian Hacman <[email protected]>

docs/operations/high_availability.md

@@ -6,13 +6,13 @@ For testing purposes, kubernetes works just fine with a single master. However,
 
 kops runs each master in a dedicated autoscaling groups (ASG) and stores data on EBS volumes. That way, if a master node is terminated the ASG will launch a new master instance with the master's volume. Because of the dedicated EBS volumes, each master is bound to a fixed Availability Zone (AZ). If the AZ becomes unavailable, the master instance in that AZ will also become unavailable.
 
-For production use, you therefore want to run kubernetes in a HA setup with multiple masters. With multiple master nodes, you will be able both to do graceful, zero-down time upgrades, and you will be able to survive AZ failures.
+For production use, you therefore want to run kubernetes in a HA setup with multiple masters. With multiple master nodes, you will be able both to do graceful (zero-downtime) upgrades and you will be able to survive AZ failures.
 
-A few regions offers less than 3 AZs. In this case, running multiple masters in the same AZ is an option. If the AZ with multiple masters in becomes unavailable, you will still have downtime, but upgrades will be graceful and without downtime.
+Very few regions offer less than 3 AZs. In this case, running multiple masters in the same AZ is an option. If the AZ with multiple masters becomes unavailable you will still have downtime with this configuration. But regular changes to master nodes such as upgrades will be graceful and without downtime.
 
 If you already have a single-master cluster you would like to convert to a multi-master cluster, read the [single to multi-master](../single-to-multi-master.md) docs.
 
-Note that running clusters spanning several AZs are more expensive than clusters spanning one or two AZs. Not only because of the master EC2 cost, but also because you have to pay for cross-AZ traffic. Depending on your workload you may therefore also want to consider running worker nodes only in two AZs.
+Note that running clusters spanning several AZs is more expensive than running clusters spanning one or two AZs. This happens not only because of the master EC2 cost, but also because you have to pay for cross-AZ traffic. Depending on your workload you may therefore also want to consider running worker nodes only in two AZs. As long as your application do not rely on quorum, you will still have AZ fault tolerance.
 
 ## Creating a HA cluster
 
@@ -56,4 +56,4 @@ kops create cluster \
     --zones cn-north-1a,cn-north-1b \
     --master-zones cn-north-1a,cn-north-1b \
     hacluster.k8s.local
-```
+```