Merge pull request #4440 from klaus993/fix-instange-groups-docs

Fix instange groups docs

cmd/kops/create_ig.go

@@ -61,7 +61,7 @@ var (
 
 		# Create an instancegroup for the k8s-cluster.example.com cluster.
 		kops create ig --name=k8s-cluster.example.com node-example \
-		  --role node --subnet my-subnet-name
+		  --role node --subnet my-subnet-name,my-other-subnet-name
 
 		# Create a YAML manifest for an instancegroup for the k8s-cluster.example.com cluster.
 		kops create ig --name=k8s-cluster.example.com node-example \

cmd/kops/delete_instancegroup.go

@@ -42,6 +42,7 @@ var (
 
 		# Delete an instancegroup for the k8s-cluster.example.com cluster.
 		# The --yes option runs the command immediately.
+		# Note that the cloud resources will be deleted immediately, without running "kops update cluster"
 		kops delete ig --name=k8s-cluster.example.com node-example --yes
 		`))
 

docs/cli/kops_create_instancegroup.md

@@ -23,7 +23,7 @@ kops create instancegroup
 ```
   # Create an instancegroup for the k8s-cluster.example.com cluster.
   kops create ig --name=k8s-cluster.example.com node-example \
-  --role node --subnet my-subnet-name
+  --role node --subnet my-subnet-name,my-other-subnet-name
   
   # Create a YAML manifest for an instancegroup for the k8s-cluster.example.com cluster.
   kops create ig --name=k8s-cluster.example.com node-example \

docs/cli/kops_delete_instancegroup.md

@@ -19,6 +19,7 @@ kops delete instancegroup
 ```
   # Delete an instancegroup for the k8s-cluster.example.com cluster.
   # The --yes option runs the command immediately.
+  # Note that the cloud resources will be deleted immediately, without running "kops update cluster"
   kops delete ig --name=k8s-cluster.example.com node-example --yes
 ```
 

docs/instance_groups.md

@@ -105,13 +105,16 @@ spec:
 
 ## Creating a new instance group
 
-Suppose you want to add a new group of nodes, perhaps with a different instance type.  You do this using
-`kops create ig <InstanceGroupName>`.  Currently it opens an editor with a skeleton configuration, allowing
-you to edit it before creation.
+Suppose you want to add a new group of nodes, perhaps with a different instance type.  You do this using `kops create ig <InstanceGroupName> --subnet <zone(s)>`. Currently the
+`--subnet` flag is required, and it recieves the zone(s) of the subnet(s) in which the instance group will be. The command opens an editor with a skeleton configuration, allowing you to edit it before creation.
 
 So the procedure is:
 
-* `kops create ig morenodes`, edit and save
+* `kops create ig morenodes --subnet us-east-1a`
+
+  or, in case you need it to be in more than one subnet, use a comma-separated list:
+
+* `kops create ig morenodes --subnet us-east-1a,us-east-1b,us-east-1c`
 * Preview: `kops update cluster <clustername>`
 * Apply: `kops update cluster <clustername> --yes`
 * (no instances need to be relaunched, so no rolling-update is needed)
@@ -200,8 +203,7 @@ If you decide you don't need an InstanceGroup any more, you delete it using: `ko
 
 Example: `kops delete ig morenodes`
 
-No rolling-update is needed (and note this is not currently graceful, so there may be interruptions to
-workloads where the pods are running on those nodes).
+No `kops update cluster` nor `kops rolling-update` is needed, so **be careful** when deleting an instance group, your nodes will be deleted automatically (and note this is not currently graceful, so there may be interruptions to workloads where the pods are running on those nodes).
 
 ## EBS Volume Optimization