chore: document update variants (#386)

* Fix #317

Author: kopachevsky

README.md

@@ -10,7 +10,6 @@ The resources/services/activations/deletions that this module will create/trigge
 
 Sub modules are provided from creating private clusters, beta private clusters, and beta public clusters as well.  Beta sub modules allow for the use of various GKE beta features. See the modules directory for the various sub modules.
 
-
 ## Compatibility
 
 This module is meant for use with Terraform 0.12. If you haven't

autogen/main/README.md

@@ -28,7 +28,30 @@ If you are using these features with a private cluster, you will need to either:
 If you are going to isolate your GKE private clusters from internet access you could check [guide](https://medium.com/google-cloud/completely-private-gke-clusters-with-no-internet-connectivity-945fffae1ccd) and [repo](https://github.com/andreyk-code/no-inet-gke-cluster)
 
 {% endif %}
+{% if update_variant %}
+## Node Pool Update Variant
 
+In [#256] update variants added support for node pools to be created before being destroyed.
+
+Before, if a node pool has to be recreated for any number of reasons,
+the node pool is deleted then, created. This can be a problem if it is the only node pool in the GKE
+cluster and the new node pool cannot be provisioned. In this scenario, pods could not be scheduled.
+[#256] allows a node pool to be created before it is deleted so that any issues with node pool creation
+and/or provisioning are discovered before the node pool is removed. This feature is controlled by the
+variable `node_pools_create_before_destroy`. In order to avoid node pool name collisions,
+a 4 character alphanumeric is added as a suffix to the name.
+
+The benefit is that you always have some node pools active.
+We don't actually cordon/drain the traffic beyond what the GKE API itself will do,
+but we do make sure the new node pool is created before the old one is destroyed.
+
+The implications of this are that:
+
+- We append a random ID on the node pool names (since you can't have two simultaneously active node pools)
+- For a brief period, you'll have 2x as many resources/node pools
+- You will indeed need sufficient IP space (and compute capacity) to create both node pools
+
+{% endif %}
 ## Compatibility
 
 This module is meant for use with Terraform 0.12. If you haven't

modules/beta-private-cluster-update-variant/README.md

@@ -25,6 +25,27 @@ If you are using these features with a private cluster, you will need to either:
 
 If you are going to isolate your GKE private clusters from internet access you could check [guide](https://medium.com/google-cloud/completely-private-gke-clusters-with-no-internet-connectivity-945fffae1ccd) and [repo](https://github.com/andreyk-code/no-inet-gke-cluster)
 
+## Node Pool Update Variant
+
+In [#256] update variants added support for node pools to be created before being destroyed.
+
+Before, if a node pool has to be recreated for any number of reasons,
+the node pool is deleted then, created. This can be a problem if it is the only node pool in the GKE
+cluster and the new node pool cannot be provisioned. In this scenario, pods could not be scheduled.
+[#256] allows a node pool to be created before it is deleted so that any issues with node pool creation
+and/or provisioning are discovered before the node pool is removed. This feature is controlled by the
+variable `node_pools_create_before_destroy`. In order to avoid node pool name collisions,
+a 4 character alphanumeric is added as a suffix to the name.
+
+The benefit is that you always have some node pools active.
+We don't actually cordon/drain the traffic beyond what the GKE API itself will do,
+but we do make sure the new node pool is created before the old one is destroyed.
+
+The implications of this are that:
+
+- We append a random ID on the node pool names (since you can't have two simultaneously active node pools)
+- For a brief period, you'll have 2x as many resources/node pools
+- You will indeed need sufficient IP space (and compute capacity) to create both node pools
 
 ## Compatibility
 

modules/beta-private-cluster/README.md

@@ -25,7 +25,6 @@ If you are using these features with a private cluster, you will need to either:
 
 If you are going to isolate your GKE private clusters from internet access you could check [guide](https://medium.com/google-cloud/completely-private-gke-clusters-with-no-internet-connectivity-945fffae1ccd) and [repo](https://github.com/andreyk-code/no-inet-gke-cluster)
 
-
 ## Compatibility
 
 This module is meant for use with Terraform 0.12. If you haven't

modules/beta-public-cluster/README.md

@@ -10,7 +10,6 @@ The resources/services/activations/deletions that this module will create/trigge
 
 Sub modules are provided from creating private clusters, beta private clusters, and beta public clusters as well.  Beta sub modules allow for the use of various GKE beta features. See the modules directory for the various sub modules.
 
-
 ## Compatibility
 
 This module is meant for use with Terraform 0.12. If you haven't

modules/private-cluster-update-variant/README.md

@@ -25,6 +25,27 @@ If you are using these features with a private cluster, you will need to either:
 
 If you are going to isolate your GKE private clusters from internet access you could check [guide](https://medium.com/google-cloud/completely-private-gke-clusters-with-no-internet-connectivity-945fffae1ccd) and [repo](https://github.com/andreyk-code/no-inet-gke-cluster)
 
+## Node Pool Update Variant
+
+In [#256] update variants added support for node pools to be created before being destroyed.
+
+Before, if a node pool has to be recreated for any number of reasons,
+the node pool is deleted then, created. This can be a problem if it is the only node pool in the GKE
+cluster and the new node pool cannot be provisioned. In this scenario, pods could not be scheduled.
+[#256] allows a node pool to be created before it is deleted so that any issues with node pool creation
+and/or provisioning are discovered before the node pool is removed. This feature is controlled by the
+variable `node_pools_create_before_destroy`. In order to avoid node pool name collisions,
+a 4 character alphanumeric is added as a suffix to the name.
+
+The benefit is that you always have some node pools active.
+We don't actually cordon/drain the traffic beyond what the GKE API itself will do,
+but we do make sure the new node pool is created before the old one is destroyed.
+
+The implications of this are that:
+
+- We append a random ID on the node pool names (since you can't have two simultaneously active node pools)
+- For a brief period, you'll have 2x as many resources/node pools
+- You will indeed need sufficient IP space (and compute capacity) to create both node pools
 
 ## Compatibility
 

modules/private-cluster/README.md

@@ -25,7 +25,6 @@ If you are using these features with a private cluster, you will need to either:
 
 If you are going to isolate your GKE private clusters from internet access you could check [guide](https://medium.com/google-cloud/completely-private-gke-clusters-with-no-internet-connectivity-945fffae1ccd) and [repo](https://github.com/andreyk-code/no-inet-gke-cluster)
 
-
 ## Compatibility
 
 This module is meant for use with Terraform 0.12. If you haven't