updated default kubernetes version to v1.18.10, fixed deprecated interpolation-only expressions (#243)

Author: hyder

docs/terraformoptions.adoc

@@ -450,8 +450,8 @@ admission_controller_options = {
 
 |`kubernetes_version`
 |The version of Kubernetes to provision. This is based on the available versions in OKE. By default, the latest version is selected. The use of 'LATEST' is no longer permitted in order to facilitate upgrades.
-|v1.15.7, v1.16.8 ,v1.17.9
-|v1.17.9
+|v1.16.8, v1.17.9, v1.18.10
+|v1.18.10
 
 |`node_pools`
 a|The number, shape of node pools and node_pool_size to create. Each key and tuple pair corresponds to 1 node pool.

docs/upgrade.adoc

@@ -42,13 +42,13 @@ This project supports only the out-of-place method of upgrading the worker nodes
 
 +
 ----
-kubernetes_version = "v1.15.7" 
+kubernetes_version = "v1.16.8" 
 ----
 to 
 
 +
 ----
-kubernetes_version = "v1.16.8"
+kubernetes_version = "v1.18.10"
 ----
 
 . Run terraform:
@@ -84,7 +84,7 @@ node_pools = {
 }
 ----
 
-When node pools 3 and 4 are created, they will be created with the cluster version of Kubernetes. Since you have already upgrade your cluster to `v1.16.8`, node pools 3 and 4 will be running Kubernetes v1.16.8
+When node pools 3 and 4 are created, they will be created with the cluster version of Kubernetes. Since you have already upgrade your cluster to `v1.18.10`, node pools 3 and 4 will be running Kubernetes v1.18.10
 
 . Set `nodepool_drain=true`. This will instruct the OKE cluster that some node pools will be drained.
 

modules/oke/drain.tf

@@ -14,7 +14,7 @@ data "template_file" "drainlist" {
      cluster_id       = oci_containerengine_cluster.k8s_cluster.id
      compartment_id   = var.compartment_id
      region           = var.region
-     pools_to_drain   = var.label_prefix == "none" ? trim(join(",", formatlist("'%s'", var.node_pools_to_drain)), "'") : trim(join(",", formatlist("'%s-%s'", "${var.label_prefix}", var.node_pools_to_drain)), "'")    
+     pools_to_drain   = var.label_prefix == "none" ? trim(join(",", formatlist("'%s'", var.node_pools_to_drain)), "'") : trim(join(",", formatlist("'%s-%s'", var.label_prefix, var.node_pools_to_drain)), "'")    
    }  
 
   count = var.nodepool_drain == true ? 1 : 0

terraform.tfvars.example

@@ -130,7 +130,7 @@ check_node_active = "none"
 
 dashboard_enabled = false
 
-kubernetes_version = "v1.17.9"
+kubernetes_version = "v1.18.10"
 
 node_pools = {
   np1 = {shape="VM.Standard.E3.Flex",ocpus=2,memory=20,node_pool_size=2,boot_volume_size=150}

variables.tf

@@ -275,7 +275,7 @@ variable "dashboard_enabled" {
 }
 
 variable "kubernetes_version" {
-  default     = "v.16.8"
+  default     = "v1.18.10"
   description = "The version of kubernetes to use when provisioning OKE or to upgrade an existing OKE cluster to."
   type        = string
 }