Barebones readme

README.md

@@ -1 +1,17 @@
-# tfmod-eks-storage-classes
+# tfmod-eks-configuration
+
+The module configures an eks cluster with additional components after the cluster is created.
+
+- Storage classes
+  - A gp3-encrypted storage class is created and made the default storage class
+    - This storage class is returned as the `rwo_storage_class`
+  - A gp2-encrypted storage class is created
+  - An efs storage class is created
+    - This storage class is returned as the `rwx_storage_class`
+- cluster-autoscaler
+  - Monitors cpu/memory usage by components being deployed to the clsuter.
+    - When the cluster is out of capacity, the autoscaler will add nodes to the cluster up to the maximum size of the node group.
+    - When the autoscaler detects excess capacity, the autoscaler will cause EKS to migrate pods running on the node to a different node and then remove the node from the cluster.
+
+When selecting which version of the cluster-autoscaler to install, use the one that is closest to the same version as the `cluster_version` or slightly higher.
+The cluster-autoscaler uses the kuberentes scheduling algorithm to appropriate scale the cluster, and if the autoscaler version sufficiently divirges from the kubernetes version, the autoscaler will scale the node groups incorrectly.