Allow multiple efs on aws clusters

terraform/aws/efs.tf

@@ -40,7 +40,10 @@ data "aws_security_group" "cluster_nodes_shared_security_group" {
 }
 
 resource "aws_efs_file_system" "homedirs" {
-  tags = merge(var.tags, { Name = "hub-homedirs" })
+  for_each = var.filestores
+  tags = merge(var.tags, {
+    Name = each.value.name_suffix == null ? "hub-homedirs" : "hub-homedirs-${each.value.name_suffix}"
+  })
 
   # Transition files to a slower, cheaper backing medium 90 days
   # after they were last *accessed*. They will be transferred back to regular
@@ -65,22 +68,38 @@ resource "aws_efs_file_system" "homedirs" {
   }
 }
 
+locals {
+  fs_ids       = toset(values(aws_efs_file_system.homedirs)[*].id)
+  fs_dns_names = toset(values(aws_efs_file_system.homedirs)[*].dns_name)
+
+  subnet_ids = toset(data.aws_subnets.cluster_node_subnets.ids)
+
+  efs_mount_targets = [
+    for pair in setproduct(local.subnet_ids, local.fs_ids) : {
+      file_system_id = pair[0]
+      subnet_id      = pair[1]
+    }
+  ]
+}
 resource "aws_efs_mount_target" "homedirs" {
-  for_each = toset(data.aws_subnets.cluster_node_subnets.ids)
+  for_each = tomap({
+    for mount_target in local.efs_mount_targets : "${mount_target.subnet_id}.${mount_target.file_system_id}" => mount_target
+  })
 
-  file_system_id  = aws_efs_file_system.homedirs.id
-  subnet_id       = each.key
+  file_system_id  = each.value.file_system_id
+  subnet_id       = each.value.subnet_id
   security_groups = [data.aws_security_group.cluster_nodes_shared_security_group.id]
 }
 
 output "nfs_server_dns" {
-  value = aws_efs_file_system.homedirs.dns_name
+  value = values(aws_efs_file_system.homedirs)[*].dns_name
 }
 
 # Enable automatic backups for user homedirectories
 # Documented in https://docs.aws.amazon.com/efs/latest/ug/awsbackup.html#automatic-backups
 resource "aws_efs_backup_policy" "homedirs" {
-  file_system_id = aws_efs_file_system.homedirs.id
+  for_each       = aws_efs_file_system.homedirs
+  file_system_id = each.value.id
 
   backup_policy {
     status = "ENABLED"

terraform/aws/variables.tf

@@ -196,3 +196,30 @@ variable "default_budget_alert" {
   A boilerplate budget alert initially setup for AWS accounts we pay the bill for.
   EOT
 }
+
+variable "filestores" {
+  type = map(object({
+    name_suffix : optional(string, null),
+    tags : optional(map(string), {}),
+  }))
+  default = {
+    "filestore" : {}
+  }
+  description = <<-EOT
+  Deploy one or more AWS ElasticFileStores for home directories.
+
+  This provisions a managed NFS solution that can be mounted as
+  home directories for users. If this is not enabled, a manual or
+  in-cluster NFS solution must be set up.
+
+  - name-suffix: Suffix to append to the name of the FileStore. This
+    prevents name-clashing. Default: null.
+
+  - tags: Tags to apply to the homedir. The value is an object as we
+    are appending existing tags to homedir specific tags.
+    We use CamelCase for tag names to match AWS's tagging style.
+    Default tag is:
+      1. Name: This tag will indicate the name of the homedir.
+        By default, this will be set to "hub-homedirs-{name_suffix}".
+  EOT
+}