Add missing bastion file

Author: Rikuoja

infra/bastion.tf

@@ -0,0 +1,20 @@
+# We don't want to create the key in terraform. Otherwise the private key would be saved in terraform state.
+# Let's save the key here as ec2 instance user data.
+
+# Just the smallest arm instance available
+resource "aws_instance" "bastion-ec2-instance" {
+  ami = "ami-0854da2f8540b70a2" # Amazon Linux 2
+  instance_type = "t4g.nano"
+  subnet_id     = aws_subnet.public[0].id
+  vpc_security_group_ids = [aws_security_group.bastion.id]
+  iam_instance_profile = aws_iam_instance_profile.ec2-iam-profile.name
+  tenancy              = "default"
+  user_data     = templatefile(
+    "bastion_user_data.tpl",
+    {bastion_public_key = "${var.bastion_public_key}"}
+    )
+
+  tags = merge(local.default_tags, {
+    Name = "${var.prefix}-bastion"
+  })
+}