[Storage] Set EBS root volume size to 45GB in ADC as we recently increased the AMI volume size.

 This is required only in ADC because in these regions the root volume must be explicitly set. In Commercial regions instead, it is inherited from the AMI volume size.

Author: gmarciani

cli/src/pcluster/config/cluster_config.py

@@ -47,6 +47,7 @@
     DEFAULT_MIN_COUNT,
     DELETE_POLICY,
     DETAILED_MONITORING_ENABLED_DEFAULT,
+    EBS_ROOT_VOLUME_SIZE_DEFAULT,
     EBS_VOLUME_SIZE_DEFAULT,
     EBS_VOLUME_TYPE_DEFAULT,
     EBS_VOLUME_TYPE_IOPS_DEFAULT,
@@ -256,12 +257,10 @@ def __init__(self, size: int = None, delete_on_termination: bool = None, **kwarg
         super().__init__(**kwargs)
         # When the RootVolume size is None, EC2 implicitly sets it as the AMI size.
         # In US Isolated regions, the root volume size cannot be left unspecified,
-        # so we consider it as the default EBS volume size.
-        # In theory, the default value should be maximum between the default EBS volume size (35GB) and the AMI size,
-        # but in US Isolated region this is fine because the only supported AMI as of 2023 Feb
-        # is the official ParallelCluster AMI for Amazon Linux 2, which has size equal to
-        # the default EBS volume size (35GB).
-        self.size = Resource.init_param(size, EBS_VOLUME_SIZE_DEFAULT if get_region().startswith("us-iso") else None)
+        # so we consider it as the default EBS root volume size.
+        self.size = Resource.init_param(
+            size, EBS_ROOT_VOLUME_SIZE_DEFAULT if get_region().startswith("us-iso") else None
+        )
         # The default delete_on_termination takes effect both on head and compute nodes.
         # If the default of the head node is to be changed, please separate this class for different defaults.
         self.delete_on_termination = Resource.init_param(delete_on_termination, default=True)

cli/src/pcluster/constants.py

@@ -126,6 +126,8 @@
     "gp3": 3000,
 }
 EBS_VOLUME_SIZE_DEFAULT = 40
+# This value must be greater than or equal to the AMI volume size
+EBS_ROOT_VOLUME_SIZE_DEFAULT = 45
 EBS_VOLUME_TYPE_DEFAULT = "gp3"
 
 DEFAULT_MAX_COUNT = 10