aws-parallelcluster: Failing to create cluster when using GPU instance with ubuntu 18 and Slurm

Environment:

• AWS ParallelCluster / CfnCluster version: 2.5.0
• OS: Ubuntu 18.04
• Scheduler: Slurm
• Master instance type: g3.4xlarge
• Compute instance type: g3.4xlarge

Bug description and how to reproduce:

Master instance initializes properly but compute instances get stuck in Initializing state in EC2 console and hence overall cluster setup fails. I let parallelcluster initialize VPCs, security groups, etc. all on its own, they should all be default/valid (I did some manual verification to e.g. make sure VPC settings matched what the docs said they should be).

$ pcluster create -c /home/foo/.parallelcluster/config cluster1
Beginning cluster creation for cluster: cluster1
Creating stack named: parallelcluster-cluster1
Status: parallelcluster-cluster1 - ROLLBACK_IN_PROGRESS                          		
Cluster creation failed.  Failed events:
  - AWS::AutoScaling::AutoScalingGroup ComputeFleet Received 2 FAILURE signal(s) out of 2.  Unable to satisfy 100% MinSuccessfulInstancesPercent requirement

Additional context:

Config file:

[aws]
aws_region_name = us-west-2

[global]
cluster_template = default
update_check = true
sanity_check = true

[aliases]
ssh = ssh {CFN_USER}@{MASTER_IP} {ARGS}

[cluster default]
key_name = gpu_keypair
base_os = ubuntu1804
scheduler = slurm
master_instance_type = g3.4xlarge
compute_instance_type = g3.4xlarge
initial_queue_size = 2
max_queue_size = 2
maintain_initial_size = true
vpc_settings = default

[vpc default]
vpc_id = vpc-02de6aff5174ff11e
master_subnet_id = subnet-0cc14c110a85fdd4e

master /var/log/cfn-init.log: attached master /var/log/cloud-init.log: attached master /var/log/cloud-init-output.log: attached master /var/log/jobwatcher: attached master /var/log/sqswatcher: attached cannot connect to compute nodes, no logs attached

cloud-init-output.log cloud-init.log cfn-init.log jobwatcher.log sqswatcher.log

Thanks in advance for your help!!