Do not enable cgroup v2 on AWS, as Slurm does not support it

aws/README.md

@@ -38,8 +38,6 @@ Wait until the last command shows `CREATE_COMPLETE`, then login:
 pcluster ssh --cluster-name hpk-cluster -i ./hpk-cluster-keypair.pem
 ```
 
-You will have to reboot the nodes to enable cgroup v2.
-
 ## Run HPK
 
 Back to the head node, as the local user:

aws/install-hpk-requirements.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 
 # Install HPK requirements.
-# Tested on Ubuntu 22.04 (CentOS 7 will be configured, but cgroup v2 not enabled).
+# Tested on Ubuntu 20.04, CentOS 7.
 
 APPTAINER_VERSION=1.1.4
 FLANNEL_VERSION=0.20.2
@@ -132,11 +132,4 @@ tar -zxvf helm-v${HELM_VERSION}-linux-amd64.tar.gz --strip-components=1 linux-am
 cp helm /usr/local/bin/helm
 rm -f helm helm-v${HELM_VERSION}-linux-amd64.tar.gz
 
-# Enable cgroup v2
-if [[ "$(. /etc/os-release; echo $ID)" == "ubuntu" ]]; then
-    sed -i 's/^GRUB_CMDLINE_LINUX_DEFAULT="/&systemd.unified_cgroup_hierarchy=1 /' /etc/default/grub.d/50-cloudimg-settings.cfg
-    update-grub
-    # shutdown -r +1
-fi
-
 exit 0