• You may resize the capacity assigned to a Virtual Machine in terms of the virtual CPUs, memory and CPU allocated
• You can take a snapshot of a VM disk to preserve or backup its state at a given point of time, using the command 'onevm saveas --hot'.
• Some VM actions can be scheduled to be executed at a later date & time using the new onevm –schedule option (#1483)
• VMware VMs can now use the RAW section of the VM Template to add metadata straight to the .vmx file. This comes in handy to specify for example a specific guestOS type.
• KVM VMs can use the IO attribute in the disks.
• You can now merge another template to the one being instantiated. The new attributes will be added, or will replace the ones fom the source template. This can be more convinient that cloning an existing template and updating it

<xterm> $ onetemplate instantiate 6 –cpu 2 –memory 1024 </xterm>

• The default permissions given to newly created resources can be set in globally in oned.conf, or individually for each user with 'oneuser umask'.
• Administrators can set default quota limits that apply to all users or groups.

• Cluster ids in ACL rules

• Rename operation for templates, images, VMs and VNets

Some onevm commands have been renamed. This is the complete list of onevm sub-commands:

	OpenNebula 3.8	OpenNebula 4.0
Creation	create
	hold
	release
Attribute updates		update
		rename
		resize
	chgrp
	chown
	chmod
Disk actions	attachdisk	disk-attach
	detachdisk	disk-detach
	saveas	disk-snapshot
		disk-snapshot –live
Nic actions		nic-attach
		nic-detach
Scheduling and deployment	deploy
	migrate
	livemigrate	migrate –live
	resched
	unresched
Power on and off	poweroff
		poweroff –hard
	shutdown
	cancel	shutdown –hard
	reboot
	reset	reboot –hard
	restart	boot
Deletion	delete	destroy
	resubmit	destroy –recreate
Stop/Resume	stop
	suspend
	resume
VM Snapshots		snapshot-create
		snapshot-revert
		snapshot-delete
Query	list
	show
	top

New CLI commands:

• onevm snapshot-*
• onevm resize
• oneuser umask

Changed CLI commands:

• New option –hold for 'onevm create' and 'onetemplate instantiate'. Using this flag, the new VMs are created on hold state instead of pending. VMs in this state are ignored by the scheduler, giving users the chance release them later or to deploy them manually.
• New option –enforce for 'onevm deploy' and 'onevm (live)migrate'. Using this flag, the core will enforce that the target host's capacity is not overcommitted.
• 'onetemplate instantiate' will accept a template file to merge with the Template being instantiated.
• New option ''--hot'' for 'onevm saveas'.

Options:

• New options –user and –password are available for all commands. They replace the current credentials, making it easier for administrators to quicky execute commands as another user.

Some of these changes are better explained, with examples, in this blog post.

• The VM REQUIREMENTS and RANK attributes must be now named SCHED_REQUIREMENTS and SCHED_RANK (#1483)
• SCHED_REQUIREMENTS and SCHED_RANK can be edited in the VM template (#1483)
• A new keyword, CURRENT_VMS, can be used in the SCHED_REQUIMENTS expression to deploy VMs in the same hosts where other VMs are (not) running (#1675)
• SCHED_RANK expression can use first level attributes, e.g. RANK=“ID” to sort the hosts by their /HOST/ID element (#1553)
• SCHED_REQUIREMENTS and SCHED_RANK expressions can use xpath to identify elements, e.g. REQUIREMENTS=“\”/HOST/HOST_SHARE/MAX_MEM\“ > 0” (#1747)
• If the scheduler cannot find a suitable host for a VM, or any other problem is found, a message is stored inside the VM template attribute SCHED_MESSAGE (#846)
• SCHED_REQUIREMENTS and SCHED_RANK expressions can use attributes from the Host's Cluster template (#1554)

• There is a new Datastores type that lets you store plain files to be used as VM kernels, ramdisks or context files.
• The system datastore used by each cluster is now set adding it to the cluster, instead of updating the cluster's template attribute SYSTEM_DS.

• New states and transitions. These transitions are only relevant to developers, users will perceive the same functionality.
  • 

New xml-rpc methods:

• New rename methods
• New one.system.config
• New user/group quota.info and quota.update
• one.vm. snapshot methods
• one.vm.resize

Changed xml-rpc methods:

• one.vm.savedisk has a new param to save the disk immediately or when the VM shuts down
• one.vm.deploy and .migrate have a new param, enforce
• one.vm.allocate and one.template.instantiate have a new param to create VMs on hold instead of pending
• one.template.instantiate extra param to merge attributes

• Library file is now called 'opennebula', require it using:

require 'opennebula'

• Now OCA is packaged as a ruby gem, if you are developing on machine that does not have OpenNebula package installed you can install it with this command:

<xterm> $ gem install opennebula-oca –pre </xterm>

X509:

• CRL Checking can be enabled in /etc/one/auth/x509_auth.conf.
• Escaped DN's

• You can set the default configuration for the cache type on newly attached disks.

Changes in /ect/one/oned.conf

• DEFAULT_UMASK The permissions for newly created objects can be set globally in oned.conf, or individually for each User.
• OpenNebula driver names changed and now they are not prefixed by the driver type. For example, im_kvm changed to kvm, vmm_xen to xen and so on. To add a kvm host the command will be:

<xterm> $ onehost create host_name –im kvm –vm kvm –net dummy </xterm>

Changes in /etc/one/sunstone-server.conf

Changes in /etc/one/auth/x509_auth.conf

• check_crl

Changes in /var/lib/one/remotes/vmm/kvm/kvmrc

• DEFAULT_ATTACH_CACHE default cache type for new attached disks.

Changes in /etc/one/occi-server.conf

Changes in EC2 Server configuration files: