Page 661 - Cloud computing: From paradigm to operation

XaaS 3

Use case
– VM reservation (refer to clause 7.1.9)
– VM image (refer to clause 7.1.10)
– VM template (refer to clause 7.1.11)

I.3.1 VM snapshot use case

Use case
Name IaaS use case on VM snapshot
Abstract CSC uses the snapshot functions during the lifecycle of a VM.

Roles CSC, CSP
Figure CSC
CSP

Snapshots
VM VM'

Computing resource pool
Portal
Cloud infrastructure
Y.3513(14)_FI.3.1
Pre-conditions – CSC accesses the IaaS through portal with appropriate security mechanism.
(optional) – CSC has created a VM which is in normal running state, stopped state or suspending
state.

Post-conditions

(optional)
Description – CSC has found that the VM is working properly; and an operation that may cause
faults, for example, conducting a software upgrade, is to be performed.
– CSC snapshots the VM, a name for the snapshot is required while the description is
optional. It also contains the runtime information, including the VM CPU and memory
states, if the VM is not powered-off.
– CSC performs the software upgrade operation, VM is in VM' (as the figure shows) state
and there is something wrong, for example, the user data of the software has been lost
and VM cannot work properly.
– CSC recovers the VM using the snapshot it created above and all the software running
on the VM is recovered to state "VM" too.
Requirements – VM snapshot (refer to clause 7.1.5)

I.3.2 VM clone use case

Use case

Name IaaS use case on VM clone
Abstract CSC uses the clone functions to create a new VM.
Roles CSC, CSP

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