DRM4G Use Cases

Implemented features

Use case: Creating cloud credentials
Description	Creates the proxy certificate that will be used to access the Federated Cloud's services
Primary Actor	User
Preconditions	The DRM4G must be running on a terminal The user must have edited correctly the configuration file The user must have a valid grid certificate
Basic Flow	The user executes the command drm4g id <resource_name> init
Postconditions	A proxy valid for 7 days will have been generated
Alternate Flow	The user uses the option "--lifetime" to create an identity for a specific period of time

Use case: Creating VMs
Description	An active and accessible Virtual Machine (VM) will be created. It will be considered a host to whom the user can submit jobs to have executed
Primary Actor	User
Preconditions	The DRM4G must be running on a terminal The user must have edited correctly the configuration file The user must have already created the proxy credentials
Basic Flow	The user executes the command drm4g resource create The program will read the configuration file For every resource defined to create VMs, it will create as many VMs as nodes were specified
Postconditions	As many VMs as nodes specified in the configuration file will have been created The VM's public IP direction will be shown Submitted jobs will also be sent to the VM
Alternate Flow	If for some reason there's a problem creating a VM, an error message is displayed The program will continue creating the rest of the specified VMs

Use case: Adding VMs
Description	Adds more VMs to those previously created
Primary Actor	User
Preconditions	User must have previously created VMs
Basic Flow	The user executes the command drm4g resource create
Postconditions	As many VMs as nodes specified in the configuration file will have been added The VM's public IP direction will be shown Submitted jobs will also be sent to the VM
Alternate Flow	If for some reason there's a problem creating a VM, an error message is displayed The program will continue creating the rest of the specified VMs

Use case: Listing VMs
Description	A list of all the accessible VMs will be displayed
Primary Actor	User
Preconditions	User must have previously created VMs
Basic Flow	User runs the commands drm4g host list
Postconditions	A list with information from every host will be shown, including from all of the active VMs created
Alternate Flow

Use case: Listing resources
Description	A list with every defined resource will be displayed. That includes the ones defined by the user and the ones created by the program for every VM created
Primary Actor	User
Preconditions	The DRM4G must be running on a terminal
Basic Flow	The user runs the command drm4g resource list --all
Postconditions	A list with information from every resource will be displayed
Alternate Flow

Use case: Sending jobs
Description	Jobs will be sent to all available hosts to be executed
Primary Actor	User
Preconditions	The user must have edited correctly a job template
Basic Flow	The user runs the command drm4g job submit path/to/job/template.job
Postconditions	The job is executed by one of the available host. This includes those defined in the configuration file with the purpose of executing jobs and VMs that may have been previously created
Alternate Flow	The user uses the option "--ntasks" to determine how many times he wants to have the same job executed The user uses the option "--dep" to define the job dependency list of the job

Use case: Destroying all VMs
Description	Regardless whether they are being used o not, every VM created by the DRM4G will be destroyed
Primary Actor	User
Preconditions	The user must have previously created VMs
Basic Flow	The user runs the command drm4g resource destroy The program will eliminate all created VMs one by one
Postconditions	There won't be any VM left
Alternate Flow	If for some reason there's a problem destroying a VM, an error message is displayed The program will continue destroying the rest of the VMs

Forthcoming features

Use case: Listing VMs with IDs
Description
Primary Actor
Preconditions
Basic Flow
Postconditions
Alternate Flow

Use case: Adding VMs dynamically
Description
Primary Actor
Preconditions
Basic Flow
Postconditions
Alternate Flow

Use case: Destroying VMs by ID
Description
Primary Actor
Preconditions
Basic Flow
Postconditions
Alternate Flow