WikiPrint - from Polar Technologies

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 his x509 certificate proxy
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	If there aren't any defined resources, none will appear

Use case: Sending jobs
Description	Jobs will be sent to all available hosts to be 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 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	When running the command `drm4g resource list --all`, the program will detect if the resource it's listing is a VM and list its ID
Primary Actor	User
Preconditions	The user must have previously created VMs
Basic Flow	The user runs the command `drm4g resource list --all` If the program detects that the resource it's listing is a VM, it will add to the rest of its information it displays its VM ID.
Postconditions	A list with information from every resource will be displayed VMs' information will display its ID
Alternate Flow

Use case: Creating VMs dynamically
Description	In the case that a user wants to create a certain number of instances with one specific configuration, instead of having to modify his configuration file, the user can determine with a command how many instances he wants to create and which specific resource configuration to use from the ones he has defined in the configuration file
Primary Actor	User
Preconditions	There must be a resource in the configuration defined with the purpose for the creation of VMs The user must have already created his x509 certificate proxy
Basic Flow	The user runs the command `drm4g resource <resource_name> create` `<resource_name>` has to be the same as the section name in the configuration file The DRM4G will use the configuration defined in the section `resource name` to create as many VM as that resource has specified
Postconditions	Even if there may be other resources defined with the purpose of creating VMs, only the ones specified for the resource `resource_name` will have been created
Alternate Flow	The user uses the option `--instances` to determine how many VMs should be created with the specified configuration This will overwrite the value specified in the configuration file

Use case: Destroying VMs by ID
Description	Instead of destroying all of the previously created VMs, the user can specify a list of VMs to destroy by passing their IDs to a command
Primary Actor	User
Preconditions	The user must have previously created VMs The user must list all resources to get the VMs ID
Basic Flow	The user runs the command `drm4g resource destroy --id <vm_id>`
Postconditions	The VM with a matching ID will have been destroyed
Alternate Flow