Information Technology Reference
In-Depth Information
The direct cloud access process contains the following tasks and roles:
Task 1: The DCI Bridge administrator downloads a public base image con-
taining a properly con
gured DCI Bridge (this will be the slave DCI Bridge)
from a corresponding repository. This image will be saved in the target cloud
environment. (The cloud service provided by the cloud provider must contain an
Amazon EC2 front-end).
Task 2: The DCI Bridge administrator properly con
gures the master (root) DCI
Bridge (which connects to gUSE).
Task 3: The user obtains an account from the Cloud Provider to the cloud where
the image was imported from the Repository (the Cloud Provider can provide
information about the exact way to get a cloud account). From this point, the
user can use the WS-PGRADE portal for job submission to the target cloud.
4.5.2 Scalability
The master DCI Bridge can start more VMs in the connected cloud service. There is
a parameter by which the gateway system administrator can de
ne the maximum
number of slave DCI Bridge VMs that can be started in parallel in the cloud. Notice
that in this way, parameter sweep applications can run in parallel on many cloud
resources. Moreover, the slave DCI Bridge images can be started in parallel in
several connected clouds. As a result, this solution gives the same multi-cloud
functionality that is provided by CloudBroker as discussed in Chap.
7
.
4.5.3 Current Restrictions
Direct cloud access from the network point of view does not need any contextu-
alization. It operates on publicly accessible (not private) IP addresses. The main
reason for this is that the portal calls the virtual machine (VM) by an IP address that
comes from the cloud service, and the VM doesn
'
t call back to the portal.
According to this, the currently available gateway
cloud communication directions
-
are: private gateway
> private cloud, private gateway
> public cloud, public
-
-
gateway
> public cloud.
However, the situation when the gateway and its master DCI Bridges are on
public networks, while the slave DCI Bridges are on private network clouds require
a special workaround (e.g., dynamic DNS usage).
The current direct cloud solution can be used in clouds that
-
implement the EC2 protocol
contain Kernel-based Virtual Machine (KVM) hypervisor.
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