<s>
CloudStack	B-General_Concept
is	O
open-source	B-Application
cloud	B-Architecture
computing	I-Architecture
software	O
for	O
creating	O
,	O
managing	O
,	O
and	O
deploying	O
infrastructure	B-General_Concept
cloud	I-General_Concept
services	I-General_Concept
.	O
</s>
<s>
It	O
uses	O
existing	O
hypervisor	B-Operating_System
platforms	O
for	O
virtualization	O
,	O
such	O
as	O
KVM	B-Application
,	O
VMware	B-Application
vSphere	I-Application
,	O
including	O
ESXi	B-Operating_System
and	O
vCenter	B-Application
,	O
and	O
XenServer/XCP	B-Operating_System
.	O
</s>
<s>
In	O
addition	O
to	O
its	O
own	O
API	O
,	O
CloudStack	B-General_Concept
also	O
supports	O
the	O
Amazon	B-Application
Web	I-Application
Services	I-Application
(	O
AWS	B-Application
)	O
API	O
and	O
the	O
Open	B-General_Concept
Cloud	I-General_Concept
Computing	I-General_Concept
Interface	I-General_Concept
from	O
the	O
Open	O
Grid	O
Forum	O
.	O
</s>
<s>
CloudStack	B-General_Concept
was	O
originally	O
developed	O
by	O
Cloud.com,	O
formerly	O
known	O
as	O
VMOps	O
.	O
</s>
<s>
In	O
May	O
2010	O
,	O
Cloud.com	O
released	O
most	O
of	O
CloudStack	B-General_Concept
as	O
free	B-Application
software	I-Application
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
,	O
version	O
3	O
(	O
GPLv3	O
)	O
.	O
</s>
<s>
Cloud.com	O
and	O
Citrix	B-Application
both	O
supported	O
OpenStack	B-Application
,	O
another	O
Apache-licensed	B-Application
cloud	B-Architecture
computing	I-Architecture
program	O
,	O
at	O
its	O
announcement	O
in	O
July	O
2010	O
.	O
</s>
<s>
In	O
October	O
2010	O
,	O
Cloud.com	O
announced	O
a	O
partnership	O
with	O
Microsoft	O
to	O
develop	O
the	O
code	O
to	O
provide	O
integration	O
and	O
support	O
of	O
Windows	O
Server	O
2008	O
R2	O
Hyper-V	O
to	O
the	O
OpenStack	B-Application
project	O
.	O
</s>
<s>
Citrix	B-Application
Systems	I-Application
purchased	O
Cloud.com	O
on	O
July	O
12	O
,	O
2011	O
,	O
for	O
approximately	O
$200	O
million	O
.	O
</s>
<s>
In	O
August	O
2011	O
,	O
Citrix	B-Application
released	O
the	O
remaining	O
code	O
under	O
the	O
Apache	B-Application
Software	I-Application
License	I-Application
with	O
further	O
development	O
governed	O
by	O
the	O
Apache	O
Foundation	O
.	O
</s>
<s>
In	O
February	O
2012	O
,	O
Citrix	B-Application
released	O
CloudStack	B-General_Concept
3.0	O
.	O
</s>
<s>
Among	O
other	O
features	O
,	O
this	O
added	O
support	O
for	O
Swift	O
,	O
OpenStack	B-Application
's	O
S3-like	O
object	O
storage	O
solution	O
.	O
</s>
<s>
In	O
April	O
2012	O
,	O
Citrix	B-Application
donated	O
CloudStack	B-General_Concept
to	O
the	O
Apache	O
Software	O
Foundation	O
(	O
ASF	O
)	O
,	O
where	O
it	O
was	O
accepted	O
into	O
the	O
Apache	B-Application
Incubator	I-Application
;	O
Citrix	B-Application
changed	O
the	O
license	O
to	O
the	O
Apache	B-Application
License	I-Application
version	O
2	O
.	O
</s>
<s>
As	O
part	O
of	O
this	O
change	O
,	O
Citrix	B-Application
also	O
ceased	O
their	O
involvement	O
in	O
OpenStack	B-Application
.	O
</s>
<s>
On	O
November	O
6	O
,	O
2012	O
,	O
CloudStack	B-General_Concept
4.0.0-incubating	O
was	O
announced	O
,	O
the	O
first	O
stable	O
release	O
after	O
joining	O
ASF	O
.	O
</s>
<s>
On	O
March	O
20	O
,	O
2013	O
,	O
CloudStack	B-General_Concept
graduated	O
from	O
Apache	B-Application
Incubator	I-Application
and	O
became	O
a	O
Top-Level	B-Application
Project	I-Application
(	O
TLP	O
)	O
of	O
ASF	O
.	O
</s>
<s>
The	O
first	O
stable	O
(	O
maintenance	O
)	O
release	O
after	O
graduation	O
is	O
CloudStack	B-General_Concept
4.0.2	O
.	O
</s>
<s>
The	O
minimum	O
production	O
installation	O
consists	O
of	O
one	O
machine	O
running	O
the	O
CloudStack	B-General_Concept
Management	O
Server	O
and	O
another	O
machine	O
to	O
act	O
as	O
the	O
cloud	O
infrastructure	O
(	O
in	O
this	O
case	O
,	O
a	O
very	O
simple	O
infrastructure	O
consisting	O
of	O
one	O
host	O
running	O
hypervisor	B-Operating_System
software	O
)	O
.	O
</s>
<s>
In	O
its	O
smallest	O
deployment	O
,	O
a	O
single	O
machine	O
can	O
act	O
as	O
both	O
the	O
Management	O
Server	O
and	O
the	O
hypervisor	B-Operating_System
host	O
(	O
using	O
the	O
KVM	B-Application
hypervisor	B-Operating_System
)	O
.	O
</s>
<s>
Multiple	O
management	O
servers	O
can	O
be	O
configured	O
for	O
redundancy	O
and	O
load	O
balancing	O
,	O
all	O
pointing	O
to	O
a	O
common	O
MySQL	B-Application
database	O
.	O
</s>
<s>
In	O
July	O
2012	O
it	O
was	O
reported	O
that	O
Datapipe	O
launched	O
the	O
largest	O
international	O
public	O
cloud	O
to	O
be	O
built	O
on	O
CloudStack	B-General_Concept
,	O
which	O
included	O
6	O
data	O
centers	O
in	O
the	O
US	O
,	O
Britain	O
,	O
and	O
Asia	O
.	O
</s>
