<s>
Serverless	B-General_Concept
computing	I-General_Concept
is	O
a	O
cloud	B-Architecture
computing	I-Architecture
execution	B-Device
model	I-Device
in	O
which	O
the	O
cloud	O
provider	O
allocates	O
machine	O
resources	O
on	O
demand	O
,	O
taking	O
care	O
of	O
the	O
servers	B-Application
on	O
behalf	O
of	O
their	O
customers	O
.	O
</s>
<s>
"	O
Serverless	B-General_Concept
"	O
is	O
a	O
misnomer	O
in	O
the	O
sense	O
that	O
servers	B-Application
are	O
still	O
used	O
by	O
cloud	B-Architecture
service	I-Architecture
providers	I-Architecture
to	O
execute	O
code	O
for	O
developers	O
.	O
</s>
<s>
However	O
,	O
developers	O
of	O
serverless	B-General_Concept
applications	O
are	O
not	O
concerned	O
with	O
capacity	O
planning	O
,	O
configuration	O
,	O
management	O
,	O
maintenance	O
,	O
fault	B-General_Concept
tolerance	I-General_Concept
,	O
or	O
scaling	O
of	O
containers	O
,	O
VMs	B-Architecture
,	O
or	O
physical	O
servers	B-Application
.	O
</s>
<s>
Serverless	B-General_Concept
computing	I-General_Concept
does	O
not	O
hold	O
resources	O
in	O
volatile	B-General_Concept
memory	I-General_Concept
;	O
computing	O
is	O
rather	O
done	O
in	O
short	O
bursts	O
with	O
the	O
results	O
persisted	O
to	O
storage	O
.	O
</s>
<s>
It	O
can	O
be	O
a	O
form	O
of	O
utility	B-Operating_System
computing	I-Operating_System
.	O
</s>
<s>
Serverless	B-General_Concept
computing	I-General_Concept
can	O
simplify	O
the	O
process	O
of	O
deploying	B-Application
code	I-Application
into	O
production	O
.	O
</s>
<s>
Serverless	B-General_Concept
code	O
can	O
be	O
used	O
in	O
conjunction	O
with	O
code	O
deployed	O
in	O
traditional	O
styles	O
,	O
such	O
as	O
microservices	O
or	O
monoliths	B-General_Concept
.	O
</s>
<s>
Alternatively	O
,	O
applications	O
can	O
be	O
written	O
to	O
be	O
purely	O
serverless	B-General_Concept
and	O
use	O
no	O
provisioned	O
servers	B-Application
at	O
all	O
.	O
</s>
<s>
Serverless	B-General_Concept
vendors	O
offer	O
compute	O
runtimes	O
,	O
also	O
known	O
as	O
Function	B-Application
as	I-Application
a	I-Application
Service	I-Application
(	O
FaaS	B-Application
)	O
platforms	O
,	O
which	O
execute	O
application	O
logic	O
but	O
do	O
not	O
store	O
data	O
.	O
</s>
<s>
Common	O
languages	O
supported	O
by	O
serverless	B-General_Concept
runtimes	O
are	O
Java	B-Language
,	O
Python	B-Language
and	O
PHP	B-Application
.	O
</s>
<s>
The	O
first	O
"	O
pay	O
as	O
you	O
go	B-Application
"	O
code	O
execution	O
platform	O
was	O
Zimki	O
,	O
released	O
in	O
2006	O
,	O
but	O
it	O
was	O
not	O
commercially	O
successful	O
.	O
</s>
<s>
In	O
2008	O
,	O
Google	B-Application
released	O
Google	B-Application
App	I-Application
Engine	I-Application
,	O
which	O
featured	O
metered	O
billing	O
for	O
applications	O
that	O
used	O
a	O
custom	O
Python	B-Language
framework	O
,	O
but	O
could	O
not	O
execute	O
arbitrary	O
code	O
.	O
</s>
<s>
PiCloud	O
,	O
released	O
in	O
2010	O
,	O
offered	O
FaaS	B-Application
support	O
for	O
Python	B-Language
.	O
</s>
<s>
Kubeless	O
and	O
Fission	O
are	O
two	O
Open	B-Application
Source	I-Application
FaaS	B-Application
platforms	O
which	O
run	O
with	O
Kubernetes	B-General_Concept
.	O
</s>
<s>
Google	B-Application
App	I-Application
Engine	I-Application
,	O
introduced	O
in	O
2008	O
,	O
was	O
the	O
first	O
abstract	O
serverless	B-General_Concept
computing	I-General_Concept
offering	O
.	O
</s>
<s>
App	B-Application
Engine	I-Application
included	O
HTTP	B-Protocol
functions	O
with	O
a	O
60-second	O
timeout	O
,	O
and	O
a	O
blob	O
store	O
and	O
data	O
store	O
with	O
their	O
own	O
timeouts	O
.	O
</s>
<s>
All	O
operations	O
had	O
to	O
be	O
executed	O
within	O
these	O
limits	O
,	O
but	O
this	O
allowed	O
apps	O
built	O
in	O
App	B-Application
Engine	I-Application
to	O
scale	O
near-infinitely	O
and	O
was	O
used	O
to	O
support	O
early	O
customers	O
including	O
Snapchat	B-Application
,	O
as	O
well	O
as	O
many	O
external	O
and	O
internal	O
Google	B-Application
apps	O
.	O
</s>
<s>
Language	O
support	O
was	O
limited	O
to	O
Python	B-Language
using	O
native	O
Python	B-Language
modules	O
,	O
as	O
well	O
as	O
a	O
limited	O
selection	O
of	O
Python	B-Language
modules	O
in	O
C	O
that	O
were	O
chosen	O
by	O
Google	B-Application
.	I-Application
</s>
<s>
Like	O
later	O
serverless	B-General_Concept
platforms	O
,	O
App	B-Application
Engine	I-Application
also	O
used	O
pay-for-what-you-use	O
billing	O
.	O
</s>
<s>
AWS	B-Application
Lambda	I-Application
,	O
introduced	O
by	O
Amazon	O
in	O
2014	O
,	O
popularized	O
the	O
abstract	O
serverless	B-General_Concept
computing	I-General_Concept
model	O
.	O
</s>
<s>
It	O
is	O
supported	O
by	O
a	O
number	O
of	O
additional	O
AWS	O
serverless	B-General_Concept
tools	O
such	O
as	O
AWS	O
Serverless	B-General_Concept
Application	O
Model	O
(	O
AWS	O
SAM	O
)	O
Amazon	O
CloudWatch	O
,	O
and	O
others	O
.	O
</s>
<s>
Google	B-General_Concept
Cloud	I-General_Concept
Platform	I-General_Concept
created	O
a	O
second	O
serverless	B-General_Concept
offering	O
,	O
Google	B-General_Concept
Cloud	I-General_Concept
Functions	I-General_Concept
in	O
2016	O
.	O
</s>
<s>
Oracle	B-General_Concept
Cloud	I-General_Concept
Functions	O
is	O
a	O
serverless	B-General_Concept
platform	O
offered	O
on	O
Oracle	B-General_Concept
Cloud	I-General_Concept
Infrastructure	O
,	O
and	O
is	O
based	O
on	O
the	O
open	B-Application
source	I-Application
Fn	O
Project	O
so	O
developers	O
can	O
create	O
applications	O
that	O
can	O
be	O
ported	O
to	O
other	O
cloud	O
and	O
on-premise	O
environments	O
.	O
</s>
<s>
It	O
supports	O
code	O
in	O
Python	B-Language
,	O
Go	B-Application
,	O
Java	B-Language
,	O
Ruby	B-Language
,	O
and	O
Node	B-Language
.	O
</s>
<s>
Several	O
serverless	B-General_Concept
databases	O
have	O
emerged	O
in	O
the	O
last	O
few	O
years	O
.	O
</s>
<s>
These	O
systems	O
extend	O
the	O
serverless	B-General_Concept
execution	B-Device
model	I-Device
to	O
the	O
RDBMS	B-Application
,	O
eliminating	O
the	O
need	O
to	O
provision	O
or	O
scale	O
virtualized	B-General_Concept
or	O
physical	O
database	O
hardware	O
.	O
</s>
<s>
Nutanix	O
offers	O
a	O
solution	O
named	O
Era	O
which	O
turns	O
an	O
existing	O
RDBMS	B-Application
such	O
as	O
Oracle	B-Application
,	O
MariaDB	B-Application
,	O
PostgreSQL	B-Application
or	O
Microsoft	B-Application
SQL	I-Application
Server	I-Application
into	O
a	O
serverless	B-General_Concept
service	O
.	O
</s>
<s>
Amazon	O
Aurora	O
offers	O
a	O
serverless	B-General_Concept
version	O
of	O
its	O
databases	O
,	O
based	O
on	O
MySQL	O
and	O
PostgreSQL	B-Application
,	O
providing	O
on-demand	O
,	O
auto-scaling	B-General_Concept
configurations	O
.	O
</s>
<s>
Azure	B-General_Concept
Data	I-General_Concept
Lake	I-General_Concept
is	O
a	O
highly	O
scalable	O
data	O
storage	O
and	O
analytics	O
service	O
.	O
</s>
<s>
The	O
service	O
is	O
hosted	O
in	O
Azure	B-Application
,	O
Microsoft	O
's	O
public	O
cloud	O
.	O
</s>
<s>
Azure	B-General_Concept
Data	I-General_Concept
Lake	I-General_Concept
Analytics	I-General_Concept
provides	O
a	O
distributed	O
infrastructure	O
that	O
can	O
dynamically	O
allocate	O
or	O
de-allocate	O
resources	O
so	O
customers	O
pay	O
for	O
only	O
the	O
services	O
they	O
use	O
.	O
</s>
<s>
Oracle	B-General_Concept
Cloud	I-General_Concept
offers	O
a	O
serverless	B-General_Concept
version	O
of	O
its	O
Oracle	B-Application
Autonomous	O
Database	O
,	O
which	O
is	O
the	O
Autonomous	O
Transaction	O
Processing	O
service	O
.	O
</s>
<s>
The	O
serverless	B-General_Concept
service	O
also	O
includes	O
a	O
JSON	O
edition	O
.	O
</s>
<s>
Firebase	B-General_Concept
,	O
also	O
owned	O
by	O
Google	B-Application
,	O
includes	O
a	O
hierarchical	B-General_Concept
database	I-General_Concept
and	O
is	O
available	O
via	O
fixed	O
and	O
pay-as-you-go	O
plans	O
.	O
</s>
<s>
Serverless	B-General_Concept
can	O
be	O
more	O
cost-effective	O
than	O
renting	O
or	O
purchasing	O
a	O
fixed	O
quantity	O
of	O
servers	B-Application
,	O
which	O
generally	O
involves	O
significant	O
periods	O
of	O
underutilization	O
or	O
idle	O
time	O
.	O
</s>
<s>
It	O
can	O
even	O
be	O
more	O
cost-efficient	O
than	O
provisioning	O
an	O
autoscaling	B-General_Concept
group	I-General_Concept
,	O
due	O
to	O
more	O
efficient	O
bin-packing	O
of	O
the	O
underlying	O
machine	O
resources	O
.	O
</s>
<s>
This	O
can	O
be	O
described	O
as	O
pay-as-you-go	O
computing	O
or	O
bare-code	O
as	O
you	O
are	O
charged	O
based	O
solely	O
upon	O
the	O
time	O
and	O
memory	O
allocated	O
to	O
run	O
your	O
code	O
;	O
without	O
associated	O
fees	O
for	O
idle	O
time	O
.	O
</s>
<s>
The	O
lack	O
of	O
personnel	O
cost	O
is	O
an	O
advantage	O
that	O
applies	O
broadly	O
to	O
cloud	B-Architecture
computing	I-Architecture
.	O
</s>
<s>
In	O
addition	O
,	O
a	O
serverless	B-General_Concept
architecture	I-General_Concept
means	O
that	O
developers	O
and	O
operators	O
do	O
not	O
need	O
to	O
spend	O
time	O
setting	O
up	O
and	O
tuning	O
autoscaling	B-General_Concept
policies	O
or	O
systems	O
;	O
the	O
cloud	O
provider	O
is	O
responsible	O
for	O
scaling	O
the	O
capacity	O
to	O
the	O
demand	O
.	O
</s>
<s>
As	O
Google	B-Application
puts	O
it	O
:	O
"	O
from	O
prototype	O
to	O
production	O
to	O
planet-scale.	O
"	O
</s>
<s>
With	O
function	B-Application
as	I-Application
a	I-Application
service	I-Application
,	O
the	O
units	O
of	O
code	O
exposed	O
to	O
the	O
outside	O
world	O
are	O
simple	O
event	O
driven	O
functions	O
.	O
</s>
<s>
This	O
means	O
that	O
typically	O
,	O
the	O
programmer	O
does	O
not	O
have	O
to	O
worry	O
about	O
multithreading	B-Operating_System
or	O
directly	O
handling	O
HTTP	B-Protocol
requests	I-Protocol
in	O
their	O
code	O
,	O
simplifying	O
the	O
task	O
of	O
back-end	O
software	O
development	O
.	O
</s>
<s>
Infrequently-used	O
serverless	B-General_Concept
code	O
may	O
suffer	O
from	O
greater	O
response	O
latency	O
than	O
code	O
that	O
is	O
continuously	O
running	O
on	O
a	O
dedicated	O
server	O
,	O
virtual	B-Architecture
machine	I-Architecture
,	O
or	O
container	O
.	O
</s>
<s>
This	O
is	O
because	O
,	O
unlike	O
with	O
autoscaling	B-General_Concept
,	O
the	O
cloud	O
provider	O
typically	O
"	O
spins	O
down	O
"	O
the	O
serverless	B-General_Concept
code	O
completely	O
when	O
not	O
in	O
use	O
.	O
</s>
<s>
This	O
means	O
that	O
if	O
the	O
runtime	O
(	O
for	O
example	O
,	O
the	O
Java	B-Language
runtime	O
)	O
requires	O
a	O
significant	O
amount	O
of	O
time	O
to	O
start	O
up	O
,	O
it	O
will	O
create	O
additional	O
latency	O
.	O
</s>
<s>
Serverless	B-General_Concept
computing	I-General_Concept
is	O
not	O
suited	O
to	O
some	O
computing	O
workloads	O
,	O
such	O
as	O
high-performance	B-Architecture
computing	I-Architecture
,	O
because	O
of	O
the	O
resource	O
limits	O
imposed	O
by	O
cloud	O
providers	O
,	O
and	O
also	O
because	O
it	O
would	O
likely	O
be	O
cheaper	O
to	O
bulk-provision	O
the	O
number	O
of	O
servers	B-Application
believed	O
to	O
be	O
required	O
at	O
any	O
given	O
point	O
in	O
time	O
.	O
</s>
<s>
Diagnosing	O
performance	O
or	O
excessive	O
resource	O
usage	O
problems	O
with	O
serverless	B-General_Concept
code	O
may	O
be	O
more	O
difficult	O
than	O
with	O
traditional	O
server	O
code	O
,	O
because	O
although	O
entire	O
functions	O
can	O
be	O
timed	O
,	O
there	O
is	O
typically	O
no	O
ability	O
to	O
dig	O
into	O
more	O
detail	O
by	O
attaching	O
profilers	O
,	O
debuggers	B-Application
or	O
APM	B-Application
tools	O
.	O
</s>
<s>
Furthermore	O
,	O
the	O
environment	O
in	O
which	O
the	O
code	O
runs	O
is	O
typically	O
not	O
open	B-Application
source	I-Application
,	O
so	O
its	O
performance	O
characteristics	O
cannot	O
be	O
precisely	O
replicated	O
in	O
a	O
local	O
environment	O
.	O
</s>
<s>
Serverless	B-General_Concept
is	O
sometimes	O
mistakenly	O
considered	O
as	O
more	O
secure	O
than	O
traditional	O
architectures	O
.	O
</s>
<s>
While	O
this	O
is	O
true	O
to	O
some	O
extent	O
because	O
OS	O
vulnerabilities	O
are	O
taken	O
care	O
of	O
by	O
the	O
cloud	O
provider	O
,	O
the	O
total	O
attack	O
surface	O
is	O
significantly	O
larger	O
as	O
there	O
are	O
many	O
more	O
components	O
to	O
the	O
application	O
compared	O
to	O
traditional	O
architectures	O
and	O
each	O
component	O
is	O
an	O
entry	O
point	O
to	O
the	O
serverless	B-General_Concept
application	O
.	O
</s>
<s>
According	O
to	O
Protego	O
,	O
the	O
"	O
solution	O
to	O
secure	O
serverless	B-General_Concept
apps	O
is	O
close	O
partnership	O
between	O
developers	O
,	O
DevOps	O
,	O
and	O
AppSec	O
,	O
also	O
known	O
as	O
DevSecOps	O
.	O
</s>
<s>
Collaborate	O
so	O
your	O
organization	O
can	O
resolve	O
security	O
risks	O
at	O
the	O
speed	O
of	O
serverless.	O
"	O
</s>
<s>
Many	O
serverless	B-General_Concept
function	O
environments	O
are	O
based	O
on	O
proprietary	B-Application
public	O
cloud	O
environments	O
.	O
</s>
<s>
Here	O
,	O
some	O
privacy	O
implications	O
have	O
to	O
be	O
considered	O
,	O
such	O
as	O
shared	B-General_Concept
resources	I-General_Concept
and	O
access	O
by	O
external	O
employees	O
.	O
</s>
<s>
However	O
,	O
serverless	B-General_Concept
computing	I-General_Concept
can	O
also	O
be	O
done	O
on	O
private	O
cloud	O
environment	O
or	O
even	O
on-premises	O
,	O
using	O
for	O
example	O
the	O
Kubernetes	B-General_Concept
platform	O
.	O
</s>
<s>
Serverless	B-General_Concept
computing	I-General_Concept
is	O
covered	O
by	O
International	O
Data	O
Center	O
Authority	O
(	O
IDCA	O
)	O
in	O
their	O
Framework	O
AE360	O
.	O
</s>
<s>
However	O
,	O
the	O
part	O
related	O
to	O
portability	O
can	O
be	O
an	O
issue	O
when	O
moving	O
business	O
logic	O
from	O
one	O
public	O
cloud	O
to	O
another	O
for	O
which	O
the	O
Docker	B-Language
solution	O
was	O
created	O
.	O
</s>
<s>
Cloud	B-Application
Native	I-Application
Computing	I-Application
Foundation	I-Application
(	O
CNCF	O
)	O
is	O
also	O
working	O
on	O
developing	O
a	O
specification	O
with	O
Oracle	B-Application
.	O
</s>
<s>
Serverless	B-General_Concept
computing	I-General_Concept
is	O
provided	O
as	O
a	O
third-party	O
service	O
.	O
</s>
<s>
Applications	O
and	O
software	O
that	O
run	O
in	O
the	O
serverless	B-General_Concept
environment	O
are	O
by	O
default	O
locked	O
to	O
a	O
specific	O
cloud	O
vendor	O
.	O
</s>
<s>
This	O
issue	O
is	O
exacerbated	O
in	O
serverless	B-General_Concept
computing	I-General_Concept
,	O
as	O
with	O
its	O
increased	O
level	O
of	O
abstraction	O
,	O
public	O
vendors	O
only	O
allow	O
customers	O
to	O
upload	O
codes	O
to	O
FaaS	B-Application
platform	O
without	O
the	O
authority	O
to	O
configure	O
underlying	O
environments	O
.	O
</s>
<s>
More	O
importantly	O
,	O
when	O
considering	O
a	O
more	O
complex	O
workflow	O
that	O
includes	O
Backend-as-a-Service	O
(	O
BaaS	O
)	O
,	O
a	O
BaaS	O
offering	O
can	O
typically	O
only	O
natively	O
trigger	O
a	O
FaaS	B-Application
offering	O
from	O
the	O
same	O
provider	O
.	O
</s>
<s>
This	O
makes	O
the	O
workload	O
migration	O
in	O
serverless	B-General_Concept
computing	I-General_Concept
virtually	O
impossible	O
.	O
</s>
<s>
Therefore	O
,	O
considering	O
how	O
to	O
design	O
and	O
deploy	O
serverless	B-General_Concept
workflows	O
from	O
a	O
multi-cloud	B-General_Concept
perspective	O
seems	O
promising	O
and	O
is	O
starting	O
to	O
prevail	O
.	O
</s>
<s>
Serverless	B-General_Concept
functions	O
can	O
be	O
used	O
for	O
:	O
</s>
