<s>
Prometheus	B-Language
is	O
a	O
free	B-Application
software	I-Application
application	O
used	O
for	O
event	O
monitoring	O
and	O
alerting	B-Application
.	O
</s>
<s>
It	O
records	O
metrics	O
in	O
a	O
time	O
series	O
database	O
(	O
allowing	O
for	O
high	O
dimensionality	O
)	O
built	O
using	O
an	O
HTTP	B-Protocol
pull	O
model	O
,	O
with	O
flexible	O
queries	O
and	O
real-time	O
alerting	B-Application
.	O
</s>
<s>
The	O
project	O
is	O
written	O
in	O
Go	B-Application
and	O
licensed	O
under	O
the	O
Apache	O
2	O
License	O
,	O
with	O
source	O
code	O
available	O
on	O
GitHub	B-Application
,	O
and	O
is	O
a	O
graduated	O
project	O
of	O
the	O
Cloud	B-Application
Native	I-Application
Computing	I-Application
Foundation	I-Application
,	O
along	O
with	O
Kubernetes	B-General_Concept
and	O
Envoy	O
.	O
</s>
<s>
Prometheus	B-Language
was	O
developed	O
at	O
SoundCloud	O
starting	O
in	O
2012	O
,	O
when	O
the	O
company	O
discovered	O
that	O
its	O
existing	O
metrics	O
and	O
monitoring	O
tools	O
(	O
using	O
StatsD	O
and	O
Graphite	B-Application
)	O
were	O
insufficient	O
for	O
their	O
needs	O
.	O
</s>
<s>
Specifically	O
,	O
they	O
identified	O
needs	O
that	O
Prometheus	B-Language
was	O
built	O
to	O
meet	O
including	O
:	O
a	O
multi-dimensional	O
data	O
model	O
,	O
operational	O
simplicity	O
,	O
scalable	O
data	O
collection	O
,	O
and	O
a	O
powerful	O
query	O
language	O
,	O
all	O
in	O
a	O
single	O
tool	O
.	O
</s>
<s>
The	O
project	O
was	O
open-source	O
from	O
the	O
beginning	O
and	O
began	O
to	O
be	O
used	O
by	O
Boxever	O
and	O
Docker	B-Language
users	O
as	O
well	O
,	O
despite	O
not	O
being	O
explicitly	O
announced	O
.	O
</s>
<s>
Prometheus	B-Language
was	O
inspired	O
by	O
the	O
monitoring	O
tool	O
Borgmon	O
used	O
at	O
Google	B-Application
.	I-Application
</s>
<s>
By	O
2013	O
,	O
Prometheus	B-Language
was	O
introduced	O
for	O
production	O
monitoring	O
at	O
SoundCloud	O
.	O
</s>
<s>
In	O
May	O
2016	O
,	O
the	O
Cloud	B-Application
Native	I-Application
Computing	I-Application
Foundation	I-Application
accepted	O
Prometheus	B-Language
as	O
its	O
second	O
incubated	O
project	O
,	O
after	O
Kubernetes	B-General_Concept
.	O
</s>
<s>
The	O
blog	O
post	O
announcing	O
this	O
stated	O
that	O
the	O
tool	O
was	O
in	O
use	O
at	O
many	O
companies	O
including	O
DigitalOcean	B-Application
,	O
Ericsson	O
,	O
CoreOS	B-Application
,	O
Weaveworks	O
,	O
Red	O
Hat	O
,	O
and	O
Google	B-Application
.	I-Application
</s>
<s>
Prometheus	B-Language
1.0	O
was	O
released	O
in	O
July	O
2016	O
.	O
</s>
<s>
Subsequent	O
versions	O
were	O
released	O
through	O
2016	O
and	O
2017	O
,	O
leading	O
to	O
Prometheus	B-Language
2.0	O
in	O
November	O
2017	O
.	O
</s>
<s>
In	O
August	O
2018	O
,	O
the	O
Cloud	B-Application
Native	I-Application
Computing	I-Application
Foundation	I-Application
announced	O
that	O
the	O
Prometheus	B-Language
project	O
had	O
graduated	O
.	O
</s>
<s>
A	O
variety	O
of	O
conferences	O
focused	O
on	O
Prometheus	B-Language
have	O
been	O
held	O
.	O
</s>
<s>
A	O
typical	O
monitoring	O
platform	O
with	O
Prometheus	B-Language
is	O
composed	O
of	O
multiple	O
tools	O
:	O
</s>
<s>
Prometheus	B-Language
to	O
centralize	O
and	O
store	O
the	O
metrics	O
.	O
</s>
<s>
Alertmanager	O
to	O
trigger	O
alerts	B-Application
based	O
on	O
those	O
metrics	O
.	O
</s>
<s>
Grafana	B-Protocol
to	O
produce	O
dashboards	O
.	O
</s>
<s>
PromQL	O
is	O
the	O
query	O
language	O
used	O
to	O
create	O
dashboards	O
and	O
alerts	B-Application
.	O
</s>
<s>
Prometheus	B-Language
data	O
is	O
stored	O
in	O
the	O
form	O
of	O
metrics	O
,	O
with	O
each	O
metric	O
having	O
a	O
name	O
that	O
is	O
used	O
for	O
referencing	O
and	O
querying	O
it	O
.	O
</s>
<s>
Labels	O
can	O
include	O
information	O
on	O
the	O
data	O
source	O
(	O
which	O
server	O
the	O
data	O
is	O
coming	O
from	O
)	O
and	O
other	O
application-specific	O
breakdown	O
information	O
such	O
as	O
the	O
HTTP	B-Protocol
status	O
code	O
(	O
for	O
metrics	O
related	O
to	O
HTTP	B-Protocol
responses	O
)	O
,	O
query	O
method	O
(	O
GET	O
versus	O
POST	O
)	O
,	O
endpoint	O
,	O
etc	O
.	O
</s>
<s>
The	O
ability	O
to	O
specify	O
an	O
arbitrary	O
list	O
of	O
labels	O
and	O
to	O
query	O
based	O
on	O
these	O
in	O
real	O
time	O
is	O
why	O
Prometheus	B-Language
 '	O
data	O
model	O
is	O
called	O
multi-dimensional	O
.	O
</s>
<s>
Prometheus	B-Language
stores	O
data	O
locally	O
on	O
disk	O
,	O
which	O
helps	O
for	O
fast	O
data	O
storage	O
and	O
fast	O
querying	O
.	O
</s>
<s>
Prometheus	B-Language
collects	O
data	O
in	O
the	O
form	O
of	O
time	O
series	O
.	O
</s>
<s>
The	O
time	O
series	O
are	O
built	O
through	O
a	O
pull	O
model	O
:	O
the	O
Prometheus	B-Language
server	O
queries	O
a	O
list	O
of	O
data	O
sources	O
(	O
sometimes	O
called	O
exporters	O
)	O
at	O
a	O
specific	O
polling	O
frequency	O
.	O
</s>
<s>
Each	O
of	O
the	O
data	O
sources	O
serves	O
the	O
current	O
values	O
of	O
the	O
metrics	O
for	O
that	O
data	O
source	O
at	O
the	O
endpoint	O
queried	O
by	O
Prometheus	B-Language
.	O
</s>
<s>
The	O
Prometheus	B-Language
server	O
then	O
aggregates	O
data	O
across	O
the	O
data	O
sources	O
.	O
</s>
<s>
Prometheus	B-Language
has	O
a	O
number	O
of	O
mechanisms	O
to	O
automatically	O
discover	O
resources	O
that	O
should	O
be	O
used	O
as	O
data	O
sources	O
.	O
</s>
<s>
Prometheus	B-Language
provides	O
its	O
own	O
query	O
language	O
PromQL	O
(	O
Prometheus	B-Language
Query	O
Language	O
)	O
that	O
lets	O
users	O
select	O
and	O
aggregate	O
data	O
.	O
</s>
<s>
Prometheus	B-Language
has	O
four	O
clearly	O
defined	O
metric	O
types	O
around	O
which	O
the	O
PromQL	O
components	O
revolve	O
.	O
</s>
<s>
Configuration	O
for	O
alerts	B-Application
can	O
be	O
specified	O
in	O
Prometheus	B-Language
which	O
specifies	O
a	O
condition	O
that	O
needs	O
to	O
be	O
maintained	O
for	O
a	O
specific	O
duration	O
in	O
order	O
for	O
an	O
alert	O
to	O
trigger	O
.	O
</s>
<s>
When	O
alerts	B-Application
trigger	O
,	O
they	O
are	O
forwarded	O
to	O
the	O
Alertmanager	O
service	O
.	O
</s>
<s>
Alertmanager	O
can	O
include	O
logic	O
to	O
silence	O
alerts	B-Application
and	O
also	O
to	O
forward	O
them	O
to	O
email	O
,	O
Slack	O
,	O
or	O
notification	O
services	O
such	O
as	O
PagerDuty	O
.	O
</s>
<s>
Some	O
other	O
messaging	O
systems	O
like	O
Microsoft	B-Application
Teams	I-Application
could	O
be	O
configured	O
using	O
the	O
Alertmanager	O
Webhook	O
Receiver	O
as	O
a	O
mechanism	O
for	O
external	O
integrations	O
.	O
</s>
<s>
also	O
Prometheus	B-Language
Alerts	B-Application
can	O
be	O
used	O
to	O
receive	O
alerts	B-Application
directly	O
on	O
android	O
devices	O
even	O
without	O
the	O
requirement	O
of	O
any	O
targets	O
configuration	O
in	O
Alert	O
Manager	O
.	O
</s>
<s>
Prometheus	B-Language
is	O
not	O
intended	O
as	O
a	O
full-fledged	O
dashboard	O
.	O
</s>
<s>
Although	O
it	O
can	O
be	O
used	O
to	O
graph	O
specific	O
queries	O
,	O
it	O
is	O
not	O
a	O
full-fledged	O
dashboard	O
and	O
needs	O
to	O
be	O
hooked	O
up	O
with	O
Grafana	B-Protocol
to	O
generate	O
dashboards	O
;	O
this	O
has	O
been	O
cited	O
as	O
a	O
disadvantage	O
due	O
to	O
the	O
additional	O
setup	O
complexity	O
.	O
</s>
<s>
Prometheus	B-Language
favors	O
white-box	O
monitoring	O
.	O
</s>
<s>
Applications	O
are	O
encouraged	O
to	O
publish	O
(	O
export	O
)	O
internal	O
metrics	O
to	O
be	O
collected	O
periodically	O
by	O
Prometheus	B-Language
.	O
</s>
<s>
Prometheus	B-Language
supports	O
some	O
monitoring	O
and	O
administration	O
protocols	O
to	O
allow	O
interoperability	O
for	O
transitioning	O
:	O
Graphite	B-Application
,	O
StatsD	O
,	O
SNMP	B-Protocol
,	O
JMX	B-Language
,	O
and	O
CollectD	O
.	O
</s>
<s>
Prometheus	B-Language
focuses	O
on	O
the	O
availability	O
of	O
the	O
platform	O
and	O
basic	O
operations	O
.	O
</s>
<s>
There	O
is	O
an	O
effort	O
to	O
promote	O
Prometheus	B-Language
exposition	O
format	O
into	O
a	O
standard	O
known	O
as	O
OpenMetrics	O
.	O
</s>
<s>
Some	O
products	O
adopted	O
the	O
format	O
:	O
InfluxData	O
's	O
TICK	O
suite	O
,	O
InfluxDB	B-Language
,	O
Google	B-General_Concept
Cloud	I-General_Concept
Platform	I-General_Concept
,	O
and	O
DataDog	O
.	O
</s>
<s>
Prometheus	B-Language
was	O
first	O
used	O
in-house	O
at	O
SoundCloud	O
,	O
where	O
it	O
was	O
developed	O
,	O
for	O
monitoring	O
their	O
systems	O
.	O
</s>
<s>
The	O
Cloud	B-Application
Native	I-Application
Computing	I-Application
Foundation	I-Application
has	O
a	O
number	O
of	O
case	O
studies	O
of	O
other	O
companies	O
using	O
Prometheus	B-Language
.	O
</s>
<s>
These	O
include	O
digital	O
hosting	O
service	O
DigitalOcean	B-Application
,	O
digital	O
festival	O
DreamHack	O
,	O
and	O
email	O
and	O
contact	O
migration	O
service	O
ShuttleCloud	O
.	O
</s>
<s>
Separately	O
,	O
Pandora	B-Application
Radio	I-Application
has	O
mentioned	O
using	O
Prometheus	B-Language
to	O
monitor	O
its	O
data	O
pipeline	O
.	O
</s>
