Cloud Foundry | How it works

@jacopen
Kazuto Kusama
NTT Communications
Developer of Cloudn PaaS

Introduction
Planned topic was originally,
• Briefly discuss about Cloud Foundry architecture
overview
• Talk about the featured changed in V2

But ! Overview slides nearly become 100, gave up to
deep dive into it.
So, this material is for beginner
Deep dive is next time！

$ ls
Gemfile README.md dora.rb instances.rb
logging_service.rb spec stress_testers.rb
Gemfile.lock config.ru get_instance_cookie_jars.sh log_utils.rb
scripts stress vendor
https://github.com/cloudfoundry/cf-acceptance-tests/tree/master/assets/dora
Deploy Sinatra
application to
Cloud Foundry

[23:08] jacopen@cape ~/Project/dora ✘╹◡╹✘ (master) cf push dora
Creating app dora in org jacopen / space jacopen-space as admin...
OK
Creating route dora.107.22.72.200.xip.io...
OK
Binding dora.107.22.72.200.xip.io to dora...
OK
Uploading dora...
Uploading from: /Users/jacopen/Project/dora
1.2M, 36 files
OK
Starting app dora in org jacopen / space jacopen-space as admin...
OK
（中略）
1 of 1 instances running
App started
Showing health and status for app dora in org jacopen / space jacopen-space as admin...
OK
requested state: started
instances: 1/1
usage: 256M x 1 instances
urls: dora.107.22.72.200.xip.io
state since cpu memory disk
#0 running 2014-04-21 11:09:25 PM 0.0% 72.2M of 256M 0 of 1G

ok
[23:09] jacopen@cape ~/Project/dora ✘╹◡╹✘ (master) cf apps
Getting apps in org jacopen / space jacopen-space as admin...
OK
name requested state instances memory disk urls
dora started 1/1 256M 1G dora.107.22.72.200.xip.io

What happened inside
CF during this time

Let’s reveal Cloud Foundry
black box

Agenda
3 chapters to understand mechanism of Cloud Foundry
• Inspect Cloud Foundry internal from external interface
• Understand role of Cloud Foundry components
• Understand communications between Cloud Foundry
components

Not included this time
• Explanation of Warden container and Buildpack
• Explanation of services such as MySQL or
Postgress.
• Explanation of related services such as
loggregator

Inspect Cloud Foundry internal
from external interface

CF_TRACE=true
[23:49] jacopen@cape ~/Project/dora ✘╹◡╹✘ export CF_TRACE=true
[23:49] jacopen@cape ~/Project/dora ✘╹◡╹✘ cf push dora
REQUEST:
GET /v2/spaces/dbf6ed0a-3108-45d8-9c78-a512d5071358/apps?q=name%3Adora&inline-relations-depth=1 HTTP/1.1
Host: api.107.22.72.200.xip.io
Accept: application/json
Authorization: [PRIVATE DATA HIDDEN]
Content-Type: application/json
User-Agent: go-cli 6.0.0-90db382 / darwin
RESPONSE:
HTTP/1.1 200 OK
Content-Length: 107
Content-Type: application/json;charset=utf-8
Date: Mon, 21 Apr 2014 14:49:13 GMT
Server: nginx
X-Content-Type-Options: nosniff
X-Vcap-Request-Id: 18dcd4aefdd000506e49c4b5cf739aaa::65195823-dac9-410a-855a-4ef5ba249198
{
"total_results": 0,
"total_pages": 0,
"prev_url": null,
"next_url": null,
"resources": [
]
}
Creating app dora in org jacopen / space jacopen-space as admin...

CF_TRACE=true : Key to inspect
CF_TRACE=true
Enable to trace requests behind cf command.

GET /v2/spaces/dbf6ed0a-3108-45d8-9c78-a512d5071358/apps?q=name%3Adora&inline-relations-depth=1 HTTP/1.1
HTTP/1.1 200 OK
POST /v2/apps?async=true HTTP/1.1
{"name":"dora","space_guid":"dbf6ed0a-3108-45d8-9c78-a512d5071358"}
HTTP/1.1 201 Created
GET /v2/shared_domains HTTP/1.1
HTTP/1.1 200 OK
GET /v2/domains?inline-relations-depth=1&q=name%3A107.22.72.200.xip.io HTTP/1.1
HTTP/1.1 200 OK
GET /v2/routes?inline-relations-depth=1&q=host%3Adora%3Bdomain_guid%3A524ba14d-4d3f-495f-a2c7-a5ed25a70e81 HTTP/1.1
HTTP/1.1 200 OK
POST /v2/routes?async=true&inline-relations-depth=1 HTTP/1.1
{"host":"dora","domain_guid":"524ba14d-4d3f-495f-a2c7-a5ed25a70e81","space_guid":"dbf6ed0a-3108-45d8-9c78-a512d5071358"}
PUT /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600/routes/ed912294-be29-4013-8b1c-735851acee24 HTTP/1.1
PUT /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600/bits?async=true HTTP/1.1
Content-Type: multipart/form-data;
GET /v2/jobs/6dd46fe7-40b0-41d1-94aa-dd2ee80fd3b2 HTTP/1.1
HTTP/1.1 200 OK
(queued)
HTTP/1.1 200 OK
(finished)
CONNECTING TO WEBSOCKET: wss://loggregator.107.22.72.200.xip.io:443/tail/?app=0e948568-aa90-47e9-a128-9ff3cc680600
PUT /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600?async=true&inline-relations-depth=1 HTTP/1.1
{"state":"STARTED"}
GET /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600/instances HTTP/1.1
HTTP/1.1 400 Bad Request
{"code":170002,"description":"App has not finished staging","error_code":"CF-NotStaged"}
HTTP/1.1 200 OK
{"0":{"state":"RUNNING","since":1398092703.1739626,"debug_ip":null,"debug_port":null,"console_ip":null,"console_port":null}}
GET /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600/stats HTTP/1.1
HTTP/1.1 200 OK
{"0":{"state":"RUNNING","stats":{"name":"dora","uris":["dora.107.22.72.200.xip.io"],"host":"10.244.0.26","port":61026,"uptime":3,"mem_quota":268435456,"disk_quota":1073741824,"fds_quota":16384,"usage"
:{"time":"2014-04-21 15:05:04 +0000","cpu":0,"mem":75673600,"disk":0}}}}
HTTP/1.1 200 OK
HTTP/1.1 200 OK
{"0":{"state":"RUNNING","stats":{"name":"dora","uris":["dora.107.22.72.200.xip.io"],"host":"10.244.0.26","port":61026,"uptime":4,"mem_quota":268435456,"disk_quota":1073741824,"fds_quota":16384,"usage"
:{"time":"2014-04-21 15:05:05 +0000","cpu":0,"mem":75673600,"disk":0}}}}
GET /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600/summary HTTP/1.1
HTTP/1.1 200 OK
HTTP/1.1 200 OK
HTTP/1.1 200 OK
Communicating something to
api.107.22.72.200.xip.io

cf push
Cloud Foundry provides API
Something which provides
API

cf push
cf push deploy using various APIs
GET xxxx
PUT xxxx
POST xxxx
GET xxxx
Something which runs
application
API

Application
dora.107.22.72.200.xip.io

$ nslookup api.107.22.72.200.xip.io
Server: 192.168.11.1
Address: 192.168.11.1#53
Non-authoritative answer:
api.107.22.72.200.xip.io canonical name = api.1jkk1uz.xip.io.
Name: api.1jkk1uz.xip.io
Address: 107.22.72.200
$ nslookup dora.107.22.72.200.xip.io
Server: 192.168.11.1
Address: 192.168.11.1#53
Non-authoritative answer:
dora.107.22.72.200.xip.io canonical name = dora.1jkk1uz.xip.io.
Name: dora.1jkk1uz.xip.io
Address: 107.22.72.200
IP addresses are same for both API and App

cf push
Something to dispatch access
based on URL
Somethingtodispatchaccess
Browser
application
API

cf scale
$ cf scale -i 3 -m 256M dora
Scaling app dora in org jacopen / space jacopen-space as admin...
OK
cf scale command changes “number of active
instances” and/or “memory size”.

cf push
Browser
application
API
Something to dispatch access
based on URL

What happens when
application die ?

dora/sigterm/KILL
Kill itself using sigterm/KILL

Something to monitor application
health status
Monitor
Health
API

External view of
Cloud Foundry
Something
to run App
Monitor
Health
API

Cloud Foundry components
(part of it)
DEA
Health
Manager
Router
Cloud Controller

Understand role of
Cloud Foundry
components

component＝？
Cloud Controller
Router
DEA
Health
Manager

Component = Application
Cloud Controller
(Ruby)
Router
(Golang)
DEA
(Ruby)
Health
Manager
(Golang)

All components can run on 1VM
Cloud Controller
(Ruby)
Router
(Golang)
DEA
(Ruby)
Health
Manager
(Golang)

(Generally) In real situation, separate VM
for each components
Cloud Controller
(Ruby)
Router
(Golang)
DEA
(Ruby)
Health
Manager
(Golang)

Let’s take a look at each
components

Router
Cloud Controller
Router
DEA
Health
Manager

Router
Based on URL, dispatches access to appropriate
component. Similar to L7 load balancer.
This is different from “router” in network equipment.
It is implemented as an application (called Gorouter)
which runs on Ubuntu. Written in Go.

Cloud Controller
Router
DEA
Health
Manager
router.register
Each component send “router.register”
message to Router
Send
api.107.22.72.200.xip.io
to 10.244.0.138:9022
Send
dora.107.22.72.200.xip.io
to 10.244.0.26:61032

Cloud Controller
Router
DEA
Health
Manager
router.register
Router dispatches accesses based on
collected information
dora.107.22.72.200.xip.io => 10.244.0.26:61032
api.107.22.72.200.xip.io => 10.244.0.138:9022
api.107.22.72.200.xip.io
dora.107.22.72.200.xip.io

Cloud Controller
Router
DEA
Health
Manager
router.register
Multiple targets are handled for the same
URL
dora.107.22.72.200.xip.io => 10.244.0.26:61032
dora.107.22.72.200.xip.io => 10.244.0.27:58719
api.107.22.72.200.xip.io => 10.244.0.138:9022
api.107.22.72.200.xip.io => 10.244.0.139:9022
api.107.22.72.200.xip.io
dora.107.22.72.200.xip.io
Cloud Controller
DEA

Cloud Controller
Cloud Controller
Router
DEA
Health
Manager

Cloud Controller
A component to provide API.
Receive application from cf command, etc.
Control application start/stop against DEA.
Control creation of service such as database.
Etc, etc. Control overall Cloud Foundry.

POST /v2/apps?async=true HTTP/1.1
{"name":"dora","space_guid":"dbf6ed0a-3108-45d8-9c78-a512d5071358"}
GET /v2/shared_domains HTTP/1.1
HTTP/1.1 200 OK
GET /v2/domains?inline-relations-depth=1&q=name%3A107.22.72.200.xip.io HTTP/1.1
HTTP/1.1 200 OK
GET /v2/routes?inline-relations-depth=1&q=host%3Adora%3Bdomain_guid%3A524ba14d-4d3f-495f-a2c7-a5ed25a70e81 HTTP/1.1
HTTP/1.1 200 OK
POST /v2/routes?async=true&inline-relations-depth=1 HTTP/1.1
{"host":"dora","domain_guid":"524ba14d-4d3f-495f-a2c7-a5ed25a70e81","space_guid":"dbf6ed0a-3108-45d8-9c78-a512d5071358"}
PUT /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600/routes/ed912294-be29-4013-8b1c-735851acee24 HTTP/1.1
PUT /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600/bits?async=true HTTP/1.1
Content-Type: multipart/form-data;
HTTP/1.1 200 OK
(queued)
HTTP/1.1 200 OK
(finished)
CONNECTING TO WEBSOCKET: wss://loggregator.107.22.72.200.xip.io:443/tail/?app=0e948568-aa90-47e9-a128-9ff3cc680600
PUT /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600?async=true&inline-relations-depth=1 HTTP/1.1
{"state":"STARTED"}
HTTP/1.1 200 OK
HTTP/1.1 200 OK
{"0":{"state":"RUNNING","stats":{"name":"dora","uris":["dora.107.22.72.200.xip.io"],"host":"10.244.0.26","port":61026,"uptime":3,"mem_quota":268435456,"disk_quota":1073741824,"fds_quota":16384,"usage":{"time":"2014-
04-21 15:05:04 +0000","cpu":0,"mem":75673600,"disk":0}}}}
HTTP/1.1 200 OK
HTTP/1.1 200 OK
{"0":{"state":"RUNNING","stats":{"name":"dora","uris":["dora.107.22.72.200.xip.io"],"host":"10.244.0.26","port":61026,"uptime":4,"mem_quota":268435456,"disk_quota":1073741824,"fds_quota":16384,"usage":{"time":"2014-
04-21 15:05:05 +0000","cpu":0,"mem":75673600,"disk":0}}}}
GET /v2/apps/0e948568-aa90-47e9-a128-9ff3cc680600/summary HTTP/1.1
HTTP/1.1 200 OK
HTTP/1.1 200 OK
HTTP/1.1 200 OK
⇐ Create app
⇐ Obtain domain
⇐verify routes
⇐create routes
⇐ bind app and routes
⇐upload source files
⇐start app

DEA
Cloud Controller
Router
DEA
Health
Manager

DEA
A component to run user’s application.
Abbreviation of “Droplet Execution Agent"
In CF V2, it is responsible for user application staging (e.g.
Ruby bundle install).
DEA uses Linux container called Warden to run user
application. (Warden is not described this time)

Receive source files from client
Cloud Controller
Router
DEA
Health
Manager
cf push
Gemfile
lib/
bin/
config.ru
app.rb

Staging request
(staging.start)
Cloud Controller
Router
DEA
Health
Manager
cf push
Gemfile
lib/
bin/
config.ru
app.rb
Gemfile
Gemfile.lock
vendor/
lib/
bin/
config.ru
app.rb

Store Droplet
Cloud Controller
Router
DEA
Health
Manager
cf push
Gemfile
Gemfile.lock
vendor/
lib/
bin/
config.ru
app.rb

Start request
(dea.start)
Cloud Controller
Router
DEA
Health
Manager
cf push
Gemfile
Gemfile.lock
vendor/
lib/
bin/
config.ru
app.rb
Gemfile
Gemfile.lock
vendor/
lib/
bin/
config.ru
app.rb

Start Request
(dea.start)
Cloud Controller
Router
DEA
Health
Manager
cf push
Gemfile
Gemfile.lock
vendor/
lib/
bin/
config.ru
app.rb

Cloud Controller
Router
DEA
Health
Manager
cf scale -i 3
Gemfile
Gemfile.lock
vendor/
lib/
bin/
config.ru
app.rb
DEA

Start request
(dea.start)
Cloud Controller
Router
DEA
Health
Manage
r
cf scale -i 3
Gemfile
Gemfile.lock
vendor/
lib/
bin/
config.ru
app.rb
DEA

Start request
(dea.start)
Cloud Controller
Router
DEA
Health
Manager
cf scale -i 3
Gemfile
Gemfile.lock
vendor/
lib/
bin/
config.ru
app.rb
DEA

Health Manager
Cloud Controller
Router
DEA
Health
Manager
DEA

Health Manager
A component to monitor user application to see if the
status is “what it should be”.
The latest version is “hm9000” written in Go.

Suddenly instance dies
Cloud Controller
Router
DEA
Health
Manager
DEA

droplet.exited
Cloud Controller
Router
DEA
Health
Manager
DEA

hm9000.start
Cloud Controller
Router
DEA
Health
Manager
DEA

dea.start
Cloud Controller
Router
DEA
Health
Manager
DEA

When the number of instances
are over…
Cloud Controller
Router
DEA
Health
Manager
DEA

dea.heartbeat
Cloud Controller
Router
DEA
Health
Manager
DEA
I got 4, it should
be 3 ….

hm9000.stop
Cloud Controller
Router
DEA
Health
Manager
DEA

dea.stop
Cloud Controller
Router
DEA
Health
Manager
DEA

Did you understand the each
relationship？
Cloud Controller
Router
DEA
Health
Manager
Internal
Communication
External Access

Understand communications
between Cloud Foundry
components

The last chart
Cloud Controller
Router
DEA
Health
Manager
Internal
Communication
External Access

Cloud Controller
Router
DEA
Health
Manager
NATS
In reality

NATS
Publish-Subscribe model lightweight messaging
Developed by Derek Collison designed and architected
the industry's first Open PaaS, Cloud Foundry
Exists at the beginning of Cloud Foundry. Key component
in the architecture.
It was implemented in Ruby using EventMachine. It is re-
written using Go language (dnatsd)

Publish-Subscribe Model
Publisher Subscriber
NATS
Subject:
foo.bar
Subject:
foo.bar

NATS
Subject: foo.bar
{“message”:
“hogefuga”}
{“message”: “hogefuga”}
{“message”: “hogefuga”}

NATS
Cloud
Controller
DEA
Router
Subject: router.register
{“host":"10.244.0.138","port":
9022,"uris":["api.107.22.72.2
00.xip.io"]}
{“host":"10.244.0.111","port":
37902,"uris":["dora.107.22.7
2.200.xip.io"]}

All subscriber receive the same message
NATS
Cloud
Controller
DEA
Router
{“host":"10.244.0.138","port":
9022,"uris":["api.107.22.72.2
00.xip.io"]}
{“host":"10.244.0.111","port":
37902,"uris":["dora.107.22.7
2.200.xip.io"]}
Router
Router

When there is no NATS component…
NATS
Direct Communication
1.Run Router
2.Router subscribe
router.register
1.Register new Router in
admin DB
2.Run Router
3.DEA or Cloud Controler
obtain Router list from
admin DB
4.Sead message to each
Router

Cloud
Controller
Router
DEA Health
Manager
NATSRouter
Router
Cloud
Controller
DEA
DEA
DEA
Cloud
Controller
Cloud
Controller

Cloud Foundry Architecture
• Centered around NATS, loosely coupled
component communications. Scalable.
• Self-organized distributed system. Administrative
information is minimal.
• Self healing. The point is that it heals by itself.
• Removes SPoF( Single Point of Failure). Except
recent NATS.

Cloud Foundry V1
What’s the difference ?

Difference between CF v1 and v2
Overall architecture has not been changed.
DEA became DEAng, and runs Linux container called
Warden
Many components were re-written in Go.
Can use Heroku Buildpack
There is no API compatibility !

We will deep dive into Cloud
Foundry next time.

End Note.
This material was translated by @ibmamnt
From original chart by @jacopen
http://www.slideshare.net/jacopen/cloud-foundry-33851040

Cloud Foundry | How it works

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