An overview on docker and container technology behind it. Lastly, we discuss few tools that might come handy when dealing with large number of containers management.

1. Docker
By:
NklMish

2. About Me
• Senior Software Developer around JVM
• Consultant + Coaching

3. Fast adoption rate

4. Fast adoption rate

5. DeploymentSingle machine vs Multiple vm’s on Single machine
Problems?

6. Common Problem
Commit’s code
It works on
my computer

7. Development & Deployment
Developer
Environment
Test
Environment
Production
Environment
QA
Environment

8. Environment Configuration
The instruction depends on the week in which you are running them

9. How about Vagrant + VM + Configuration
Mangement(chef, ansible, puppet, etc.)
• Step in a right direction
• Still too heavy weight and Fragile.
• Time dependent because can
return different minor versions
apt-get install xxx

11. • Docker is a consumer of container based technology
providing lightweight packages for apps.
• Utilises containers for application deployment
(provides illusion that app is running in separate OS),
separating infrastructure.
What is Docker

12. Docker a deeper look

13. Containers and Linux
2005 2006 20082007 2011 2013
Open VZ CGroups Google +
CGroups
LXC Unification Patch Free

14. Hypervisor vs Container
Shared OSBase Emulate virtual hardware
Hardware
OS
Hypervisor
Guest OS Guest OS
App1 App2
Hardware
OS
Container Container
App1 App2

15. Docker Components
• Daemon
• Client
• Image
• File

16. Docker Benefits
• Lightweight + Speed
• Portable
• Isolation
• Security
• Cloud ready

17. Lightweight + Speed
• No separate OS
• Run’s as a process
• Boot time.

18. Portable
• Run on all platform (i.e mac, linux, cloud, amazon
linux, etc.).
• Allow developers to generate and commit
container diffs

19. Isolation
• Each container gets :
• It’s own file system
• Full range of port i.e. 0-65535

20. Security
• Root under container is “nobody” outside
• Namespace are now enabled by default

21. Cloud Ready
• Small size, easy to scale (both vertical and
horizontal!)
• Compatible with existing cloud solutions

22. With Docker, Development &
Deployment
Developer
Environment
Test
Environment
Production
Environment
QA
Environment

23. Installation
• Requires kernel >= 3.9 , default nowadays
• Linux
• RPM sudo rpm install docker
• Debian based distribution apt-get install docker
doesn’t work instead use docker.io repo &
execute sudo apt-get install docker.io
• Mac and Windows : boot2docker

24. Sample DockerFile
FROM debian:jessie
MAINTAINER Allan Espinosa "allan.espinosa@outlook.com"
RUN apt-get update &&
apt-get --no-install-recommends install -q -y openjdk-7-jre-headless &&
rm -rf /var/lib/apt/lists/*
ADD http://mirrors.jenkins-ci.org/war/1.624/jenkins.war /opt/jenkins.war
RUN chmod 644 /opt/jenkins.war
ENV JENKINS_HOME /jenkins
ENTRYPOINT ["java", "-jar", "/opt/jenkins.war"]
EXPOSE 8080
CMD [""]

25. Docker
Command
execution
Every docker command
generates new layer.
DevOps real time time saver.
Take precaution about env
variables.

26. Docker commands
docker pull <#>

27. Docker commands
docker images <#>
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
tpires/neo4j latest 0fd121ddd75b 4 days ago 892.8 MB

28. Docker commands
docker run <#>
docker run -i -t -d --name neo4j --cap-add=SYS_RESOURCE -p 7474:7474 tpires/neo4j

29. Docker commands
docker ps <#>
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
0fabcaa1e3fe tpires/neo4j "/bin/bash -c /launc 9 minutes ago Up 9 minutes 0.0.0.0:7474->7474/tcp, 1337/tcp neo4j

30. Docker commands
docker diff <#>
docker diff 0fabcaa1e3fe
/etc
C /etc/neo4j
C /etc/neo4j/neo4j-server.properties
A /etc/neo4j/ssl
A /etc/neo4j/ssl/snakeoil.cert
A /etc/neo4j/ssl/snakeoil.key
C /tmp
C /tmp/hsperfdata_root
A /tmp/hsperfdata_root/84
A /tmp/jetty-0fabcaa1e3fe-7474-browser-_browser-any-24337275114314781.dir
A /tmp/jetty-0fabcaa1e3fe-7474-webadmin-html-_webadmin-any-3550160901111854765.dir
C /var
C /var/lib
C /var/lib/neo4j
C /var/lib/neo4j/data
A /var/lib/neo4j/data/dbms
A /var/lib/neo4j/data/dbms/auth
A /var/lib/neo4j/data/graph.db
A /var/lib/neo4j/data/graph.db/index
A /var/lib/neo4j/data/graph.db/lock
A /var/lib/neo4j/data/graph.db/messages.log
A /var/lib/neo4j/data/graph.db/neostore
A /var/lib/neo4j/data/graph.db/neostore.counts.db.a
A /var/lib/neo4j/data/graph.db/neostore.id
A /var/lib/neo4j/data/graph.db/neostore.labeltokenstore.db
A /var/lib/neo4j/data/graph.db/neostore.labeltokenstore.db.id
A /var/lib/neo4j/data/graph.db/neostore.labeltokenstore.db.names
A /var/lib/neo4j/data/graph.db/neostore.labeltokenstore.db.names.id
A /var/lib/neo4j/data/graph.db/neostore.nodestore.db
A /var/lib/neo4j/data/graph.db/neostore.nodestore.db.id
A /var/lib/neo4j/data/graph.db/neostore.nodestore.db.labels
A /var/lib/neo4j/data/graph.db/neostore.nodestore.db.labels.id
A /var/lib/neo4j/data/graph.db/neostore.propertystore.db
A /var/lib/neo4j/data/graph.db/neostore.propertystore.db.arrays
A /var/lib/neo4j/data/graph.db/neostore.propertystore.db.arrays.id
A /var/lib/neo4j/data/graph.db/neostore.propertystore.db.id
A /var/lib/neo4j/data/graph.db/neostore.propertystore.db.index
A /var/lib/neo4j/data/graph.db/neostore.propertystore.db.index.id
A /var/lib/neo4j/data/graph.db/neostore.propertystore.db.index.keys
A /var/lib/neo4j/data/graph.db/neostore.propertystore.db.index.keys.id

31. Docker commands
docker logs <#>
docker logs 0fabcaa1e3fe
Starting Neo4j Server console-mode...
Using additional JVM arguments: -server -XX:+DisableExplicitGC -Dorg.neo4j.server.properties=conf/neo4j-server.properties -Djava.util.logging.config.file=conf/logging.properties -XX:+UseCon
2015-08-11 20:04:36.742+0000 INFO [API] Setting startup timeout to: 120000ms based on 120000
2015-08-11 20:04:38.016+0000 INFO [API] Successfully started database
2015-08-11 20:04:38.079+0000 INFO [API] Starting HTTP on port :7474 with 8 threads available
2015-08-11 20:04:38.220+0000 INFO [API] Enabling HTTPS on port :7473
2015-08-11 20:04:38.220+0000 INFO [API] No SSL certificate found, generating a self-signed certificate..
20:04:38.432 [main] INFO org.eclipse.jetty.util.log - Logging initialized @2302ms
2015-08-11 20:04:38.469+0000 INFO [API] Mounting static content at [/webadmin] from [webadmin-html]
2015-08-11 20:04:38.509+0000 INFO [API] Mounting static content at [/browser] from [browser]
20:04:38.512 [main] INFO org.eclipse.jetty.server.Server - jetty-9.2.4.v20141103
20:04:38.531 [main] INFO o.e.j.server.handler.ContextHandler - Started o.e.j.s.h.MovedContextHandler@71da109{/,null,AVAILABLE}
20:04:38.575 [main] INFO o.e.j.w.StandardDescriptorProcessor - NO JSP Support for /webadmin, did not find org.apache.jasper.servlet.JspServlet
20:04:38.594 [main] INFO o.e.j.server.handler.ContextHandler - Started o.e.j.w.WebAppContext@6602d014{/webadmin,jar:file:/usr/share/neo4j/system/lib/neo4j-server-2.2.3-static-web.jar!/web
20:04:38.900 [main] INFO o.e.j.server.handler.ContextHandler - Started o.e.j.s.ServletContextHandler@4e671f1e{/db/manage,null,AVAILABLE}
20:04:39.036 [main] INFO o.e.j.server.handler.ContextHandler - Started o.e.j.s.ServletContextHandler@4ad697ef{/db/data,null,AVAILABLE}
20:04:39.046 [main] INFO o.e.j.w.StandardDescriptorProcessor - NO JSP Support for /browser, did not find org.apache.jasper.servlet.JspServlet
20:04:39.047 [main] INFO o.e.j.server.handler.ContextHandler - Started o.e.j.w.WebAppContext@60921cf7{/browser,jar:file:/usr/share/neo4j/system/lib/neo4j-browser-2.2.3.jar!/browser,AVAIL
20:04:39.110 [main] INFO o.e.j.server.handler.ContextHandler - Started o.e.j.s.ServletContextHandler@7929a090{/,null,AVAILABLE}
20:04:39.120 [main] INFO o.e.jetty.server.ServerConnector - Started ServerConnector@5129d373{HTTP/1.1}{0fabcaa1e3fe:7474}
20:04:39.178 [main] INFO o.e.jetty.server.ServerConnector - Started ServerConnector@3938bdec{SSL-HTTP/1.1}{0fabcaa1e3fe:7473}
20:04:39.178 [main] INFO org.eclipse.jetty.server.Server - Started @3052ms
2015-08-11 20:04:39.179+0000 INFO [API] Server started on: http://0fabcaa1e3fe:7474/
2015-08-11 20:04:39.179+0000 INFO [API] Remote interface ready and available at [http://0fabcaa1e3fe:7474/]

32. Docker commands
docker stats <#>
docker stats 0fabcaa1e3fe
CONTAINER CPU % MEM USAGE/LIMIT MEM % NET I/O
0fabcaa1e3fe 2.87% 232.9 MB/4.142 GB 5.62% 162.6 kB/3.7 MB

33. Docker Registry
• docker pull jessie translates to docker
pull registry-
1.docker.io/library/jessie
• For internal registry docker pull
companyDomain:port/foo/bar

34. Custom Registry
• Commercial - Docker trusted registry
• Non-commercial - set up your own service
registry (Docker Trusted Registry can help you
get started)

35. Docker useful tools
• Multi container application - Docker Compose
• Container clustering - Docker Swarm
• Third party integration - Yes you can use Chef
and Puppet

36. Cons
• kernel sharing (Different flavours of same OS
rather the different OS)
• You can end up with large number of containers.
(Google launch every week 2 billion container
instances)

37. Solution
• Manage containers as a single system
• Kubernetes, mesos, etc. helps to achieve this

38. Kubernetes
• Pods
• Replication controllers
• Labels
• Services

39. Summary
• Developer environment should be close to production
• Works on my machine is way too common problem.
• Manual setup is too time consuming , fragile and cumbersome
• Vm are too bulky, fragile and carries lot of additional noise.
• Container technology provides alternative approach(extremely lightweight) and docker
utilises it.
• Docker, build once run anywhere.
• Easy to scale , cloud ready.
• Not possible to run various OS , can run various flavours .
• Provides rich tools for enterprise tasks.
• Tools like Kubernetes can help.

40. Thank you.
Questions?