Docker for Java Developers

Docker for Java Developers
Arun Gupta, @arungupta
VP Developer Advocacy, Couchbase

©2016 Couchbase Inc.
What is Docker?
▪Open source project and company 
 
 
 
 
 
▪Used to create containers for software applications
3

©2016 Couchbase Inc. 4
Mac OS X Ubuntu CentOSWindows
{J,W,E}AR
Mac OS X Ubuntu CentOSWindows
Image
WORA = Write Once Run Anywhere
PODA = Package Once Deploy Anywhere

Docker Mission
5
Build Ship Run
Anywhere
Distributed/Applications

FROM ubuntu 
 
CMD echo “Hello world”
FROM openjdk
 
COPY target/hello.jar /usr/src/hello.jar 
 
CMD java -cp /usr/src/hello.jar org.example.App

https://docs.docker.com/engine/reference/builder/

Docker Workﬂow
9

Image Layers - OpenJDK
~ > docker images openjdk 
REPOSITORY TAG IMAGE ID CREATED SIZE 
openjdk latest ea40c858f006 13 days ago 643.1 MB 
~ > docker history openjdk 
IMAGE CREATED CREATED BY SIZE
COMMENT 
ea40c858f006 13 days ago /bin/sh -c /var/lib/dpkg/info/ca-certificates 418.2 kB  
<missing> 13 days ago /bin/sh -c set -x && apt-get update && apt- 349.3 MB  
<missing> 13 days ago /bin/sh -c #(nop) ENV CA_CERTIFICATES_JAVA_V 0 B  
<missing> 13 days ago /bin/sh -c #(nop) ENV JAVA_DEBIAN_VERSION=8u 0 B  
<missing> 13 days ago /bin/sh -c #(nop) ENV JAVA_VERSION=8u102 0 B  
<missing> 13 days ago /bin/sh -c #(nop) ENV JAVA_HOME=/usr/lib/jvm 0 B  
<missing> 13 days ago /bin/sh -c { echo '#!/bin/sh'; echo 'set 87 B  
<missing> 13 days ago /bin/sh -c #(nop) ENV LANG=C.UTF-8 0 B  
<missing> 13 days ago /bin/sh -c echo 'deb http://httpredir.debian. 61 B  
<missing> 13 days ago /bin/sh -c apt-get update && apt-get install 1.289 MB  
<missing> 2 weeks ago /bin/sh -c apt-get update && apt-get install 122.6 MB  
<missing> 2 weeks ago /bin/sh -c apt-get update && apt-get install 44.31 MB  
<missing> 2 weeks ago /bin/sh -c #(nop) CMD ["/bin/bash"] 0 B  
<missing> 2 weeks ago /bin/sh -c #(nop) ADD file:f2453b914e7e026efd 125.1 MB
10

Docker for Mac/Windows
▪Native application and UI
▪Auto update capability
▪No additional software required, e.g. VirtualBox
– OSX: xhyve VM using Hypervisor.framework
– Windows: Hyper-V VM
▪Download: docker.com/getdocker
▪Requires Yosemite 10.10+ or Windows 10 64-bit
11

Docker for AWS/Azure
▪Amazon Web Services
– Amazon CloudFormation templates
– Integrated with Autoscaling, ELB, and EBS
▪Azure
– Integrated with VM Scale Sets for autoscaling, Azure Load
Balancer, Azure Storage
▪beta.docker.com (restricted availability)
12

Docker Toolbox
▪Docker Engine
▪Docker Machine
▪Docker Compose
▪Docker Kitematic
▪Virtual box
▪Quickstart Terminal
13
https://www.docker.com/toolbox

Docker Machine
▪Create Docker Host on computer or cloud provider 
 
docker-machine create --driver=virtualbox myhost
– Conﬁgure Docker client to talk to host
– Create and pull images
– Start, stop, restart containers
– Upgrade Docker
14

Docker Machine Providers
15

Docker Compose
▪Defining and running multi-container applications
▪Configuration defined in one or more files
– docker-compose.yml (default)
– docker-compose.override.yml (default)
– Multiple files specified using -f
– All paths relative to base configuration file
▪Great for dev, staging, and CI
16

Docker Compose - One Service
17
version: “2”
services:
db:
image: couchbase
volumes:
- ~/couchbase:/opt/couchbase/var
ports:
- 8091:8091
- 8092:8092
- 8093:8093
- 11210:11210
docker-compose up -d

Docker Compose - Two Services
18
GET
POST
PUT
DELETE
CRUD
using
N1QL

version: “2”
services:
db:
image: couchbase
ports:
- 8091:8091
- 8092:8092
- 8093:8093
- 11210:11210
web:
image: arungupta/wildfly
environment:
- COUCHBASE_URI=db
ports:
- 8080:8080
- 9990:9990
Docker Compose - Two Services
19

Overriding Services in Docker Compose
20
web:
image: jboss/wildfly
ports:
- 8080:8080
docker-compose.yml
web:
ports:
- 9080:8080
docker-compose.override.yml

Dev/Prod with Compose
21
db-dev:
image: arungupta/couchbase
ports:
- . . .
web:
image: arungupta/wildfly
environment:
- COUCHBASE_URI=db-dev:8093
ports:
- 8080:8080
web:
environment:
- COUCHBASE_URI=db-prod:8093
ports:
- 80:8080
db-prod: 
image: . . .
docker-compose.yml
production.yml
docker-compose up  
-f docker-compose.yml  
-f production.yml
-d

Docker Compose Common Use Cases
22
Use Case Command
Dev Setup docker-compose up
Local/remote host DOCKER_HOST, DOCKER_TLS_VERIFY,
DOCKER_CERT_PATH
Single/multiple hosts Integrated with Swarm
Multiple isolated environments docker-compose up -p <project>
Automated test setup docker-compose up 
mvn test 
docker-compose down
Dev/Prod Impedance mismatch docker-compose up -f docker-compose.yml -f
production.yml

Swarm Mode
▪New in 1.12
▪Natively managing a cluster of Docker Engines called a Swarm
▪Docker CLI to create a swarm, deploy apps, and manage swarm
▪No Single Point of Failure (SPOF)
▪Declarative state model
▪Self-organizing, self-healing
▪Service discovery, load balancing and scaling
▪Rolling updates
▪Optional feature, need to be explicitly enabled
23

Swarm Mode: Initialize
24
docker swarm init --listen-addr <ip>:2377

Swarm Mode: Add Worker
25
docker swarm join --token <worker_token> <manager>:2377

Swarm Mode: Add More Workers
26
docker swarm join --token <worker_token> <manager>:2377

Swarm Mode: Primary/Secondary Master
27
docker swarm join --manager --token <manager_token> --listen-
addr <master2>:2377 <master1>:2377

Swarm Mode using Docker Machine
28
https://github.com/docker/labs/blob/master/swarm-mode/quickstart/buildswarm-node-vbox-setup.sh
Task Command
Create manger docker-machine create -d virtualbox managerX
Create worker docker-machine create -d virtualbox workerX
Initialize Swarm mode docker swarm init --listen-addr <ip1> --advertise-addr <ip1>
Manager token docker swarm join-token manager -q
Worker token docker swarm join-token worker -q
Manager X join docker swarm join --token manager_token --listen-addr <ipX>
--advertise-addr <ipX> <ip1>
Worker X join docker swarm join --token worker_token --listen-addr <ipX>
--advertise-add <ipX> <ip1>

Swarm Manager
Swarm Worker Swarm WorkerSwarm Worker Swarm WorkerSwarm Worker
Swarm Manager Swarm Manager
Raft Consensus Group
Gossip Network
primary secondary secondary Container
Swarm Mode: Protocols
Strongly consistent
Replicated (Raft based)
Extremely fast (in-memory reads)

Swarm Mode in Production
30
https://blog.online.net/2016/07/29/docker-swarm-an-analysis-of-a-very-large-scale-container-system/

Swarm Mode: Replicated Service
31
docker service create --replicas 3 --name web jboss/wildfly

Swarm Mode - Routing Mesh
▪Load balancers are host-aware, not container-aware
▪Swarm mode introduces container-aware routing mesh
▪Reroutes trafﬁc from any host to a container
– Reserves a Swarm-wide ingress port
– Uses DNS-based service discovery
32

docker service create --replicas 3 --name web -p 8080:8080 jboss/
wildfly
Swarm Mode: Routing Mesh
Load
Balancer

Why NGINX Load Balancer?
▪SSL Termination
▪Content-based routing
▪Access control and authorization
▪Rewrites and redirects
▪Load Balancing Algorithms
▪Multiprotocol support - HTTP/2, WebSockets
▪Advanced logging
34

Load Balancing using NGINX
35
upstream wildfly {
server IP1:8080;
server IP2:8080;
server IP3:8080;
}
server {
listen 8080;
location / {
proxy_pass http://wildfly;
}
}
version: "2"
services:
web:
image: arungupta/wildfly-app
lb:
image: nginx
ports:
- 80:80
- 8080:8080

Load Balancing using NGINX
36
upstream wildfly {
least_conn;
server IP1:8080;
server IP2:8080;
server IP3:8080;
}
upstream wildfly {
ip_hash;
server IP1:8080;
server IP2:8080;
server IP3:8080;
}
upstream wildfly {
server IP1:8080 weight=2;
server IP2:8080;
server IP3:8080;
}
Weighted
Load
Balancing
Sticky
Sessions
Least 
number of 
active 
connections

Load Balancing a Swarm Service
37
upstream wildfly {
server backend-service;
}
server {
listen 8080;
location / {
proxy_pass http://wildfly;
}
}

Swarm Mode: Node Failure
38
X

Swarm Mode: Desired != Actual
39

Swarm Mode: Reconcile
40

Swarm Mode: Container Failure
41
X

Swarm Mode: Desired != Actual
42

Swarm Mode: Reconcile
43

Swarm Mode: Scale
44
docker service scale web=6

Swarm Mode: Global Service
45
docker service create --mode=global --name=prom prom/prometheus

Swarm Mode: Pause Node
46
docker node update --availability pause <nodename>
X

Swarm Mode: Active Node
47
docker node update --availability active <nodename>

Swarm Mode: Drain Node
48
docker node update --availability drain <nodename>
X

Swarm Mode: Rolling Updates
49
docker service update web --image wildfly:2 --update-parallelism
2 --update-delay 10s

Swarm Mode: Label
50
DOCKER_OPTS="--label=wildfly.storage=ssd"
“docker daemon --label 
=wildﬂy.storage=ssd”

Swarm Mode: Constraints
51
docker service create --replicas=3 --name=web --constraint
engine.labels.wildfly.storage==ssd jboss/wildfly

52
docker service scale web=6
=com.example.storage=ssd”

53
docker service create --replicas=3 --name=db couchbase

Scheduling Backends using Filters
▪Label: Metadata attached to Docker Daemon
▪Filters: Used by Docker Swam scheduler to create and run container
54
Node
Constraint Default or custom tags node, operatinsystem, kernelversion, …
Health Schedule containers on healthy nodes only
Container Slots Maximum number of containers on a node --labels containerslots=3
Container
Afﬁnity “Attraction” between containers -e affinity:container=<name>/<id>, image, …
Dependency Dependent containers on same node --volumes-from=<id>, --net=container:<id>, …
Port Port availability on the host -p <host>:<container>

Docker Lifecycle
55
FROM …
COPY …
RUN …
CMD …
Image CONTAINERCONTAINERCONTAINERContainer
Dockerﬁle
Single service 
distributable
image
format
Single service 
image
description
Single service
runtime
format
docker 
build
docker
run

Distributed Application Bundle
56
version: "2"
services:
db: 
…
web:
…
Distributed
Application  
Bundle
CONTAINERCONTAINERCONTAINERStack
docker-compose.yml
Multiservice 
distributable
image
format
Multiservice 
image
description
Multiservice
runtime
format
docker-compose 
build
docker 
deploy
Experimental
feature
NOTE: Docker Engine and Registry do not support distribution of DABs

Monitoring Docker Containers
▪docker stats command
– LogEntries
▪Docker Remote API: /container/{container-name|cid}/
stats
▪Docker Universal Control Plane
▪cAdvisor
– Prometheus
– InﬂuxDB
57

CI/CD with Docker + Jenkins
58
Git
Server
Run Test
web hook/poll
git push
clone
Create
Image
Docker Hub
1. Developer updates workspace
2. Jenkins receives the notiﬁcation
3. Clones the workspace
4. Creates an image
5. Runs the test
6. Pushes the image to Docker Hub
1
2
3
4 5 6
http://blog.couchbase.com/2016/september/deployment-pipeline-docker-jenkins-java-couchbase

Docker Support in Java IDEs
59
https://github.com/arun-gupta/docker-java-ides

bit.ly/kubejavabit.ly/dockerjava

• Training to both
newcomers and
intermediate
Docker users 
• Advanced users
will act as mentors  
• Encourage
connection and
collaboration

References
▪Slides: github.com/docker/labs/tree/master/slides
▪Workshop: github.com/docker/labs/tree/master/java
▪Docs: docs.docker.com
62

Docker for Java Developers

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