Разработка cloud-native Java-приложений для Kubernetes, Егор Волков,Senior Java Developer

Containers, Java and You
Building cloud-native Java applications with
Docker and Kubernetes

Hello, ${username}!
● Senior Java developer @ DataArt
● Working with Java since early 2014
● Background in networking and game
development, mostly C/C++
● Wrote first program in 2004, first network
protocol in 2007
● Interested in everything DevOps related
since started working with Java

import all.the.tools.*;
1. Get Java https://jdk.java.net/10/
2. Get Docker https://www.docker.com/get-started (18.06 CE +)
3. Get Kompose https://kompose.io/
4. Get ready!
BONUS STAGE:
5. Get the code: https://github.com/wollfxp/project1/tree/master-february
6. Get ready for real!

Evolution of Environments
Bare metal
Virtualization (HW)
Virtualization (SW)
OS
Container Engine
JVM
Your app
1. Bare metal, VM software-based, VM hardware-based
2. IaaS, PaaS, SaaS
3. Amazon Services, Amazon ECS ,Amazon EC2
4. Google Services, Google App Engine, Google
Kubernetes Engine
5. CloudFoundry, Heroku, etc.

my-project-0.0.1-SNAPSHOT.jar app-build-2541.war
./exploded jar/
./exploded war/
Java developers only care about these!

… sometimes about these also ...
java version "10.0.2" 2018-07-17
Java(TM) SE Runtime Environment 18.3 (build 10.0.2+13)
Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10.0.2+13, mixed mode)
openjdk version "9-internal"
OpenJDK Runtime Environment (build 9-internal+0-2016-04-14-195246.buildd.src)
OpenJDK 64-Bit Server VM (build 9-internal+0-2016-04-14-195246.buildd.src, mixed mode)

1. As long as the JRE is the same, that we develop against - everything should
be fine
2. As long as the Servlet container version is the same, that we develop
against - everything should be fine
3. As long as the RDBMS version is the same, that we develop against -
everything should be fine
4. …

1. We need to solidify versions of everything (JVM, JDK/JRE, servers, servlet
containers, databases, etc)
2. There’s no good way to limit Ops people from screwing everything up
3. This should be done by software, not people
4. We already have solutions for similar problems in Java world - dependency
managers!

Dockerization: starting small
1. Docker to the rescue!
2. Make a snapshot of your environment
3. Redistribute and run anywhere ©
4. Bake internal custom service versions and builds

Demo
Dockerfile for “Spaceships”
https://github.com/wollfxp/project1/blob/master/Dockerfile

FROM openjdk:10-jre
VOLUME /tmp
COPY target/project1-0.0.1-SNAPSHOT.jar app.jar
ENTRYPOINT ["java",
"-Djava.security.egd=file:/dev/./urandom",
"-jar",
"/app.jar"]
Run with:
gradlew clean build && docker build -t starships .
docker run -p 8443:8443 --name starships --network space-net starships:latest
Dockerfile:

Caused by: java.net.ConnectException: Connection refused: connect
at java.base/java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) ~[na:na]
at java.base/java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:400) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:243) ~[na:na]
at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:225) ~[na:na]
at java.base/java.net.PlainSocketImpl.connect(PlainSocketImpl.java:148) ~[na:na]
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:402) ~[na:na]
at java.base/java.net.Socket.connect(Socket.java:591) ~[na:na]
at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:173) ~[mysql-connector-java-8.0.11.jar:8.0.11]
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:66)
~[mysql-connector-java-8.0.11.jar:8.0.11]
... 58 common frames omitted
WARN 2196 --- [ restartedMain] o.h.e.j.e.i.JdbcEnvironmentInitiator : HHH000342: Could not obtain connection to query metadata :
Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

This time we remember about the database!
Re-Run with:
docker run -p 3306:3306 -v C:/dev/docker/mysql-project1:/var/lib/mysql --env
MYSQL_ROOT_PASSWORD=s3cur1ty@maks --env MYSQL_DATABASE=space --name mysql-project1
--network space-net mysql:5.6
docker run -p 8443:8443 --name starships --network space-net starships:latest

Dockerization: next steps
Demo
docker-compose file for “Spaceships”
https://github.com/wollfxp/project1/blob/master/docker-compose.yml

Run with:
docker-compose up

Hello, world with Kubernetes!

Kubernetes from scratch
1. Enabling Kubernetes in Docker for Windows/Docker for Mac

2. Checking that everything works

$ kubectl version
Client Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.11",
GitCommit:"637c7e288581ee40ab4ca210618a89a555b6e7e9", GitTreeState:"clean",
BuildDate:"2018-11-26T14:38:32Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"windows/amd64"}
Server Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.11",
GitCommit:"637c7e288581ee40ab4ca210618a89a555b6e7e9", GitTreeState:"clean",
BuildDate:"2018-11-26T14:25:46Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"linux/amd64"}
$ kubectl get all
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 443/TCP 4d

2. Checking that everything works
3. Running Kompose
4. Deploy to Kubernetes

Kubernetes and Kompose demo
Let’s try it!
https://github.com/wollfxp/project1/tree/master-february

Kubernetes from scratch … ?
Problem: we cannot reach our service!
Solution: Ingress! Deploy NGINX!

https://kubernetes.github.io/ingress-nginx/user-guide/tls/#ssl-passthrough

Problem: we cannot reach our service! And NGINX won’t help!
Solution: NodePort! Expose our service!

Kubernetes: next steps
1. Get rid of HTTPS in the application and use NGINX for that
2. Proper load balancing via Ingress
3. Deploy multiple types of the same instances (/app,/api,/admin)
4. Utilize namespaces to limit visibility of environments
5. Start using K8S metric API to get more info about your cluster
6. Deploy anywhere* with the same** configuration
7. Log aggregation (maybe?)

Разработка cloud-native Java-приложений для Kubernetes, Егор Волков,Senior Java Developer

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