This tutorial walks you through the basics of using a Java app server (WildFly) via a Linux container, running on Windows with Docker Toolbox. We have been testing this tutorial on Windows 7 and 8.1, you will notice that the screenshots come from either of those versions as this document has been tested and maintained.
There are notes for people running on Macs as well.
First follow installation steps for Docker Toolbox:
Install all the components.
Mac: The docker binaries are in
/usr/local/bin
which you can access from your terminal.
Windows: The docker binaries lands in
C:\Program Files\Docker Toolbox
for Windows
Windows: C:\Users\<your_username>\.docker\machine\cache\boot2docker.iso
Mac: ~/.docker/machine/cache/boot2docker.iso
C:\Users\<your_username>\.docker\machine\machines\default\default
You can make this change on the Docker Quickstart Terminal
command window as well
VirtualBox installed prior to Docker Toolbox has no mention of any docker-machine until we create any docker-machine host. Also, if you have previously installed Docker Toolbox, you can often use
docker-machine upgrade <docker host name>
to simply update to the latest version.
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Look for and select the
Docker Quickstart Terminal
menu option in your Start MenuOr use start.sh to launch the command prompt (not the normal Windows command prompt)
You should be able to double-click on start.sh in C:\Program Files\Docker Toolbox
If you successfully launch start.sh, it will execute
up
,status
andip
, therefore you can skip to step 8 below. Do make note of the IP address that is printed out, you will need it later. -
You might also execute docker-machine commands from the Windows (DOS) Command Prompt aka "cmd.exe" and type
docker-machine version
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docker-machine.exe create -d virtualbox default
You should see the docker host called default listed in VirtualBox Manager
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docker-machine status default
Note: When it is time to shutdown, run
docker-machine stop default
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This will show all environments variables needed to connect to the docker-machine host called default
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docker-machine env --shell cmd default
Alternatively you can specify which type of shell you are using. So the proper instructions for environments variables will be created.
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From this point forward, you will be inside of a Linux shell, using Linux commands
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docker version
-
docker images
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docker run centos /bin/echo "Hello World"
This will take some time if this is the first run of the "centos" image (size: 200 MB).
If you run the same command again, you will notice that is runs immediately, no download required. A Docker container starts incredibly fast when compared to traditional virtual machine technology.
To prove that point, run the same command again.
Note: the container stops as soon as it finishes the /bin/echo command
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On Windows, with docker-machine, the Users directory is shared as
/c/Users
On Mac the Users directory is shared as
/Users
ls /c/Users
This shared folder will allow you to add and edit files using your traditional Windows tools instead of having to learn vi or nano.
Using your File Explorer, create a
demo
sub-directory to your home directory and then use als -l
to see it via the boot2docker-vm (in this exampleBurr
is the username):ls -l /c/Users/<your_username>/demo
Mac:
ls -l /Users/<your_username>/demo
In this screenshot, I already some sample projects in my C:\Users\Burr\demo directory
Note: We won't be using "demo" in this tutorial, the goal here was to let you see the connection between /c/Users and C:\Users
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docker run -i -t centos /bin/bash
-i means interactive and -t allows your keyboard input
You can also use
-it
as well as-i -t
. Remember this trick - if you have an app server failing to start, you can see the console output and review the logs by using "-it"If this is your first time running the centos image, it may take over a minute to download.
You are now running inside of the Centos-based container, to prove that point, use the following command
cat /etc/system-release
Type
exit
to leave the container and drop back into the boot2docker-vm shell. -
docker ps
There should be no currently running containers since
exit
terminated the last centos container -
docker ps -a
but there have been previously run containers
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docker images
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docker pull centos/wildfly
Docker Hub contains a large number of pre-configured images that are ready to use via a simple "pull" e.g. https://registry.hub.docker.com/u/centos/wildfly/
run
does an implicit "pull" if the image is not already downloadedDocker images are typically identified by two words
"owner"/"imagename"
Thecentos/wildfly
image includes nice documentation on how to use it - we will be following several of those steps next. -
docker run -it centos/wildfly
The
t
is important so you canCtrl-C
to stop wildfly and the container.Hit
Ctrl-C
and run adocker ps
to see that the container has been stopped.In this particular case, the WildFly instance does not expose any ports to the outside world, so we don't have any access to WilFly. let's try enabling external access next.
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docker run -it -p 8080:8080 centos/wildfly
The
-p <host_port>:<container_port>
flag exposes the container port to the docker host machinedefault
. The first port8080
relates to the docker host machine port, and the second parameter8080
port relates to the container port that will be exposed.Each docker container process runs inside the docker host called
default
created by docker-machine previously. To get the ip of the docker host, just open another CMD.exe terminal and typedocker-machine ip default
.Press
Ctrl-C
to terminate the WildFly container. -
docker history centos/wildfly
The history command allows you to see more detail into how the image was crafted
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If you remember way back to
ls /c/Users/<your_username>/demo
, theUsers
directory on your Windows host is shared with the dockerdefault
host (thanks to VirtualBox Guest Additions). In your home directory, create a directory calleddocker_projects
that is a sibling ofdemo
. You can create the directory from within the docker-machine hostdefault
with the following command (or just use File Explorer).mkdir /c/Users/<your_username>/docker_projects
Use your home directory name in place of "Burr"
and then create a sub-directory called
myapp
mkdir /c/Users/<your_username>/docker_projects/myapp
You can create the "myapp" directory via Windows Explorer or the boot2docker-vm shell
and then change to the directory, it is important that you do this inside of the boot2docker-vm shell
cd /c/Users/<your_username>/docker_projects/myapp
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In the
myapp
directory, create a text file calledDockerfile
, with no extension.On Windows you might use the Atom editor from Atom.io for text editing.
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Edit the newly created
Dockerfile
and add the following two lines:FROM centos/wildfly COPY javaee6angularjs.war /opt/wildfly/standalone/deployments/
Note: On Macs, we have seen Wildfly have a permissions problem with the .war. The workaround is to switch to Root and use chown to make the ajustment to the .war file by adding the following two lines:
USER root RUN chown wildfly:wildfly /opt/wildfly/standalone/deployments/javaee6angularjs.war
The trailing "/" does matter
You can find
javaee6angularjs.war
at https://github.com/burrsutter/docker_tutorial/blob/master/javaee6angularjs.war?raw=true Download the war and copy it to themyapp
directory. -
Back in the boot2docker ssh session
docker build --tag=myapp .
the trailing "." is important
Use the docker
docker images
command to see if the image was created -
Let's see if that worked
docker run -it -p 8080:8080 myapp
you should see the deployment of
javaee6angularjs.war
in the wildfly console logging -
And test the app via your browser http://192.168.99.100:8080/javaee6angularjs
The IP address in my screenshots change from time to time as this document has been maintained. Just make sure to remember YOUR IP address as seen via
docker-machine ip default
Now it is time for a victory dance around the room! You have your first Java EE application deployed as part of a Docker container. Remember, Ctrl-C to shut down the app server.
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Run detached
You could also use a
-d
instead of-it
to run the container detached, in the backgrounddocker run -d -p 8080:8080 myapp
If detached, you will need to use
docker ps
to see the active containers and then usedocker stop CONTAINER_ID
anddocker rm CONTAINER_ID
Note: Docker automatically generated the name "agitated_hawking" which you can use instead of the CONTAINER_ID. Each time that you execute
docker run
command, it will create a different (and funny) name for your container. -
Container naming
Adding a --name=some_name allows you to give override the default name of agitated_hawking or whatever was randomly assigned to your container by Docker
docker run --name=myapp_is_running -d -p 8080:8080 myapp
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Viewing logs
docker logs myapp_is_running
and you can
docker stop myapp_is_running
when it is time to shutdown the -d detached app server container -
Dive into a live container
docker exec -it myapp_is_running bash cd /opt/wildfly/standalone/log tail server.log
This is a very useful technique if you find things are misbehaving and you wish poke around inside the running container.
OPTIONAL - Clean Slate: If you wish to completely clean up and run through the above steps again:
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Remove/Delete all containers
docker rm `docker ps -a -q`
the back ticks are important! You might also need to "stop" or "kill" any containers that are running and will not remove.
docker ps -a docker stop CONTAINER_ID docker kill CONTAINER_ID
Replace CONTAINER_ID with the id seen in the
docker ps
results. -
Remove/Delete all images
docker rmi `docker images -a -q`
watch those back ticks again
You will probably see some scary error messages. You can ignore it since it's caused because there's dependencies between certain docker images. This bulk command doesn't follow the dependencies order.
Check out the follow-on tutorial for adding MySQL. https://github.com/burrsutter/docker_mysql_tutorial