Docker Cookbook

"tasks"
:
[
{
"appId"
:
"/nginx"
,
"host"
:
"10.141.141.10"
,
"id"
:
"nginx.404b7376-d47b-11e4-8cd2-56847afe9799"
,
"ports"
:
[
31236
],
"servicePorts"
:
[
10001
],
"stagedAt"
:
"2015-03-27T12:17:35.285Z"
,
"startedAt"
:
null
,
"version"
:
"2015-03-27T12:17:29.312Z"
},
{
"appId"
:
"/http"
,
"host"
:
"10.141.141.10"
,
"id"
:
"http.a55c2bd5-d479-11e4-8cd2-56847afe9799"
,
"ports"
:
[
31235
],
"servicePorts"
:
[
10000
],
"stagedAt"
:
"2015-03-27T12:06:05.873Z"
,
"startedAt"
:
"2015-03-27T12:14:49.986Z"
,
"version"
:
"2015-03-27T12:06:00.485Z"
}
]
}
You see the 
http
application that you started earlier. And you also see the new 
nginx
application, which uses Docker. The application will take a little bit of time to deploy,
just enough time to 
docker pull nginx
. To take into account the time it may take to
download an image from a registry, you define the 
executor_registration_timeout
before restarting the 
mesos-slave
. Marathon also allocates a port dynamically to bind
port 80 of the Nginx container to the host, and in this case it chooses 31236. If you
open your browser at 
http://10.141.141.10:31236
, you will see the familiar web page of
Nginx.
222 | Chapter 7: The Docker Ecosystem: Tools

---

Discussion
The Docker application definition specified in JSON format can contain volume
mounts, can specify arguments that will overwrite the CMD arguments defined in a
Dockerfile, can specify 
docker run
parameters, and can also run in privileged mode.
The Docker 
containerizer
 documentation has detailed information. But as a quick
reference, you could also define an application with all those extra functionalities, like
so:
{