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updates to voting app intro, moved services descriptions under config file topic 

Signed-off-by: Victoria Bialas <victoria.bialas@docker.com>
This commit is contained in:
Victoria Bialas 2017-03-08 13:23:40 -08:00
parent 3fbdd218ba
commit a08459dd67
2 changed files with 41 additions and 28 deletions
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2
engine/getstarted-voting-app/customize-app.md
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@ -16,7 +16,7 @@ the application available as built images. So, all you need to do is reconfigure
## Update docker-stack.yml to reference new images
Go back to `docker-stack.yml` and replace the `before` tags on both the `vote` and `result` images to reference `after` tags.
Go back to `docker-stack.yml` and replace the `before` tags on both the `vote` and `result` images to reference `after` tags. These new image tags will call different versions of the images.
![before tags for vote and result in yml](images/customize-before.png)

67
engine/getstarted-voting-app/index.md
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@ -41,9 +41,11 @@ the `docker stack deploy` command
`vote` image to implement a poll on different choices
* Use features new in Compose Version 3, highlighted in the sample app
## Preview of the deployed application
## Preview of voting app stack and how it works
This diagram is a preview of the application stack at runtime. It shows
These next few topics provide a quick tour of the services, deployment configuration, files, and commands we will use.
This diagram represents the application stack at runtime. It shows
dependencies among the services, and a potential division of services between
the manager and worker nodes in a swarm. As you'll discover in the tutorial,
some services are constrained to always run on a manager node, while others can
@ -59,7 +61,7 @@ containers. Defining a service configuration for your app (above and beyond
`docker run` commands in a Dockerfile) enables you to deploy the app to a swarm
and manage it as a distributed, multi-container application.
The voting app you are about to deploy is composed of several services, each
The voting app you are about to deploy is made up of several services, each
based on an [image](/engine/reference/glossary.md#image) that the app will pull
from [Docker Hub](/engine/reference/glossary.md#docker-hub) at runtime:
@ -76,6 +78,26 @@ Each service will run in its own [container](/engine/reference/glossary.md#conta
we can also scale the application to deploy replicas
of containerized services distributed across multiple nodes.
### docker-stack.yml deployment configuration file
In the Getting Started with Docker tutorial, you wrote a
[Dockerfile for the whalesay app](/engine/getstarted/step_four.md) then used
it to build a single image and run it as a single container.
For this tutorial, the images are pre-built, and we use a _stack file_ instead
of a Dockerfile to specify the images. When we deploy, each image will run as a
service in a container (or in multiple containers, for those that have replicas
defined to scale the app).
To follow along, you need only have Docker running and a [copy of
the `docker-stack.yml` file provided
**here**](https://github.com/docker/example-voting-app/blob/master/docker-stack.yml).
This file defines all the services we want to use along with details about how
and where those services will run; their base images, configuration
details such as ports, networks, volumes, application dependencies, and the
swarm configuration.
Here is an example of one of the services fully defined:
```
@ -95,34 +117,24 @@ vote:
condition: on-failure
```
The `image` key defines which image the service will use. The `vote` service
uses `dockersamples/examplevotingapp_vote:before`.
* The **image** key defines which image the service will use. The `vote` service
uses `dockersamples/examplevotingapp_vote:before`. This specifies the path to
the image on Docker Hub (as shown in the table above), and an [image
tag](/engine/reference/commandline/tag.md), `before` to indicate the version of
the image we want to start with. In the second part of the tutorial, we will
edit this file to call a different verson of this image with an `after` tag.
The `depends_on` key allows you to specify that a service is only
* The **depends_on** key allows you to specify that a service is only
deployed after another service. In our example, `vote` only deploys
after `redis`.
The `deploy` key specifies aspects of a swarm deployment. For example, in this configuration we create _replicas_ of the `vote` service (2 containers for `vote` will be deployed to the swarm). The `result` service, not shown in the file snip-it above, will also have 2 replicas. Additionally, we will use the `deploy` key to constrain some other services (`db` and `visualizer`) to run only on a `manager` node.
* The **deploy** key specifies aspects of a swarm deployment. For example,
in this configuration we create _replicas_ of the `vote` service (2 containers
for `vote` will be deployed to the swarm). The `result` service, not shown in
the file snip-it above, will also have 2 replicas. Additionally, we will use the
`deploy` key to constrain some other services (`db` and `visualizer`) to run
only on a manager node.
### docker-stack.yml deployment configuration file
In the Getting Started with Docker tutorial, you wrote a
[Dockerfile for the whalesay app](/engine/getstarted/step_four.md) then used
it to build a single image and run it as a single container.
For this tutorial, the images are pre-built, and we use a stack file instead of
a Dockerfile to specify the images. When we deploy, each image will run as a
service in a container (or in multiple containers, for those that have replicas
defined to scale the app).
To follow along, you need only have Docker running and the copy of
`docker-stack.yml` we provide
[**here**](https://github.com/docker/example-voting-app/blob/master/docker-stack.yml).
This file defines all the services we want to use along with details about how
and where those services will run: their base images, configuration details such
as ports, networks, volumes, application dependencies, and the swarm
configuration.
### docker stack deploy command
@ -140,4 +152,5 @@ tutorial.
## What's next?
Ready to get started? In the next step, we'll [set up two Dockerized hosts](node-setup.md).
Ready to get started? In the next step, we'll [set up two Dockerized
hosts](node-setup.md).