Docker Cookbook

7.10 Running Containers on a Cluster Using Lattice
Problem
You are looking for a container orchestration system to schedule containers on a clus‐
ter of machines. Additionally, you may have experience with Cloud Foundry and are
interested in its approach to containers.
Solution
Use 
Lattice
. Lattice, a cluster scheduler for container-based applications, includes an
HTTP load-balancing feature, log aggregation, health management, and dynamic
scaling of the applications. This lightweight container scheduler gives developers the
experience of working with native cloud applications and gives them a taste of the
Cloud Foundry
 PaaS.
To get started quickly, you can follow the Getting Started guide from the Lattice 
web‐
site
. It uses a Vagrant box to deploy a 
Lattice cell
on your local machine. After instal‐
ling the Lattice client 
ltc
, you can communicate with your Lattice setup and deploy
Docker images.
Let’s clone the Lattice project, check out the latest release, and boot the Vagrant box:
7.10 Running Containers on a Cluster Using Lattice | 217

---

$ git clone https://github.com/cloudfoundry-incubator/lattice.git
$ cd lattice
$ git checkout v0.3.0
$ vagrant up
...
==> default: Lattice is now installed and running.
==> default: You may target it using: ltc target 192.168.11.11.xip.io
==> default:
Download the 
ltc
CLI and make the file executable. For example, to get the CLI in
your 
PATH
, you could do the following:
$ sudo wget https://lattice.s3.amazonaws.com/releases/latest/darwin-amd64/ltc \
-O /usr/local/bin/ltc
$ sudo chmod +x /usr/local/bin/ltc
You are now ready to configure the CLI to point to your local Lattice deployment
done via Vagrant. Follow the last message of the Vagrant deployment and use 
ltc
:
$ ltc target 192.168.11.11.xip.io
Blob store is targeted.
Api Location Set
All that is left now is to start a container with the 
ltc create
command, specifying
the Docker image from the Docker Hub that you want to run. As a quick test, let’s run
nginx
in Lattice:
$ ltc create nginx-app nginx -r
...
nginx-app is now running.
App is reachable at:
http://nginx-app.192.168.11.11.xip.io
Once the application is created, you can reach it at the URL returned by 
ltc
. The
URL uses 
xip.io
, a wildcard DNS service that makes reaching services on your local
network by DNS names easy. In this example, if you open your browser at 
http://
nginx-app.192.168.11.11.xip.io
, you will see the Nginx welcome screen.
You can easily scale the number of instances of an application with 
ltc scale
, termi‐
nate an application with 
ltc rm
, and many other operational tasks. See 
ltc help
for
more information.
Discussion
The Lattice cell started via Vagrant does not run the Docker engine. However, you
specified a Docker image and Lattice accepted it. In fact, the Lattice runtime extracts
the filesystem of the Docker image and executes the application in its own container
runtime.