1. Stackato PaaS Architecture: How it works and why.

2. www.activestate.com
Extending your Cloud Infrastructure with a Private Platform-as-a-Service
Stackato Offers a Fast, Secure Way to Deploy Applications to your Private Cloud
© ActiveState Software Inc. Published in 2013. Originally published in 2012.
2
Stackato PaaS Architecture: How it works and why.
Stackato is software for creating a private Platform-as-a-Service (PaaS). It lets you use a more
advanced and efficient application hosting model than Infrastructure-as-a-Service (IaaS) or
cloud orchestration software.
Traditionally, applications were hosted directly on the physical server that ran them, with only
the OS layer between the application software and the “bare metal”. This method yielded some
efficiencies because the software stack was relatively thin, but the model was more difficult to
scale because physical server deployment is a very manual process.
With Moore’s Law providing faster processors and more memory, there was room for another
layer of abstraction. With IaaS providers and private clouds, virtual machine (VM) instances
can be easily created on demand. This speeds up the process of server allocation, but
applications still require supporting software to be installed and configured on each server.
The PaaS model provides an additional level of automation while sharing resources between
multiple tenants and applications. This is why application hosting from PaaS providers is
generally less expensive than VM hosting from an IaaS. Typically PaaS providers have to limit
the range of runtimes and services offered and strictly control access to the system.
Stackato combines the flexibility offered by direct VM access on IaaS with the highly automated
configuration provided by PaaS. Computing resources are shared efficiently and securely
by giving each application its own Linux container (using LXC) which can be extensively
customized to suit the application it is hosting.
Elements of the Stackato System
A single Stackato VM instance can run all services required for operation. This configuration,
called a micro cloud, can be used on a desktop hypervisor such as VirtualBox or VMware Fusion to
emulate a Stackato PaaS.
This same VM is also the building block used to construct a fullscale PaaS cluster, using a simple
command to assign a role to each VM and connect them together.

3. www.activestate.com
Extending your Cloud Infrastructure with a Private Platform-as-a-Service
Stackato Offers a Fast, Secure Way to Deploy Applications to your Private Cloud
© ActiveState Software Inc. Published in 2013. Originally published in 2012.
3
These Stackato roles are:
»» Cloud Controller: responsible for directing all of the elements of the system. The attached Health Monitor
keeps track of DEA availability. All Stackato VMs communicate with the Cloud Controller over NATS, “a
lightweight publish-subscribe and distributed queuing messaging system.” This system handles the
orchestration of the components and sets up other communication channels between components as
appropriate (e.g. TCP connections between apps and databases). During cluster configuration, all VMs are
connected to the Cloud Controller via NATS.
»» Stager: responsible for assembling all of the software required to run each application. Application
prerequisites are bundled together in an application “droplet” ready for deployment to a Droplet Execution
Agent (DEA).
»» Router: maps application URLs to the application instances running on the DEAs. Application users
connecting from the web are redirected transparently to an internal URL and port. Connections from
Stackato clients are routed directly to the Cloud Controller.
»» DEAs: the worker nodes of the system. Each hosts multiple applications within separate Linux containers.
Application droplets are pulled from the Cloud Controller and launched inside a pre-allocated container. If
a DEA becomes unresponsive for any reason, the Health Manager will notice and have the Cloud Controller
redeploy the assigned applications to “healthy” DEAs.
»» Services: database, messaging, file system, and other services can be automatically provisioned by the
Cloud Controller. Services are bound to applications by way of a special environment variable that exposes
the connection information in the application container. Any services requested by a user can be bound
to any application deployed by that user, so multiple services can be bound to an application and vice
versa. Services can be run on separate VMs, or can share VMs as required. Applications can use external
services as well. For example, if an existing high-availability database cluster is exposed to the DEAs, the
applications can connect directly, as it would in a traditional application hosting scenario.
Message Bus (NATS)
Databases
Messaging
Services
File
Systems
Services
DEA(s)
(Droplet Execution Agents)
Web UsersMonitoring Deploy & Upgrade
Cloud
Controller
Health Manager
Controller
Stager
HTTP(S) HTTPS
TCP
Router
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from
HP Cloud aPaaS powered by
How Stackato Works on a VM cluster or hosted with a public IaaS provider

4. www.activestate.com
Extending your Cloud Infrastructure with a Private Platform-as-a-Service
Stackato Offers a Fast, Secure Way to Deploy Applications to your Private Cloud
© ActiveState Software Inc. Published in 2013. Originally published in 2012.
4
Pushing Applications
The Stackato client ‘targets’ the API URL of the Stackato system (e.g. api.stackato.example.net) and
is authenticated with the ‘stackato login’ command. Users have a quota of application instances,
services and reservable memory available to them.
The ‘stackato push’ command initiates the process of deploying application code to Stackato. The
client either prompts for configuration information (application name, required services, how much
memory to reserve, etc.) or reads information from a local YAML configuration file.
Stackato checks to see if all the resources required by the application are available to the user
(within quotas, services and runtimes available). If they are, the client bundles the application
directory and uploads it to the Cloud Controller.
An application URL is created and any requested services are provisioned. A temporary container is
created in the Stager, application dependencies are assembled, and a “droplet” package is created
for deployment. The Cloud Controller queries the DEAs and requests app containers. An available
DEA starts a container and downloads the droplet, then executes any ‘pre-running’ hooks specified
in stackato.yml before starting the application.
The Health Monitor works in conjunction with the Cloud Controller to monitor DEA responsiveness
and re-deploy applications to healthy DEAs as necessary.
Advantages
Building your own PaaS with Stackato allows you to take full advantage your virtualized
infrastructure or use computing resources from an IaaS provider more cost effectively.
Enterprises with their own private clouds can give their developers self-service access to application
hosting resources in a safe way. Development teams get instant access to an application hosting
service that automates the assembly of the application runtime software, letting them focus on
their code. IT staff are freed from manual configuration of individual application environments, but
maintain control of the cloud deployment platform.
Smaller organizations relying on public cloud infrastructure can more efficiently share resources
between applications, reducing the number of VMs required and driving down the cost of cloud
deployment. Stackato also provides freedom from infrastructure lock-in. VM images are available
for all major hypervisors, so if you change virtualization platforms, or move from a public IaaS to a
private cloud, you can create a new Stackato cluster and import all user and application data.
And finally, using Stackato to build your own PaaS keeps applications and data where they should
be, under the direct control of your organization.

5. About ActiveState
ActiveState empowers innovation from code to cloud smarter, safer, and faster. ActiveState’s cutting-edge solutions give developers and enterprises the power and flexibility to
develop in Java, Ruby, Python, Perl, Node.js, PHP, Tcl, and more. Stackato is ActiveState’s groundbreaking cloud platform for creating a private platform as a service (PaaS), and is the
cost-effective, secure, and portable way to develop and deploy apps to the cloud. ActiveState is proven for the enterprise: More than two million developers and 97% of Fortune-1000
companies use ActiveStateís end-to-end solutions to develop, distribute, and manage their software applications. Global customers like Cisco, CA, HP, Bank of America, Siemens, and
Lockheed Martin look to ActiveState to save time, save money, minimize risk, ensure compliance, and reduce time to market.
© 2013 ActiveState Software Inc. All rights reserved. ActiveState®
, Komodo®,
, ActivePerl®
, ActivePython®
and Stackato®
are trademarks or registered trademarks of ActiveState.
All other marks are property of their respective owners.
ActiveState Software Inc.
1700-409 Granville Street
Vancouver, BC V6C 1T2
stackato-sales@activestate.com
Phone: +1.778.786.1100
Fax: +1.778.786.1133
Toll-free in North America:
1.866.631.4581
Learn More. Try Stackato.
Are you interested in a private PaaS? Sign up for the Stackato Micro Cloud to try it today, or test it out on a Sandbox on
Amazon EC2.
Go to www.activestate.com/stackato
Looking for pricing information? Contact us for options and a quote today.
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