Big Things Come in Small Packages: Getting Started with Pivotal Cloud Foundry Small Footprint

October 17, 2017 Ryan Moran

The most popular enterprise application platform just got smaller.

Pivotal Cloud Foundry (PCF) now has a small footprint edition. It features a deployment configuration with as few as 6 VMs. Review the documentation for download and installation instructions.

Big things are in this small package. Operators can enjoy the same benefits of BOSH, stemcells, CredHub, and Operations Manager. Those components are unchanged. What’s new is the smaller Elastic Runtime (ERT).

ERT is an application-centric abstraction designed with Day 2 operations in mind. The world’s largest brands trust ERT to run their most important apps at scale. Use this app runtime to get a piece of code from developer laptop to production as fast as possible.

The new, smaller version requires far fewer virtual machines - which is really useful! Consider these scenarios:

  • Testing. Need to lower your infrastructure costs in your dev, test, and QA environments? Give Small Footprint a spin.

  • Proof-of-concepts. Whether you’re trying PCF for the first time, or expanding usage into a new division, Small Footprint is an efficient alternative. Quickly deploy Small Footprint in a public cloud, then tear it down when you’re done.

  • Non-production environments. Exchange less high availability and scaleout characteristics for lower cost and less resource consumption. This tradeoff makes sense in some cases.

  • Running PCF outside of a data center. If your need to apps run on-site (say at a warehouse, retail store, hospital, or factory), Small Footprint is a solid choice.

Let’s dive into the differences.

What’s Inside

Here’s a look at the VMs in each configuration, the full-featured and the small footprint.

The Small Footprint repackages the full-size components into a more efficient deployment.

As shown above, components that run on many VMs in PCF are hyper-collocated onto a handful of virtual servers in the small footprint edition. Developers still enjoy all the same bits and configuration of the full-size version. The only difference is, well, the size of the footprint!

At its smallest, PCF’s Small Footprint is deployed with only 6 VMs. This configuration consists of Database, Control, Compute, Router, Cloud Foundry BOSH, and Operations Manager VMs.

Let’s go into some detail on each of these. It’s important to understand what they are doing, and how they differ from the full-size PCF. Another important note: each VM can be scaled out to boost availability according to your requirements.

Database

The Database VM stores the stateful services used by the platform. This VM hosts the internal MySQL database, Consul servers, and NATS. These components are located on distinct VMs in the full-size ERT, but have been collocated onto a single VM for the smaller footprint.

Control

The Control VM contains the brains of the platform. It houses the components that make decisions about where and how to run your applications. This VM provides many of the APIs used to interact with the platform itself. The Control VM handles application lifecycles, logging, and user authentication and authorization.

You’ll find many familiar Cloud Foundry services here, including Cloud Controller (Workers and Clock), UAA, Diego Brain, Diego Database, Loggregator Traffic Controller, Doppler, and the Syslog Drain Scheduler and Adapter. In the full-size ERT, these components consume 10 VMs.

Compute

The Compute VM remains largely unchanged from the full-size Elastic Runtime (where it’s called Diego Cell). Similarly, this VM runs your applications in a safe, efficient, containerized runtime.

Router

The Router VM is completely unchanged from the full-size Elastic Runtime. You’ll notice a full complement of configuration options for routing into your apps.

Cloud Foundry BOSH (and CredHub)

The Cloud Foundry BOSH VM performs a highly automated PCF deployment based on user-provided configuration details. This VM and its function is unchanged. That’s good news on the InfoSec front. Why? Pivotal’s commitment to providing rapid fixes to high or critical CVEs extends to Small Footprint. Remediate with zero downtime, using the familiar stemcell model. Refer to Pivotal Application Security.

Also hosted on this VM: CredHub, the tool that delivers centralized management of platform and application creds.

Operations Manager

Operations Manager is a set of APIs (and a web application) used to deploy and manage PCF. Ops Manager communicates with Cloud Foundry BOSH to deploy app runtime components and other services. Again, this VM and its function remain the same.

Optional and Extended Configurations

When you view the Resource Config page in the Small Footprint Elastic Runtime tile, you will notice a few more VMs than those listed above.

Each component works exactly the same way it does in the full-size version. They should be used the same way in both versions.

These VMs all offer optional functionality to complement the base requirements. In each case, the VMs are unchanged compared to the full-size version of PCF.

Specifically, you will see File Storage, HAProxy, MySQL Backup Prepare, MySQL Monitor, and TCP Router VMs.

If you want an internal blobstore, deploy the File Storage VM. For TCP Routing to your applications, deploy the HAProxy VM. The HAProxy VM also offers extra features, like rejecting requests to the System Domain that originate from an unknown source.

These VMs are entirely optional. You might find them useful to create a Small PCF, to support your specific use-cases.

Things to Know Before You Deploy Small Footprint

The Small Footprint PCF has a few constraints for scaling and capacity. Read through these guidelines before running your workload in production.

The Small Footprint edition is designed to support 2500 or fewer application instances per installation. That translates into a limit on the number of Compute VMs that can be deployed. The upper bound for that VM type in the Small Footprint is 10 VMs.

If you want to deploy multiple thousands of application instances - or expect to see a large amount of growth in the number of application instances - then the full-size Pivotal Cloud Foundry is more well-suited to handle this type of workload and scale.

Small Footprint gives you highly available containers, but loss of a VM could result in application outage

When you push your app to Small Footprint, it will containerize your app, and run it HA at the container layer. A failure at the VM layer is more likely to have an application impact with Small Footprint. There's simply fewer VMs in play. Scale the Compute VM for greater HA if your needs dictate.

Expansion beyond 10 VMs requires greater scale

There is no supported upgrade path between the Small Footprint  and a full-size PCF deployment. So, if you are expecting your platform usage to increase to a size that would exceed the capacity of the Small Footprint, consider using the full-size version.

The good news: your apps port over directly with no code changes. More good news: app developers see no difference when pushing apps. It works the same across both editions.

Upgrades require downtime

Because so much of the management plane has been co-located onto a single VM, the platform cannot make strict uptime guarantees for the management plane components during an upgrade. When upgrading the Small Footprint Elastic Runtime, there can be brief periods of time where new applications cannot be deployed, or when APIs may not be available. But never fear - there’s a useful workaround for app upgrades. If you have scaled your Compute VMs to a highly available configuration (with enough excess capacity to move app instances between Compute instances during an upgrade) then you can rely upon application availability during an upgrade. This will add to the infrastructure footprint of course.

To recap:

 

PCF

Small Footprint PCF

Designed for

Maximum High Availability and Horizontal Scalability

Efficiency & Maximum Colocation

Number of VMs

22-1250

4-20

Number of Containers

250,000+

2500

Multi-cloud

Yes

Yes

Remediate CVEs with Zero Downtime

Yes

Yes

Runs atop Cloud Foundry BOSH

Yes

Yes

Includes CredHub

Yes

Yes

Compatibility

Other than the caveats listed above, you can expect the Small Footprint edition to work and integrate with all of the services currently available on Pivotal Network.

The canonical PCF Suite services like RabbitMQ, Redis, and Pivotal Cloud Cache will run and work as expected alongside Small Footprint.

You will also be able to use the new BOSH Backup and Restore tooling to continue to backup and restore your platform at will.

Installation

The installation process for Small Footprint is not dramatically different than the process you would follow for PCF. You’ll find the familiar configuration and deployment options in the Small Footprint version as well.

Check out the documentation for more of the details. 

Summary

Companies are finding that app-centric abstractions like Pivotal Cloud Foundry help them increase development velocity. We offer PCF Dev and Pivotal Web Services as easy ways to get started with the platform. Now, with Small Footprint, you have yet another way to bring PCF to your organization!

We’re also working to add Small Footprint templates to partner marketplaces. Stay tuned!

About the Author

Ryan Moran

Ryan Moran is a software engineer and product manager at Pivotal, working on Cloud Foundry. Previously, he built software for healthcare and education startups in the Los Angeles area. Including his current work in Golang, Ryan has spent years developing software in languages like Ruby and Javascript. When not writing code, Ryan likes to collect vinyl and backpacking in the national parks of the western US.

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