Cloud Foundry Advisory Board Meeting, Mar 2019: YAML Templating Tool

by Carlo GutierrezMarch 21, 2019
The YAML Templating Tool enables easier management of YAML templates working on their structure, not text, via a sandboxed Pythonic scripting language.

The Cloud Foundry Community Advisory Board (CAB) meeting for March 2019 featured demonstrations of YAML Templating Tool, as well as weighted routing under the Istio and Cloud Foundry integration. The call also included the usual updates from the members of the development teams.


YAML Templating Tool

Nima Kaviani

The creation of the YAML templates often involves dealing with tools, which use text templates. These tools don’t always understand YAML structure, making the process of managing the YAML templates complex.

As stated by Nima Kaviani of IBM, Helm and similar tools treat YAML templates as text ones. This means that users have to go through the trouble of ensuring that their YAML configurations follow proper structure.

YAML Templating Tool (ytt) is a solution that understands YAML structure through the Phythonic scripting language. According to Dmitriy Kalinin of Pivotal, ytt was developed to enable a more convenient method of creating YAML templates.

Dmitriy Kalinin

“We wanted to embrace some of the templating tools that communities use, but we wanted our templating tool to be more useable, less error-prone, and more intuitive.” —Dmitriy Kalinin, Pivotal

ytt is currently at v0.1.0 with the following features available:

  • Templating works on the YAML structure, not text.
  • Includes a sandboxed Pythonic scripting language.
  • Reuses YAML structures via functions.
  • Merges YAML structures.
  • Validates data.
  • Provides optional text templating.

ytt is a new take on YAML templating, and when we say templating, what we really mean is data structure building.” —Nima Kaviani, IBM

Editing data types using ytt (Image credit)

YAML Templating Tool’s GitHub repo


Istio and Cloud Foundry integration

Nitya Dhanushkodi

Nitya Dhanushkodi and Shubha Anjur Tupil from Pivotal shared some of the work in progress under the ongoing integration between Istio and Cloud Foundry. One of the features in active development is weighted routing.

“When you include Istio in your deployment, it adds an Istio domain to your Cloud Foundry domain. If you push applications to the Istio domain, then you can leverage features like weighted routing.” —Nitya Dhanushkodi, Pivotal

According to Shubha, the integration of Istio and Cloud Foundry is still at the early stages, and production is still a ways off. The team plans to add the following functionality in the near future:

Shubha Anjur Tupil

  • support for dynamically configured sidecars
  • client-side load balancing
  • transparent mutual TLS for an app-to-app communication

“We will start working on a lot of the gorouter parity features. We need to get to parity at some point to be able to deprecate the gorouter and actually start using this.” —Shubha Anjur Tupil, Pivotal

Istio’s GitHub repo


Runtime PMC

Eric Malm

Eric Malm of Pivotal provided the following updates:

  • The CLI team released v6.43, which now supports multi-service registrations.
  • The CAPI team is finishing up application revisions. They are about to start work on attaching sidecar processes.
  • The Loggregator team has settled on a 6-month window for the Firehose endpoint.
  • The networking team finished working on transparent client-side load balancing for internal routes. They are now moving on to transparent mutual TLS.
  • The Garden team is making progress in improving application CPU usage reporting and containerd support.

Runtime PMC’s GitHub repo



Morgan Fine

Morgan Fine of Pivotal reported the following BOSH updates:

  • BOSH v268.7.0 was released.
  • The team is experimenting with a new life cycle hook—PreStop.
  • Static IP addresses were moved to Cloud Config.
  • There are plans to stop providing support for the v1 manifest.

BOSH’s GitHub repo


CF Extensions

Dr. Max

Michael Maximilien of IBM (aka Dr. Max) noted the following changes:

  • App-AutoScaler has graduated from the Cloud Foundry incubator.
  • Stratos
    • v2.3.0 was released.
    • Two common vulnerabilities and exposures were fixed.
    • User-provided service support is being added.
    • BlockHead
      • Hyperledger is now supported.

    CF Extensions’ GitHub repo


    The summit is approaching!

    Swarna Podila

    With the Cloud Foundry Summit in Philadelphia less than two weeks away, Swarna Podila of the CF Foundation reported that there are over 800 registrants. There’s not much else to say besides see you in Philly!

    The next CAB call is scheduled for Wednesday, April 17. The call will start at 8 a.m. Pacific Time. Anyone interested can join the Cloud Foundry’s CAB Slack channel.


    Want details? Watch the video!