Exploring New Heat Orchestration Features in OpenStack Juno

While OpenStack Release notes is a great source to get updated quickly on the changes and new features that are introduced in each release, the Release Notes do not provide much details on how to use and  leverage the new features. Here’s a bit more detailed description of what’s new with HEAT in OpenStack Juno release and expected in the supported product “RHEL OpenStack Platform 6” to be released in late January 2015.

Recovery From Failures During Stack Updates

Heat allows to update existing stacks, while stack updates occur new resources are created created and added. If a failure happens during Stack Update Heat can attempt to roll back to the previous state or keep the Stack at failed state. If the roll-back fails or if roll-back is disabled for a Stack, Heat now tracks all changes that happen in Stack’s resources, so instead of just failing a Stack Update operation and keeping it in failed state,where in this state all we can do is to delete a stack, Heat now keeps track of all changes in resources and updates the current template accordingly.


API to cancel and roll back an in-progress stack update

Heat now allows to cancel a Stack Update operation while stack update is in progress.

usage: heat stack-cancel-update <NAME or ID>



Remember the previously-supplied parameters when updating a stack

Heat Update now can re-use the set of parameters of the current stack. Parameters specified in –parameters will patch over the existing values in the current stack. Parameters omitted will keep the existing values when –existing flag is specified.

Usage: heat stack-update --existing <NAME or ID>



Improved visibility into trees of nested stacks

Heat API and CLI added a new flag to list all stacks including nested stacks.

Usage: heat stack-list --nested



Implementation of new resource types:

New resource types that were added in the Juno release cycle to the already large list of existing resources you can use within Heat Orchestration Templates:

  • OS::Glance::Image
  • OS::Heat::SwiftSignal
    Provides the option to store Wait Condition (and Software Deployment) data in Swift
  • OS::Heat::StructuredDeployments
    Groups code for multiple lifecycle events into a single deployment resource
  • OS::Heat::SoftwareDeployments
    Provides a way of avoiding circular dependencies when deploying an interdependent cluster of servers
  • OS::Heat::SoftwareComponent
  • OS::Nova::ServerGroup
  • OS::Sahara::NodeGroupTemplate
  • OS::Sahara::ClusterTemplate


All new Implemented HEAT blueprints in Juno:



What else are you interested in related to OpenStack HEAT? Let me know in the comments below.


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1 Comment on Exploring New Heat Orchestration Features in OpenStack Juno

  1. Ashish Singh // August 18, 2015 at 11:28 am // Reply


    If we have a update failure and with a rollback, The stack goes back to its initial state upon update fail. But how can I know why the update has failed for the stack.


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