Migrating applications between releases

This document describes how a developer of murano application can update existing packages to make them synchronized with all implemented features and requirements.

Migrate applications from Murano v0.5 to Stable/Juno

Applications created for murano v0.5, unfortunately, are not supported in Murano stable/juno. This document provides the application code changes required for compatibility with the stable/juno murano version.

Rename ‘Workflow’ to ‘Methods’

In stable/juno the name of section containing class methods is renamed to Methods, as the latter is more OOP and doesn’t cause confusion with Mistral. So, you need to change it in app.name/Classes in all classes describing workflow of your app.

For example:

      - $._environment.reporter.report($this, 'Creating VM')

Should be changed to:

      - $._environment.reporter.report($this, 'Creating VM')

Change the Instance type in the UI definition ‘Application’ section

The Instance class was too generic and contained some dirty workarounds to differently handle Windows and Linux images, to bootstrap an instance in a number of ways, etc. To solve these problems more classes were added to the Instance inheritance hierarchy.

Now, base Instance class is abstract and agnostic of the desired OS and agent type. It is inherited by two classes: LinuxInstance and WindowsInstance.

  • LinuxInstance adds a default security rule for Linux, opening a standard SSH port;
  • WindowsInstance adds a default security rule for Windows, opening an RDP port. At the same time WindowsInstance prepares a user-data allowing to use Murano v1 agent.

LinuxInstance is inherited by two other classes, having different software config method:

  • LinuxMuranoInstance adds a user-data preparation to configure Murano v2 agent;
  • LinuxUDInstance adds a custom user-data field allowing the services to supply their own user data.

You need to specify the instance type which is required by your app. It specifies a field in UI, where user can select an image matched to the instance type. This change must be added to UI form definition in app.name/UI/ui.yaml.

For example, if you are going to install your application on Ubuntu, you need to change:

      type: io.murano.resources.Instance


      type: io.murano.resources.LinuxMuranoInstance

Migrate applications to Stable/Kilo

In Kilo, there are no breaking changes that affect backward compatibility. But there are two new features which you can use since Kilo.

1. Pluggable Pythonic classes for murano

Now you can create plug-ins for MuranoPL. A plug-in (extension) is an independent Python package implementing functionality which you want to add to the workflow of your application.

For a demo application demonstrating the usage of plug-ins, see the murano/contrib/plugins/murano_exampleplugin folder.

The application consist of the following components:

  • An ImageValidatorMixin class that inherits the generic instance class (io.murano.resources.Instance) and adds a method capable of validating the instance image for having an appropriate murano metadata type. This class may be used as a mixin when added to inheritance hierarchy of concrete instance classes.
  • A concrete class called DemoInstance that inherits from io.murano.resources.LinuxMuranoInstance and ImageValidatorMixin to add the image validation logic to a standard, murano-enabled and Linux-based instance.
  • An application that deploys a single VM using the DemoInstance class if the tag on the user-supplied image matches the user-supplied constant.

The ImageValidatorMixin demonstrates the instantiation of plug-in provided class and its usage, as well as handling of exception which may be thrown if the plug-in is not installed in the environment.

2. Murano mistral integration

The core library has a new system class for mistral client that allows to call Mistral APIs from the murano application model.

The system class allows you to:

  • Upload a mistral workflow to mistral.
  • Trigger the mistral workflow that is already deployed, wait for completion and return the execution output.

To use this feature, add some mistral workflow to Resources folder of your package. For example, create file TestEcho_MistralWorkflow.yaml:

version: '2.0'

  type: direct
    - input_1
    out_1: <% $.task1_output_1 %>
    out_2: <% $.task2_output_2 %>
    out_3: <% $.input_1 %>
     action: std.echo output='just a string'
       task1_output_1: 'task1_output_1_value'
       task1_output_2: 'task1_output_2_value'
       - my_echo_test_2

     action: std.echo output='just a string'
       task2_output_1: 'task2_output_1_value'
       task2_output_2: 'task2_output_2_value'

And provide workflow to use the mistral client:

=: io.murano.apps.test
std: io.murano
sys: io.murano.system

Name: MistralShowcaseApp

Extends: std:Application

    Contract: $.string().notNull()

    Contract: $.class(sys:MistralClient)
    Usage: Runtime

      - $this.mistralClient: new(sys:MistralClient)

      - $resources: new('io.murano.system.Resources')
      - $workflow: $resources.string('TestEcho_MistralWorkflow.yaml')
      - $.mistralClient.upload(definition => $workflow)
      - $output: $.mistralClient.run(name => 'test_echo', inputs => dict(input_1 => input_1_value))
      - $this.find(std:Environment).reporter.report($this, $output.get('out_3'))

Migrate applications to Stable/Liberty

In Liberty a number of useful features that can be used by developers creating their murano applications were implemented. This document describes these features and steps required to include them to new apps.

1. Versioning

Package version

Now murano packages have a new optional attribute in their manifest called Version - a standard SemVer format version string. All MuranoPL classes have the version of the package they contained in. To specify the version of your package, add a new section to the manifest file:

Version: 0.1.0

If no version specified, the package version will be equal to 0.0.0.

Package requirements

There are cases when packages may require other packages for their work. Now you need to list such packages in the Require section of the manifest file:

  package1_FQN: version_spec_1
  packageN_FQN: version_spec_N

version_spec here denotes the allowed version range. It can be either in semantic_version specification pip-like format or as partial version string. If you do not want to specify the package version, leave this value empty:

  package1_FQN: >=0.0.3

In this case, the last dependency 0.x.y is used.


All packages depend on the io.murano package (core library). If you do not specify this requirement in the list (or the list is empty or even there is no Require key in package manifest), then dependency io.murano: 0 will be automatically added.

Object version

Now you can specify the version of objects in UI definition when your application requires specific version of some class. To do this, add new key classVersion to section ? describing object:

  type: io.test.apps.TestApp
  classVersion: 0.0.1

classVersion of all classes included to package equals Version of this package.


In Liberty, murano was updated to use yaql 1.0.0. The new version of yaql allows you to use a number of new functions and features that help to increase the speed of developing new applications.


Usage of these features makes your applications incompatible with older versions of murano.

Also, in Liberty you can change Format in the manifest of package from 1.0 to 1.1 or 1.2.

  • 1.0 - supported by all versions of murano.
  • 1.1 - supported by Liberty+. Specify it, if you want to use features from yaql 0.2 and yaql 1.0.0 at the same time in your application.
  • 1.2 - supported by Liberty+. A number of features from yaql 0.2 do not work with this format (see the list below). We recommend you to use it for new applications where compatibility with Kilo is not required.

Some examples of yaql 0.2 features that are not compatible with the 1.2 format

  • Several functions now cannot be called as MuranoObject methods: id(), cast(), super(), psuper(), type().
  • Now you do not have the ability to compare non-comparable types. For example “string != false”
  • Dicts are not iterable now, so you cannot do this: If: $key in $dict. Use $key in $dict.keys() or $v in $dict.values()
  • Tuples are not available. => always means keyword argument.

3. Simple software configuration

Previously, you always had to create execution plans even when some short scripts had to be executed on a VM. This process included creating a template file, creating a script, and describing the sending of the execution plan to the murano agent.

Now you can use a new class io.murano.configuration.Linux from murano core-library. This allows sending short commands to the VM and putting files from the Resources folder of packages to some path on the VM without the need of creating execution plans.

To use this feature you need to:

  • Declare a namespace (for convenience)

      conf: io.murano.configuration
  • Create object of io.murano.configuration.Linux class in workflow of your application:

    $linux: new(conf:Linux)
  • Run one of the two feature methods: runCommand or putFile:

    # first agrument is agent of instance, second - your command
    $linux.runCommand($.instance.agent, 'service apache2 restart')


    # getting content of file from 'Resources' folder
    - $resources: new(sys:Resources)
    - $fileContent: $resources.string('your_file.name')
    # put this content to some directory on VM
    - $linux.putFile($.instance.agent, $fileContent, '/tmp/your_file.name')


At the moment, you can use this feature only if your app requires an instance of LinuxMuranoInstance type.

4. UI network selection element

Since Liberty, you can provide users with the ability to choose where to join their VM: to a new network created during the deployment, or to an already existing network. Dynamic UI now has a new type of field - NetworkChoiseField. This field provides a selection of networks and their subnetworks as a dropdown populated with those which are available to the current tenant.

To use this feature, you should make the following updates in the Dynamic UI of an application:

  • Add network field:

      - name: network
        type: network
        label: Network
        description: Select a network to join. 'Auto' corresponds to a default environment's network.
        required: false
        murano_networks: translate

    To see the full list of the network field arguments, refer to the UI forms specification.

  • Add template:

        - ?:
            type: io.murano.resources.ExistingNeutronNetwork
          internalNetworkName: $.instanceConfiguration.network[0]
          internalSubnetworkName: $.instanceConfiguration.network[1]
  • Add declaration of networks instance property:

        type: io.murano.apps.exampleApp
          type: io.murano.resources.LinuxMuranoInstance
        useEnvironmentNetwork: $.instanceConfiguration.network[0]=null
        useFlatNetwork: false
        customNetworks: switch($.instanceConfiguration.network[0], $=null=>list(), $!=null=>$customJoinNet)

For more details about this feature, see use-cases


To use this feature, the version of UI definition must be 2.1+

5. Remove name field from fields and object model in dynamic UI

Previously, each class of an application had a name property. It had no built-in predefined meaning for MuranoPL classes and mostly used for dynamic UI purposes.

Now you can create your applications without this property in classes and without a corresponding field in UI definitions. The field for app name will be automatically generated on the last management form before start of deployment. Bonus of deleting this - to remove unused property from muranopl class that is needed for dashboard only.

So, to update existing application developer should make 3 steps:

  1. remove name field and property declaration from UI definition;
  2. remove name property from class of application and make sure that it is not used anywhere in workflow
  3. set version of UI definition to 2.2 or higher