95f1049054
This patch adds support for pkgcloud to the First App tutorial in section one. The code has been tested on a cloud with nova-network. Partial-Bug: 1449331 Change-Id: I50e5211b6f6df5c26fdcf6f2b39cc5a8308f787c
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199 lines
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=============
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Orchestration
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=============
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.. todo:: Needs to be restructured so that the fractals app is used as the example for the explanatory material.
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.. note:: Sorry! We're not quite happy with this chapter. It will give you an introduction to heat,
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but it's a little dry at the moment. We'd like to write a template for the Fractals app instead
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of using the "hello world" style ones, so stay tuned!
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Throughout this guide, we've talked about the importance of durability and scalability
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for your cloud-based applications. In most cases, really achieving these qualities means
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automating tasks such as scaling and other operational tasks.
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The Orchestration module provides a template-based way to describe a cloud
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application, then coordinates running the needed OpenStack API calls to run
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cloud applications. The templates allow you to create most OpenStack resource
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types, such as instances, networking information, volumes, security groups
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and even users. It also provides more advanced functionality, such as
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instance high availability, instance auto-scaling, and nested stacks.
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The OpenStack Orchestration API contains the following constructs:
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* Stacks
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* Resources
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* Templates
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Stacks are created from Templates, which contain Resources. Resources
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are an abstraction in the HOT (Heat Orchestration Template) template language, which enables you to define different
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cloud resources by setting the `type` attribute.
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For example, you might use the Orchestration API to create two compute
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instances by creating a Stack and by passing a Template to the Orchestration API.
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That Template would contain two Resources with the `type` attribute set to `OS::Nova::Server`.
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That's a simplistic example, of course, but the flexibility of the Resource object
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enables the creation of Templates that contain all the required cloud
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infrastructure to run an application, such as load balancers, block storage volumes,
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compute instances, networking topology, and security policies.
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.. note:: The Orchestration module isn't deployed by default in every cloud. If these commands don't work, it means the Orchestration API isn't available; ask your support team for assistance.
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This section introduces the `HOT templating language <http://docs.openstack.org/developer/heat/template_guide/hot_guide.html>`_,
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and takes you through some of the common calls you will make when working with OpenStack Orchestration.
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Unlike previous sections of this guide, in which you used your SDK to programmatically interact with
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OpenStack, in this section you'll be using the Orchestration API directly through Template files,
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so we'll work from the command line.
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Install the 'heat' commandline client by following this guide:
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http://docs.openstack.org/cli-reference/content/install_clients.html
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then set up the necessary variables for your cloud in an 'openrc' file using this guide:
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http://docs.openstack.org/cli-reference/content/cli_openrc.html
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.. only:: dotnet
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.. warning:: the .NET SDK does not currently support OpenStack Orchestration
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.. only:: fog
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.. note:: fog `does support OpenStack Orchestration <https://github.com/fog/fog/tree/master/lib/fog/openstack/models/orchestration>`_.
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.. only:: jclouds
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.. warning:: Jclouds does not currently support OpenStack Orchestration. See this `bug report <https://issues.apache.org/jira/browse/JCLOUDS-693>`_.
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.. only:: libcloud
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.. warning:: libcloud does not currently support OpenStack Orchestration.
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.. only:: pkgcloud
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.. note:: Pkgcloud supports OpenStack Orchestration :D:D:D but this section is `not written yet <https://github.com/pkgcloud/pkgcloud/blob/master/docs/providers/openstack/orchestration.md>`_
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.. only:: openstacksdk
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.. warning:: OpenStack SDK does not currently support OpenStack Orchestration.
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.. only:: phpopencloud
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.. note:: PHP-opencloud supports orchestration :D:D:D but this section is not written yet.
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HOT Templating Language
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-----------------------
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The best place to learn about the template syntax for OpenStack Orchestration is the
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`Heat Orchestration Template (HOT) Guide <http://docs.openstack.org/developer/heat/template_guide/hot_guide.html>`_
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You should read the HOT Guide first to learn how to create basic templates, their inputs and outputs.
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Working with Stacks: Basics
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---------------------------
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.. todo::
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This section needs to have a HOT template written for deploying the Fractal Application
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.. todo::
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Replace the hello_world.yaml templte with the Fractal template
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* Stack create
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In the following example, we use the `hello_world <https://github.com/openstack/heat-templates/blob/master/hot/hello_world.yaml>`_ Hot template to demonstrate creating
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a Nova compute instance, with a few configuration settings passed in, such as an administrative password and the unique identifier (UUID)
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of an image:
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::
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$ wget https://raw.githubusercontent.com/openstack/heat-templates/master/hot/hello_world.yaml
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$ heat stack-create --template-file hello_world.yaml \
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--parameters admin_pass=Test123\;key_name=test\;image=5bbe4073-90c0-4ec9-833c-092459cc4539 hello_world
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+--------------------------------------+-------------+--------------------+----------------------+
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| id | stack_name | stack_status | creation_time |
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+--------------------------------------+-------------+--------------------+----------------------+
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| 0db2c026-fb9a-4849-b51d-b1df244096cd | hello_world | CREATE_IN_PROGRESS | 2015-04-01T03:20:25Z |
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+--------------------------------------+-------------+--------------------+----------------------+
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The resulting stack creates a Nova instance automatically, which you can see here:
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::
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$ nova list
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+--------------------------------------+---------------------------------+--------+------------+-------------+------------------+
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| ID | Name | Status | Task State | Power State | Networks |
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+--------------------------------------+---------------------------------+--------+------------+-------------+------------------+
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| 9bdf0e2f-415e-43a0-90ea-63a5faf86cf9 | hello_world-server-dwmwhzfxgoor | ACTIVE | - | Running | private=10.0.0.3 |
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+--------------------------------------+---------------------------------+--------+------------+-------------+------------------+
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Verify that the stack was successfully created using the following command:
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::
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$ heat stack-list
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+--------------------------------------+-------------+-----------------+----------------------+
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| id | stack_name | stack_status | creation_time |
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+--------------------------------------+-------------+-----------------+----------------------+
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| 0db2c026-fb9a-4849-b51d-b1df244096cd | hello_world | CREATE_COMPLETE | 2015-04-01T03:20:25Z |
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+--------------------------------------+-------------+-----------------+----------------------+
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Remove the stack:
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::
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$ heat stack-delete hello_world
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+--------------------------------------+-------------+--------------------+----------------------+
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| id | stack_name | stack_status | creation_time |
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+--------------------------------------+-------------+--------------------+----------------------+
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| 0db2c026-fb9a-4849-b51d-b1df244096cd | hello_world | DELETE_IN_PROGRESS | 2015-04-01T03:20:25Z |
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+--------------------------------------+-------------+--------------------+----------------------+
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Verify that the removal of the stack has deleted the nova instance:
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::
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$ nova list
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+----+------+--------+------------+-------------+----------+
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| ID | Name | Status | Task State | Power State | Networks |
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+----+------+--------+------------+-------------+----------+
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+----+------+--------+------------+-------------+----------+
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While this stack is not very interesting - it just starts a single instance - it
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is possible to make very complicated templates that involve dozens of instances
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or adds and removes instances based on demand. Continue to the next section to
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learn more.
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Working with Stacks: Advanced
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-----------------------------
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.. todo:: needs more explanatory material
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.. todo:: needs a heat template that uses fractal app
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With the use of the Orchestration API, the Fractal app can create an autoscaling
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group for all parts of the application, in order to dynamically provision more
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compute resources during periods of heavy utilization, and also terminate compute
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instances to scale down, as demand decreases.
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There are two helpful articles available to learn about autoscaling with the
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Orchestration API:
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* http://superuser.openstack.org/articles/simple-auto-scaling-environment-with-heat
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* http://superuser.openstack.org/articles/understanding-openstack-heat-auto-scaling
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An example template that creates an auto-scaling wordpress instance can be found in
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`the heat template repository <https://github.com/openstack/heat-templates/blob/master/hot/autoscaling.yaml>`_
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Next Steps
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----------
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You should now be fairly confident working with the Orchestration service.
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There are several calls we did not cover. To see these and more,
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refer to the volume documentation of your SDK, or try a different step in the tutorial, including:
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* :doc:`/networking` - to learn about more complex networking
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* :doc:`/advice` - for advice for developers new to operations
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* :doc:`/craziness` - to see all the crazy things we think ordinary folks won't want to do ;)
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