Karen Bradshaw 86cfe26fcf Text updates to firstapp tutorial
-Updated wording for clarity.
-Updated section description links to be consistent
in each section of the tutorial.

Change-Id: I59a0d4cabc653f8c52e15d504059ba7905f7857f
2015-04-30 12:25:12 -04:00

21 KiB

Getting started

Who should read this guide

This guide is for software developers who want to deploy applications to OpenStack clouds.

We assume that you're an experienced programmer who has not created a cloud application in general or an OpenStack application in particular.

If you're familiar with OpenStack, this section teaches you how to program with its components.

What you will learn

Deploying applications in a cloud environment can be very different from deploying them in a traditional IT environment. This guide teaches you how to deploy applications on OpenStack and some best practices for cloud application development.

A general overview

This tutorial shows two applications. The first application is a simple fractal generator that uses mathematical equations to generate beautiful fractal images . We show you this application in its entirety so that you can compare it to the second, more robust, application.

The second application is an OpenStack application that enables you to:

  • Create and destroy compute resources. These resources are virtual machine instances where the Fractals application runs.
  • Make cloud-related architecture decisions such as turning functions into micro-services and modularizing them.
  • Scale available resources up and down.
  • Use Object and Block storage for file and database persistence.
  • Use Orchestration services to automatically adjust to the environment.
  • Customize networking for better performance and segregation.
  • Explore and apply advanced OpenStack cloud features.

Choose your OpenStack SDK

This guide focuses on how to use Python with Apache Libcloud. Anyone with a programming background can easily read the code in this guide. Although this guide focuses on Libcloud, you can use other languages and toolkits with the OpenStack cloud:

Language Name Description URL

Python

Libcloud

A Python-based library managed by the Apache Foundation. This library enables you to work with multiple types of clouds.

https://libcloud.apache.org

Python OpenStack SDK A python-based library specifically developed for OpenStack. https://github.com/stackforge/python-openstacksdk

Java

jClouds

A Java-based library. Like Libcloud, it's also managed by the Apache Foundation and works with multiple types of clouds.

https://jclouds.apache.org

Ruby fog A Ruby-based SDK for multiple clouds. http://www.fogproject.org
node.js pkgcloud A Node.js-based SDK for multiple clouds. https://github.com/pkgcloud/pkgcloud
PHP php-opencloud A library for developers using PHP to work with OpenStack clouds. http://php-opencloud.com/

NET Framework

OpenStack SDK for Microsoft .NET

A .NET based library that can be used to write C++ applications.

https://www.nuget.org/packages/OpenStack-SDK-DotNet

For a list of available SDKs, see Software Development Kits.

Future versions of this guide will show you how to use the OpenStack SDK and languages such as Java and Ruby to complete these tasks. If you're a developer for another toolkit that you would like this guide to include, feel free to submit code snippets. You can also contact OpenStack Documentation team members.

What you need

We assume that you can already access an OpenStack cloud. You must have a project (also known as a tenant) with a minimum quota of six instances. Because the Fractals application runs in Ubuntu, Debian, Fedora-based, and openSUSE-based distributions, you must create instances that use one of these operating systems.

To interact with the cloud, you must also have

dotnet

OpenStack SDK for Microsoft .NET 0.9.1 or higher installed.

Warning

This document has not yet been completed for the .NET SDK.

fog

fog 1.19 or higher installed and working with ruby gems 1.9.

Warning

This document has not yet been completed for the fog SDK.

jclouds

jClouds 1.8 or higher installed.

Warning

This document has not yet been completed for the jclouds SDK.

node

a recent version of pkgcloud installed.

Warning

This document has not yet been completed for the pkgcloud SDK.

openstacksdk

the OpenStack SDK installed.

Warning

This document has not yet been completed for the OpenStack SDK.

phpopencloud

a recent version of php-opencloud installed.

Warning

This document has not yet been completed for the php-opencloud SDK.

You need the following information that you can obtain from your cloud provider:

  • auth URL
  • user name
  • password
  • project ID or name (projects are also known as tenants)
  • cloud region

You can also download the OpenStack RC file from the OpenStack dashboard. Log in to the Horizon dashboard and click Project->Access & Security->API Access->Download OpenStack RC file. If you choose this route, be aware that the "auth URL" doesn't include the path. For example, if your openrc.sh file shows:

export OS_AUTH_URL=http://controller:5000/v2.0

the actual auth URL will be

http://controller:5000

How you'll interact with OpenStack

In this tutorial, you interact with your OpenStack cloud through one of the SDKs listed in "Choose your OpenStack SDK." The code snippets in this initial version of the guide assume that you're using Libcloud.

fog

../../samples/fog/section1.rb

libcloud

To try it, add the following code to a Python script (or use an interactive Python shell) by calling python -i.

../../samples/libcloud/section1.py

openstacksdk

from openstack import connection
conn = connection.Connection(auth_url="http://controller:5000/v3",
                             user_name="your_auth_username",
                             password="your_auth_password", ...)

Note

Because the tutorial uses the conn object, make sure that you always have one handy.

libcloud

Note

If you receive the libcloud.common.types.InvalidCredsError: 'Invalid credentials with the provider' exception while trying to run one of the following API calls, double-check your credentials.

Note

If your provider does not support regions, try a blank string ('') for the region_name.

Flavors and images

To run your application, you must launch an instance. This instance serves as a virtual machine.

To launch an instance, you choose a flavor and an image. The flavor represents the size of the instance, including the number of CPUs and amount of RAM and disk space. An image is a prepared OS installation from which you clone your instance. When you boot instances in a public cloud, larger flavors can be more expensive than smaller ones in terms of resources and monetary cost.

To list the images that are available in your cloud, run some API calls:

fog

../../samples/fog/section1.rb

libcloud

../../samples/libcloud/section1.py

You should see a result something like:

<NodeImage: id=2cccbea0-cea9-4f86-a3ed-065c652adda5, name=ubuntu-14.04, driver=OpenStack  ...>
<NodeImage: id=f2a8dadc-7c7b-498f-996a-b5272c715e55, name=cirros-0.3.3-x86_64, driver=OpenStack  ...>

You can also get information about available flavors:

fog

../../samples/fog/section1.rb

libcloud

../../samples/libcloud/section1.py

This code produces output like:

<OpenStackNodeSize: id=1, name=m1.tiny, ram=512, disk=1, bandwidth=None, price=0.0, driver=OpenStack, vcpus=1,  ...>
<OpenStackNodeSize: id=2, name=m1.small, ram=2048, disk=20, bandwidth=None, price=0.0, driver=OpenStack, vcpus=1,  ...>
<OpenStackNodeSize: id=3, name=m1.medium, ram=4096, disk=40, bandwidth=None, price=0.0, driver=OpenStack, vcpus=2,  ...>
<OpenStackNodeSize: id=4, name=m1.large, ram=8192, disk=80, bandwidth=None, price=0.0, driver=OpenStack, vcpus=4,  ...>
<OpenStackNodeSize: id=5, name=m1.xlarge, ram=16384, disk=160, bandwidth=None, price=0.0, driver=OpenStack, vcpus=8,  ...>

Your images and flavors will be different, of course.

Choose an image and flavor for your instance. You need about 1GB RAM, 1 CPU, and a 1GB disk. This example uses the Ubuntu image with the m1.small flavor, which are safe choices. In subsequent tutorial sections in this guide, you must change the image and flavor IDs to correspond to the image and flavor that you choose.

If the image that you want is not available in your cloud, you can usually upload one depending on your cloud's policy settings. For information about how to upload images, see obtaining images.

Set the image and size variables to appropriate values for your cloud. We'll use these variables in later sections.

First, tell the connection to get a specifed image by using the ID of the image that you picked in the previous section:

fog

../../samples/fog/section1.rb

libcloud

../../samples/libcloud/section1.py

You should see output something like this:

<NodeImage: id=2cccbea0-cea9-4f86-a3ed-065c652adda5, name=ubuntu-14.04, driver=OpenStack  ...>

Next, tell the script which flavor you want to use:

fog

../../samples/fog/section1.rb

libcloud

../../samples/libcloud/section1.py

You should see output something like this:

<OpenStackNodeSize: id=3, name=m1.medium, ram=4096, disk=40, bandwidth=None, price=0.0, driver=OpenStack, vcpus=2,  ...>

Now, you're ready to launch the instance.

Launch an instance

Use your selected image and flavor to create an instance.

libcloud

Note

The following instance creation example assumes that you have a single-tenant network. If you receive the 'Exception: 400 Bad Request Multiple possible networks found, use a Network ID to be more specific' error, you have multiple-tenant networks. You must add a networks parameter to the create_node call. See /appendix for details.

Create the instance.

Note

Your SDK might call an instance a 'node' or 'server'.

fog

../../samples/fog/section1.rb

libcloud

../../samples/libcloud/section1.py

You should see output something like:

<Node: uuid=1242d56cac5bcd4c110c60d57ccdbff086515133, name=testing, state=PENDING, public_ips=[], private_ips=[], provider=OpenStack ...>

openstacksdk

args = {
    "name": "testing",
    "flavorRef": flavor,
    "imageRef": image,
}
instance = conn.compute.create_server(**args)

If you list existing instances:

fog

../../samples/fog/section1.rb

libcloud

../../samples/libcloud/section1.py

The new instance appears.

libcloud

<Node: uuid=1242d56cac5bcd4c110c60d57ccdbff086515133, name=testing, state=RUNNING, public_ips=[], private_ips=[], provider=OpenStack ...>

openstacksdk

instances = conn.compute.list_servers()
for instance in instances:
    print(instance)

Before you move on, you must do one more thing.

Destroy an instance

Cloud resources such as running instances that you no longer use can cost money. Destroy cloud resources to avoid unexpected expenses.

fog

../../samples/fog/section1.rb

libcloud

../../samples/libcloud/section1.py

If you list the instances again, the instance disappears.

Leave your shell open to use it for another instance deployment in this section.

Deploy the application to a new instance

Now that you know how to create and destroy instances, you can deploy the sample application. The instance that you create for the application is similar to the first instance that you created, but this time, we'll briefly introduce a few extra concepts.

Note

Internet connectivity from your cloud instance is required to download the application.

When you create an instance for the application, you'll want to give it a bit more information than you supplied to the bare instance that you just created and destroyed. We'll go into more detail in later sections, but for now, simply create the following resources so that you can feed them to the instance:

  • A key pair. To access your instance, you must import an SSH public key into OpenStack to create a key pair. OpenStack installs this key pair on the new instance. Typically, your public key is written to .ssh/id_rsa.pub. If you do not have an SSH public key file, follow these instructions first. We'll cover these instructions in depth in /section2.

fog

Warning

This section has not been completed.

libcloud

In the following example, pub_key_file should be set to the location of your public SSH key file.

../../samples/libcloud/section1.py

<KeyPair name=demokey fingerprint=aa:bb:cc... driver=OpenStack>
  • Network access. By default, OpenStack filters all traffic. You must create a security group and apply it to your instance. The security group allows HTTP and SSH access. We'll go into more detail in /section2.

fog

../../samples/fog/section1.rb

libcloud

../../samples/libcloud/section1.py

  • Userdata. During instance creation, you can provide userdata to OpenStack to configure instances after they boot. The cloud-init service applies the userdata to an instance. You must pre-install the cloud-init service on your chosen image. We'll go into more detail in /section2.

fog

Warning

This section has not been completed.

libcloud

../../samples/libcloud/section1.py

Now, you can boot and configure the instance.

Boot and configure an instance

Use the image, flavor, key pair, and userdata to create a instance. After you request the instance, wait for it to build.

fog

Warning

This section has not been completed.

libcloud

../../samples/libcloud/section1.py

When the instance boots, the ex_userdata variable value instructs the instance to deploy the Fractals application.

Associate a floating IP for external connectivity

We'll cover networking in detail in /section7.

To see the application running, you must know where to look for it. By default, your instance has outbound network access. To make your instance reachable from the Internet, you need an IP address. By default in some cases, your instance is provisioned with a publicly rout-able IP address. In this case, you'll see an IP address listed under public_ips or private_ips when you list the instances. If not, you must create and attach a floating IP address to your instance.

fog

Warning

This section has not been completed.

libcloud

Use ex_list_floating_ip_pools() and select the first floating IP address pool. Allocate this pool to your project and attach it to your instance.

../../samples/libcloud/section1.py

remove extra blank line after break

You should see the floating IP output to the command line:

<OpenStack_1_1_FloatingIpAddress: id=4536ed1e-4374-4d7f-b02c-c3be2cb09b67, ip_addr=203.0.113.101, pool=<OpenStack_1_1_FloatingIpPool: name=floating001>, driver=<libcloud.compute.drivers.openstack.OpenStack_1_1_NodeDriver object at 0x1310b50>>

You can then attach it to the instance:

../../samples/libcloud/section1.py

Run the script to start the deployment.

Access the application

Deploying application data and configuration to the instance can take some time. Consider enjoying a cup of coffee while you wait. After the application deploys, you can visit the awesome graphic interface at the following link using your preferred browser.

libcloud

../../samples/libcloud/section1.py

Note

If you do not use floating IPs, substitute another IP address as appropriate

Next steps

Don't worry if these concepts are not yet completely clear. In /section2, we explore these concepts in more detail.

  • /section3: Learn how to scale your application
  • /section4: Learn how to use Object Storage to make your application durable
  • /section5: Migrate the database to block storage, or use the database-as-a-service component
  • /section6: Automatically orchestrate your application
  • /section7: Learn about complex networking
  • /section8: Get advice about operations
  • /section9: Learn some crazy things that you might not think to do ;)

List the next sections here or simply reference section2.

Complete code sample

The following file contains all of the code from this section of the tutorial. This comprehensive code sample lets you view and run the code as a single script.

Before you run this script, confirm that you have set your authentication information, the flavor ID, and image ID.

libcloud

../../samples/libcloud/section1.py