Getting started¶

Who should read this guide¶

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

If you are familiar with OpenStack but have not created a cloud application in general or an OpenStack application in particular, this section teaches you how to program with OpenStack 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 a second, more robust, application.

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

• Create and delete 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¶

Anyone with a programming background can easily read the code in this guide. Although this guide focuses on a particular SDK, you can use other languages and toolkits with the OpenStack cloud:

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

Other versions of this guide show you how to use the other SDKs and languages to complete these tasks. If you are a developer for another toolkit that you would like this guide to include, feel free to submit code snippets. For more information, contact OpenStack Documentation team members.

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

http://controller:5000

How you interact with OpenStack¶

In this tutorial, you interact with your OpenStack cloud through the SDK that you chose in “Choose your OpenStack SDK.” This guide assumes that you know how to run code snippets in your language of choice.

Use your credentials above to specify the cloud provider name, username, password, project_name and region_name in the file ~/.config/openstack/clouds.yml.

clouds:
    myfavoriteopenstack:
        auth:
            auth_url: https://controller:5000/
            username: $YOUR_USERNAME
            password: $YOUR_PASSWORD
            project_name: $YOUR_PROJECT
        region_name: $REGION

To configure shade using a profile, use your credentials above to specify the cloud provider name, username, password, project name, and region name in the file ~/.config/openstack/clouds.yml.

my-provider:
    profile: $PROVIDER_NAME
    auth:
        username: $YOUR_USERNAME
        password: $YOUR_PASSWORD
        project_name: $YOUR_PROJECT
    region_name: $REGION

See configure shade, to configure your cloud using a profile.

from shade import *

simple_logging(debug=True)
conn = openstack_cloud(cloud='myfavoriteopenstack')

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:

images = conn.list_images()
for image in images:
    print(image)

This code returns output like this:

checksum: 750a56555d4ec7303f5dc33b007ff632
container_format: bare
created_at: '2014-07-14T19:02:15Z'
direct_url:
rbd://7e14670e-a6f8-445b-b632-4b79bafc4781/masseffect-images/b4efbc2a-6130-4f2e-b436-55a618c4de20/snap
disk_format: raw
file: /v2/images/b4efbc2a-6130-4f2e-b436-55a618c4de20/file
id: b4efbc2a-6130-4f2e-b436-55a618c4de20
min_disk: 10
min_ram: 1024
name: Debian-7.0-Wheezy
owner: 0bacd8121bb548698f340455b38bf561
protected: false
schema: /v2/schemas/image
size: 5242880000
status: active
tags: []
updated_at: '2014-10-15T22:42:52Z'
visibility: public

You can also get information about available flavors:

flavors =  conn.list_flavors()
for flavor in flavors:
    print(flavor)

This code returns output like this:

HUMAN_ID: true
NAME_ATTR: name
OS-FLV-DISABLED:disabled: false
OS-FLV-EXT-DATA:ephemeral: 0
disk: 80
ephemeral: 0
human_id: supersonic
id: '200'
is_public: true
links:
-   href:
    https://compute.dream.io:8774/v2/5d013ac5962749a49af7ff18c2fb228c/flavors/200
    rel: self
-   href:
    https://compute.dream.io:8774/5d013ac5962749a49af7ff18c2fb228c/flavors/200
    rel: bookmark
name: supersonic
os-flavor-access:is_public: true
ram: 2048
swap: ''
vcpus: 1

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 a small flavor, which is a safe choice. 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 the policy settings of your cloud. For information about how to upload images, see obtaining images.

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

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

image_id = 'c55094e9-699c-4da9-95b4-2e2e75f4c66e'
image = conn.get_image(image_id)
print(image)

This code returns output like this:

checksum: da578dd59289a35a0ac7744a0bd85cf5
container_format: bare
created_at: '2014-10-27T22:05:37Z'
direct_url:
rbd://7e14670e-a6f8-445b-b632-4b79bafc4781/masseffect-images/c55094e9-699c-4da9-95b4-2e2e75f4c66e/snap
disk_format: raw
file: /v2/images/c55094e9-699c-4da9-95b4-2e2e75f4c66e/file
id: c55094e9-699c-4da9-95b4-2e2e75f4c66e
min_disk: 0
min_ram: 0
name: Ubuntu-14.04-Trusty
owner: 0bacd8121bb548698f340455b38bf561
protected: false
schema: /v2/schemas/image
size: 10737418240
status: active
tags: []
updated_at: '2014-10-27T22:08:55Z'
visibility: public

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

Specify the flavor ID that you would like to use.

flavor_id = '100'
flavor = conn.get_flavor(flavor_id)
print(flavor)

This code returns output like this:

HUMAN_ID: true
NAME_ATTR: name
OS-FLV-DISABLED:disabled: false
OS-FLV-EXT-DATA:ephemeral: 0
disk: 80
ephemeral: 0
human_id: subsonic
id: '100'
is_public: true
links:
-   href:
    https://compute.dream.io:8774/v2/5d013ac5962749a49af7ff18c2fb228c/flavors/100
    rel: self
-   href:
    https://compute.dream.io:8774/5d013ac5962749a49af7ff18c2fb228c/flavors/100
    rel: bookmark
name: subsonic
os-flavor-access:is_public: true
ram: 1024
swap: ''
vcpus: 1

Now, you can launch the instance.

Launch an instance¶

Use your selected image and flavor to create an instance.

Create the instance.

instance_name = 'testing'
testing_instance = conn.create_server(wait=True, auto_ip=True,
    name=instance_name,
    image=image_id,
    flavor=flavor_id)
print(testing_instance)

If you list existing instances:

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

The new instance appears.

HUMAN_ID: true
 NAME_ATTR: name
 OS-DCF:diskConfig: MANUAL
 OS-EXT-AZ:availability_zone: iad-1
 OS-EXT-STS:power_state: 1
 OS-EXT-STS:task_state: null
 OS-EXT-STS:vm_state: active
 OS-SRV-USG:launched_at: '2015-07-20T20:31:10.000000'
 OS-SRV-USG:terminated_at: null
 accessIPv4: ''
 accessIPv6: ''
 addresses:
     private-network:
     -   OS-EXT-IPS-MAC:mac_addr: fa:16:3e:60:f5:cd
         OS-EXT-IPS:type: fixed
         addr: 2607:f298:6050:4e14:f816:3eff:fe60:f5cd
         version: 6
     -   OS-EXT-IPS-MAC:mac_addr: fa:16:3e:60:f5:cd
         OS-EXT-IPS:type: fixed
         addr: 10.10.10.14
         version: 4
 config_drive: ''
 created: '2015-07-20T20:30:23Z'
 flavor:
     id: '100'
     links:
     -   href:
         https://compute.dream.io:8774/5d013ac5962749a49af7ff18c2fb228c/flavors/100
         rel: bookmark
 hostId: f71865b497e6fa71063e292b11846eb64b5a41cd5c00fbb7465b6a48
 human_id: testing
 id: 67ecebdc-daff-4d84-bd04-bc76c67b48ec
 image:
     id: c55094e9-699c-4da9-95b4-2e2e75f4c66e
     links:
     -   href:
         https://compute.dream.io:8774/5d013ac5962749a49af7ff18c2fb228c/images/c55094e9-699c-4da9-95b4-2e2e75f4c66e
         rel: bookmark
 key_name: null
 links:
 -   href:
     https://compute.dream.io:8774/v2/5d013ac5962749a49af7ff18c2fb228c/servers/67ecebdc-daff-4d84-bd04-bc76c67b48ec
     rel: self
 -   href:
     https://compute.dream.io:8774/5d013ac5962749a49af7ff18c2fb228c/servers/67ecebdc-daff-4d84-bd04-bc76c67b48ec
     rel: bookmark
 metadata: {}
 name: testing
 networks:
     private-network:
     - 2607:f298:6050:4e14:f816:3eff:fe60:f5cd
     - 10.10.10.14
 os-extended-volumes:volumes_attached: []
 progress: 0
 security_groups:
 -   name: default
 status: ACTIVE
 tenant_id: 5d013ac5962749a49af7ff18c2fb228c
 updated: '2015-07-20T20:31:10Z'
 user_id: bfd3dbf1c8a242cd90884408de547bb9

Before you continue, you must do one more thing.

Destroy an instance¶

Cloud resources, such as running instances that you no longer use, can cost money. To avoid unexpected expenses, destroy cloud resources.

conn.delete_server(name_or_id=instance_name)

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 delete 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 introduce a few extra concepts.

When you create an instance for the application, you want to give it a bit more information than you supplied to the bare instance that you just created and deleted. We will 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 will cover these instructions in depth in Introduction to the fractals application architecture.

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

print('Checking for existing SSH keypair...')
keypair_name = 'demokey'
pub_key_file = '/home/username/.ssh/id_rsa.pub'

if conn.search_keypairs(keypair_name):
    print('Keypair already exists. Skipping import.')
else:
    print('Adding keypair...')
    conn.create_keypair(keypair_name, open(pub_key_file, 'r').read().strip())

for keypair in conn.list_keypairs():
    print(keypair)

• 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 will go into more detail in Introduction to the fractals application architecture.

print('Checking for existing security groups...')
sec_group_name = 'all-in-one'
if conn.search_security_groups(sec_group_name):
    print('Security group already exists. Skipping creation.')
else:
    print('Creating security group.')
    conn.create_security_group(sec_group_name, 'network access for all-in-one application.')
    conn.create_security_group_rule(sec_group_name, 80, 80, 'TCP')
    conn.create_security_group_rule(sec_group_name, 22, 22, 'TCP')

conn.search_security_groups(sec_group_name)

• Userdata. During instance creation, you can provide userdata to OpenStack to configure instances after they boot. The cloud-init service applies the user data to an instance. You must pre-install the cloud-init service on your chosen image. We will go into more detail in Introduction to the fractals application architecture.

ex_userdata = '''#!/usr/bin/env bash

curl -L -s https://git.openstack.org/cgit/openstack/faafo/plain/contrib/install.sh | bash -s -- \
-i faafo -i messaging -r api -r worker -r demo
'''

Now, you can boot and configure the instance.

instance_name = 'all-in-one'
testing_instance = conn.create_server(wait=True, auto_ip=False,
    name=instance_name,
    image=image_id,
    flavor=flavor_id,
    key_name=keypair_name,
    security_groups=[sec_group_name],
    userdata=ex_userdata)

f_ip = conn.available_floating_ip()

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 use your preferred browser to visit the awesome graphic interface at the following link.

print('The Fractals app will be deployed to http://%s' % f_ip['floating_ip_address'] )

Note

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

Next steps¶

Do not worry if these concepts are not yet completely clear. In Introduction to the fractals application architecture, we explore these concepts in more detail.

• Scaling out: Learn how to scale your application.
• Make it durable: Learn how to use Object Storage to make your application durable.
• Block Storage: Migrate the database to block storage, or use the database-as-a-service component.
• Orchestration: Automatically orchestrate your application.
• Networking: Learn about complex networking.
• Advice for developers new to operations: Get advice about operations.
• Going crazy: Learn some crazy things that you might not think to do ;)

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.

#step-1
from shade import *

simple_logging(debug=True)
conn = openstack_cloud(cloud='myfavoriteopenstack')

#step-2
images = conn.list_images()
for image in images:
    print(image)

#step-3
flavors =  conn.list_flavors()
for flavor in flavors:
    print(flavor)

#step-4
image_id = 'c55094e9-699c-4da9-95b4-2e2e75f4c66e'
image = conn.get_image(image_id)
print(image)

#step-5
flavor_id = '100'
flavor = conn.get_flavor(flavor_id)
print(flavor)

#step-6
instance_name = 'testing'
testing_instance = conn.create_server(wait=True, auto_ip=True,
    name=instance_name,
    image=image_id,
    flavor=flavor_id)
print(testing_instance)

#step-7
instances = conn.list_servers()
for instance in instances:
    print(instance)

#step-8
conn.delete_server(name_or_id=instance_name)

#step-9
print('Checking for existing SSH keypair...')
keypair_name = 'demokey'
pub_key_file = '/home/username/.ssh/id_rsa.pub'

if conn.search_keypairs(keypair_name):
    print('Keypair already exists. Skipping import.')
else:
    print('Adding keypair...')
    conn.create_keypair(keypair_name, open(pub_key_file, 'r').read().strip())

for keypair in conn.list_keypairs():
    print(keypair)

#step-10
print('Checking for existing security groups...')
sec_group_name = 'all-in-one'
if conn.search_security_groups(sec_group_name):
    print('Security group already exists. Skipping creation.')
else:
    print('Creating security group.')
    conn.create_security_group(sec_group_name, 'network access for all-in-one application.')
    conn.create_security_group_rule(sec_group_name, 80, 80, 'TCP')
    conn.create_security_group_rule(sec_group_name, 22, 22, 'TCP')

conn.search_security_groups(sec_group_name)

#step-11
ex_userdata = '''#!/usr/bin/env bash

curl -L -s https://git.openstack.org/cgit/openstack/faafo/plain/contrib/install.sh | bash -s -- \
-i faafo -i messaging -r api -r worker -r demo
'''

#step-12
instance_name = 'all-in-one'
testing_instance = conn.create_server(wait=True, auto_ip=False,
    name=instance_name,
    image=image_id,
    flavor=flavor_id,
    key_name=keypair_name,
    security_groups=[sec_group_name],
    userdata=ex_userdata)

#step-13
f_ip = conn.available_floating_ip()

#step-14
conn.add_ip_list(testing_instance, [f_ip['floating_ip_address']])

#step-15
print('The Fractals app will be deployed to http://%s' % f_ip['floating_ip_address'] )