ansible/docsite/rst/guide_rax.rst

Rackspace Cloud Guide

Introduction

Note

This section of the documentation is under construction. We are in the process of adding more examples about the Rackspace modules and how they work together. Once complete, there will also be examples for Rackspace Cloud in ansible-examples.

Ansible contains a number of core modules for interacting with Rackspace Cloud.

The purpose of this section is to explain how to put Ansible modules together (and use inventory scripts) to use Ansible in Rackspace Cloud context.

Prerequisites for using the rax modules are minimal. In addition to ansible itself, all of the modules require and are tested against pyrax 1.5 or higher. You'll need this Python module installed on the execution host.

pyrax is not currently available in many operating system package repositories, so you will likely need to install it via pip:

$ pip install pyrax

The following steps will often execute from the control machine against the Rackspace Cloud API, so it makes sense to add localhost to the inventory file. (Ansible may not require this manual step in the future):

[localhost]
localhost ansible_connection=local

In playbook steps we'll typically be using the following pattern:

- hosts: localhost
  connection: local
  gather_facts: False
  tasks:

Credentials File

The rax.py inventory script and all rax modules support a standard pyrax credentials file that looks like:

[rackspace_cloud]
username = myraxusername
api_key = d41d8cd98f00b204e9800998ecf8427e

Setting the environment parameter RAX_CREDS_FILE to the path of this file will help Ansible find how to load this information.

More information about this credentials file can be found at https://github.com/rackspace/pyrax/blob/master/docs/getting_started.md#authenticating

Running from a Python Virtual Environment (Optional)

Special considerations need to be taken if pyrax is not installed globally but instead using a python virtualenv (it's fine if you install it globally).

Ansible assumes, unless otherwise instructed, that the python binary will live at /usr/bin/python. This is done so via the interpret line in the modules, however when instructed using ansible_python_interpreter, ansible will use this specified path instead for finding python.

If using virtualenv, you may wish to modify your localhost inventory definition to find this location as follows:

[localhost]
localhost ansible_connection=local ansible_python_interpreter=/path/to/ansible_venv/bin/python

Provisioning

Now for the fun parts.

The 'rax' module provides the ability to provision instances within Rackspace Cloud. Typically the provisioning task will be performed from your Ansible control server against the Rackspace cloud API.

Note

Authentication with the Rackspace-related modules is handled by either specifying your username and API key as environment variables or passing them as module arguments.

Here is a basic example of provisioning a instance in ad-hoc mode:

$ ansible localhost -m rax -a "name=awx flavor=4 image=ubuntu-1204-lts-precise-pangolin wait=yes" -c local

Here's what it would look like in a playbook, assuming the parameters were defined in variables:

tasks:
  - name: Provision a set of instances
    local_action:
        module: rax
        name: "{{ rax_name }}"
        flavor: "{{ rax_flavor }}"
        image: "{{ rax_image }}"
        count: "{{ rax_count }}"
        group: "{{ group }}"
        wait: yes
    register: rax

By registering the return value of the step, it is then possible to dynamically add the resulting hosts to inventory (temporarily, in memory). This facilitates performing configuration actions on the hosts immediately in a subsequent task:

- name: Add the instances we created (by public IP) to the group 'raxhosts'
  local_action:
      module: add_host 
      hostname: "{{ item.name }}"
      ansible_ssh_host: "{{ item.rax_accessipv4 }}"
      ansible_ssh_pass: "{{ item.rax_adminpass }}"
      groupname: raxhosts
  with_items: rax.success
  when: rax.action == 'create'

With the host group now created, a second play in your provision playbook could now configure them, for example:

- name: Configuration play
  hosts: raxhosts
  user: root
  roles:
    - ntp
    - webserver

The method above ties the configuration of a host with the provisioning step. This isn't always what you want, and leads us to the next section.

Host Inventory

Once your nodes are spun up, you'll probably want to talk to them again.

The best way to handle his is to use the rax inventory plugin, which dynamically queries Rackspace Cloud and tells Ansible what nodes you have to manage.

You might want to use this even if you are spinning up Ansible via other tools, including the Rackspace Cloud user interface.

The inventory plugin can be used to group resources by their meta data. Utilizing meta data is highly recommended in rax and can provide an easy way to sort between host groups and roles.

If you don't want to use the rax.py dynamic inventory script, you could also still choose to manually manage your INI inventroy file, though this is less recommended.

In Ansible it is quite possible to use multiple dynamic inventory plugins along with INI file data. Just put them in a common directory and be sure the scripts are chmod +x, and the INI-based ones are not.

rax.py

To use the rackspace dynamic inventory script, copy rax.py from plugins/inventory into your inventory directory. You can specify credentials for rax.py utilizing the RAX_CREDS_FILE environment variable.

Note

Users of AnsibleWorks AWX will note that dynamic inventory is natively supported by AWX, and all you have to do is associate a group with your Rackspace Cloud credentials, and it will easily synchronize without going through these steps:

$ RAX_CREDS_FILE=~/.raxpub ansible all -i rax.py -m setup

rax.py also accepts a RAX_REGION environment variable, which can contain an individual region, or a comma separated list of regions.

When using rax.py, you will not have a 'localhost' defined in the inventory.

As mentioned previously, you will often be running most of these modules outside of the host loop, and will need 'localhost' defined. The recommended way to do this, would be to create an inventory directory, and place both the rax.py script and a file containing localhost in it.

Executing ansible or ansible-playbook and specifying the inventory directory instead of an individual file, will cause ansible to evaluate each file in that directory for inventory.

Let's test our inventory script to see if it can talk to Rackspace Cloud.

$ RAX_CREDS_FILE=~/.raxpub ansible all -i inventory/ -m setup

Assuming things are properly configured, the rax.py inventory script will output information similar to the following information, which will be utilized for inventory and variables.

{
    "ORD": [
        "test"
    ],
    "_meta": {
        "hostvars": {
            "test": {
                "ansible_ssh_host": "1.1.1.1",
                "rax_accessipv4": "1.1.1.1",
                "rax_accessipv6": "2607:f0d0:1002:51::4",
                "rax_addresses": {
                    "private": [
                        {
                            "addr": "2.2.2.2",
                            "version": 4
                        }
                    ],
                    "public": [
                        {
                            "addr": "1.1.1.1",
                            "version": 4
                        },
                        {
                            "addr": "2607:f0d0:1002:51::4",
                            "version": 6
                        }
                    ]
                },
                "rax_config_drive": "",
                "rax_created": "2013-11-14T20:48:22Z",
                "rax_flavor": {
                    "id": "performance1-1",
                    "links": [
                        {
                            "href": "https://ord.servers.api.rackspacecloud.com/111111/flavors/performance1-1",
                            "rel": "bookmark"
                        }
                    ]
                },
                "rax_hostid": "e7b6961a9bd943ee82b13816426f1563bfda6846aad84d52af45a4904660cde0",
                "rax_human_id": "test",
                "rax_id": "099a447b-a644-471f-87b9-a7f580eb0c2a",
                "rax_image": {
                    "id": "b211c7bf-b5b4-4ede-a8de-a4368750c653",
                    "links": [
                        {
                            "href": "https://ord.servers.api.rackspacecloud.com/111111/images/b211c7bf-b5b4-4ede-a8de-a4368750c653",
                            "rel": "bookmark"
                        }
                    ]
                },
                "rax_key_name": null,
                "rax_links": [
                    {
                        "href": "https://ord.servers.api.rackspacecloud.com/v2/111111/servers/099a447b-a644-471f-87b9-a7f580eb0c2a",
                        "rel": "self"
                    },
                    {
                        "href": "https://ord.servers.api.rackspacecloud.com/111111/servers/099a447b-a644-471f-87b9-a7f580eb0c2a",
                        "rel": "bookmark"
                    }
                ],
                "rax_metadata": {
                    "foo": "bar"
                },
                "rax_name": "test",
                "rax_name_attr": "name",
                "rax_networks": {
                    "private": [
                        "2.2.2.2"
                    ],
                    "public": [
                        "1.1.1.1",
                        "2607:f0d0:1002:51::4"
                    ]
                },
                "rax_os-dcf_diskconfig": "AUTO",
                "rax_os-ext-sts_power_state": 1,
                "rax_os-ext-sts_task_state": null,
                "rax_os-ext-sts_vm_state": "active",
                "rax_progress": 100,
                "rax_status": "ACTIVE",
                "rax_tenant_id": "111111",
                "rax_updated": "2013-11-14T20:49:27Z",
                "rax_user_id": "22222"
            }
        }
    }
}

Standard Inventory

When utilizing a standard ini formatted inventory file (as opposed to the inventory plugin), it may still be adventageous to retrieve discoverable hostvar information from the Rackspace API.

This can be achieved with the rax_facts module and an inventory file similar to the following:

[test_servers]
hostname1 rax_region=ORD
hostname2 rax_region=ORD

- name: Gather info about servers
  hosts: test_servers
  gather_facts: False
  tasks:
    - name: Get facts about servers
      local_action:
        module: rax_facts
        credentials: ~/.raxpub
        name: "{{ inventory_hostname }}"
        region: "{{ rax_region }}"
    - name: Map some facts
      set_fact:
        ansible_ssh_host: "{{ rax_accessipv4 }}"

While you don't need to know how it works, it may be interesting to know what kind of variables are returned.

The rax_facts module provides facts as followings, which match the rax.py inventory script:

{
    "ansible_facts": {
        "rax_accessipv4": "1.1.1.1",
        "rax_accessipv6": "2607:f0d0:1002:51::4",
        "rax_addresses": {
            "private": [
                {
                    "addr": "2.2.2.2",
                    "version": 4
                }
            ],
            "public": [
                {
                    "addr": "1.1.1.1",
                    "version": 4
                },
                {
                    "addr": "2607:f0d0:1002:51::4",
                    "version": 6
                }
            ]
        },
        "rax_config_drive": "",
        "rax_created": "2013-11-14T20:48:22Z",
        "rax_flavor": {
            "id": "performance1-1",
            "links": [
                {
                    "href": "https://ord.servers.api.rackspacecloud.com/111111/flavors/performance1-1",
                    "rel": "bookmark"
                }
            ]
        },
        "rax_hostid": "e7b6961a9bd943ee82b13816426f1563bfda6846aad84d52af45a4904660cde0",
        "rax_human_id": "test",
        "rax_id": "099a447b-a644-471f-87b9-a7f580eb0c2a",
        "rax_image": {
            "id": "b211c7bf-b5b4-4ede-a8de-a4368750c653",
            "links": [
                {
                    "href": "https://ord.servers.api.rackspacecloud.com/111111/images/b211c7bf-b5b4-4ede-a8de-a4368750c653",
                    "rel": "bookmark"
                }
            ]
        },
        "rax_key_name": null,
        "rax_links": [
            {
                "href": "https://ord.servers.api.rackspacecloud.com/v2/111111/servers/099a447b-a644-471f-87b9-a7f580eb0c2a",
                "rel": "self"
            },
            {
                "href": "https://ord.servers.api.rackspacecloud.com/111111/servers/099a447b-a644-471f-87b9-a7f580eb0c2a",
                "rel": "bookmark"
            }
        ],
        "rax_metadata": {
            "foo": "bar"
        },
        "rax_name": "test",
        "rax_name_attr": "name",
        "rax_networks": {
            "private": [
                "2.2.2.2"
            ],
            "public": [
                "1.1.1.1",
                "2607:f0d0:1002:51::4"
            ]
        },
        "rax_os-dcf_diskconfig": "AUTO",
        "rax_os-ext-sts_power_state": 1,
        "rax_os-ext-sts_task_state": null,
        "rax_os-ext-sts_vm_state": "active",
        "rax_progress": 100,
        "rax_status": "ACTIVE",
        "rax_tenant_id": "111111",
        "rax_updated": "2013-11-14T20:49:27Z",
        "rax_user_id": "22222"
    },
    "changed": false
}

Use Cases

This section covers some additional usage examples built around a specific use case.

Example 1

Create an isolated cloud network and build a server

- name: Build Servers on an Isolated Network
  hosts: localhost
  connection: local
  gather_facts: False
  tasks:
    - name: Network create request
      local_action:
        module: rax_network
        credentials: ~/.raxpub
        label: my-net
        cidr: 192.168.3.0/24
        region: IAD
        state: present

    - name: Server create request
      local_action:
        module: rax
        credentials: ~/.raxpub
        name: web%04d.example.org
        flavor: 2
        image: ubuntu-1204-lts-precise-pangolin
        disk_config: manual
        networks:
          - public
          - my-net
        region: IAD
        state: present
        count: 5
        exact_count: yes
        group: web
        wait: yes
        wait_timeout: 360
      register: rax

Example 2

Build a complete webserver environment with servers, custom networks and load balancers, install nginx and create a custom index.html

---
- name: Build environment
  hosts: localhost
  connection: local
  gather_facts: False
  tasks:
    - name: Load Balancer create request
      local_action:
        module: rax_clb
        credentials: ~/.raxpub
        name: my-lb
        port: 80
        protocol: HTTP
        algorithm: ROUND_ROBIN
        type: PUBLIC
        timeout: 30
        region: IAD
        wait: yes
        state: present
        meta:
          app: my-cool-app
      register: clb

    - name: Network create request
      local_action:
        module: rax_network
        credentials: ~/.raxpub
        label: my-net
        cidr: 192.168.3.0/24
        state: present
        region: IAD
      register: network

    - name: Server create request
      local_action:
        module: rax
        credentials: ~/.raxpub
        name: web%04d.example.org
        flavor: performance1-1
        image: ubuntu-1204-lts-precise-pangolin
        disk_config: manual
        networks:
          - public
          - private
          - my-net
        region: IAD
        state: present
        count: 5
        exact_count: yes
        group: web
        wait: yes
      register: rax

    - name: Add servers to web host group
      local_action:
        module: add_host
        hostname: "{{ item.name }}"
        ansible_ssh_host: "{{ item.rax_accessipv4 }}"
        ansible_ssh_pass: "{{ item.rax_adminpass }}"
        ansible_ssh_user: root
        groupname: web
      with_items: rax.success
      when: rax.action == 'create'

    - name: Add servers to Load balancer
      local_action:
        module: rax_clb_nodes
        credentials: ~/.raxpub
        load_balancer_id: "{{ clb.balancer.id }}"
        address: "{{ item.rax_networks.private|first }}"
        port: 80
        condition: enabled
        type: primary
        wait: yes
        region: IAD
      with_items: rax.success
      when: rax.action == 'create'

- name: Configure servers
  hosts: web
  handlers:
    - name: restart nginx
      service: name=nginx state=restarted

  tasks:
    - name: Install nginx
      apt: pkg=nginx state=latest update_cache=yes cache_valid_time=86400
      notify:
        - restart nginx

    - name: Ensure nginx starts on boot
      service: name=nginx state=started enabled=yes

    - name: Create custom index.html
      copy: content="{{ inventory_hostname }}" dest=/usr/share/nginx/www/index.html
            owner=root group=root mode=0644

Advanced Usage

AWX Autoscaling

AnsibleWorks's "AWX" solution also contains a very nice feature for auto-scaling use cases. In this mode, a simple curl script can call a defined URL and the server will "dial out" to the requester and configure an instance that is spinning up. This can be a great way to reconfigure ephmeral nodes. See the AWX documentation for more details. Click on the AWX link in the sidebar for details.

A benefit of using the callback in AWX over pull mode is that job results are still centrally recorded and less information has to be shared with remote hosts.

Pending Information

More to come!