February 2016

While Openstack provides a python client(s) for interactions….

[root@diamond ~]# source keystonerc_tuxninja
[root@diamond ~(keystone_tuxninja)]# openstack server list
+--------------------------------------+-------+--------+----------------------------------------+
| ID                                   | Name  | Status | Networks                               |
+--------------------------------------+-------+--------+----------------------------------------+
| e5b35d6a-a9ba-4714-a9e1-6361706bd047 | spin1 | ACTIVE | private_tuxlabs=10.0.0.8, 192.168.1.52 |
+--------------------------------------+-------+--------+----------------------------------------+
[root@diamond ~(keystone_tuxninja)]#

I frequently, finding myself needing to get data out of it without the pain of awk/sed’ing out the ASCII art.

Thus to quickly access the raw data, we can directly query the API’s using curl & parsing JSON instead, which is much better 🙂

Authentication

Before we can interact with the other Openstack API’s we need to authenticate to Keystone openstack’s identity service. After authenticating we receive a token to use with our subequent API requests. So step 1 we are going to create a JSON object with the required authentication details.

Create a file called ‘token-request.json’ with an object that looks like this.

{
    "auth": {
        "identity": {
            "methods": [
                "password"
            ],
            "password": {
                "user": {
                    "domain": {
                        "id": "default"
                    },
                    "name": "tuxninja",
                    "password": "put_your_openstack_pass"
                }
            }
        }
    }
}

Btw, if you followed my tutorial on how to install Openstack Kilo, your authentication details for ‘admin’ is in your keystonerc_admin file.

Now we can use this file to authenticate like so:

export TOKEN=`curl -si -d @token-request.json -H "Content-type: application/json" http://localhost:35357/v3/auth/tokens | awk '/X-Subject-Token/ {print $2}'`

The token is actually returned in the header of the HTTP response, so this is why we need ‘-i’ when curling. Notice we are parsing out the token and returning the value to an environment variable $TOKEN.

Now we can include this $TOKEN and run whatever API commands we want (assuming admin privileges for the tenant/project)

Curl Commands (Numerous Examples!)

# list domains
curl -si -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:35357/v3/domains

# create a domain
curl  -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" -d '{"domain": {"description": "--optional--", "enabled": true, "name": "dom1"}}'  http://localhost:35357/v3/domains


# list users
curl -si -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:35357/v3/users

# To create a users, create file named create_user.json file like this:

{
    "user": {
           "default_project_id": "18ed894bb8b84a5b9144c129fc754722",
            "description": "Description",
            "domain_id": "default",
            "email": "tuxninja@tuxlabs.com",
            "enabled": true,
            "name": "tuxninja",
            "password": "changeme" }
}

# then run
curl -si -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:35357/v3/users -d @create_user.json


# list images in nova
                                                                                             <tenant_id>
curl -s -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:8774/v2/18ed894bb8b84a5b9144c129fc754722/images | python -m json.tool

# list servers (vms)

curl -s -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:8774/v2/18ed894bb8b84a5b9144c129fc754722/servers | python -m json.tool

# neutron networks

curl -s -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:9696/v2.0/networks | python -m json.tool

# neutron subnets

curl -s -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:9696/v2.0/networks | python -m json.tool

I sometimes pipe the output to python -m json.tool, which provides formatting for JSON. Lets take a closer look at an example.

Listing servers (vm’s)

[root@diamond ~(keystone_tuxninja)]# curl -s -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:8774/v2/18ed894bb8b84a5b9144c129fc754722/servers | python -m json.tool
{
    "servers": [
        {
            "id": "e5b35d6a-a9ba-4714-a9e1-6361706bd047",
            "links": [
                {
                    "href": "http://localhost:8774/v2/18ed894bb8b84a5b9144c129fc754722/servers/e5b35d6a-a9ba-4714-a9e1-6361706bd047",
                    "rel": "self"
                },
                {
                    "href": "http://localhost:8774/18ed894bb8b84a5b9144c129fc754722/servers/e5b35d6a-a9ba-4714-a9e1-6361706bd047",
                    "rel": "bookmark"
                }
            ],
            "name": "spin1"
        }
    ]
}
[root@diamond ~(keystone_tuxninja)]#

I only have 1 VM currently called spin1, but for the tutorials sake, if I had ten’s or hundred’s of VM’s and all I cared about was the VM name or ID, I would still need to parse this JSON object to avoid getting all this other meta-data.

My favorite command line way to do that without going full Python is using the handy JQ tool.

Here is how to use it !

[root@diamond ~(keystone_tuxninja)]# curl -s -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:8774/v2/18ed894bb8b84a5b9144c129fc754722/servers | jq .
{
  "servers": [
    {
      "name": "spin1",
      "links": [
        {
          "rel": "self",
          "href": "http://localhost:8774/v2/18ed894bb8b84a5b9144c129fc754722/servers/e5b35d6a-a9ba-4714-a9e1-6361706bd047"
        },
        {
          "rel": "bookmark",
          "href": "http://localhost:8774/18ed894bb8b84a5b9144c129fc754722/servers/e5b35d6a-a9ba-4714-a9e1-6361706bd047"
        }
      ],
      "id": "e5b35d6a-a9ba-4714-a9e1-6361706bd047"
    }
  ]
}
[root@diamond ~(keystone_tuxninja)]#
[root@diamond ~(keystone_tuxninja)]# curl -s -H"X-Auth-Token:$TOKEN" -H "Content-type: application/json" http://localhost:8774/v2/18ed894bb8b84a5b9144c129fc754722/servers | jq .servers[0].name -r
spin1
[root@diamond ~(keystone_tuxninja)]#

The first command just takes whatever the STDOUT from curl is and indent’s and color’s the JSON making it pretty (colors gives it +1 vs. python -m json.tool).

The second example we actually parse what were after. As you can see it is pretty simple, but jq’s query language may not be 100% intuitive at first, but I promise it is pretty easy to understand if you have ever parsed JSON before. Read up more on JQ @ https://stedolan.github.io/jq/ & check out the Openstack docs for more API commands http://developer.openstack.org/api-ref.html

Hope you enjoyed this post ! Until next time.