In the cloud computing, alongside of the hosting monsters such as amazon or google, there is the Openstack Platform.

Openstack is not a single software, it is more a galaxy of components aim to control the infrastructure, such as hardware pools, storage, network. The management can then be done via a Web based interface or via a bunch of RESTful API.

I would like to evaluate its identity service named keystone and use it as a AuthN and AuthZ backend for my simple_iaas example.

Note : I will consider that the openstack keystone is installed (The release I’m using is liberty). As I don’t want to rewrite an installation procedure as many exists already on the web. For my tests, I’m using an keystone installation from sources in a Ubuntu VM

My goal

My goal is to have a webservice that will protect the scopes of my IAAS. I may declare two users:

  • One may list the nodes via a GET request
  • The other one may also create and destroy nodes via POST and DELETE request

This post is about setting up keystone so I can use it as a lab to understand the concepts and maybe achieve my goal with it.

Let’s go

I won’t use any external web server. Instead I will rely on the builtin Eventlet based web server.

The documentation says it is deprecated, indeed I will use it for testing purpose, so that will do the job.

The WSGI pipeline configuration

To be honest, I don’t know anything about the python ecosystem. And as it is my blog, I will write anything I’ve learned from this experience…

So:

  • WSGI is a gateway interface for python, and my understanding is that it’s like the good old CGI we used in the beginning of this century;
  • Is is configured by a ini file based on Paste and especially Paste Deploy which is a system made for loading and configuring WSGI components.

The WSGI interface is configured by a ini file as written in the Openstack keystone documentation. This file is called keystone-paste.ini. I won’t touch it and use the provided one. It sounds ok and when I start the service with keystone-all I can see in the logs:

2015-11-17 10:05:04.918 7068 INFO oslo_service.service [-] Starting 2 workers
2015-11-17 10:05:04.920 7068 INFO oslo_service.service [-] Started child 7082
2015-11-17 10:05:04.922 7068 INFO oslo_service.service [-] Started child 7083
2015-11-17 10:05:04.925 7082 INFO eventlet.wsgi.server [-] (7082) wsgi starting up on http://0.0.0.0:35357/
2015-11-17 10:05:04.927 7068 INFO keystone.common.environment.eventlet_server [-] Starting /usr/bin/keystone-all on 0.0.0.0:5000
2015-11-17 10:05:04.927 7068 INFO oslo_service.service [-] Starting 2 workers
2015-11-17 10:05:04.930 7068 INFO oslo_service.service [-] Started child 7084
2015-11-17 10:05:04.934 7083 INFO eventlet.wsgi.server [-] (7083) wsgi starting up on http://0.0.0.0:35357/
2015-11-17 10:05:04.936 7068 INFO oslo_service.service [-] Started child 7085
2015-11-17 10:05:04.940 7085 INFO eventlet.wsgi.server [-] (7085) wsgi starting up on http://0.0.0.0:5000/
2015-11-17 10:05:04.941 7084 INFO eventlet.wsgi.server [-] (7084) wsgi starting up on http://0.0.0.0:5000/
2015-11-17 10:17:01.005 7085 INFO keystone.common.wsgi [-] GET http://localhost:5000/

which sounds ok and a curl call to the endpoint reply at least something:

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$ curl -s http://localhost:5000/v3 | jsonformat
{
  "version": {
    "id": "v3.4",
    "links": [
      {
        "href": "http://localhost:5000/v3/",
        "rel": "self"
      }
    ],
    "media-types": [
      {
        "base": "application/json",
        "type": "application/vnd.openstack.identity-v3+json"
      }
    ],
    "status": "stable",
    "updated": "2015-03-30T00:00:00Z"
  }
}

The keystone configuration

The proper keystone configuration is done in the file keystone.conf. This configuration file is decomposed into different sections as explained in the documentation.

The general configuration (Default section)

I will only set the admin token randomly as it will be used to create the users, roles and so on.

Let’s generate a token with openssl rand -hex 10 and report it to my configuration:

[DEFAULT]
admin_token = 8a0b4eacc6a81c3bc5aa

The rest will use all the default values for the General configuration (the [DEFAULT] section). This means that this section may be empty or full of comments.

The assignment configuration

In this section, we choose the driver for the assignment service. This purpose of this service is

[to] provide data about roules and role assignments to the entities managed by the Identity and Resource services

(source Keystone architecture)

I plan to use a SQL backend instead of a LDAP for my tests, so the configuration may be:

[assignment]
driver = sql

The authentication plugin configuration

Keystone supports authentication plugins; those plugins are specified in the [auth] section. In my test, the password plugin will be used.

[auth]
methods = password

The credentials

The credentials are stored in a sql database as well:

[credential]
driver = sql

The DB configuration

For my tests I will use a sqlite database as configured in this section:

[database]
sqlite_db = oslo.sqlite
sqlite_synchronous = true
backend = sqlalchemy
connection = sqlite:////var/lib/keystone/keystone.db

Restart the keystone server and play

# service keystone restart
# service keystone status
● keystone.service - OpenStack Identity service
   Loaded: loaded (/lib/systemd/system/keystone.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2015-11-17 14:47:06 GMT; 3s ago
  Process: 15505 ExecStartPre=/bin/chown keystone:keystone /var/lock/keystone /var/log/keystone /var/lib/keystone (code=exited, status=0/SUCCESS)
  Process: 15502 ExecStartPre=/bin/mkdir -p /var/lock/keystone /var/log/keystone /var/lib/keystone (code=exited, status=0/SUCCESS)
 Main PID: 15508 (keystone-all)
   CGroup: /system.slice/keystone.service
           ├─15508 /usr/bin/python /usr/bin/keystone-all --config-file=/etc/keystone/keystone.conf --log-file=/var/log/keystone/keystone.log
           ├─15523 /usr/bin/python /usr/bin/keystone-all --config-file=/etc/keystone/keystone.conf --log-file=/var/log/keystone/keystone.log
           ├─15524 /usr/bin/python /usr/bin/keystone-all --config-file=/etc/keystone/keystone.conf --log-file=/var/log/keystone/keystone.log
           ├─15525 /usr/bin/python /usr/bin/keystone-all --config-file=/etc/keystone/keystone.conf --log-file=/var/log/keystone/keystone.log
           └─15526 /usr/bin/python /usr/bin/keystone-all --config-file=/etc/keystone/keystone.conf --log-file=/var/log/keystone/keystone.log

Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.479 15508 INFO oslo_service.service [-] Started child 15523
Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.482 15508 INFO oslo_service.service [-] Started child 15524
Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.486 15508 INFO keystone.common.environment.eventlet_server [-] Starting /usr/bin/keystone-all on 0.0.0.0:5000
Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.490 15508 INFO oslo_service.service [-] Starting 2 workers
Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.491 15523 INFO eventlet.wsgi.server [-] (15523) wsgi starting up on http://0.0.0.0:35357/
Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.493 15508 INFO oslo_service.service [-] Started child 15525
Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.499 15524 INFO eventlet.wsgi.server [-] (15524) wsgi starting up on http://0.0.0.0:35357/
Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.502 15508 INFO oslo_service.service [-] Started child 15526
Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.506 15525 INFO eventlet.wsgi.server [-] (15525) wsgi starting up on http://0.0.0.0:5000/
Nov 17 14:47:08 UBUNTU keystone[15508]: 2015-11-17 14:47:08.510 15526 INFO eventlet.wsgi.server [-] (15526) wsgi starting up on http://0.0.0.0:5000/

so far so good… let’s check if the DB is here now:

# sqlite3 /var/lib/keystone/keystone.db
SQLite version 3.8.11.1 2015-07-29 20:00:57
Enter ".help" for usage hints.
sqlite> .tables
access_token            identity_provider       revocation_event
assignment              idp_remote_ids          role
config_register         mapping                 sensitive_config
consumer                migrate_version         service
credential              policy                  service_provider
domain                  policy_association      token
endpoint                project                 trust
endpoint_group          project_endpoint        trust_role
federation_protocol     project_endpoint_group  user
group                   region                  user_group_membership
id_mapping              request_token           whitelisted_config
sqlite> .quit

Interacting with openstack

A tools called python-openstackclient is available in my ubuntu release and will be used for testing purpose.

The binary provided is openstack (dpkg-query -L python-openstackclient | grep bin)

Creating a user

We need to define a couple of environment variables to be able to connect to the keystone server with the root power:

I will create a simple file that I will source when I need to interact as admin of keystone

cat << EOF > admin.sh
# The value of admin_token defined in the keystone.conf
export OS_TOKEN=8a0b4eacc6a81c3bc5aa 
# This is the default value if not overridden by the directive admin_endpoint
export OS_URL=http://localhost:35357/v2.0 
export OS_IDENTITY_API_VERSION=3
EOF

and another file to unset those variables:

cat << EOF > noadmin.sh 
unset OS_TOKEN
unset OS_URL
unset OS_IDENTITY_API_VERSION
EOF

Then we create the user:

source admin.sh
openstack user create olivier
'links'

Then set its password:

source admin.sh
openstack user set --password-prompt olivier
User Password:
Repeat User Password:
'users'

And see if it’s actually here:

source admin.sh
openstack user list
+----------------------------------+---------+
| ID                               | Name    |
+----------------------------------+---------+
| c80f5244c7d3486fbf4059b7197b4770 | olivier |
+----------------------------------+---------+

Creating a project

openstack project create --description 'demo project' demo

Assigning the admin role

Let’s first get the role list

source admin.sh
openstack role list
+----------------------------------+----------+
| ID                               | Name     |
+----------------------------------+----------+
| 5f772b617b5d4758badb7746934124e8 | admin    |
| 9fe2ff9ee4384b1894a90878d3e92bab | _member_ |
+----------------------------------+----------+

And add the admin right to the user olivier for the project demo

source admin.sh
openstack role add --user olivier --project 0e07a734d54e4f3799a31768b13a38c2 admin

Getting a token

With the openstack tool

I’ve a default domain, I’ve setup a demo project, and assigne the my user the admin role for testing purpose. I may now be able to generate an access token

Let’s try:

source noadmin.sh
openstack --os-auth-url http://localhost:5000/v3 --os-username olivier --os-password olivier --os-auth-type=password --os-project-name demo token issue
Expecting to find domain in project - the server could not comply with the request since it is either malformed or otherwise incorrect. The client is assumed to be in error. (HTTP 400) (Request-ID: req-09cad46b-9a5f-4b0f-8f2b-82b4442ed999)

Ok, now add the domain:

source noadmin.sh
openstack --os-auth-url http://localhost:5000/v3 --os-username olivier --os-password olivier --os-auth-type=password --os-project-name demo --os-domain-name default token issue
Authentication cannot be scoped to multiple targets. Pick one of: project, domain, trust or unscoped

Too bad, remove the project…

source noadmin.sh
openstack --os-auth-url http://localhost:5000/v3 --os-username olivier --os-password olivier --os-auth-type=password --os-domain-name default token issue
The request you have made requires authentication. (HTTP 401) (Request-ID: req-59c39895-8e96-42c4-b5c5-1477001da618)

Still no luck… Google gave me a lot of answers, but I couldn’t figure whether it was:

  • a bug
  • a misconfiguration of the service
  • a bad usage of the tools
  • a totally bad apprehension of the product

I may continue to experiment, but I’m far from my goal actually, and I hate the idea of being lost. no help from Google, so DIY method:

  • openstack client in debug mode with –debug
  • keystone in debug with a debug=true directive in keystone.conf

The message is now clear:

2015-11-18 10:37:33.337 7164 WARNING keystone.common.wsgi [req-27dadee6-51d9-475d-a426-99e3b4f77f4a - - - - -] Authorization failed. User c80f5244c7d3486fbf4059b7197b4770 has no access to domain default

So let’s re-set the password, just in case, as done in the previous section of this post and try again:

source noadmin.sh
openstack --os-auth-url http://localhost:5000/v3 --os-username olivier --os-password olivier --os-auth-type=password --os-project-name demo --os-domain-name default token issue
...
Unauthorized: User c80f5244c7d3486fbf4059b7197b4770 has no access to domain default (Disable debug mode to suppress these details.)

Ok, let’s add olivier as admin of the Default domain:

source admin.sh
openstack role add --user olivier --domain Default admin

And try again:

source noadmin.sh
openstack --os-auth-url http://localhost:5000/v3 --os-username olivier --os-password olivier --os-auth-type=password --os-domain-name Default token issue
+-----------+----------------------------------+
| Field     | Value                            |
+-----------+----------------------------------+
| domain_id | default                          |
| expires   | 2015-11-18T11:44:23.325817Z      |
| id        | 0525e008619748848735d9122f8f2e81 |
| user_id   | c80f5244c7d3486fbf4059b7197b4770 |
+-----------+----------------------------------+

Bingo!!!

Conclusion

That’s enough information for this first post about OpenStack keystone. By now, I will continue the investigations and use this installation as a lab to understand the full concepts of this identity management software.

I leave my test with a bitter taste.

I may not have understood all the concepts behind the scene, but I can say that this product, at least in the current release, is by far too complex and has too much contributors to evaluate it in a simple way. Therefore, the quite complete but messy documentation, a mix in the releases and some major incompatibilities in the tools using V2.0 and V3 gave me a bad impression. The tool may be useful, but the TCO sounds high and the entry ticket is not negligible.