Zenoss uses the Zope database (ZODB) to store its information. Since the ZODB is an Object-Oriented DataBase, this is not organized by tables, rows and columns, but by objects. The object that Zenoss uses to store the basic model of your network is in the Device Management Database (DMD) object.

You can access the DMD through an interactive, programmable interpreter: zendmd. zendmd is the Python interpreter, with a handle to the database stored in the default namespace, and a few handy functions.

To start zendmd and see how the interpreter works, use the following commands:

$ zendmd
>>> 1 + 2
3
>>> len('hello there')
11
>>> for i in range(5):
...    print i
0
1
2
3
4

These are all basic Python interpreter features. zendmd adds in a reference to the root of the object tree which is known as dmd. You can see this root name in the URLs used to refer to objects when using Zenoss from the browser.

There is a built-in function that can be used to find devices.

$ zendmd
>>> print dmd
<DataRoot at /zport/dmd>
>>> find('localhost.localdomain')
<Device at /zport/dmd/Devices/Server/Linux/devices/localhost.localdomain>

The find() function also takes wildcards:

>>> find('local*')
<Device at /zport/dmd/Devices/Server/Linux/devices/localhost.localdomain>

You can perform scripting at the command prompt. For example, we can count the number of interfaces on our device:

>>> d = find('local*')
len(d.os.interfaces())
5

You can inspect the objects:

>>> d.getManageIp()
  '127.0.0.1'
for i in d.os.interfaces():
... for a in i.ipaddresses():
... print a.name(), a.getIpAddress()
  eth0 192.168.1.148/24

You can perform low-level checks such as re-indexing all the objects:

>>> reindex()

Or check/repair relationships on all devices:

>>> for d in dmd.Devices.getSubDevices():
...   d.checkRelations(repair=True)
... 

Finally, after making changes you can commit them to the database:

>>> commit()

or synch against the database and restore the old state to your interpreter, reverting any changes:

>>> synch()

Zendmd can be used to automate repetitive tasks. For example, you can enter in a large list of devices. First, create a text file containing the names of those devices:

$ cat >lotsOfDevices.txt
device1
myhost.mydomain.com
host2.mydomain.com
^D

Of course, the data could come from an inventory list or other database. Then, you can use the dmd to process the file:

$ zendmd
for line in file('lotsOfDevices.txt'):
... d = dmd.Devices.Server.Linux.createInstance(line.strip())
... commit()
... d.collectDevice()

You can feed zendmd commands on stdin:

$ zendmd < AddDevices.py

You can also import scripts:

$ zendmd
import MyScripts
MyScripts.loadDevices(dmd)

If you want to create a stand-alone command, reading the $ZENHOME/ZenModel/zendmd.py file is a good start.

The full List of zendmd names is described below.