WS-Management + Openwsman + openSUSE + Ruby

Yet another failed attempt at using SNMP for monitoring application-level services led me to WS-Management, an HTTP/SOAP-based protocol meant to replace SNMP. DS-Management might not be the first protocol to attempt usurping SNMP, but this one looks promising. Widespread support and implementation is claimed by Microsoft, and a reasonably mature open-source implementation -- Openwsman -- is sponsored by SuSE.

Documentation for Openwsman unfortunately seems rather lacking. It took some poking around, but I was able to get a basic client-server session going under openSUSE 10.3. Here's how:

First, add the development channel for openwsman and install the openwsman packages:

1. sudo smart channel --add http://download.opensuse.org/repositories/home:/kwk:/Management/openSUSE_10.3/home:kwk:Management.repo  
2. sudo smart update home_kwk_Management  
3. sudo smart install openwsman openwsman-client openwsman-server wsmancli openwsman-yast  

sudo smart channel --add http://download.opensuse.org/repositories/home:/kwk:/Management/openSUSE_10.3/home:kwk:Management.repo
sudo smart update home_kwk_Management
sudo smart install openwsman openwsman-client openwsman-server wsmancli openwsman-yast

If you run into PGP key problems, try disabling PGP key checking first:

1. smart config --set rpm-check-signatures=false  

smart config --set rpm-check-signatures=false

The openwsman-server package installs openwsmand -- a stand-alone server providing WS-Management services. We'll need to configure the authentication system before running the server. I was unable to get things going with the default Basic authentication, but Digest worked for me:

1. htdigest2 -c /etc/openwsman/digest_auth.passwd OPENWSMAN admin  
2. Adding password for admin in realm OPENWSMAN.  
3. New password: test  
4. Re-type new password: test  

htdigest2 -c /etc/openwsman/digest_auth.passwd OPENWSMAN admin
Adding password for admin in realm OPENWSMAN.
New password: test
Re-type new password: test

Now edit the Openwsman config file to use Digest authentication. The config file is under /etc/openwsman/openwsman.conf and should be altered to look something like this (note that we've uncommented the 'digest_password_file' option):

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1. [server]  
2. port = 8889  
3. #ssl_port = 8888  
4. ssl_cert_file = /etc/openwsman/servercert.pem  
5. ssl_key_file = /etc/openwsman/serverkey.pem  
6. digest_password_file = /etc/openwsman/digest_auth.passwd  
7. #basic_password_file = /etc/openwsman/simple_auth.passwd  
8.   
9. min_threads = 4  
10. max_threads = 10  
11.   
12. #use_digest is OBSOLETED, see below.  
13.   
14. #  
15. # Authentication backend for BASIC authentication. Default is to read a configuration file defined with 'basic_password_file'  
16. #  
17.   
18. basic_authenticator = libwsman_pam_auth.so  
19. basic_authenticator_arg = openwsman  
20.   
21.   
22. [client]  
23. port = 8889  
24. agent = openwsman 0.6.0  
25.   
26. #  
27. # settings for the CIM plugin  
28. #  
29.   
30. [cim]  
31. default_cim_namespace = root/cimv2  
32.   
33. # The following are in part fake namespaces for some publicly available CIM implementations.  
34. vendor_namespaces = OpenWBEM=http://schema.openwbem.org/wbem/wscim/1/cim-schema/2,Linux=http://sblim.sf.net/wbem/wscim/1/cim-schema/2,OMC=http://schema.omc-project.org/wbem/wscim/1/cim-schema/2  
35.   
36. # CIMOM host, default is localhost  
37. # host = localhost  
38.   
39. # CIMOM port, default is 5988  
40. # port = 5988  

[server]
port = 8889
#ssl_port = 8888
ssl_cert_file = /etc/openwsman/servercert.pem
ssl_key_file = /etc/openwsman/serverkey.pem
digest_password_file = /etc/openwsman/digest_auth.passwd
#basic_password_file = /etc/openwsman/simple_auth.passwd

min_threads = 4
max_threads = 10

#use_digest is OBSOLETED, see below.

#
# Authentication backend for BASIC authentication. Default is to read a configuration file defined with 'basic_password_file'
#

basic_authenticator = libwsman_pam_auth.so
basic_authenticator_arg = openwsman


[client]
port = 8889
agent = openwsman 0.6.0

#
# settings for the CIM plugin
#

[cim]
default_cim_namespace = root/cimv2

# The following are in part fake namespaces for some publicly available CIM implementations.
vendor_namespaces = OpenWBEM=http://schema.openwbem.org/wbem/wscim/1/cim-schema/2,Linux=http://sblim.sf.net/wbem/wscim/1/cim-schema/2,OMC=http://schema.omc-project.org/wbem/wscim/1/cim-schema/2

# CIMOM host, default is localhost
# host = localhost

# CIMOM port, default is 5988
# port = 5988

Okay, now we can run the server:

1. sudo /usr/sbin/openwsmand -d  

sudo /usr/sbin/openwsmand -d

We can now connect to the server using a few simple Ruby commands. Open an interactive ruby session (using irb) and enter the following:

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1. require 'rwsman'  
2. client = WsMan::Client.new('http', 'localhost', 8889, '/wsman', 'admin', 'test')  
3. client_opt = WsMan::ClientOption.new  
4. identify = client.identify(client_opt)  
5. puts identify.rawxml  

require 'rwsman'
client = WsMan::Client.new('http', 'localhost', 8889, '/wsman', 'admin', 'test')
client_opt = WsMan::ClientOption.new
identify = client.identify(client_opt)
puts identify.rawxml

If everything worked, you should get a response that looks something like this:

1. <s:envelope s="http://www.w3.org/2003/05/soap-envelope" wsmid="http://schemas.dmtf.org/wbem/wsman/identity/1/wsmanidentity.xsd">  
2.  <s:header>  
3.  <s:body>  
4.    <wsmid:identifyresponse>  
5.      <wsmid:protocolversion>http://schemas.dmtf.org/wbem/wsman/1/wsman.xsd</wsmid:protocolversion>  
6.      <wsmid:productvendor>Openwsman Project</wsmid:productvendor>  
7.      <wsmid:productversion>1.5.9</wsmid:productversion>  
8.    </wsmid:identifyresponse>  
9.  </s:body>  
10. </s:header>  
11. </s:envelope>  

 
 
   
     http://schemas.dmtf.org/wbem/wsman/1/wsman.xsd
     Openwsman Project
     1.5.9
   
 

The identify object returned by the client also exposes product_version, protocol_version, and product_vendor methods that return their respective values from the parsed XML data.

With the YAST plugin installed, Openwsman can access diagnostic information about your SuSE system. For example try this:

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1. client_opt.property_add('ycp', '{ import "SuSERelease"; return SuSERelease::ReleaseInformation("/"); }' )  
2. result = client.invoke('http://schema.opensuse.org/YaST/wsman-schema/10-3/YCP', 'eval', client_opt)  
3. puts "SUSE Version: #{result.body}"  

client_opt.property_add('ycp', '{ import "SuSERelease"; return SuSERelease::ReleaseInformation("/"); }' )
result = client.invoke('http://schema.opensuse.org/YaST/wsman-schema/10-3/YCP', 'eval', client_opt)
puts "SUSE Version: #{result.body}"