RE: Multihomed hosts and virtual web hosts

I'll focus first on the problem of multiple ethernet (or other) ports, each
with its own IP address.

With the present Sidai net-config design, each hosts configuration file
specifies a single name and IP address:

  <host name="gold" xml-version="1">
    ...
    <ip-addresses><list>
      <item>192.168.1.1</item>
    </list></ip-addresses>
  </host>

For our Sun Solaris systems, Ark applies this information to two files:

  /etc/hostname.hme0:
    192.168.1.1

  /etc/hosts:
    ...
    192.168.1.1  gold gold.abc.com
    ...

When a host has multiple network ports, it needs a /etc/hostname.xxx file
for each.  It also needs multiple entries in /etc/hosts.  For example, if a
second ethernet port, qfe1, had IP address 192.168.2.1, these files should
be generated:

  /etc/hostname.hme0:
    192.168.1.1

  /etc/hostname.qfe1:
    192.168.2.1

  /etc/hosts:
    ...
    192.168.1.1  gold gold.abc.com gold-hme0 gold-hme0.abc.com
    192.168.2.1  gold gold.abc.com gold-qfe1 gold-qfe1.abc.com
    ...

[Some administrators may prefer to list the port-specific name first.]

I see two (small) challenges:  How do we specify the interface information
with Ark's lists, tables, parameters, etc.?  How do we use the
hostname.if0.tmpl template more than once?

One possible representation model comes from the component table found in
some of Verilab2's hosts.  This scheme uses tables nested inside of tables.
Here is how it might look:

  <interfaces><table>
    <entry name="hme0"><table>
      <entry name="ip-address">192.168.1.1</entry>
      <entry name="local-name">gold-hme0</entry>
    </table></entry>
    <entry name="qfe1"><table>
      <entry name="ip-address">192.168.2.1</entry>
      <entry name="local-name">gold-qfe1</entry>
    </table></entry>
  </table></interfaces>

This table scheme should easily support Ark's discovering and processing the
various interfaces.

-----Original Message-----
From: Will Partain [mailto:[email protected]]
Sent: Sunday, May 04, 2003 12:36 PM
To: [email protected]
Subject: Re: Multihomed hosts and virtual web hosts


Joel S writes:

> None of the Sidai host and network configurations support multiple IP
> addresses per host. Instead, the code is sprinkled with error messages
like
> this:
> 
>   raise ark.error.GeneralPanic, 'Can only have one IP address at the
moment
> :-('
> 
> Has anyone turned those frowns into smiles?

No, but I am happy to help.  If you tell me/us "I've got this
here, and I want that to appear in yonder file", I'll see
what I can do.

...


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