Direct Host Address

[Muli Salem]

----- Original Message -----
> From: "Mike Kolesnik" <mkolesni at redhat.com>
> To: "Muli Salem" <msalem at redhat.com>
> Cc: arch at ovirt.org
> Sent: Sunday, 10 February, 2013 5:26:42 PM
> Subject: Re: Direct Host Address
> 
> ----- Original Message -----
> > Hi All,
> > 
> > Below please find a short wiki page regarding the Direct Host
> > Address
> > feature, which will allow the admin to define a separate "direct"
> > IP
> > address on a host, for SSH purposes only.
> > 
> > http://www.ovirt.org/Features/DirectHostAddress
> > 
> > Would love to here your comments.
> 
> Hi Muli,
> 
> Sounds good overall, here are my comments:
> 
> In 'Detailed Description':
> 
> "When adding a host, admin sets the host address. The engine uses
> this address to manage the host in two ways. The first is via SSH
> for host installation, and the second is via xml-rpc for any other
> action."
> 
> What do you mean "the second is via xml-rpc"..? What commands will go
> over this channel?

Except for host installation, all other communication between engine and host (for example, VdsCommands).

> 
> "Current behaviour assumes the network interface with the specified
> address is configured properly in the engine although this may not
> be the case initially"
> 
> I don't understand what does this mean, which interface are you
> referring to and what does it have to do with being configured in
> the engine?
> The next line is also unclear to me:
> "The direct address allows the engine to connect to the host, without
> knowing the exact configuration of the network interface that has
> the address. "
> 

Regarding the last two sentences you quoted:

I am referring to the interface that has the IP that the user gives us (with regards to current behavior).
At the moment, we assume that the given IP is for an interface that can communicate with the engine (when in practice, this may not be the case).
So separating the two addresses, allows us to ask the admin for an alternate IP address that will allow communication without needing to know the specific configuration (for example, whether this is a VLAN network or not).

Perhaps the wording should be changed a bit to clarify.

> In 'Motivation':
> 
> "To allow another route to the host to a network interface other than
> the one used for the management network, since that network
> interface may need to be configured in the engine first."
> 
> I would say simply that the management traffic might go over a
> channel which requires connectivity  (e.g. VLAN) with the engine to
> be established prior to being able to communicate with the host.
> 

Not quite sure I see a noteworthy difference between the two sentences.

> 
> > 
> > Thanks,
> > Muli
> > _______________________________________________
> > Arch mailing list
> > Arch at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/arch
> > 
>