[Twg] [Discuss] [Lustre-devel] your opinion about testing

[Nathan Rutman]

> -----Original Message-----
> From: twg-bounces at lists.opensfs.org [mailto:twg-bounces at lists.opensfs.org] On Behalf Of Christopher J. Morrone
> Sent: Monday, April 30, 2012 1:59 PM
> To: twg at lists.opensfs.org
> Subject: Re: [Twg] [Lustre-devel] your opinion about testing
> 
> On 04/30/2012 01:41 PM, Nathan Rutman wrote:
> 
>> 3. Remote operations via lctl messages.
>> The tests frequently fail to work on many clusters due to passwordless ssh requirements.  Instead, remote commands / function calls should be sent to other Lustre nodes via a new LNET command, similar to 'lctl ping', that allows arbitrary data to be sent.  A "testing upcall" procedure would be registered on the remote node and would receive the messages.  Obviously this could be a more broadly useful mechanism.  Due to security issues some sites may chose not to register an upcall. A response mechanism is also required.
> 
> It is not immediately clear how this fixes anything.  Such a facility 
> built into lnet needs to have exactly the same configuration issues as 
> ssh, munge, or whatever.  If it DOESN'T have the same issues, then it 
> sounds like it would be a very serious security risk.
What it fixes is the ease of testing, by not requiring a separate communication path outside of LNET.  No router problems, no ssh'isms; if your client can talk to your servers, you're good to go.  
Obviously it doesn't resolve any security issues, and may introduce new ones.

> 
> Such a feature needs to at least be off by default and only enabled by a 
> human deciding that such a remote-access feature is acceptable.
Agreed. Hopefully it might be easier to qualify a particular upcall program as "safe", rather than allowing arbitrary code execution as ssh does, but that's not the intent here.  
The goal is to fix the testing, and I think this is one useful component of that.