Bug 21781

Summary:	RFE: use ssh instead of rsh
Product:	[Retired] Red Hat Powertools	Reporter:	Enrico Scholz <rh-bugzilla>
Component:	mpich	Assignee:	Trond Eivind Glomsrxd <teg>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	7.0	Keywords:	FutureFeature
Target Milestone:	---
Target Release:	---
Hardware:	i386
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2000-12-05 23:18:04 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Enrico Scholz 2000-12-05 22:34:38 UTC

since rh7 is using openssh now, rsh becomes obsoleted in most environments.
But without rsh the p4 device of mpich (default at linux) won't work
anymore.

So I suggest to ./configure with '-rsh=ssh'.

Comment 1 Enrico Scholz 2000-12-05 22:50:24 UTC

The /usr/lib/mpich/{s,}bin dirs contain a lot of scripts having `rsh' hardly
coded inside. These must be fixed manually.

Comment 2 Trond Eivind Glomsrxd 2000-12-05 23:00:23 UTC

I don't think this is a good idea... it adds connection overhead in what usually
is a strictly controlled environment.

Comment 3 Enrico Scholz 2000-12-05 23:18:01 UTC

The additional overhead occurs only when the `master' starts its slaves on the
other machines. The plain MPI-communications isn't affected by ssh; ssh serves
only to start the slaves.

This overhead is very low related to the time MPI programs are running usually,
so I think it can be neglected.

Additionally I don't know any system in my environment using rsh (rsh-server
isn't installed even).

Comment 4 Trond Eivind Glomsrxd 2000-12-05 23:38:28 UTC

I think opting for least surprises is good... being able to choose your program
would be good.

Also, in many environments ssh won't be suitable as keys should have passphrases

Comment 5 Enrico Scholz 2000-12-05 23:48:22 UTC

Yes, choosing the program would be good. But mpich seems to compile the name
statically into the 
libraries. mpich-1.2.1 is out but I had no time to check if it contains the
possibility to choose the remote-shell dynamically.

Passphrases aren't a problem with ssh. You can start ssh-agent which holds your
identity and transfers it cryptographical safe to the sshd. Although this method
is commonly used, install.ps.gz of the mpich package contains in chapter 4.6 a
short description also.