topic Re: VMS-to-VMS RPC in Operating System - OpenVMS

VMS-to-VMS RPC

Robert Atkinson — Tue, 24 May 2011 14:57:26 GMT

Rather than schedule a batch job on a remote node, I'd like to use some form of RPC to trigger the job instead. The main limitation is that I can only use TCP/IP and DCL.

Does anyone know of a built-in method that would work better than the method below.

My thoughts so far are to create a local TELNET port and remote listener service. When I open the local port, I can send commands through that can be read from the BG mailbox device.

The commands could then be used to trigger specific actions, such as starting a backup.

Cheers, Rob.

Re: VMS-to-VMS RPC

RBrown_1 — Tue, 24 May 2011 15:11:12 GMT

What do you mean "schedule a batch job"? Do you mean SUBMIT/AFTER?

Is DECnet really not available? If you do have DECnet, then it is as simple as SUBMIT/REMOTE.

Failing that, I would look into the TCP/IP "R_commands". If you are using Digital UCX or TCP/IP, then see HELP UCX R_COMMANDS or HELP TCP/IP R_COMMANDS. Otherwise see the corresponding help for whichever TCP stack you are using.

Re: VMS-to-VMS RPC

Hoff — Tue, 24 May 2011 15:26:42 GMT

Ok, so we have the usual questions around the particular platform and the version and (for this case) the IP stack.

Basic IP network communications? Via telnet? Um, OK. Not my first choice here. Use of telnet means you have to mess around with and even embed cleartext passwords, if security is a concern (and if you don't have kerberized telnet configured), and passing over commands and sequences, which gets gnarly. telnet can be good as a basic troubleshooting tool. It's not so good in a production environment.

curl to a CGI in a web server can be an option, if there's a web server on the target. But that's probably reasonable only if you already have a web server running on the target.

Task-to-task DCL DECnet (yes, DECnet) can be an option here, given that DECnet Phase V (if you have that configured) operates over an IP connection. Or (depending on what you're up to here) the generic SUBMIT /REMOTE command, also via DECnet over IP.

One of the simplest approaches here is ssh. Not because it has similarities to telnet, but because ssh can trigger commands on the remote host. Details on remote commands here:

http://h71000.www7.hp.com/openvms/products/ssh/ssh_restrictions.pdf

And of course rexec and rsh are also an option, and those are part of basic IP shells, and VMS has those with most IP stacks. Details in the TCP/IP Services shelf here:

http://www.hp.com/go/openvms/doc

VMS doesn't cluster all that well, so you're fairly limited in the remote options via IP; VMS is substantially lacking in modern IP tools, unfortunately. Even something as simple as netcat (nc) completely blows the sneakers off of most of what VMS has to offer, for instance.

Re: VMS-to-VMS RPC

Robert Atkinson — Tue, 24 May 2011 16:06:54 GMT

Thanks Hoff - RSH/REXEC should work fine :-

$ rsh/pass=xxxxxxxx
_Hostname: delta
_Command: sh user
%%%%%%%%%%% OPCOM 24-MAY-2011 18:08:13.75 %%%%%%%%%%%
Message from user INTERnet on DELTA
INTERnet ACP REXEC Accept Request from Host: 192.168.244.240 Port: 1023

OpenVMS User Processes at 24-MAY-2011 18:08:13.82

Total number of users = 2, number of processes = 2
........

Re: VMS-to-VMS RPC

Robert Atkinson — Tue, 24 May 2011 16:15:41 GMT

Suggestion to use RSH/REXEC.