I received the following errors whilst running dsh on a NIM master recently.

 

root@nim1 : / # dsh -waixlpar1 date

0042-053 lsnim: there is no NIM object named "aixlpar1"

The node aixlpar1 is not defined in NIM database.

aixlpar1: Mon Aug  4 14:01:57 EET 2014

 

I had to set the following environment variable, shown below. By setting DSH_CONTEXT to DSH this prevented the dsh command from referring to the NIM database and instead forced it to query a user-defined node list.

 

root@nim1 : / # export DSH_CONTEXT=DSH

 

root@nim1 : / # dsh -waixlpar1 date

aixlpar1: Mon Aug  4 14:02:22 EET 2014

 

root@nim1 : / # env | grep -i dsh

DSH_CONTEXT=DSH

DSH_NODE_RSH=/usr/bin/ssh

 

root@nim1 : / # dsh -q

DSH:DCP_DEVICE_OPTS=

DSH:DCP_DEVICE_RCP=

DSH:DCP_NODE_OPTS=-q

DSH:DCP_NODE_RCP=/usr/bin/scp

DSH:DSH_CONTEXT=DSH

DSH:DSH_DEVICE_LIST=

DSH:DSH_DEVICE_OPTS=

DSH:DSH_DEVICE_RCP=

DSH:DSH_DEVICE_RSH=

DSH:DSH_ENVIRONMENT=

DSH:DSH_FANOUT=

DSH:DSH_LOG=

DSH:DSH_NODEGROUP_PATH=

DSH:DSH_NODE_LIST=/usr/local/etc/csmnodes.list

DSH:DSH_NODE_OPTS=

DSH:DSH_NODE_RCP=

DSH:DSH_NODE_RSH=/usr/bin/ssh

DSH:DSH_OUTPUT=

DSH:DSH_PATH=

DSH:DSH_REPORT=

DSH:DSH_SYNTAX=

DSH:DSH_TIMEOUT=

DSH:RSYNC_RSH=

 

Here’s another dsh tip I picked up. By default dsh will use the default port for ssh connections to nodes. For example, by default sshd listens on port 22 on an AIX node. I recently came across a customer environment where they had configured sshd to listen on port 6666 (not the real port number!). They wanted to use dsh from a NIM master which would connect to all the defined nodes in their custom list. When they ran it they got the following error message:

 

# dsh date

aixlpar1: ssh: connect to host aixlpar1 port 22: Connection refused

dsh:  2617-009 aixlpar1 remote shell had exit code 255

 

On the AIX node, we could see that sshd was listening on port 6666:

 

# netstat -a | grep 6666 | grep LIST

tcp6       0      0  *.6666                 *.*                    LISTEN

tcp4       0      0  *.6666                 *.*                    LISTEN

 

We needed to find a way to force dsh to use a different port number when starting the ssh connection. This was accomplished by setting the DSH_REMOTE_OPTS variable, as shown below.

 

[root@nim1]/ # export DSH_REMOTE_OPTS=-p6666

 

[root@nim1]/ # dsh date

aixlpar1: Tue Aug  5 17:37:16  2014

 

[root@nim1]/ # env | grep DSH

DSH_REMOTE_CMD=/usr/bin/ssh

DSH_NODE_LIST=/etc/ibm/sysmgt/dsm/nodelist

DSH_REMOTE_OPTS=-p6666

DSH_NODE_RSH=/usr/bin/ssh

 

DSH CONTEXT    

The DSH CONTEXT is the in-built context for all the DSH Utilities commands. It permits a user-defined node group database contained in the local file system. The DSH_NODEGROUP_PATH environment variable specifies the path to the node group database. Each file in this directory represents a node group, and contains one host name or TCP/IP address for each node that is a group member. Blank lines and comment lines beginning with a # symbol are ignored. If all nodes are requested for the DSH CONTEXT, a full node list is built from all groups in the DSH_NODEGROUP_PATH directory, and cached in /var/ibm/sysmgt/dsm/dsh/$DSH_NODEGROUP_PATH/AllNodes. This file is recreated each time a group file is modified or added to the DSH_NODEGROUP_PATH directory. Device targets are not supported in the DSH context.

 

http://www-01.ibm.com/support/knowledgecenter/ssw_aix_71/com.ibm.aix.cmds2/dsh.htm?lang=en

 

DSH_REMOTE_OPTS

Includes the options specified in the remote command when the command is forwarded to the remote nodes.

 

http://ps-2.kev009.com/wisclibrary/aix52/usr/share/man/info/en_US/a_doc_lib/cmds/aixcmds3/mgmtsvr.htm

Tags:  is dsh_context gibson dsh 0042-053 aix no there port dsh_remote_opts different nim 22 chris lsnim named object