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Log Insight: li_rexec

One of the great things about Log Insight is that you do not need a CLI to use it. If you do decide to use the CLI you may find yourself wishing to execute commands on every node in a Log Insight cluster. While this can be done with a simple for loop, I wrote a quick wrapper script to make it even easier.
li-script

WARNING: This script is not supported by VMware or me. Use at your own risk!

From any node within a Log Insight cluster you can determine all other nodes in the cluster. This means with a simple wrapper script you can point to a single node like a master, worker, or VIP and based on configuration data, issue a command to all nodes within the cluster. Note that this script uses SSH so you will want to have SSH keys configured on the nodes. To use the script I created, simply run li_rexec:

$ li_rexec
USAGE: li_rexec   [-v]

As you can see, the script requires two inputs being the Log Insight instance (e.g. master, worker, VIP, standalone) and the command(s) you wish to run. By default the output is not very verbose:

$ li_rexec li.sflanders.net date
Tue Dec 30 20:34:37 UTC 2014
Tue Dec 30 20:34:37 UTC 2014
Tue Dec 30 20:34:37 UTC 2014

To make the output more verbose, use the -v flag at the end of the command:

$ li_rexec li.sflanders.net date -v
===================================
Host: li01.sflanders.net
Command(s): date
===================================
Tue Dec 30 20:34:37 UTC 2014
===================================
Host: li02.sflanders.net
Command(s): date
===================================
Tue Dec 30 20:34:37 UTC 2014
===================================
Host: li03.sflanders.net
Command(s): date
===================================
Tue Dec 30 20:34:37 UTC 2014

That’s it! So without further adieu, here is the script:

#!/usr/bin/env sh
#
# li_rexec
# Steve Flanders (stevesflandersnet)
#
# Description - Wrapper to run commands on every node in a Log Insight instance
#
# ***PLEASE DO NOT REMOVE THIS HEADER AND PLEASE CREDIT THE AUTHOR***
#
### VALIDATIONS
if [ -z "$2" -o ! -z "$4" ]; then echo "USAGE: $0   [-v]"; exit; fi
### VARIABLES
LOGINSIGHT="$1"
SSHCOMMAND="$2"
SSHUSER="root"
### DO NOT CHANGE ANYTHING BELOW HERE!!!
# Assume a cluster and get the list of nodes
NODELIST=$(ssh -q -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no [email protected]$LOGINSIGHT "grep \"daemon host\" \$(ls /storage/core/loginsight/config/loginsight-config.xml* | sort -k1.55n | tail -n 1) | awk '{ split(\$0,a,\"\\\"\"); print a[2];}'")
NODES=()
if [ ! -z "$NODELIST" ]; then for N in $NODELIST; do NODES+=($N); done; fi
# If unable to get a list of nodes then assume standalone
if [ -z "$NODES" ]; then NODES=($loginsight); fi
for NODE in ${NODES[@]}; do
   if [ "$3" == "-v" ]; then echo "
===================================
Host: $NODE
Command(s): $SSHCOMMAND
==================================="; fi
      ssh -q -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no [email protected]$NODE $SSHCOMMAND
done
if [ "$3" == "-v" ]; then echo; fi

© 2015, Steve Flanders. All rights reserved.

Published inVMware

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