How to run a single command on multiple Linux machines at once

Introduction

In this tutorial, How to run a single command on multiple Linux machines at once. I will create a script on the Linux servers to send commands to multiple servers.

Prerequisites

• 2 Virtual Machine
• ssh Connectivity Between 2 Servers

Configure SSH on Server 1

For example, The Server calls the name controller. This server is using the operating system Ubuntu.

create the SSH config file with the command:

cat ~/.ssh/config

For example, the content as output below

Create the script to run a single command on multiple Linux machines at once

We will create 1 script to run a command for a remote Linux server.

sudo vi /usr/local/bin/script_node1

In that file, paste the following:

#!/bin/bash

# Get the user's input as command
[[ -z ${@} ]] && exit || CMD_EXEC="${@}"

# Get the hosts from ~/.ssh/config
HOSTS=$(grep -Po 'Host\s\Knode1' "$HOME/.ssh/config")

# Test weather the input command uses sudo
if [[ $CMD_EXEC =~ ^sudo ]]
then
    # Ask for password
    read -sp '[sudo] password for remote_admin: ' password; echo

    # Rewrite the command
    CMD_EXEC=$(sed "s/^sudo/echo '$password' | sudo -S/" <<< "$CMD_EXEC")
fi

# loop over the hosts and execute the SSH command, remove `-a` to override the>
while IFS= read -r host
do
   echo -e '\n\033[1;33m'"HOST: ${host}"'\033[0m'
   ssh -n "$host" "$CMD_EXEC 2>&1" | tee -a "/tmp/$(basename "${0}").${host}"
done <<< "$HOSTS"

Save and close the file.

Now, We will update the package for server calls name node1 as command below:

script_node1 sudo apt-get update

Via youtube

Conclusion

You have to run a single command on multiple Linux machines at once. I hope will this your helpful. Thank you for reading the DevopsRoles page!