Introduction
In this article, we will explore how to use the terminal multiplexer, tmux, to connect to several remote hosts and perform daily checks upon startup. The idea is to create a detached session and attach it to a terminal to run the checks.
What is tmux?
tmux is a terminal multiplexer that allows you to run multiple terminal sessions simultaneously in a single window. It is particularly useful when working with remote servers, as it enables you to keep multiple terminal sessions open, even when you close your local terminal window.
Setting up tmux Connections to Several Remote Hosts
To set up tmux connections to several remote hosts, you need to follow these steps:
- Install tmux on your local machine.
- Create a new tmux session.
- Split the tmux window into several panes, each representing a different remote host.
- Connect to each remote host in a separate pane.
- Save the tmux session for future use.
Step 1: Install tmux
To install tmux on your local machine, you can use the package manager for your operating system. For example, on Ubuntu, you can use the following command:
sudo apt-get install tmuxStep 2: Create a New tmux Session
To create a new tmux session, run the following command:
tmux new -s mysessionThis will create a new tmux session named "mysession". You can replace "mysession" with any name you prefer.
Step 3: Split the tmux Window into Several Panes
To split the tmux window into several panes, you can use the following command:
Ctrl-b "This will split the tmux window into two panes. You can repeat this command to create more panes. Each pane can represent a different remote host.
Step 4: Connect to Each Remote Host in a Separate Pane
To connect to each remote host in a separate pane, you can use the following command:
ssh user@remotehostReplace "user" with your username and "remotehost" with the hostname or IP address of the remote server. Repeat this command for each remote host you want to connect to.
Step 5: Save the tmux Session for Future Use
To save the tmux session for future use, you can use the following command:
tmux detachThis will detach the tmux session from the current terminal window. To reattach the session later, run the following command:
tmux attach -t mysessionReplace "mysession" with the name of your tmux session.
Performing Daily Checks on Remote Hosts
To perform daily checks on remote hosts using tmux, you can create a script that runs the checks and attach it to a tmux session. For example, you can create a script called "checks.sh" with the following content:
#!/bin/bash
echo "Checking disk usage on remotehost1"
ssh user@remotehost1 "df -h"
echo "Checking CPU load on remotehost2"
ssh user@remotehost2 "top -bn1 | grep 'Cpu(s)' | \
sed 's/.*, *\([0-9.]*\)%* id.*/\1/' | \
awk '{print 100 - \
1
```