What is the best and secure way for a terminal to ping a server for a list of commands to execute every 60 secs? For example, it could download a file (that houses the command) or query a database and then execute what is on there.
Are there more efficient/secure ways to accomplish the above?
Thanks
If you want to make it into a script:
commands.ssh
echo "This will run on the remote machine."
# Do a backup or something...
Then you can execute pass this file to the remote machine using:
ssh user#remote -i id_rsa < commands.ssh
I recommend using an sshkey so that you don't have to keep your login information in the commands file.
Note: make sure the permissions for the commands.ssh file are secure!
chmod 600 commands.ssh
You can use SSH connections which are SSL enabled. If commands are predefined you can depend on a cron job, then you don't need to login to terminal again and again to run it.
Related
One of my tasks at work is to check the health/status of multiple Linux servers everyday. I'm thinking of a way to automate this task (without having to login to each server everyday). I'm a newbie system admin by the way. Initially, my idea was to setup a cron job that would run scripts and email the output. Unfortunately, it's not possible to send mail from the servers as of the moment.
I was thinking of running the command in parallel, but I don't know how. For example, how can I see output of df -h without logging in to servers one by one.
You can run ssh with the -t flag to open a ssh session, run a command and then close the session. But to get this fully automated you should automate the login process to every server so that you don't need to type the password for every server.
So to run df -hon a remote server and then close the session you would run ssh -t root#server.com "df -h". Then you can process that output however you want.
One way of automating this could be to write a bash script that runs this command for every server and process the output to check the health of the server.
For further information about the -t flag or how you can automate the login process for ssh.
https://www.novell.com/coolsolutions/tip/16747.html
https://serverfault.com/questions/241588/how-to-automate-ssh-login-with-password
You can use ssh tunnels or just simply ssh for this purpose. With ssh tunnel you can redirect the outputs to your machine, or as an alternative, you can run the ssh with the remote commands on your machine then get the ouput on your machine too.
Please check the following pages for further reading:
http://blog.trackets.com/2014/05/17/ssh-tunnel-local-and-remote-port-forwarding-explained-with-examples.html
https://www.google.hu/amp/s/www.cyberciti.biz/faq/unix-linux-execute-command-using-ssh/amp/
If you want to avoid manual login, use ssh keys.
Create a file /etc/sxx/hosts
populate like so:
[grp_ips]
1.1.1.1
2.2.2.2
3.3.3.3
share ssh key on all machines.
Install sxx from package:
https://github.com/ericcurtin/sxx/releases
Then run command like so:
sxx username#grp_ips "whatever bash command"
My requirement is to save history of the commands into a file called history_yymmdd.txt by running the following command on a remote server.
history > history_20170523.txt
I tried with the following command, but it was creating a blank file on remote server(10.12.13.14).
ssh 10.12.13.14 "history > history_20170523.txt"
When I log in to the remote server and run the history command, then the file was created successfully. But I need to run the command on 20 servers so creating a script to run it remotely on each server is my objective here.
Thanks in advance.
ssh user#machine_name "cat ~/.bash_history > history_20170523.txt"
The 'history' command dumps the contents of .bash_history, so this may be useful to you.
A more elegant solution might be:
scp user#machine_name:~/.bash_history history_20170523.txt
you are doing it in a wrong way, also there is no user for the remote machine. Correct way to do is
ssh -q -tt user#10.12.13.14 'history > history_20170523.txt'
SOLVED
Scenario: I am a beginner in bash script, windows task scheduler and such. I am able to run a local bash script in my Windows Task Scheduler successfully.
Problem: I need to do this on many computers, thus I think storing just 1 copy of the bash script on a remote server may be of help. What my Task Scheduler needs to do is just to run the script and output a log. However, I can't get the correct syntax for the argument.
The below is what I have currently:
Program/Script: C:\cygwin64\bin\bash.exe
Argument (works successfully):
-l -c "ssh -p 222 ME#ME.com "httpdocs/bashscript.sh" >> /cygdrive/c/Users/ME/Desktop/`date +%Y%m%d`.log 2>&1"
Start in: C:\cygwin64\bin
Also had to make sure that the user account under Properties in Task Scheduler is correct, as mine was incorrect before. And need key authentication for ME#ME.com too.
For the password issue, you really should use ssh keys. I think your command would simply be ssh -p 222 ME#ME.com:.... I.e., just get rid of the --rsh stuff. – chrisaycock
i wanted to execute commands on remote linux box from windows and also wanted to collect result of executed command. Basically i have to pass 2 boxes to execute that command here is flow.
Login to a box
ssh to another box
run command
collect output of command locally (in file)
I tried following
F:\xyz>plink xyz#a1.b1.com -i F:\x\y\PRIVATEKEY.ppk -pw xyz
ssh -f root#166.1.8.1 yum upgrade Cyberc
but this is asking for password. I can do it by adding id_rsa.pub value in to authorized_keys but we dont have permission to do. So instead of that i wanted to write EXPECT script to pass user/pass and commands to complete my job.
Any help on EXPECT script would be much appreciated.
Unless the program on the remote linux host is interactive (i.e. it has prompts that the user must respond to), then you probably don't need to use expect - you can simply use plink to connect to the remote Linux host from your windows machine and run the command. You can specify the username and password to authenticate with the remote host in the plink command. See the following links for more info:
http://the.earth.li/~sgtatham/putty/0.58/htmldoc/Chapter7.html
http://stackoverflow.com/questions/12844944/login-syntax-for-plink-using-ip-username-and-password
I'm trying to set up mysql database backups with cron in order to backup the mysql database to my local NAS storage. I would like to store the command(s) in the .sh file on the server and then use cron to execute it.
Up to now I've managed to get the command to save the database to my NAS (QNAP) from the remote server, which is:
mysqldump
--add-drop-table
--comments [database_name]
-u [database_username]
-p[database_password] |
gzip -c |
ssh [nas_user]#[nas_ip_address]
"cat > /share/mysqlBackup/backup-`date +%Y-%m-%d_%H-%M-%S`.sql.gz"
The above works fine, but the problems I have are:
I'm not sure how to create the .sh file on the remote server and put
the command in
This command asks for the password each time you
execute it - is there a way to put it in the .sh file so that i can
be executed in the background without prompting for it / or define
the password in the command?
Examples of how to solve the above would be very welcome.
I believe that the expect() dialog could be used, but again - I'm not familiar with it and its documentation is a bit confusing for me.
I guess password is asked for ssh connection, so you can make your ssh connection passwordless.
Here in the answer passwordless ssh connection is explained:
https://serverfault.com/questions/241588/how-to-automate-ssh-login-with-password
After this step is done on your remote server rest is pretty straightforward you write the command you give above in an .sh file. And add it to cron to do this backing up periodically.