fabric difference sudo() run('sudo cmd') - python

I'm wondering what is the difference between the function sudo() and the function run('sudo -u user smth')
On the doc there is :
sudo is identical in every way to run, except that it will always wrap
the given command in a call to the sudo program to provide superuser
privileges.
But a few time, sudo('cmd') prompt me a password, but if I switch with run('sudo cmd') it works without prompting me anything. Is there anything that change between the two ? (I remember someone on SO saying that sudo and run(sudo cmd) are not for the same use, but I can't find it back)

I found these two difference.
1: Fabric maintains an in-memory password
2: sudo accepts additional user and group arguments
First, fabric would get password from cache when using sudo(), then you do not need to enter password. But if you use run('sudo cmd'), you need to enter password for each 'sudo cmd'.
Second, if you want to execute a command not under root but other user group like www, you just need to set env.sudo_user = 'www' or sudo('cmd', user='www'). The first would execute each sudo() under www, the second would execute this single cmd under www. But you need to edit to run("sudo -u 'www' cmd") when use run() command.
from fabric.api import sudo, run, env
env.hosts = ['host_ip',]
env.user = 'user_name'
env.sudo_user = 'sudo_user'
def test_1():
run('sudo pwd')
def test_2():
sudo('pwd')
$ fab -I --show=debug test_1 test_2
Initial value for env.password: # enter password
Commands to run: test_1, test_2
Parallel tasks now using pool size of 1
[ip_address] Executing task 'test_1'
[ip_address] run: /bin/bash -l -c "sudo pwd"
[ip_address] out: [sudo] password for billy: # needs to enter password here
[ip_address] out: /home/billy
[ip_address] out:
Parallel tasks now using pool size of 1
[ip_address] Executing task 'test_2'
[ip_address] sudo: sudo -S -p 'sudo password:' -u "root" /bin/bash -l -c "pwd"
[ip_address] out: sudo password: # only prompt, do not need enter password
[ip_address] out: /home/billy
[ip_address] out:
Done.
Disconnecting from ip_address... done.

Since Fabric 2, you can invoke sudo via run(), which will prompt for the password unless you use the auto-responder, details here. Note that the sudo command usually caches the password remotely, so next invocations of sudo during the same connection will not prompt for password.
However, the Fabric sudo() helper makes using sudo much easier, details here. You need to ensure that the sudo.password configuration value is filled in (via config object, config file, environment variable, or --prompt-for-sudo-password). Here's how I do it with the keyring module:
from fabric import task
import keyring
#task
def restart_apache(connection):
# set the password with keyring.set_password('some-host', 'some-user', 'passwd')
connection.config.sudo.password = keyring.get_password(connection.host, 'some-user')
connection.sudo('service apache2 restart')

Related

SSHing from within a python script and run a sudo command having to give sudo password

I am trying to SSH into another host from within a python script and run a command that requires sudo.
I'm able to ssh from the python script as follows:
import subprocess
import sys
import json
HOST="hostname"
# Ports are handled in ~/.ssh/config since we use OpenSSH
COMMAND="sudo command"
ssh = subprocess.Popen(["ssh", "%s" % HOST, COMMAND],
shell=False,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
print(error)
else:
print(result)
But I want to run a command like this after sshing :
extract_response = subprocess.check_output(['sudo -u username internal_cmd',
'-m', 'POST',
'-u', 'jobRun/-/%s/%s' % (job_id, dataset_date)])
return json.loads(extract_response.decode('utf-8'))[0]['id']
How do I do that?
Also, I don't want to be providing the sudo password every time I run this sudo command, for that I have added this command (i.e., internal_cmd from above) at the end of visudo in the new host I'm trying to ssh into. But still when just typing this command directly in the terminal like this:
ssh -t hostname sudo -u username internal_cmd -m POST -u/-/1234/2019-01-03
I am being prompted to give the password. Why is this happening?
You can pipe the password by using the -S flag, that tells sudo to read the password from the standard input.
echo 'password' | sudo -S [command]
You may need to play around with how you put in the ssh command, but this should do what you need.
Warning: you may know this already... but never store your password directly in your code, especially if you plan to push code to something like Github. If you are unaware of this, look into using environment variables or storing the password in a separate file.
If you don't want to worry about where to store the sudo password, you might consider adding the script user to the sudoers list with sudo access to only the command you want to run along with the no password required option. See sudoers(5) man page.
You can further restrict command access by prepending a "command" option to the beginning of your authorized_keys entry. See sshd(8) man page.
If you can, disable ssh password authentication to require only ssh key authentication. See sshd_config(5) man page.

How to Automate Login to Intermediate Host using ProxyCommand with Paramiko in Python [duplicate]

I need to create a script that automatically inputs a password to OpenSSH ssh client.
Let's say I need to SSH into myname#somehost with the password a1234b.
I've already tried...
#~/bin/myssh.sh
ssh myname#somehost
a1234b
...but this does not work.
How can I get this functionality into a script?
First you need to install sshpass.
Ubuntu/Debian: apt-get install sshpass
Fedora/CentOS: yum install sshpass
Arch: pacman -S sshpass
Example:
sshpass -p "YOUR_PASSWORD" ssh -o StrictHostKeyChecking=no YOUR_USERNAME#SOME_SITE.COM
Custom port example:
sshpass -p "YOUR_PASSWORD" ssh -o StrictHostKeyChecking=no YOUR_USERNAME#SOME_SITE.COM:2400
Notes:
sshpass can also read a password from a file when the -f flag is passed.
Using -f prevents the password from being visible if the ps command is executed.
The file that the password is stored in should have secure permissions.
After looking for an answer to the question for months, I finally found a better solution: writing a simple script.
#!/usr/bin/expect
set timeout 20
set cmd [lrange $argv 1 end]
set password [lindex $argv 0]
eval spawn $cmd
expect "password:"
send "$password\r";
interact
Put it to /usr/bin/exp, So you can use:
exp <password> ssh <anything>
exp <password> scp <anysrc> <anydst>
Done!
Use public key authentication: https://help.ubuntu.com/community/SSH/OpenSSH/Keys
In the source host run this only once:
ssh-keygen -t rsa # ENTER to every field
ssh-copy-id myname#somehost
That's all, after that you'll be able to do ssh without password.
You could use an expects script. I have not written one in quite some time but it should look like below. You will need to head the script with #!/usr/bin/expect
#!/usr/bin/expect -f
spawn ssh HOSTNAME
expect "login:"
send "username\r"
expect "Password:"
send "password\r"
interact
Variant I
sshpass -p PASSWORD ssh USER#SERVER
Variant II
#!/usr/bin/expect -f
spawn ssh USERNAME#SERVER "touch /home/user/ssh_example"
expect "assword:"
send "PASSWORD\r"
interact
sshpass + autossh
One nice bonus of the already-mentioned sshpass is that you can use it with autossh, eliminating even more of the interactive inefficiency.
sshpass -p mypassword autossh -M0 -t myusername#myserver.mydomain.com
This will allow autoreconnect if, e.g. your wifi is interrupted by closing your laptop.
With a jump host
sshpass -p `cat ~/.sshpass` autossh -M0 -Y -tt -J me#jumphost.mydomain.com:22223 -p 222 me#server.mydomain.com
sshpass with better security
I stumbled on this thread while looking for a way to ssh into a bogged-down server -- it took over a minute to process the SSH connection attempt, and timed out before I could enter a password. In this case, I wanted to be able to supply my password immediately when the prompt was available.
(And if it's not painfully clear: with a server in this state, it's far too late to set up a public key login.)
sshpass to the rescue. However, there are better ways to go about this than sshpass -p.
My implementation skips directly to the interactive password prompt (no time wasted seeing if public key exchange can happen), and never reveals the password as plain text.
#!/bin/sh
# preempt-ssh.sh
# usage: same arguments that you'd pass to ssh normally
echo "You're going to run (with our additions) ssh $#"
# Read password interactively and save it to the environment
read -s -p "Password to use: " SSHPASS
export SSHPASS
# have sshpass load the password from the environment, and skip public key auth
# all other args come directly from the input
sshpass -e ssh -o PreferredAuthentications=keyboard-interactive -o PubkeyAuthentication=no "$#"
# clear the exported variable containing the password
unset SSHPASS
I don't think I saw anyone suggest this and the OP just said "script" so...
I needed to solve the same problem and my most comfortable language is Python.
I used the paramiko library. Furthermore, I also needed to issue commands for which I would need escalated permissions using sudo. It turns out sudo can accept its password via stdin via the "-S" flag! See below:
import paramiko
ssh_client = paramiko.SSHClient()
# To avoid an "unknown hosts" error. Solve this differently if you must...
ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
# This mechanism uses a private key.
pkey = paramiko.RSAKey.from_private_key_file(PKEY_PATH)
# This mechanism uses a password.
# Get it from cli args or a file or hard code it, whatever works best for you
password = "password"
ssh_client.connect(hostname="my.host.name.com",
username="username",
# Uncomment one of the following...
# password=password
# pkey=pkey
)
# do something restricted
# If you don't need escalated permissions, omit everything before "mkdir"
command = "echo {} | sudo -S mkdir /var/log/test_dir 2>/dev/null".format(password)
# In order to inspect the exit code
# you need go under paramiko's hood a bit
# rather than just using "ssh_client.exec_command()"
chan = ssh_client.get_transport().open_session()
chan.exec_command(command)
exit_status = chan.recv_exit_status()
if exit_status != 0:
stderr = chan.recv_stderr(5000)
# Note that sudo's "-S" flag will send the password prompt to stderr
# so you will see that string here too, as well as the actual error.
# It was because of this behavior that we needed access to the exit code
# to assert success.
logger.error("Uh oh")
logger.error(stderr)
else:
logger.info("Successful!")
Hope this helps someone. My use case was creating directories, sending and untarring files and starting programs on ~300 servers as a time. As such, automation was paramount. I tried sshpass, expect, and then came up with this.
# create a file that echo's out your password .. you may need to get crazy with escape chars or for extra credit put ASCII in your password...
echo "echo YerPasswordhere" > /tmp/1
chmod 777 /tmp/1
# sets some vars for ssh to play nice with something to do with GUI but here we are using it to pass creds.
export SSH_ASKPASS="/tmp/1"
export DISPLAY=YOURDOINGITWRONG
setsid ssh root#owned.com -p 22
reference: https://www.linkedin.com/pulse/youre-doing-wrong-ssh-plain-text-credentials-robert-mccurdy?trk=mp-reader-card
This is how I login to my servers:
ssp <server_ip>
alias ssp='/home/myuser/Documents/ssh_script.sh'
cat /home/myuser/Documents/ssh_script.sh
ssp:
#!/bin/bash
sshpass -p mypassword ssh root#$1
And therefore:
ssp server_ip
This is basically an extension of abbotto's answer, with some additional steps (aimed at beginners) to make starting up your server, from your linux host, very easy:
Write a simple bash script, e.g.:
#!/bin/bash
sshpass -p "YOUR_PASSWORD" ssh -o StrictHostKeyChecking=no <YOUR_USERNAME>#<SEVER_IP>
Save the file, e.g. 'startMyServer', then make the file executable by running this in your terminal:
sudo chmod +x startMyServer
Move the file to a folder which is in your 'PATH' variable (run 'echo $PATH' in your terminal to see those folders). So for example move it to '/usr/bin/'.
And voila, now you are able to get into your server by typing 'startMyServer' into your terminal.
P.S. (1) this is not very secure, look into ssh keys for better security.
P.S. (2) SMshrimant answer is quite similar and might be more elegant to some. But I personally prefer to work in bash scripts.
I am using below solution but for that you have to install sshpass If its not already installed, install it using sudo apt install sshpass
Now you can do this,
sshpass -p *YourPassword* ssh root#IP
You can create a bash alias as well so that you don't have to run the whole command again and again.
Follow below steps
cd ~
sudo nano .bash_profile
at the end of the file add below code
mymachine() { sshpass -p *YourPassword* ssh root#IP }
source .bash_profile
Now just run mymachine command from terminal and you'll enter your machine without password prompt.
Note:
mymachine can be any command of your choice.
If security doesn't matter for you here in this task and you just want to automate the work you can use this method.
If you are doing this on a Windows system, you can use Plink (part of PuTTY).
plink your_username#yourhost -pw your_password
I have a better solution that inclueds login with your account than changing to root user.
It is a bash script
http://felipeferreira.net/index.php/2011/09/ssh-automatic-login/
The answer of #abbotto did not work for me, had to do some things differently:
yum install sshpass changed to - rpm -ivh http://dl.fedoraproject.org/pub/epel/6/x86_64/sshpass-1.05-1.el6.x86_64.rpm
the command to use sshpass changed to - sshpass -p "pass" ssh user#mysite -p 2122
I managed to get it working with that:
SSH_ASKPASS="echo \"my-pass-here\""
ssh -tt remotehost -l myusername
This works:
#!/usr/bin/expect -f
spawn ssh USERNAME#SERVER "touch /home/user/ssh_example"
expect "assword:"
send "PASSWORD\r"
interact
BUT!!! If you have an error like below, just start your script with expect, but not bash, as shown here: expect myssh.sh
instead of bash myssh.sh
/bin/myssh.sh: 2: spawn: not found /bin/myssh.sh: 3: expect: not found /bin/myssh.sh: 4: send: not found /bin/myssh.sh: 5: expect: not found /bin/myssh.sh: 6: send: not found
I got this working as follows
.ssh/config was modified to eliminate the yes/no prompt - I'm behind a firewall so I'm not worried about spoofed ssh keys
host *
StrictHostKeyChecking no
Create a response file for expect i.e. answer.expect
set timeout 20
set node [lindex $argv 0]
spawn ssh root#node service hadoop-hdfs-datanode restart
expect "*?assword {
send "password\r" <- your password here.
interact
Create your bash script and just call expect in the file
#!/bin/bash
i=1
while [$i -lt 129] # a few nodes here
expect answer.expect hadoopslave$i
i=[$i + 1]
sleep 5
done
Gets 128 hadoop datanodes refreshed with new config - assuming you are using a NFS mount for the hadoop/conf files
Hope this helps someone - I'm a Windows numpty and this took me about 5 hours to figure out!
In the example bellow I'll write the solution that I used:
The scenario: I want to copy file from a server using sh script:
#!/usr/bin/expect
$PASSWORD=password
my_script=$(expect -c "spawn scp userName#server-name:path/file.txt /home/Amine/Bureau/trash/test/
expect \"password:\"
send \"$PASSWORD\r\"
expect \"#\"
send \"exit \r\"
")
echo "$my_script"
Solution1:use sshpass
#~/bin/myssh.sh
sshpass -p a1234b ssh myname#somehost
You can install by
# Ubuntu/Debian
$ sudo apt-get install sshpass
# Red Hat/Fedora/CentOS
$ sudo yum install sshpass
# Arch Linux
$ sudo pacman -S sshpass
#OS X
brew install https://raw.githubusercontent.com/kadwanev/bigboybrew/master/Library/Formula/sshpass.rb
or download the Source Code from here, then
tar xvzf sshpass-1.08.tar.gz
cd sshpass-1.08.tar.gz
./configure
sudo make install
Solution2:Set SSH passwordless login
Let's say you need to SSH into bbb#2.2.2.2(Remote server B) with the password 2b2b2b from aaa#1.1.1.1(Client server A).
Generate the public key(.ssh/id_rsa.pub) and private key(.ssh/id_rsa) in A with the following commands
ssh-keygen -t rsa
[Press enter key]
[Press enter key]
[Press enter key]
Use the following command to distribute the generated public key(.ssh/id_rsa.pub) to server B under bbb‘s .ssh directory as a file name authorized_keys
ssh-copy-id bbb#2.2.2.2
You need to enter a password for the first ssh login, and it will be logged in automatically in the future, no need to enter it again!
ssh bbb#2.2.2.2 [Enter]
2b2b2b
And then your script can be
#~/bin/myssh.sh
ssh myname#somehost
Use this script tossh within script, First argument is the hostname and second will be the password.
#!/usr/bin/expect
set pass [lindex $argv 1]
set host [lindex $argv 0]
spawn ssh -t root#$host echo Hello
expect "*assword: "
send "$pass\n";
interact"
To connect remote machine through shell scripts , use below command:
sshpass -p PASSWORD ssh -o StrictHostKeyChecking=no USERNAME#IPADDRESS
where IPADDRESS, USERNAME and PASSWORD are input values which need to provide in script, or if we want to provide in runtime use "read" command.
This should help in most of the cases (you need to install sshpass first!):
#!/usr/bin/bash
read -p 'Enter Your Username: ' UserName;
read -p 'Enter Your Password: ' Password;
read -p 'Enter Your Domain Name: ' Domain;
sshpass -p "$Password" ssh -o StrictHostKeyChecking=no $UserName#$Domain
In linux/ubuntu
ssh username#server_ip_address -p port_number
Press enter and then enter your server password
if you are not a root user then add sudo in starting of command

How fabric work with 'sudo su user'

My request is simple:
ssh to a remote server with user0
switch user to user1 using: 'sudo su user1'
list all items in current folder
My expected code:
def startRedis():
run('sudo su - user1')
print(run('ls'))
However, it ends with out: user1#server:~$
And waiting for my interactive command forever, never executing the second line. It seems sudo su opened a new shell.
Can anyone help solving this simple task?
You can set sudo_user property in env. this way fabric will switch user to the desired user.
Official doc: http://docs.fabfile.org/
Password for switching user can be specified in the env. itself to avoid getting a prompt when the method is invoked.
fabfile.py
from fabric.api import env, sudo
env.sudo_user='user1'
env.password = '***'
def list_items():
sudo('ls')
Run below command & specify the hosts after -H
fab -H host1 list_items

Python - Using Fabric with Sudo

I'm pretty new to python and fabric and I am trying to do a simple code where I can get the output on two hosts that uses sudo, although I keep getting an error.... Can anyone help me out with what I might be missing ?
My code:
from fabric.api import *
from getpass import getpass
from fabric.decorators import runs_once
env.hosts = ['host1','host2']
env.port = '22'
env.user = 'username'
env.password="password"
def sudo_dsmc(cmd):
sudo("-l")
When I run: fab sudo_dsmc:"-1" :
MacBookPRO:PYTHON username$ fab sudo_dsmc:"-l"
[host1] Executing task 'sudo_dsmc'
[host1] sudo: -l
[host1] out: sudo password:
[host1] out: Sorry, user username is not allowed to execute '/bin/bash -l -c - l' as root on host1.
[host1] out:
Fatal error: sudo() received nonzero return code 1 while executing!
Requested: -l
Executed: sudo -S -p 'sudo password:' /bin/bash -l -c "-l"
Aborting.
Disconnecting from host1... done.
Although I can run the apt-get update with my below function fine without any errors:
def sudo_command(cmd):
sudo("apt-get update")
# run like: fab sudo_command:"apt-get-update"
It looks like your sudoers file is preventing you from running that command as sudo. Check your /etc/sudoers file and read the sudo documentation.
Also "-l" isn't a valid command. sudo takes -l as an optional flag (which lists commands allowed by the user). But Fabric's sudo appears to be taking unknown strings and routing them through /bin/bash instead of using them directly as sudo command parameters.

Switching user in Fabric

I have a problem when using Fabric to mimic my SSH workflow to deploy my web application.
Here's my usual flow of commands when I SSH to a server:
SSH using root user. ssh root#1.2.3.4
Switch to web user: su - web
Change directory: cd /srv/web/prod/abc_project
Start virtualenv: workon abc_env
Perform git pull: git pull origin master
Run a script: build_stuff -m build
Run another script: ./run
I tried to write this as a deploy script in Fabric and I get a shell output when su - web is entered. I have to hit Ctrl-D to continue the script. I am also unable to activate my virtualenv....because: su - web successfully switches the user to web but because of the Ctrl-d (so that I can continue the Fabric script), it logs out of that user and back to root.
Here's my script:
env.user = 'root'
#roles('web')
def deploy():
dev_path = '/srv/web/prod'
app_path = '/srv/web/prod/rhino'
workon = 'workon rhino_env'
with prefix('su - web'):
puts('Switched to `web` user')
with settings(warn_only=True):
run('kill -9 `cat /srv/web/run/rhino/rhino.pid`')
puts('Stopped rhino...')
with cd(app_path):
run('git reset --hard HEAD')
puts('Discarded all untracked and modified files')
run('git checkout master')
run('git pull origin master')
users = run('users')
puts('Output from `users` command: %s' % users)
run(workon)
run('build_assets -m build')
run('cd %(dev_path)s; chown -R web:ebalu rhino' % {'dev_path': dev_path})
run('cd %(app_path)s; ./run' % {'app_path': app_path})
pid = run('cat /srv/web/run/rhino/rhino.pid')
puts('Rhino started again with pid: %s.' % pid)
...there's one more thing: No, I can't login as web initially, I have to login as root. It is the web user that has the virtualenv not the root user.
First of all, you should use sudo when executing commands under another user. Second, workon sets environment variables for current shell. Since fabric invokes new shell for every command, you should run workon rhino_env in every command, where you need virtualenv (i.e. as prefix). With this edits yor code should look like this:
env.user = 'root'
#roles('web')
def deploy():
dev_path = '/srv/web/prod'
app_path = '/srv/web/prod/rhino'
workon = 'workon rhino_env; '
with settings(warn_only=True):
run('kill -9 `cat /srv/web/run/rhino/rhino.pid`')
puts('Stopped rhino...')
with cd(app_path):
sudo('git reset --hard HEAD', user='web')
puts('Discarded all untracked and modified files')
sudo('git checkout master', user='web')
sudo('git pull origin master', user='web')
users = run('users')
puts('Output from `users` command: %s' % users)
with prefix(workon):
sudo('build_assets -m build', user='web')
with cd(dev_path):
run('chown -R web:ebalu rhino')
with cd(app_path):
sudo('./run', user='web')
pid = run('cat /srv/web/run/rhino/rhino.pid')
puts('Rhino started again with pid: %s.' % pid)
The way I achieve this is with
from fabric.api import settings
with settings(user='otheruser'):
...
You will be prompted for the password of otheruser, though only once. So it is not equivalent so sudo su otheruser, where root logs in to the user account without a password, but is is a simple way to switch between users in your script, only typing each password once
One possible solution is to use the sudo operation instead of changing the remote user with su.

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