So I am aware one can edit bash tab completion scripts with functions for a variety of behaviors
I have configured a long list of aws hosts on my .ssh/config, written as dot sepparated names, like so:
Host aws.<stack_name>.<instance_name>
HostName X.X.X.X
by default ssh bash completion scripts display the full list of hosts declared in the config file, and this is pretty good already. But I would like to add to this behavior, which currently displays the list like so:
$ ssh aws.[tab][tab]
aws.stack1.inst1 aws.stack2.inst1
aws.stack1.inst2 aws.stack2.inst2
aws.stack1.inst3 aws.stack3.inst1
aws.stack1.inst4 aws.stack4.inst1
so that I can do the following:
$ ssh aws.[tab][tab]
stack1 stack2 stack3
$ ssh aws.stack1.[tab][tab]
inst1 inst2 inst3 inst4
But I have not been able to figure out how, and where, to add this functionality by navigating through available bash_completion scripts.
I don't want to overwrite the current ssh completion, just extend its behavior when ssh is followed by aws
How/Where can/should I implement this behavior?
This question has a good answer for how to put multiple command in an alias for bash.
But how would you do it in the case where you first need to ssh into a server, then do something like change a directory and then launch jupyter notebook?
I tried something like:
alias shortcut='ssh user#server -p 1234 -L 5678:localhost:91011; cd ~/somedir; jupyter notebook --ip=127.0.0.1
Maybe it's because my ssh requires me to type in a password, the last 2 commands aren't being executed.
There are some possible improvements for further convenience, if allowed by the system configuration.
If your need include executing a series of commands on the remote host, and you need to repeat this often, it's reasonable to put the commands in their own shell script and place it on the remote host.
For example in this case the script could be just
#!/bin/sh
cd ~/somedir && jupyter notebook --ip=127.0.0.1
Saving them in a file, add execution bit to it, and you can start the session like ssh user#server -p 1234 -L 5678:localhost:91011 path/to/script.sh
This is touched in this question but my preferred way is the low-score one about putting the script on remote -- I'd like to have each resource reside where they belong.
There's also the problem about what you want to do after starting the session. It seems the command is to start a server process that runs the Jupyter web service. If you just want to stay in the SSH session while monitoring the server, then the simple command should suffice. But if you want to keep the server in the background and log the output (and likely leave the SSH session for now) it's possible to run the server with nohup and redirect its output, by putting in the script something like
nohup jupyter notebook --ip="127.0.0.1" >> stdout.log 2>> stderr.log &
echo "$!" > jupyter-notebook.pid
The second command saves the PID in the file so it'll be easier to check or terminate it later without manually searching for the background process.
I am working in Hosted Chef environment in windows.We have a UI from where we run Chef Scripts.When there are no parameters to be passed we just select the script to be executed and run the batch file with knife commands in the background execute the scripts.
Now I need to pass parameters dynamically to the recipes.I have tried adding attributes in the attribute file.It is working fine.But each time, I need to download and change the attributes and upload the recipes to chef server and run it using batch file which is quite tedious and time consuming.
Is there any other way to fulfil this requirement ?
Thanks for your help.
You can use environment variables in your recipe code, but that is often very brittle. You can also read a local file either via the -j option mentioned above or by just opening and reading the file yourself in your recipe code. There is no direct way to pass parameters to recipes, and it generally indicates you are doing something non-convergent.
You can add attributes to the chef-client call directly. That kills the "when there are no parameters to be passed", but it does allow you to get attributes in at run-time. There are two ways to do this. Either you pass in a file with the -j option (which might work nicely with your GUI), or you can hack it. This hack works with linux, not sure how you'd do it with windows, but I'm sure there is a similar option.
echo '{ "myjson": "here" }' | chef-client -j /dev/stdin
Or if you are using winrm to run chef-client something like this:
knife winrm -m ipaddress 'echo "{ \"param\":\"test\"}" | chef-client -c c:/ chef/client.rb -j /dev/sdin' -m -x Administrator -P '######'
That assumes you have a linux machine on the other end. Otherwise, I'm not sure how to read stdin as if it were a file. -j /dev/stdin probably won't work for windows clients.
How would I go about creating a Bash script that will ssh into a list of computers and run a command and have the output of that command append to a file on the server?
posting this as an answer since I do not have the required reputation for making comments...
You should use the following shell syntax :
for ip in $(<filename.txt); do ssh "$ip" 'yourcommand >> yourfile'; done;
Pro tip: If you foresee doing this a lot -- you have a bunch of servers on which you must routinely issue commands, capture output, whatever -- it would pay to setup and use Ansible or any of the commonly available infra orchestration tools like Chef/Puppet etc. The reason I recommend ansible is that it requires minimal setup, and that too only on the master machine. It also supports ad-hoc commands pretty well.
Ps: I do not have experience with Chef/Puppet, I've just used Ansible.
I've searched around a bit for similar questions, but other than running one command or perhaps a few command with items such as:
ssh user#host -t sudo su -
However, what if I essentially need to run a script on (let's say) 15 servers at once. Is this doable in bash? In a perfect world I need to avoid installing applications if at all possible to pull this off. For argument's sake, let's just say that I need to do the following across 10 hosts:
Deploy a new Tomcat container
Deploy an application in the container, and configure it
Configure an Apache vhost
Reload Apache
I have a script that does all of that, but it relies on me logging into all the servers, pulling a script down from a repo, and then running it. If this isn't doable in bash, what alternatives do you suggest? Do I need a bigger hammer, such as Perl (Python might be preferred since I can guarantee Python is on all boxes in a RHEL environment thanks to yum/up2date)? If anyone can point to me to any useful information it'd be greatly appreciated, especially if it's doable in bash. I'll settle for Perl or Python, but I just don't know those as well (working on that). Thanks!
You can run a local script as shown by che and Yang, and/or you can use a Here document:
ssh root#server /bin/sh <<\EOF
wget http://server/warfile # Could use NFS here
cp app.war /location
command 1
command 2
/etc/init.d/httpd restart
EOF
Often, I'll just use the original Tcl version of Expect. You only need to have that on the local machine. If I'm inside a program using Perl, I do this with Net::SSH::Expect. Other languages have similar "expect" tools.
The issue of how to run commands on many servers at once came up on a Perl mailing list the other day and I'll give the same recommendation I gave there, which is to use gsh:
http://outflux.net/unix/software/gsh
gsh is similar to the "for box in box1_name box2_name box3_name" solution already given but I find gsh to be more convenient. You set up a /etc/ghosts file containing your servers in groups such as web, db, RHEL4, x86_64, or whatever (man ghosts) then you use that group when you call gsh.
[pdurbin#beamish ~]$ gsh web "cat /etc/redhat-release; uname -r"
www-2.foo.com: Red Hat Enterprise Linux AS release 4 (Nahant Update 7)
www-2.foo.com: 2.6.9-78.0.1.ELsmp
www-3.foo.com: Red Hat Enterprise Linux AS release 4 (Nahant Update 7)
www-3.foo.com: 2.6.9-78.0.1.ELsmp
www-4.foo.com: Red Hat Enterprise Linux Server release 5.2 (Tikanga)
www-4.foo.com: 2.6.18-92.1.13.el5
www-5.foo.com: Red Hat Enterprise Linux Server release 5.2 (Tikanga)
www-5.foo.com: 2.6.18-92.1.13.el5
[pdurbin#beamish ~]$
You can also combine or split ghost groups, using web+db or web-RHEL4, for example.
I'll also mention that while I have never used shmux, its website contains a list of software (including gsh) that lets you run commands on many servers at once. Capistrano has already been mentioned and (from what I understand) could be on that list as well.
Take a look at Expect (man expect)
I've accomplished similar tasks in the past using Expect.
You can pipe the local script to the remote server and execute it with one command:
ssh -t user#host 'sh' < path_to_script
This can be further automated by using public key authentication and wrapping with scripts to perform parallel execution.
You can try paramiko. It's a pure-python ssh client. You can program your ssh sessions. Nothing to install on remote machines.
See this great article on how to use it.
To give you the structure, without actual code.
Use scp to copy your install/setup script to the target box.
Use ssh to invoke your script on the remote box.
pssh may be interesting since, unlike most solutions mentioned here, the commands are run in parallel.
(For my own use, I wrote a simpler small script very similar to GavinCattell's one, it is documented here - in french).
Have you looked at things like Puppet or Cfengine. They can do what you want and probably much more.
For those that stumble across this question, I'll include an answer that uses Fabric, which solves exactly the problem described above: Running arbitrary commands on multiple hosts over ssh.
Once fabric is installed, you'd create a fabfile.py, and implement tasks that can be run on your remote hosts. For example, a task to Reload Apache might look like this:
from fabric.api import env, run
env.hosts = ['host1#example.com', 'host2#example.com']
def reload():
""" Reload Apache """
run("sudo /etc/init.d/apache2 reload")
Then, on your local machine, run fab reload and the sudo /etc/init.d/apache2 reload command would get run on all the hosts specified in env.hosts.
You can do it the same way you did before, just script it instead of doing it manually. The following code remotes to machine named 'loca' and runs two commands there. What you need to do is simply insert commands you want to run there.
che#ovecka ~ $ ssh loca 'uname -a; echo something_else'
Linux loca 2.6.25.9 #1 (blahblahblah)
something_else
Then, to iterate through all the machines, do something like:
for box in box1_name box2_name box3_name
do
ssh $box 'commmands_to_run_everywhere'
done
In order to make this ssh thing work without entering passwords all the time, you'll need to set up key authentication. You can read about it at IBM developerworks.
You can run the same command on several servers at once with a tool like cluster ssh. The link is to a discussion of cluster ssh on the Debian package of the day blog.
Well, for step 1 and 2 isn't there a tomcat manager web interface; you could script that with curl or zsh with the libwww plug in.
For SSH you're looking to:
1) not get prompted for a password (use keys)
2) pass the command(s) on SSH's commandline, this is similar to rsh in a trusted network.
Other posts have shown you what to do, and I'd probably use sh too but I'd be tempted to use perl like ssh tomcatuser#server perl -e 'do-everything-on-one-line;' or you could do this:
either scp the_package.tbz tomcatuser#server:the_place/.
ssh tomcatuser#server /bin/sh <<\EOF
define stuff like TOMCAT_WEBAPPS=/usr/local/share/tomcat/webapps
tar xj the_package.tbz or rsync rsync://repository/the_package_place
mv $TOMCAT_WEBAPPS/old_war $TOMCAT_WEBAPPS/old_war.old
mv $THE_PLACE/new_war $TOMCAT_WEBAPPS/new_war
touch $TOMCAT_WEBAPPS/new_war [you don't normally have to restart tomcat]
mv $THE_PLACE/vhost_file $APACHE_VHOST_DIR/vhost_file
$APACHECTL restart [might need to login as apache user to move that file and restart]
EOF
You want DSH or distributed shell, which is used in clusters a lot. Here is the link: dsh
You basically have node groups (a file with lists of nodes in them) and you specify which node group you wish to run commands on then you would use dsh, like you would ssh to run commands on them.
dsh -a /path/to/some/command/or/script
It will run the command on all the machines at the same time and return the output prefixed with the hostname. The command or script has to be present on the system, so a shared NFS directory can be useful for these sorts of things.
Creates hostname ssh command of all machines accessed.
by Quierati
http://pastebin.com/pddEQWq2
#Use in .bashrc
#Use "HashKnownHosts no" in ~/.ssh/config or /etc/ssh/ssh_config
# If known_hosts is encrypted and delete known_hosts
[ ! -d ~/bin ] && mkdir ~/bin
for host in `cut -d, -f1 ~/.ssh/known_hosts|cut -f1 -d " "`;
do
[ ! -s ~/bin/$host ] && echo ssh $host '$*' > ~/bin/$host
done
[ -d ~/bin ] && chmod -R 700 ~/bin
export PATH=$PATH:~/bin
Ex Execute:
$for i in hostname{1..10}; do $i who;done
There is a tool called FLATT (FLexible Automation and Troubleshooting Tool) that allows you to execute scripts on multiple Unix/Linux hosts with a click of a button. It is a desktop GUI app that runs on Mac and Windows but there is also a command line java client.
You can create batch jobs and reuse on multiple hosts.
Requires Java 1.6 or higher.
Although it's a complex topic, I can highly recommend Capistrano.
I'm not sure if this method will work for everything that you want, but you can try something like this:
$ cat your_script.sh | ssh your_host bash
Which will run the script (which resides locally) on the remote server.
Just read a new blog using setsid without any further installation/configuration besides the mainstream kernel. Tested/Verified under Ubuntu14.04.
While the author has a very clear explanation and sample code as well, here's the magic part for a quick glance:
#----------------------------------------------------------------------
# Create a temp script to echo the SSH password, used by SSH_ASKPASS
#----------------------------------------------------------------------
SSH_ASKPASS_SCRIPT=/tmp/ssh-askpass-script
cat > ${SSH_ASKPASS_SCRIPT} <<EOL
#!/bin/bash
echo "${PASS}"
EOL
chmod u+x ${SSH_ASKPASS_SCRIPT}
# Tell SSH to read in the output of the provided script as the password.
# We still have to use setsid to eliminate access to a terminal and thus avoid
# it ignoring this and asking for a password.
export SSH_ASKPASS=${SSH_ASKPASS_SCRIPT}
......
......
# Log in to the remote server and run the above command.
# The use of setsid is a part of the machinations to stop ssh
# prompting for a password.
setsid ssh ${SSH_OPTIONS} ${USER}#${SERVER} "ls -rlt"
Easiest way I found without installing or configuring much software is using plain old tmux. Say you have 9 linux servers. Pick a box as your main. Start a tmux session:
tmux
Then create 9 split tmux panes by doing this 8 times:
ctrl-b + %
Now SSH into each box in each pane. You'll need to know some tmux shortcuts. To navigate, press:
ctrl+b <arrow-keys>
Once your logged in to all your boxes on each pane. Now turn on pane synchronization where it lets you type the same thing into each box:
ctrl+b :setw synchronize-panes on
now when you press any keys, it will show up on every pane. to turn it off, just make on to off. to cycle resize panes, press ctrl+b < space-bar >.
This works alot better for me since I need to see each terminal output as sometimes servers crash or hang for whatever reason when downloading or upgrade software. Any issues, you can just isolate and resolve individually.