:Let's pretend that we needed to deploy a web server need collect the disk usage on several machinesso that we can plan for storage maintenance. We'll set up a simple example of such a deployment here.

:You'll find that yum prompts you to answer questions, which you don't want to do in an automated environment. And also yum prints too much output, which also isn't helpful in an automated environment. We'll fix it by adding two switches to yum: "-y" and "-d1":

Fatal error:<source lang="html"><h1>My fancy web server</h1></source>run() received nonzero return code 1 while executing!

Requested:And since we're pretending that it's a large website with many files and directories, we'll compress it into an archive named '''webcontents.tar.bz2''' using a tar command. You've done this since OPS235.yum update -yExecuted: /bin/bash -l -c "yum update -y"

:Once you have your archive, make sure it's in the same directory as your fab fileAborting. Then add the following to your setupWebServer() function: :<source lang="python"> with cd("/var/www/html/"): put("webcontentsDisconnecting from 192.tar168.bz2", "122.") run("tar xvf webcontents169.tar.bz2") run("rm webcontents.tardone.bz2")

:There is something weird in the code above that you haven't seen before but it's required for some uses of Fabric: the '''with'env.user = 'root' statement.

:The problem is that separate '''run''' commands each execute in a brand new session, each with its own shell. They are not like separate lines in a single shell script even though they look like they should be.</source>:That means if you run a cd command and then a tar command separately - the tar command will not run in Save the directory where you think it willfabfile. In order to fix this you have to nest commands inside a '''py with''' - the change and run it's like a '''run''' but with persistant resultsagain. :The code we added to the function will cd to If you see the default web site directory on the workerpassword prompt again, upload your web contents tarball make sure that you can ssh from your controller as a regular user to that directory on the your worker, extract it, and delete the tarball. :After it's done - you should have a working web server and simple website on your worker1. :Except you won't be able to access it because of the firewall. We'll deal with that in the next sectionvm as root without password.