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howtos:emulators:helper_script_for_managing_qemu_virtual_machines [2016/09/01 07:11 (UTC)] – [Networking] louigi600howtos:emulators:helper_script_for_managing_qemu_virtual_machines [2016/09/02 08:04 (UTC)] – [Sources] louigi600
Line 365: Line 365:
   #!/bin/bash   #!/bin/bash
   NAME=$(basename $0)   NAME=$(basename $0)
-    tun_up ()+  tun_up ()
   { /sbin/ifconfig $1 0.0.0.0 promisc up   { /sbin/ifconfig $1 0.0.0.0 promisc up
     /usr/bin/sleep 0.5     /usr/bin/sleep 0.5
Line 383: Line 383:
   esac   esac
  
 +===== Using Qemu from Unprivileged Users =====
 +Using root for doing your everyday tasks is commonly discouraged so let's see how we can work around using qemu from unprivileged users.
 +Some say that it's sufficient to give sudo execution on /etc/qemi-if* but that not really enough because qemu-system-* needs to run as root or it will not be able to create the taps and access other resources. Although it is technically possible to give an unprivileged user sufficient privileges to execute correctly qemu-system-* emulators it is much easier to give users the sudo right to run qemu-system-* as privileged user.
 +
 +  User_Alias QEMUERS = al, john, jack
 +  
 +  Cmnd_Alias QEMUCMD = /usr/bin/qemu-system-*
 +  
 +  QEMUERS ALL=(ALL) NOPASSWD: QEMU
 +
 +This would be sufficient to run the VMs as any of the unprivileged users in QEMUERS user alias (al, john, jack) but the management script would need to run sudo qemu-system-* .... this is easy to obtain:
 +
 +  [ $(/usr/bin/id -u) -ne 0 ] && CMD="sudo qemu-system-.... " || CMD="qemu-system-...."
 +  eval $(echo "$CMD &")
 +
 +Alternatively you could give privileges to execute the management script as root.
 ===== Examples ===== ===== Examples =====
 Here are examples of the dialogs that user would see wile creating, starting, stopping and deleting a VM. Here are examples of the dialogs that user would see wile creating, starting, stopping and deleting a VM.
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 ====== Sources ====== ====== Sources ======
 +I've a blog entry on LQ where I talk a little more extensively on minimizing the code in bash scripts.
 +[[http://www.linuxquestions.org/questions/blog/louigi600-808242/minimize-the-amount-of-code-in-your-bash-scripts-37137/|Minimize the amount of code in your bash scripts ]]
  
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 howtos:emulators:helper_script_for_managing_qemu_virtual_machines ()