Backup of ESXi Virtual Machines using Affa

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PythonIcon.png Skill level: Advanced
The instructions on this page may require deviations from standard procedures. A good understanding of linux and Koozali SME Server is recommended.


Affa supports hot backing up virtual machines running on the VMWare ESXi server. It uses the VMware Infrastructure Perl Toolkit to communicate with the EXSi and rsync over ssh to transfer the data. Before the backup starts, the state of the running VM is freezed by creating a snapshot of all its disks. After the freezed virtual disk files were backed up, the snapshot is deleted and the config points to the just backed up disks again. Then, as a last step the config files are backed up.

A restore of a VM can be done by simply copying back all archived files to the original location on the ESXi host. It is also possible to copy the files to a different directory (or to another ESXi server) and add the vmx file to the inventory. Alternatively with SambaShare=yes the VMWare Converter tool can be used.

Important.png Note:
This document is applicable to ESX3i with an USB boot device. It will most likely not work with other type of boot devices

Warning.png Warning:
This software comes 'as is' without any warranty. Errors in design and/or implementation cannot be completely eliminated. Therefore take precautions to avoid negative impacts to your system.

Preparing the Affa Server

Affa Installation

Install the Affa program as descibed here: Affa#Installation_or_Update

VMware Infrastructure (VI) Perl Toolkit Installation

Configure the DAG repository

You need to activate the Dag reposity before installing this contrib.

see dag repository

Login as root and run:

/usr/bin/yum install openssl-devel
/usr/bin/yum --enable=dag install perl-XML-SAX
Install the VMware Infrastructure (VI) Perl Toolkit

Download the VI Perl Toolkit tarball from the VMWare web site:

tar xzf VMware-VIPerl-1.6.0-104313.i386.tar.gz
cd vmware-viperl-distrib

Edit the script and comment out these lines

  4738 #      if ( -d '/proc/xen' ) {
  4739 #        error('You cannot install ' .
  4740 #              vmware_product_name() .
  4741 #              ' on a system running a xen kernel.');
  4742 #      }

Run the script


Ignore this warning: The following Perl modules were found on the system but may be too old to work with VIPerl: URI XML::NamespaceSupport

Preparing the ESXi Host for use with Affa

To make the ESXi server ready to cooperate with Affa you must install the rsync program, enable the ssh service, configure passwordless ssh login and add a user for API communication using the VMware Infrastructure (VI) Perl Toolkit.

Adding an ESXi User with restricted Permissions

Run the Virtual Infrastructure Client and logon to the ESXi host.

Adding Affa role

Switch to the Administration module and add a new role with permissions to create and delete snapshots

Affa add new esxi role.gif

Adding Affa user

Switch back to the Inventory module and add a new user with password:

Affa add new esxi user.gif

Assigning permissions

In the Permission Tab assign the new role to the new user.

Affa add new esxi permission.gif

Configuring SSH and RSYNC on the ESX3i Host

On ESXi the SSH service Dropbear is installed but disabled. To use rsync the SSH service must be enabled and the rsync program must be installed. To enable passwordless login a .ssh directory for storing the keys must be created.

A script is provided that does this:

  • enable SSH service by configuring inetd.conf and restarting the inetd service
  • install rsync (statically linked binary)
  • create a /root home directory with a .ssh sub directory to store the public keys for password-less login
  • link the .ssh directory to the non-volatile USB device
  • add a command to /etc/rc.local that executes all the steps above at boot time
Download and install the script

On the ESXi Server console hit Alt-F1 to get the service shell. Now blind-type the word unsupported to unlock the shell.

Login with the root password.

Affa esxi service console.gif

Download the tarball. The tarball contains the rsync binary and the script.

cd /bootbank

Verify the download

 md5sum -c affa-esxi-setup-02.tgz.md5sum

Unpack it

tar xzf affa-esxi-setup-02.tgz 
rm affa-esxi-setup-02.tgz* 

and run the script


Now you can ssh login and use rsync.

Setting up an Affa job

The following assumes, that you are already familiar with configuring Affa and only focus on the ESXi specific parts.

Assume you want to backup the virtual machine named 'myvm' on ESXi server with IP

  • log into the 'affabox' and copy the config helper script
cp -a /usr/lib/affa/ /root/
  • edit /root/ and set
my $jobname='esxi-myvm';


  • tell Affa that this job backups a ESXi virtual machine
'ESXi' => 'yes',
  • set the VM name
'ESXiVMName' => 'myvm',
  • set the username and password (this is the ESXi User with restricted permissions created above)
'ESXiUsername' => 'affa',
'ESXiPassword' => 'secret',
  • configure virtual disk files to be compressed and chunked
'chunkFiles' => '*.vmdk',
  • save the script, then run it
  • send the public key
affa --send-key esxi-myvm
  • run the job manually
affa --run esxi-myvm

When the Affa job starts, you can watch the snapshot create task in the Virtual Infrastructure Client. Affa esxi viclient tasks.gif

The name of the snaphot starts with "BEXI-". Do not delete it or revert to it while Affa is running.


SSH login as root on the ESXi host and run these commands carefully:

grep -v "#BEXI" < /etc/rc.local >/etc/rc.local.affa; mv -f /etc/rc.local.affa /etc/rc.local
sed -e 's#^\(root:.*\)\(:/root:\)\(.*\)#\1:/:\3#' < /etc/passwd > /etc/passwd.affa; mv -f /etc/passwd.affa /etc/passwd
sed -e 's/^\(ssh.*\)/#\1/' < /etc/inetd.conf > /etc/inetd.conf.affa; mv -f /etc/inetd.conf.affa /etc/inetd.conf
kill -HUP `ps | grep inetd | sed -e 's/ .*//'`
rm -rf /bin/rsync /root /bootbank/bexi
tar -C / -xzf /bootbank/environ.tgz sbin/dropbearmulti

Addtional Information

How to update the ESXi System Image

Shutdown the ESXi server. Remove the USB Memory stick and plug it into a linux computer. run the dmesg command to find out the device the memory stick is assigned to. The following example assumes that it is /dev/sdf. Replace is by the correct device.

mkdir -p /mnt/esxi
mount -t vfat /dev/sdf5 /mnt/esxi

Save local.tgz and the bexi/ directory to the local machine

cp -a /mnt/esxi/local.tgz /mnt/esxi/bexi .
umount /mnt/esxi

Download the ISO from the VMWare website and extract the image.

mount -o loop VMware-VMvisor-InstallerCD*iso /mnt/esxi/
mkdir -p /tmp/esxi
tar -xvzf /mnt/esxi/install.tgz -C /tmp/esxi/
umount /mnt/esxi
cd /tmp/esxi/usr/lib/vmware/installer/
bzip2 -d VMware-VMvisor-big*.dd.bz2

Write the new image to the memory stick. Make sure that you use the correct target device of=...

dd if=VMware-VMvisor-big-3.5.0_Update_3-123629.i386.dd of=/dev/sdf
rm -rf /tmp/esxi

Copy local.tgz and the bexi/ directory to the memory stick.

mount -t vfat /dev/sdf5 /mnt/esxi
cp -a local.tgz bexi /mnt/esxi
umount /mnt/esxi

Plug the memory stick into the ESXi server and power on.

Note: Alternatively you can install the new ESXi image on a second memory stick and then remote copy local.tgz and bexi/ from the running ESXi. Then shut down the ESXi server, replace the stick and power on. This minimizes the down time.

How to make a statically linked Rsync Binary

(This is just for information. A pre-build Rsync static is included in the affa-esxi-setup-*.tgz tarball)

tar xzf rsync-3.0.4.tar.gz
cd rsync-3.0.4
  • build the statically linked binary
make CFLAGS="-static" EXEEXT="-static"
strip rsync-static


Wiki article Affa