“Device eth0 does not seem to be present” error when we move or clone a CentOS 6.3 virtual machine in vSphere

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"
When we move or clone a CentOS 6.3 Virtual machine made in vSphere5.5, and boot the machine once it is moved/cloned, we get the following error:

“Device eth0 does not seem to be present”.

This is due the fact that whenever we move or clone a Virtual machine, vSphere changes the MAC Address and CentOS renames the NIC from eth0 to eth1.  CentOS stores the network interface hardware configuration using udev.  The file is:

/etc/udev/rules.d/70-persistent-net.rules

Open this file in vi editor and delete the old entry for eth0 and edit the new entry for eth1 to eth0.
Then you need to edit the following file:

/etc/sysconfig/network-scripts/ifcfg-eth0

Record the HWADDR from the 70-persistent-net.rules configuration file and replace it with the existing HWADDR in ifcfg-eth0 configuration file.

Reboot the machine.
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Configuring proxy on Nagios Linux CentOS

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Problems Using Nagios XI With Proxies

We do not officially support Nagios XI when you install and use proxy software that restricts traffic to or from the Nagios XI server. There are several reasons for this. First, Nagios XI requires external access for package installation and updates. Package installation and updates may not work when proxies are used. Additionally, the Nagios XI code makes several internal HTTP calls to the local Nagios XI server to import configuration data, apply configuration changes, process AJAX requests, etc. These functions may not work properly when you deploy a proxy, which would result in a non-functional Nagios XI installation.

There are two things that need to be configured to make XI installation work with a proxy; the yum and wget configurations. Do both of these before starting anything about the installation process.

In /etc/yum.conf :

 proxy=http://someproxyserver:port/ # Shouldn't need to be quoted, remember the trailing slash
 proxy_username=myname  # The username you authenticate to your proxy with, if applicable
 proxy_password=mypass  # The password you provide to your proxy, if applicable

In /etc/wgetrc :

 http_proxy=http://myname:mypass@someproxyserver:port/ # All in one string this time
 no_proxy=localhost,127.0.0.0/8,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16 # Hosts to exclude from proxying

If you are using an https proxy:

 https_proxy=https://myname:mypass@someproxyserver:port/ 

Quoting is not needed (or helpful) in any of these, but if you have special characters in passwords (especially : or @) and are having problems you probably need to escape them with backslashes.

Linux open-vm-tools

Open-VM-Tools (OVT): The Future of VMware Tools for Linux

http://blogs.vmware.com/vsphere/2015/09/open-vm-tools-ovt-the-future-of-vmware-tools-for-linux.html

Installation guide

http://partnerweb.vmware.com/GOSIG/home.html

 

HowTo : Install VMware Tools on CentOS/RHEL

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VMware Tools is a suite of utilities that enhances the performance of the virtual machine's guest operating system and improves management of the virtual machine.
Without VMware Tools installed in your guest operating system, guest performance lacks important functionality.

Installing VMware Tools

Open Vmware Worstation or ESX console and Locate the VM you need to install VMware Tools to.
Right click the VM and choose "Tools", then select "Install VMware Tools".
It will connect the virtual CD-ROM device to the appropriate CD image containing the tools for your virtual machine.
Log into VMware Guest you need to install VMware Tools to.

Install the kernel-devel, gcc, dracut, make and perl packages using yum :
$ yum -y install kernel-devel gcc dracut make perl

Mount CD image with VMware Tools :
$ mkdir /mnt/cdrom
$ mount /dev/cdrom /mnt/cdrom

Copy the archive with VMware Tools to temporary directory :
$ cp /mnt/cdrom/VMwareTools-*.tar.gz /tmp

Uncompress the archive and run the installer :
$ tar -zxf /tmp/VMwareTools-*.tar.gz -C /tmp
$ /tmp/vmware-tools-distrib/vmware-install.pl --default

Remove temporary files :
$ rm -f /tmp/VMwareTools-*.tar.gz
$ rm -rf /tmp/vmware-tools-distrib

Validating VMware Tools Installation

Use the command as follows to validate that VMware Tools is running :
$ initctl list | grep vmware-tools
vmware-tools start/running

To determine the vmware-tools version, run the command :
$ vmware-toolbox-cmd -v