Troubleshooting virtual machine network connectivity issues
Networking problems in virtual machines are not caused by infrastructure issues, but by other errors in the virtual machine network configuration. The most common ones are
1. There is no access to the default gateway.
The availability of the default gateway is checked on the virtual machine using the ping command.
To do this, run the command line in Windows by pressing win + r and in the window that appears, type cmd and press Enter or click OK.
Type the ping command, specifying the gateway IP address from the network adapter settings.
The figure shows that the default gateway is not available. It is therefore incorrectly specified.
The correct default gateway IP address can be found in the vCloudDirector Networking -> Networks section.
Specify IP address in network settings
Use the ping command to check the availability of a correctly configured gateway.
2. Incorrectly configured IP address.
A network problem might occur after cloning a virtual machine. It might remember the IP address of the original virtual machine, resulting in two identical IP addresses assigned to different virtual machines on the same network.
In vCloudDirector, you need to check the IP addresses of all virtual machines. If you are using the Windows operating system, you should take the following actions:
They must be unique. If they are, we take the virtual machine out of service.
Then it is necessary to carry out a recastomisation, for this step we select the corresponding item in the menu.
Let's analyse the case of the Nix-based OS - the Centos7 system:
1. Type ifconfig at the command prompt. Information about configuring the VM's network interface will be displayed.
If this virtual machine was cloned from another virtual machine, you need to check the network interface settings of the source virtual machine in the same way.
1. If there is a match, you will need to change the IP address of the second VM.
2. You can change the IP address using the ifconfig ens160 ip address command, where ens160 is the name of the interface and ip address is a free IP address from your network.
3. Restart the network with the command # /etc/init.d/network restart.
4. There is another way to find out if there are matching IP addresses on the network. Use an arp query.
The output will be a list of available arp entries in the form of mac addresses and the IP addresses assigned to them. If there are two identical IP addresses on the network, this will be visible in the table.
3. The virtual machine's network adapter is turned off.
If it's not enabled, the VM's network will not work. You must check and apply the changes.
