Turning On and Off Network Bandwidth Management

Traffic shaping (also known as network bandwidth management) allows you to control what network bandwidth a virtual machine or Container receives for outgoing traffic. Traffic shaping is off by default in Parallels Cloud Server and is controlled by the TRAFFIC_SHAPING parameter in the /etc/vz/vz.conf global configuration file.

Note: Incoming traffic cannot be controlled for virtual machines and Containers in Parallels Cloud Server.

To turn traffic shaping on, you need to complete the following steps:

1. Set the value of TRAFFIC_SHAPING to yes in the global configuration file.
2. Correctly set up the BANDWIDTH and TOTALRATE parameters values.
3. Start traffic shaping with the /etc/init.d/vz shaperon command.

The BANDWIDTH variable is used for specifying the network rate, in kilobits per second, of available network adapters. By default, it is set to eth0:100000 , which corresponds to a 100Mb/s Fast Ethernet card. If your Hardware Node has more network adapters installed, update this parameter by listing all the adapters participating in shaping. For example, if you have two Fast Ethernet cards, set the parameter to eth0:100000 eth1:100000 .

The TOTALRATE variable specifies the size of the so-called bandwidth pool for each network class being shaped. The bandwidth from the pool can be borrowed by virtual machines and Containers when they need more bandwidth for communicating with hosts from the corresponding network class. It is used to limit the total available outgoing traffic virtual machines and Containers can consume. The format of this variable is < NIC >:< network_class >:< bandwidth_in_Kbits_per_second > and defines the pool size per network class for a given network adapter. Multiple entries for different network classes and adapters can be separated by spaces. The default value for TOTALRATE is eth0:1:4000 , which corresponds to the pool size of 4Mb/s for Network Class 1 on the first Ethernet adapter.

In the /etc/vz/vz.conf configuration file, you can also define the RATE variable whose value amounts to the number of kilobits per second any virtual machine or Container is guaranteed to receive for outgoing traffic with a network class on an Ethernet device. The default value of this parameter is eth0:1:8 , which means that any virtual machine or Container is guaranteed to receive the bandwidth of at least 8 Kbps for sending data to Class 1 hosts on the first Ethernet device. This bandwidth is not the limit for a virtual machine or Container (unless the RATEBOUND parameter is enabled for the virtual machine or Container); the virtual machine or Container can take the needed bandwidth from the TOTALRATE bandwidth pool if it is not used by other virtual machines and Containers.

After setting up the above parameters, start bandwidth management as follows:

# /etc/init.d/vz shaperon

Starting shaping: Ok

Set shaping on running Container :

vz WARNING: Can't get tc class for Container(101).

vz WARNING: Can't access file /var/run/vz_tc_classes. \

Creating new one.

vz WARNING: Can't get tc class for Container(1).

Now you have activated the network bandwidth limits. To turn traffic shaping off temporarily, use the /etc/init.d/vz shaperoff command. If you want to disable bandwidth management permanently, set the TRAFFIC_SHAPING variable to no in the /etc/vz/vz.conf configuration file.