3.4. Managing Network Accounting and Bandwidth¶

3.4.1. Network Traffic Parameters¶

The table below summarizes the network traffic parameters that you can control in Virtuozzo Hybrid Server.

3.4.2. Configuring Network Classes¶

Virtuozzo Hybrid Server allows you to track the inbound and outbound network traffic and shape the outgoing traffic for virtual machines and containers. To provide the ability to distinguish between types of traffic, e.g., domestic and international, a concept of network classes is introduced. IP address ranges fall into several network classes. Each network class represents traffic to specific resources. Access to such resources is charged at a different rate than the rest of the traffic.

Classes are specified in the /etc/vz/conf/networks_classes file. The file is in the ASCII format, and all empty lines and lines starting with the # sign are ignored. Other lines have the following format:

<class_id> <IP_address>/<prefix_length>

where <class_id> defines the network class ID, and the <IP_address>/<prefix_length> pair defines the range of IP addresses for this class. There may be several lines for each class.

Classes 0 and 1 have special meanings:

• Class 0 defines the IP address range for which no accounting is performed. Usually, it corresponds to the hardware node subnet (the node itself and its virtual machines and containers). Setting up class 0 is not required; however, its correct setup improves performance.

• Class 1 is defined by Virtuozzo Hybrid Server to match any IP address. It must be always present in the network classes definition file. Therefore, it is suggested not to change the default line in the networks_classes file.

  1 0.0.0.0/0
  

  If your virtual machines and containers are using IPv6 addresses, you can also add the following line to this file:

  1 ::/0
  

Other classes should be defined after class 1. They represent exceptions from the “matching-everything” rule of class 1. The example below illustrates a possible configuration of the network classes definition file containing rules for both IPv4 and IPv6 addresses:

# Hardware node networks
0 192.168.0.0/16
0 fe80::/64
# any IP address (all traffic)
1 0.0.0.0/0
1 ::/0
# class 2 - addresses for the "foreign" traffic
2 10.0.0.0/8
2 2001:db88::/64
# inside "foreign" network there
# is a hole belonging to "local" traffic
1 10.10.16.0/24
1 2001:db88:3333::/64

In this example, IPv4 addresses in the range of 192.168.0.0 to 192.168.255.255 and IPv6 addresses in the range of fe80:: to fe80::ffff:ffff:ffff:ffff are treated as class 0 addresses and no accounting is done for the traffic from virtual machines and containers destined to these addresses.

Class 2 matches the following IP addresses:

• IPv4 addresses from 10.0.0.0 to 10.255.255.255 with the exception of addresses in the sub-range of 10.10.16.0 to 10.10.16.255, which are treated as class 1.

• IPv6 addresses from 2001:db88:: to 2001:db88::ffff:ffff:ffff:ffff with the exception of addresses in the sub-range of 2001:db88:3333:: to 2001:db88:3333::ffff:ffff:ffff:ffff, which are also treated as class 1.

All other IP addresses (both IPv4 and IPv6) belong to class 1.

To apply changes after editing the /etc/vz/conf/networks_classes file, restart either the virtual machine(s) or/and container(s) for which changes have been made or the hardware node itself if the changes are global.

3.4.3. Viewing Network Traffic Statistics¶

In Virtuozzo Hybrid Server, you can view the current network traffic statistics for virtual machines and containers using the vznetstat utility. For example:

# vznetstat
UUID         Net.Class  Input(bytes)  Input(pkts)  Output(bytes)  Output(pkts)
0            0          566093064     2800575      3120481        41736
47406484...  0          67489         155          8033           110
fbb30afa-... 0          9369          78           12692          71

By default, vznetstat shows network statistics for both virtual machines and containers. Keep in mind that the vznetstat utility displays statistics only about virtual machines and containers that were started at least once.

The vznetstat utility displays the following information:

For example, from the command output above, you can see that around 9 MB of data were uploaded to the container MyCT, (2) about 12 MB were downloaded from it, and all the traffic was exchanged with servers from class 0 networks.

If necessary, you can view network traffic statistics separately for virtual machine or container by passing the -t option to vznetstat:

• For containers only:

  # vznetstat -t ct
  CTID         Net.Class  Input(bytes)  Input(pkts)  Output(bytes)  Output(pkts)
  0            0          566093064     2800575      3120481        41736
  fbb30afa-... 0          9369          78           12692          71
  

• For virtual machines only:

  # vznetstat -t vm
  UUID         Net.Class  Input(bytes)  Input(pkts)  Output(bytes)  Output(pkts)
  0            0          566093064     2800575      3120481        41736
  47406484...  0          67489         155          8033           110
  

You can also view network statistics for a particular virtual machine or container by specifying its ID after the -v option, for example:

# vznetstat -v fbb30afa-e770-4081-9d9e-6b9c262eb091
UUID         Net.Class  Input(bytes)  Input(pkts)  Output(bytes)  Output(pkts)
fbb30afa-... 0          9369          78           12692          71

This command displays statistics only for the container MyCT.

3.4.4. Configuring Traffic Shaping¶

Traffic shaping (also known as network bandwidth management) allows you to control what network bandwidth a virtual machine or container may use for outgoing traffic. This feature is disabled by default.

Note the following:

• Traffic within a host cannot be shaped in the current version of Virtuozzo Hybrid Server. This includes traffic between virtual machines and containers on the same host and between those and the host itself.

• Incoming traffic cannot be shaped for virtual machines and containers in the current version of Virtuozzo Hybrid Server.

• VM and container traffic is shaped by marking packets’ fwmark field. If the hardware node uses custom packet filtering rules set with the MARK and CONNMARK iptables modules, the traffic shaping feature of Virtuozzo Hybrid Server will not work. Traffic statistics reported by vznetstat, however, will be correct even if the node uses custom traffic marks.

The following parameters control traffic shaping in Virtuozzo Hybrid Server:

• TRAFFIC_SHAPING, enables and disables traffic shaping.

• BANDWIDTH, sets bandwidth for specific network adapters.

• TOTALRATE, sets the size of a bandwidth pool divided between virtual machines and containers on the host.

• RATEMPU, limits packet rate in addition to byte rate.

• RATE, sets a bandwidth guarantee for virtual machines and containers.

• RATEBOUND, forces RATE as a limit.

Traffic shaping in Virtuozzo Hybrid Server works as follows. The bandwidth pool for a given network class (set by TOTALRATE) is divided among the virtual machines and containers transmitting data proportionally to their RATE settings. If the sum of RATE values of all virtual machines and containers transmitting data does not exceed TOTALRATE, each virtual machine or container gets the bandwidth equal to or greater than its RATE value (unless RATEBOUND is enabled for the VM or container). If the sum of RATE values of all virtual machines and containers transmitting data exceeds the TOTALRATE value, each virtual machine or container may get less than its RATE value.

To enable and configure traffic shaping, do the following:

1. Set the value of TRAFFIC_SHAPING to yes in the global configuration file /etc/vz/vz.conf.

2. Set the parameters BANDWIDTH, TOTALRATE in /etc/vz/vz.conf.

3. If required, set the optional parameters RATEMPU, RATE, RATEBOUND in /etc/vz/vz.conf.

4. If required, set RATE and RATEBOUND for specific virtual machines and containers with prlctl set --rate and prlctl set --ratebound commands.

5. To apply changes, restart either the virtual machines and containers for which changes have been made or the hardware node itself if the changes are global.

The following sections provide more details on and explain how to set traffic shaping parameters listed above.