vppcfg/docs/config-guide.md

A VPP Configuration Utility

Configuration Guide

vppcfg consumes YAML files of a specific format. Their validity is asserted by two main types of validation:

1. syntax checks are performed by Yamale and this ensures that all fields in the YAML file are correctly formed, that field-names are correctly spelled, that no extra fields are given, and their values are of the correct type.
2. semantic validations are performed to ensure that configurations are safely applyable to a running VPP. Note: Some semantic checks are stricter than VPP, because applying them may leave the dataplane in a non-recoverable state.

For the curious, the Yamale syntax validation lives in this schema. If you want to get started quickly and don't mind cargo-culting, take a look at this example.

Basic structure

The YAML configuration file has the following structure, consisting of several maps of a given object type, which specify names of those objects:

loopbacks:
  loop0:
    [ Loopback Configuration ]

bondethernets:
  BondEthernet0:
    [ BondEthernet (bond) Configuration ]

vxlan_tunnels:
  vxlan_tunnel0:
    [ VXLAN (tunnel) Configuration ]

bridgedomains:
  bd1:
    [ BridgeDomain Configuration ]

interfaces:
  GigabitEthernet3/0/0:
    [ Interface Configuration ]
  BondEthernet0:
    [ BondEthernet (interface) Configuration ]
  vxlan_tunnel0:
    [ VXLAN (interface) Configuration ]

Object names are strictly enforced, they must be unique in their scope, and they are case sensitive. For example, any loopback MUST be named loopN, and any bondethernet MUST be named BondEthernetN (note here the camel case). A distinction is made between the object and the resulting interface: A BondEthernet occurs twice in the configuration. The first time, in the bondethernets section, the bond configuration is specified. That bond configuration yields an interface in VPP named BondEthernetN, which occurs in the interfaces section where it can then be manipulated like any other interface (eg. have IP addresses, Linux Control Plane names, sub-interfaces and so on). The same is true for VXLAN tunnels, the only currently supported tunnel type.

Loopbacks

Loopbacks are required to be named loopN where N in [0,4096). The configuration allows the following fields:

• description: A string, no longer than 64 characters, and excluding the single quote ' and double quote ". This string is currently not used anywhere, and serves for enduser documentation purposes.
• lcp: A Linux Control Plane interface pair LIP. If specified, the loopback will be presented in Linux under this name. Its name may be at most 15 characters long, and match the regular expression [a-z]+[a-z0-9-]*.
• mtu: An integer value between [128,9216], noting the (packet) MTU of the loopback. It will default to 1500 if not specified.
• addresses: A list of between one and six IPv4 or IPv6 addresses including prefixlen in CIDR format. VPP requires IP addresses to be unique in the entire dataplane, with one notable exception: Multiple IP addresses in the same prefix/len can be added on one and the same interface.

Although VPP would allow it, vppcfg does not allow for loopbacks to have sub-interfaces.

Examples:

loopbacks:
  loop0:
    description: "loopback with default 1500 byte MTU"
    lcp: lo0
    addresses: [ 10.0.0.1/32, 2001:db8::1/128 ]
  loop1:
    lcp: bvi1
    mtu: 9000
    addresses: [ 10.0.1.1/24, 10.0.1.2/24, 2001:db8:1::1/64 ]

Bridge Domains

BridgeDomains are required to be named bdN where N in [1, 16777216). Note that bridgedomain bd0 is reserved and cannot be used. The configuration allows the following fields:

• description: A string, no longer than 64 characters, and excluding the single quote ' and double quote ". This string is currently not used anywhere, and serves for enduser documentation purposes.
• mtu: An integer value between [128,9216], noting the (packet) MTU of the bridgedomain. It will default to 1500 if not specified. All member interfaces, including the BVI, are required to have the same MTU as their bridge.
• bvi: An optional bridge virtual interface (sometimes also referred to as an IRB) which refers to an existing loopback interface by name (ie loop0).
• interfaces: A list of zero or more interfaces or sub-interfaces that are bridge members. If the bridge has a BVI, it MUST NOT appear in this list. Bridges are allowed to exist with no member interfaces.

Any member sub-interfaces that are added, will automatically be configured to tag-rewrite the number of tags they have, so a simple dot1q sub-interface will be configured as pop 1, while a QinQ or QinAD sub-interface will be configured as pop 2. Conversely, when interfaces are removed from the bridge, their tag-rewriting will be disabled.

Caveat: Currently, bridgedomains are always created with their default attributes in VPP, that is to say with learning and unicast forwarding turned on, unknown-unicast flooding enabled, and ARP terminating and aging turned off. In a future release, vppcfg will give more configuration options.

Examples:

bridgedomains:
  bd10:
    mtu: 2000
    bvi: loop1
    interfaces: [ BondEthernet0.500, HundredGigabitEthernet12/0/1, vxlan_tunnel1 ]
  bd11:
    description: "No member interfaces, default 1500 byte MTU"

BondEthernets

BondEthernets are required to be named BondEthernetN (note the camelcase) where N in [0,4294967294). The configuration allows the following fields:

• description: A string, no longer than 64 characters, and excluding the single quote ' and double quote ". This string is currently not used anywhere, and serves for enduser documentation purposes.
• interfaces: A list of zero or more interfaces that are bond members. The interfaces must be PHYs, and in their interface configuration, members are allowed only to set the MTU.

Note that the configuration object here only specifies the link aggregation and its members. BondEthernets are expected to occur as well in the interfaces section, where their sub-interfaces and IP addresses and so on are specified.

Caveat: Currently, BondEthernets are always created as LACP typed devices with a loadbalance strategy of l34. In a future release of vppcfg, the type and strategy will be configurable.

Examples:

bondethernets:
  BondEthernet0:
    description: "Core: LACP to fsw0.lab.ipng.ch"
    interfaces: [ GigabitEthernet3/0/0, GigabitEthernet3/0/1 ]

VXLAN Tunnels

VXLAN Tunnels are required to be named vxlan_tunnelN (note the underscore), where N in [0,2G). The configuration allows the following fields:

• description: A string, no longer than 64 characters, and excluding the single quote ' and double quote ". This string is currently not used anywhere, and serves for enduser documentation purposes.
• local: A required IPv4 or IPv6 address for our (source) side of the tunnel.
• remote: A required IPv4 or IPv6 address for their (destination) side of the tunnel.
• vni: A Virtual Network Indentifier, a required integer number between [1,16M).

Local and Remote sides of the tunnel MUST have the same address family.

Caveat: VXLAN tunnels are currently only possible as unicast (src/dst), with static source and destination ports (4789), and with a decap-next of L2. Also, VNIs must be globally unique. In a future release of vppcfg, these fields will be configurable, and VNI reuses will be allowed between different dst endpoints.

Examples:

vxlan_tunnels:
  vxlan_tunnel0:
    description: "Some IPv6 VXLAN tunnel"
    local: 2001:db8::1
    remote: 2001:db8::2
    vni: 100
  vxlan_tunnel1:
    local: 192.0.2.1
    remote: 192.0.2.2
    vni: 101

Interfaces

Interfaces and their sub-interfaces are configured very similarly. Interface names MUST either exist as a PHY in VPP (ie. HundredGigabitEthernet12/0/0) or as a specified BondEthernetN or vxlan_tunnel0 device. The configuration allows the following fields:

• description: A string, no longer than 64 characters, and excluding the single quote ' and double quote ". This string is currently not used anywhere, and serves for enduser documentation purposes.
• lcp: A Linux Control Plane interface pair LIP. If specified, the interface will be presented in Linux under this name. Its name may be at most 15 characters long, and match the regular expression [a-z]+[a-z0-9-]*. In sub-interfaces, a LIP may only be specified if its direct parent has an LIP as well. In the case of a QinQ or QinAD sub-interface, there must exist an intermediary interface with the correct encapsulation, and it too must have a LIP.
• mtu: An integer value between [128,9216], noting the MTU of the interface. The MTU for a PHY will be set as its Max Frame Size in addition to its packet MTU. Parents must always have a larger MTU than any of their children (this is done to satisfy Linux Control Plane).
• addresses: A list of between one and six IPv4 or IPv6 addresses including prefixlen in CIDR format. VPP requires IP addresses to be unique in the entire dataplane, with one notable exception: Multiple IP addresses in the same prefix/len can be added on one and the same interface.
• l2xc: A Layer2 Cross Connect interface name. An l2xc will be configured, after which this interface cannot have any L3 configuration (IP addresses or LCP), and neither can the target interface.
• state: An optional string that configures the link admin state, either up or down. If it is not specified, the link is considered admin 'up'.

Further, top-level interfaces, that is to say those that do not have an encapsulation, are permitted to have any number of sub-interfaces specified by subid, an integer between [0,2G), which further allow the following field:

• encapsulation: An encapsulation for the sub-interface:
  • dot1q: An outer Dot1Q tag, an integer between [1,4096).
  • dot1ad: An outer Dot1AD tag, an integer between [1,4096).
  • inner-dot1q: An inner Dot1Q tag, an integer between [1,4096).
  • exact-match: A boolean, signalling the sub-interface should match on the exact number of tags specified. This is required for any L3 interface (carrying an IP address or LCP), but allowed to be False for L2 interfaces (ie. bridge-domain members or L2XC targets).

It's permitted to omit the encapsulation fields, in which case an exact-matching Dot1Q encapsulation with tag value equal to the subid will be configured. Obviously, it is forbidden to specify both dot1q and dot1ad fields at the same time.

Examples:

interfaces:
  HundredGigabitEthernet12/0/0:
    lcp: "ice0"
    mtu: 9000
    addresses: [ 192.0.2.1/30, 2001:db8:1::1/64 ]
    sub-interfaces:
      1234:
        mtu: 9000
        lcp: "ice0.dot1q"
        addresses: [ 192.0.2.5/30, 2001:db8:2::1/64 ]
      1235:
        mtu: 1500
        lcp: "ice0.qinq"
        addresses: [ 192.0.2.9/30, 2001:db8:3::1/64 ]
        encapsulation:
          dot1q: 1234
          inner-dot1q: 1000
          exact-match: True

  BondEthernet0:
    mtu: 9000
    lcp: "bond0"
    sub-interfaces:
      100:
        mtu: 2500
        l2xc: BondEthernet0.200
        encapsulation:
           dot1q: 100
           exact-match: False
      200:
        mtu: 2500
        l2xc: BondEthernet0.100
        encapsulation:
           dot1q: 200
           exact-match: False