Docker nodes configuration

Pre-configured nodes

By default, 4 kind of docker nodes have been pre-configured in gonetem

• router to emulate a router thanks to FRR

• host to emulate a simple machine

• server to emulate a server machine with DHCP/TFTP/HTTP/DNS server

• p4sw to emulate a P4 switch based on the bmv2 implementation

These 3 nodes has a default configuration that can be modified in the docker.nodes section of server configuration file. By default, this section looks like this:

docker:
  nodes:
    router:
      image: mroy31/gonetem-frr
    host:
      image: mroy31/gonetem-host
    server:
      image: mroy31/gonetem-server
    p4sw:
      image: mroy31/gonetem-bmv2

with only docker image set in the configuration. However, many other options exist and can be overriden in the server configuration file. For example, this is the full configuration for the node host:

docker:
  nodes:
    host:
      type: host
      image: mroy31/gonetem-host
      volumes: []
      options:
        log: true
        tso: false
      commands:
        console: /bin/bash
        shell: /bin/bash
        loadConfig:
        - command: network-config.py -l /tmp/custom.net.conf
          checkFiles:
          - /tmp/custom.net.conf
        - command: /bin/bash /gonetem-init.sh
          checkFiles:
          - /gonetem-init.sh
        saveConfig:
        - command: network-config.py -s /tmp/custom.net.conf
          checkFiles: []
      configurationFiles:
      - destSuffix: init.conf
        source: /gonetem-init.sh
        label: Init
      - destSuffix: net.conf
        source: /tmp/custom.net.conf
        label: Network
      - destSuffix: ntp.conf
        source: /etc/ntpsec/ntp.conf
        label: NTP

List of parameters:

• type (string): type of node (used in the topology file to declare a docker node)

• image (string): docker image used to launch the container

• volumes (string list): Allow to bind host path in container filesystem (like -v option in docker run`). The syntax is /host/path:/container/path and can be completed in the topology definition.

• options

  • log (boolean): show output messages of loadConfig commands

  • tso (boolean): set to false to disable TSO (TCP Segmentation Offload) on interfaces node

• commands: list of commands needed by gonetem to manage the node

  • console: command used by gonetem when a console is launch

  • shell: command used by gonetem when a shell is launch

  • loadConfig: list of commands used by gonetem when the node is started to load the configuration

    • command: command executed on the node

    • checkFiles: list of files that have to exist to launch the command

  • saveConfig: list of commands used by gonetem when the save command is required by the user

  • configurationFiles: list of files save in the .gnet project for this kind of node

Define new nodes

It is also possible to declare a new kind of node than can be used in topology file, in the server configuration file (section docker.extraNodes as a list). The parameters are exactly the same than the integrated nodes in gonetem. Example:

docker:
  extraNodes:
  - type: myhost
    image: mydocker-img
    volumes: []
    options:
      log: false
      tso: true
    commands:
      console: /bin/myconsole
      shell: /bin/bash
      loadConfig:
      - command: my-load-script.sh
        checkFiles: []
      saveConfig:
      - command: my-save-script.sh
        checkFiles: []
    configurationFiles:
    - destSuffix: myappconf.conf
      source: /path/myconf.conf
      label: MyConf

Once define in the server configuration file, you can use this new node in the topology like that:

nodes:
  Host:
    type: docker.myhost

VyOS

A concrete example of this feature is the possibility to use VyOS router with gonetem. To do that:

1. Build VyOS docker image compatible with gonetem (look at the docker/README.md file to do that)

2. Add this extra node configuration in the server configuration file

docker:
  extraNodes:
  - type: vyos
    image: gonetem-vyos:1.4
    options:
      log: false
      tso: true
    commands:
      console: su - vyos
      shell: /bin/bash
      loadConfig:
      - command: /bin/bash /usr/bin/start-vyos.sh
        checkFiles: []
      saveConfig:
      - command: /bin/bash /usr/bin/save-vyos-config.sh
        checkFiles: []
    configurationFiles:
    - destSuffix: vyos.conf
      source: /opt/vyatta/etc/config/config.boot
      label: VyOS

Finally, restart gonetem server and after you can use docker.vyos node in your topology.