ohmyadd/ovn-node repository overview

⁠Architecture

⁠Overview

• network: provide capacity of generate any topology
• application: specify application containers
• juction: plug apps into corresponding logical switch port in ovn

⁠Network layer

• central node running:
  • ovn northdb + ovn northd + ovn southdb
  • can be running as deployment in k8s in anywhere
• every hypervisor running:
  • ovn controller + ovs switchd + ovs db
  • must be running as daemonset in k8s on each compute node

⁠Application layer

• now docker-compose is used (only single node)
• maybe openstack or k8s or openstack + zun(kvm & docker mixed) later

⁠Junction component

• a docker libnetwork remote driver is implemented for connecting apps into switch
• source code in infra/driver

⁠Install

⁠Network layer related

• start ovn central, ovn node and docker libnetwork remote drvier (single node deploy)
  • cd infra/ovn/
  • docker-compose up -d
• ip netns reach docker's netns
  • ln -s /var/run/docker/netns/ /var/run/netns
  • after reboot this link command should be run again

⁠Application layer related

• install docker-compose and its dependencies

  • docker-compose under version 1.25 is based on python2.7 which is no longer supported
  • pip3 install docker-compose==1.26.0rc1
  • pip3 install -r https://raw.githubusercontent.com/docker/compose/1.26.0-rc1/requirements.txt

• modify compose's source code, and make compose create container first, then connect its networks

  • vi /usr/local/lib/python3.6/site-packages/compose/service.py
  • 1. change connect under container.start()

  • def start_container(self, container, use_network_aliases=True):
        self.connect_container_to_networks(container, use_network_aliases)
        try:
            container.start()
        except APIError as ex:
    

    Copy

  • def start_container(self, container, use_network_aliases=True):
        try:
            container.start()
            self.connect_container_to_networks(container, use_network_aliases)
        except APIError as ex:
    

    Copy
  • 1. do not pass any netowrk arguments to dockerd when create container

  • def build_default_networking_config(self):
        return {}
    

    Copy

• when dokcer-compose throw error: WARNING: Connection pool is full, discarding connection:localhost

  • count of compose parallel process larger than urllib3 default pool's size
  • COMPOSE_PARALLEL_LIMIT should a little higher than pool default maxsize
  • 1. export COMPOSE_PARALLEL_LIMIT=30; export COMPOSE_HTTP_TIMEOUT=6000
  • 1. vi /usr/local/lib/python3.6/site-packages/docker/transport/unixconn.py

  • class UnixHTTPConnectionPool(urllib3.connectionpool.HTTPConnectionPool):
        def __init__(self, base_url, socket_path, timeout=60, maxsize=15):
    

    Copy

• yum install python-lxml

⁠Run a topology

• edit source code
  • open draw.io⁠
  • export a chart xml in topology/src
  • modify it to what you want
  • finally you can export the chart as xml
  • do not export as compressed file
  • do not use formatted text in any component in chart
• convert src to ir
  • cd topology/front
  • python3 drawio.py your-chart-name.xml
• run it up
  • cd topology/back
  • ./all your-chart-name up
  • ./all your-chart-name down
  • it's better to systemctl restart docker every time you turn down the apps
• new front complier plugin
  • you can write some new code to convert anything into IR

⁠Error handling

• ./all run up or down stuck:
  1. rm /var/lib/docker/network/files/local-kv.db
  2. reboot
  3. docker rm -f $(docker ps -qa)
  4. start again