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container.training/slides/containers/Network_Drivers.md
Jerome Petazzoni fcfcb127b4 📃 Update section summaries
2021-03-30 18:09:24 +02:00

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# Container network drivers
The Docker Engine supports many different network drivers.
The built-in drivers include:
* `bridge` (default)
* `none`
* `host`
* `container`
The driver is selected with `docker run --net ...`.
The different drivers are explained with more details on the following slides.
---
## The default bridge
* By default, the container gets a virtual `eth0` interface.
<br/>(In addition to its own private `lo` loopback interface.)
* That interface is provided by a `veth` pair.
* It is connected to the Docker bridge.
<br/>(Named `docker0` by default; configurable with `--bridge`.)
* Addresses are allocated on a private, internal subnet.
<br/>(Docker uses 172.17.0.0/16 by default; configurable with `--bip`.)
* Outbound traffic goes through an iptables MASQUERADE rule.
* Inbound traffic goes through an iptables DNAT rule.
* The container can have its own routes, iptables rules, etc.
---
## The null driver
* Container is started with `docker run --net none ...`
* It only gets the `lo` loopback interface. No `eth0`.
* It can't send or receive network traffic.
* Useful for isolated/untrusted workloads.
---
## The host driver
* Container is started with `docker run --net host ...`
* It sees (and can access) the network interfaces of the host.
* It can bind any address, any port (for ill and for good).
* Network traffic doesn't have to go through NAT, bridge, or veth.
* Performance = native!
Use cases:
* Performance sensitive applications (VOIP, gaming, streaming...)
* Peer discovery (e.g. Erlang port mapper, Raft, Serf...)
---
## The container driver
* Container is started with `docker run --net container:id ...`
* It re-uses the network stack of another container.
* It shares with this other container the same interfaces, IP address(es), routes, iptables rules, etc.
* Those containers can communicate over their `lo` interface.
<br/>(i.e. one can bind to 127.0.0.1 and the others can connect to it.)
???
:EN:Advanced container networking
:EN:- Transparent network access with the "host" driver
:EN:- Sharing is caring with the "container" driver
:FR:Paramétrage réseau avancé
:FR:- Accès transparent au réseau avec le mode "host"
:FR:- Partage de la pile réseau avece le mode "container"