177 lines
7.5 KiB
Markdown
177 lines
7.5 KiB
Markdown
|
[](https://travis-ci.org/containernetworking/cni)
|
||
|
|
[](https://coveralls.io/github/containernetworking/cni?branch=master)
|
||
|
|
[](https://cryptic-tundra-43194.herokuapp.com/)
|
||
|
|
|
||
|
|
# CNI - the Container Network Interface
|
||
|
|
|
||
|
|
## What is CNI?
|
||
|
|
|
||
|
|
The CNI (_Container Network Interface_) project consists of a specification and libraries for writing plugins to configure network interfaces in Linux containers, along with a number of supported plugins.
|
||
|
|
CNI concerns itself only with network connectivity of containers and removing allocated resources when the container is deleted.
|
||
|
|
Because of this focus, CNI has a wide range of support and the specification is simple to implement.
|
||
|
|
|
||
|
|
As well as the [specification](SPEC.md), this repository contains the Go source code of a library for integrating CNI into applications, an example command-line tool, a template for making new plugins, and the supported plugins.
|
||
|
|
|
||
|
|
The template code makes it straight-forward to create a CNI plugin for an existing container networking project.
|
||
|
|
CNI also makes a good framework for creating a new container networking project from scratch.
|
||
|
|
|
||
|
|
## Why develop CNI?
|
||
|
|
|
||
|
|
Application containers on Linux are a rapidly evolving area, and within this area networking is not well addressed as it is highly environment-specific.
|
||
|
|
We believe that many container runtimes and orchestrators will seek to solve the same problem of making the network layer pluggable.
|
||
|
|
|
||
|
|
To avoid duplication, we think it is prudent to define a common interface between the network plugins and container execution: hence we put forward this specification, along with libraries for Go and a set of plugins.
|
||
|
|
|
||
|
|
## Who is using CNI?
|
||
|
|
### Container runtimes
|
||
|
|
- [rkt - container engine](https://coreos.com/blog/rkt-cni-networking.html)
|
||
|
|
- [Kurma - container runtime](http://kurma.io/)
|
||
|
|
- [Kubernetes - a system to simplify container operations](http://kubernetes.io/docs/admin/network-plugins/)
|
||
|
|
- [Cloud Foundry - a platform for cloud applications](https://github.com/cloudfoundry-incubator/netman-release)
|
||
|
|
- [Mesos - a distributed systems kernel](https://github.com/apache/mesos/blob/master/docs/cni.md)
|
||
|
|
|
||
|
|
### 3rd party plugins
|
||
|
|
- [Project Calico - a layer 3 virtual network](https://github.com/projectcalico/calico-cni)
|
||
|
|
- [Weave - a multi-host Docker network](https://github.com/weaveworks/weave)
|
||
|
|
- [Contiv Networking - policy networking for various use cases](https://github.com/contiv/netplugin)
|
||
|
|
- [SR-IOV](https://github.com/hustcat/sriov-cni)
|
||
|
|
- [Cilium - BPF & XDP for containers](https://github.com/cilium/cilium)
|
||
|
|
- [Infoblox - enterprise IP address management for containers](https://github.com/infobloxopen/cni-infoblox)
|
||
|
|
|
||
|
|
The CNI team also maintains some [core plugins](plugins).
|
||
|
|
|
||
|
|
|
||
|
|
## Contributing to CNI
|
||
|
|
|
||
|
|
We welcome contributions, including [bug reports](https://github.com/containernetworking/cni/issues), and code and documentation improvements.
|
||
|
|
If you intend to contribute to code or documentation, please read [CONTRIBUTING.md](CONTRIBUTING.md). Also see the [contact section](#contact) in this README.
|
||
|
|
|
||
|
|
## How do I use CNI?
|
||
|
|
|
||
|
|
### Requirements
|
||
|
|
|
||
|
|
CNI requires Go 1.5+ to build.
|
||
|
|
|
||
|
|
Go 1.5 users will need to set GO15VENDOREXPERIMENT=1 to get vendored
|
||
|
|
dependencies. This flag is set by default in 1.6.
|
||
|
|
|
||
|
|
### Included Plugins
|
||
|
|
|
||
|
|
This repository includes a number of common plugins in the `plugins/` directory.
|
||
|
|
Please see the [Documentation/](Documentation/) directory for documentation about particular plugins.
|
||
|
|
|
||
|
|
### Running the plugins
|
||
|
|
|
||
|
|
The scripts/ directory contains two scripts, `priv-net-run.sh` and `docker-run.sh`, that can be used to exercise the plugins.
|
||
|
|
|
||
|
|
**note - priv-net-run.sh depends on `jq`**
|
||
|
|
|
||
|
|
Start out by creating a netconf file to describe a network:
|
||
|
|
|
||
|
|
```bash
|
||
|
|
$ mkdir -p /etc/cni/net.d
|
||
|
|
$ cat >/etc/cni/net.d/10-mynet.conf <<EOF
|
||
|
|
{
|
||
|
|
"cniVersion": "0.2.0",
|
||
|
|
"name": "mynet",
|
||
|
|
"type": "bridge",
|
||
|
|
"bridge": "cni0",
|
||
|
|
"isGateway": true,
|
||
|
|
"ipMasq": true,
|
||
|
|
"ipam": {
|
||
|
|
"type": "host-local",
|
||
|
|
"subnet": "10.22.0.0/16",
|
||
|
|
"routes": [
|
||
|
|
{ "dst": "0.0.0.0/0" }
|
||
|
|
]
|
||
|
|
}
|
||
|
|
}
|
||
|
|
EOF
|
||
|
|
$ cat >/etc/cni/net.d/99-loopback.conf <<EOF
|
||
|
|
{
|
||
|
|
"cniVersion": "0.2.0",
|
||
|
|
"type": "loopback"
|
||
|
|
}
|
||
|
|
EOF
|
||
|
|
```
|
||
|
|
|
||
|
|
The directory `/etc/cni/net.d` is the default location in which the scripts will look for net configurations.
|
||
|
|
|
||
|
|
Next, build the plugins:
|
||
|
|
|
||
|
|
```bash
|
||
|
|
$ ./build
|
||
|
|
```
|
||
|
|
|
||
|
|
Finally, execute a command (`ifconfig` in this example) in a private network namespace that has joined the `mynet` network:
|
||
|
|
|
||
|
|
```bash
|
||
|
|
$ CNI_PATH=`pwd`/bin
|
||
|
|
$ cd scripts
|
||
|
|
$ sudo CNI_PATH=$CNI_PATH ./priv-net-run.sh ifconfig
|
||
|
|
eth0 Link encap:Ethernet HWaddr f2:c2:6f:54:b8:2b
|
||
|
|
inet addr:10.22.0.2 Bcast:0.0.0.0 Mask:255.255.0.0
|
||
|
|
inet6 addr: fe80::f0c2:6fff:fe54:b82b/64 Scope:Link
|
||
|
|
UP BROADCAST MULTICAST MTU:1500 Metric:1
|
||
|
|
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
|
||
|
|
TX packets:0 errors:0 dropped:1 overruns:0 carrier:0
|
||
|
|
collisions:0 txqueuelen:0
|
||
|
|
RX bytes:90 (90.0 B) TX bytes:0 (0.0 B)
|
||
|
|
|
||
|
|
lo Link encap:Local Loopback
|
||
|
|
inet addr:127.0.0.1 Mask:255.0.0.0
|
||
|
|
inet6 addr: ::1/128 Scope:Host
|
||
|
|
UP LOOPBACK RUNNING MTU:65536 Metric:1
|
||
|
|
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
|
||
|
|
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
|
||
|
|
collisions:0 txqueuelen:0
|
||
|
|
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
|
||
|
|
```
|
||
|
|
|
||
|
|
The environment variable `CNI_PATH` tells the scripts and library where to look for plugin executables.
|
||
|
|
|
||
|
|
## Running a Docker container with network namespace set up by CNI plugins
|
||
|
|
|
||
|
|
Use the instructions in the previous section to define a netconf and build the plugins.
|
||
|
|
Next, docker-run.sh script wraps `docker run`, to execute the plugins prior to entering the container:
|
||
|
|
|
||
|
|
```bash
|
||
|
|
$ CNI_PATH=`pwd`/bin
|
||
|
|
$ cd scripts
|
||
|
|
$ sudo CNI_PATH=$CNI_PATH ./docker-run.sh --rm busybox:latest ifconfig
|
||
|
|
eth0 Link encap:Ethernet HWaddr fa:60:70:aa:07:d1
|
||
|
|
inet addr:10.22.0.2 Bcast:0.0.0.0 Mask:255.255.0.0
|
||
|
|
inet6 addr: fe80::f860:70ff:feaa:7d1/64 Scope:Link
|
||
|
|
UP BROADCAST MULTICAST MTU:1500 Metric:1
|
||
|
|
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
|
||
|
|
TX packets:0 errors:0 dropped:1 overruns:0 carrier:0
|
||
|
|
collisions:0 txqueuelen:0
|
||
|
|
RX bytes:90 (90.0 B) TX bytes:0 (0.0 B)
|
||
|
|
|
||
|
|
lo Link encap:Local Loopback
|
||
|
|
inet addr:127.0.0.1 Mask:255.0.0.0
|
||
|
|
inet6 addr: ::1/128 Scope:Host
|
||
|
|
UP LOOPBACK RUNNING MTU:65536 Metric:1
|
||
|
|
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
|
||
|
|
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
|
||
|
|
collisions:0 txqueuelen:0
|
||
|
|
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
|
||
|
|
```
|
||
|
|
|
||
|
|
## What might CNI do in the future?
|
||
|
|
|
||
|
|
CNI currently covers a wide range of needs for network configuration due to it simple model and API.
|
||
|
|
However, in the future CNI might want to branch out into other directions:
|
||
|
|
|
||
|
|
- Dynamic updates to existing network configuration
|
||
|
|
- Dynamic policies for network bandwidth and firewall rules
|
||
|
|
|
||
|
|
If these topics of are interest, please contact the team via the mailing list or IRC and find some like-minded people in the community to put a proposal together.
|
||
|
|
|
||
|
|
## Contact
|
||
|
|
|
||
|
|
For any questions about CNI, please reach out on the mailing list:
|
||
|
|
- Email: [cni-dev](https://groups.google.com/forum/#!forum/cni-dev)
|
||
|
|
- IRC: #[containernetworking](irc://irc.freenode.org:6667/#containernetworking) channel on freenode.org
|
||
|
|
- Slack: [containernetworking.slack.com](https://cryptic-tundra-43194.herokuapp.com)
|