78daffc479
This introduces a notion of a "meta" plugin. A meta plugin
is one that delegates the actual work of setting up the interface
to the main plugin. The meta plugin is used to select and dynamically
configure the main plugin. The sequence of events, is as follows:
Given netconf like:
{
"name": "mynet",
"type": "flannel",
"delegate": {
"type": "bridge"
}
}
flannel fills in values like "mtu", "ipam.subnet" and delegates to
"bridge" main plugin. "bridge" plugin will operate as usual, calling
into ipam module for IP assignment.
Delegate dictionary should not contain "name" field as it will be
filled in by the flannel plugin.
105 lines
3.9 KiB
Markdown
105 lines
3.9 KiB
Markdown
# cni - the Container Network Interface
|
|
|
|
## What is CNI?
|
|
|
|
CNI, the _Container Network Interface_, is a proposed standard for configuring network interfaces for Linux application containers.
|
|
The standard consists of a simple specification for how executable plugins can be used to configure network namespaces.
|
|
The specification itself is contained in [SPEC.md](SPEC.md)
|
|
|
|
## Why develop CNI?
|
|
|
|
Application containers on Linux are a rapidly evolving area, and within this space networking is a particularly unsolved problem, as it is highly environment-specific.
|
|
We believe that every container runtime will seek to solve the same problem of making the network layer pluggable.
|
|
In order to avoid duplication, we think it is prudent to define a common interface between the network plugins and container execution.
|
|
Hence we are proposing this specification, along with an initial set of plugins that can be used by different container runtime systems.
|
|
|
|
## How do I use CNI?
|
|
|
|
## Included Plugins
|
|
This repository includes a number of common plugins that can be found in plugins/ directory.
|
|
Please see Documentation/ folder 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 excercise the plugins.
|
|
|
|
Start out by creating a netconf file to describe a network:
|
|
|
|
```
|
|
$ mkdir -p /etc/cni/net.d
|
|
$ cat >/etc/cni/net.d/10-mynet.conf <<EOF
|
|
{
|
|
"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
|
|
```
|
|
|
|
Next, build the plugins:
|
|
|
|
```
|
|
$ ./build
|
|
```
|
|
|
|
Finally, execute a command (`ifconfig` in this example) in a private network namespace that has joined `mynet` network:
|
|
|
|
```
|
|
$ 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)
|
|
```
|
|
|
|
## Running a Docker container with network namespace set up by CNI plugins
|
|
|
|
Use instructions in the previous section to define a netconf and build the plugins.
|
|
Next, docker-run.sh script wraps `docker run` command to execute the plugins prior to entering the container:
|
|
|
|
```
|
|
$ CNI_PATH=`pwd`/bin
|
|
$ cd scripts
|
|
$ sudo CNI_PATH=$CNI_PATH ./docker-run.sh --rm busybox:latest /sbin/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)
|
|
```
|