A generic CNI library to provide APIs for CNI plugin interactions. The library provides APIs to:
- Load CNI network config from different sources
- Setup networks for container namespace
- Remove networks from container namespace
- Query status of CNI network plugin initialization
- Check verifies the network is still in desired state
go-cni aims to support plugins that implement Container Network Interface
package main
import (
"context"
"fmt"
"log"
gocni "github.com/containerd/go-cni"
)
func main() {
id := "example"
netns := "/var/run/netns/example-ns-1"
// CNI allows multiple CNI configurations and the network interface
// will be named by eth0, eth1, ..., ethN.
ifPrefixName := "eth"
defaultIfName := "eth0"
// Initializes library
l, err := gocni.New(
// one for loopback network interface
gocni.WithMinNetworkCount(2),
gocni.WithPluginConfDir("/etc/cni/net.d"),
gocni.WithPluginDir([]string{"/opt/cni/bin"}),
// Sets the prefix for network interfaces, eth by default
gocni.WithInterfacePrefix(ifPrefixName))
if err != nil {
log.Fatalf("failed to initialize cni library: %v", err)
}
// Load the cni configuration
if err := l.Load(gocni.WithLoNetwork, gocni.WithDefaultConf); err != nil {
log.Fatalf("failed to load cni configuration: %v", err)
}
// Setup network for namespace.
labels := map[string]string{
"K8S_POD_NAMESPACE": "namespace1",
"K8S_POD_NAME": "pod1",
"K8S_POD_INFRA_CONTAINER_ID": id,
// Plugin tolerates all Args embedded by unknown labels, like
// K8S_POD_NAMESPACE/NAME/INFRA_CONTAINER_ID...
"IgnoreUnknown": "1",
}
ctx := context.Background()
// Teardown network
defer func() {
if err := l.Remove(ctx, id, netns, gocni.WithLabels(labels)); err != nil {
log.Fatalf("failed to teardown network: %v", err)
}
}()
// Setup network
result, err := l.Setup(ctx, id, netns, gocni.WithLabels(labels))
if err != nil {
log.Fatalf("failed to setup network for namespace: %v", err)
}
// Get IP of the default interface
IP := result.Interfaces[defaultIfName].IPConfigs[0].IP.String()
fmt.Printf("IP of the default interface %s:%s", defaultIfName, IP)
}The go-cni is a containerd sub-project, licensed under the Apache 2.0 license. As a containerd sub-project, you will find the:
information in our containerd/project repository.