ipam

ECS IPAM plugin

Overview

The ECS IPAM plugin constructs the IP, Gateway and Routes, which are used by the ECS Bridge plugin to configure the bridge and veth pair in the container network namespace. An example of this configuration looks like:

{
    "ipam": {
        "type": "ecs-ipam",
        "id": "12345",
        "ipv4-address": "10.0.0.2/24",
        "ipv4-gateway": "10.0.0.1",
        "ipv4-subnet": "10.0.0.0/24",
        "ipv4-routes": [
            {"dst": "169.254.170.2/32"},
            {"dst": "169.254.170.0/20", "gw": "10.0.0.1"}
        ]
    }
}

Parameters

• id (string, optional): information about this ip, can be any information related to this ip.
• ipv4-address (string, optional): ipv4 address of the veth inside the container network namespace.
• ipv4-routes (string, optional): list of routes to add to the container network namespace. Each route is a dictionary with "dst" and optional "gw" fields. If "gw" is omitted, value of "gateway" will be used.
• ipv4-gateway (string, optional): IP inside of "subnet" to designate as the gateway. Defaults to ".1" IP inside of the "subnet" block.
• ipv4-subnet (string, required): CIDR block for allocations. Note: either id or ipv4-address must be specified in delete operation.

Environment Variables

• IPAM_DB_PATH (string, optional): path of the boltdb file.
• IPAM_DB_CONNECTION_TIMEOUT (string, optional): timeout for the connection to the boltdb.

Example

Before running the command you should set up these environment variable:

• CNI_COMMAND: Command to execute eg: ADD.
• CNI_PATH: Plugin binary path eg: pwd/bin.
• CNI_IFNAME: Interface name inside the container, this is only required for bridge plugin, but is hard coded in skel package which we consume. So for using the ipam plugin separately, it should be set but won't be used. Ref: https://github.com/containernetworking/cni/blob/v0.5.1/pkg/skel/skel.go#L53

Add:

export CNI_COMMAND=ADD && cat mynet.conf | ../bin/ecs-ipam

Del:

export CNI_COMMAND=DEL && cat mynet.conf | ../bin/ecs-ipam

mynet.conf is the configuration file for the plugin, it's the same as described in the overview above.

Then you can use the following program to check the content of the db, be sure to change the boltdb path and bucket name:

package main

import (
    "fmt"
    "github.com/docker/libkv"
    "github.com/docker/libkv/store"
    "github.com/libkv/store/boltdb"
    "time"
)

func init() {
    boltdb.Register()
}

func main() {
    db := "${BOLTDB_PATH}"
    bucket := "${BUCKET_NAME}"

    kv, err := libkv.NewStore(
        store.BOLTDB,
        []string{db},
        &store.Config{
            Bucket:            bucket,
            ConnectionTimeout: 10 * time.Second,
        },
    )
    if err != nil {
        fmt.Printf("Creating db failed: %v\n", err)
    }

    entries, err := kv.List("1")
    for _, pair := range entries {
        fmt.Printf("key=%v - value=%v\n", pair.Key, string(pair.Value))
    }
}