Terway CNI Network Plugin

CNI plugin for Alibaba Cloud VPC/ENI

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Try It

Install Kubernetes

• Prepare Aliyun ECS instance. The ECS OS we tested is Centos 7.4/7.6.
• Install Kubernetes via kubeadm: create-cluster-kubeadm

After setup kubernetes cluster.

• Change iptables Forward default policy to ACCEPT on every node of cluster: iptables -P FORWARD ACCEPT.
• Check the rp_filter in sysctl parameters, set them to "0" on every node of cluster.

Make sure cluster up and healthy by kubectl get cs.

Install Terway network plugin

Terway plugin have two installation modes

• VPC Mode

  VPC Mode, Using Aliyun VPC route table to connect the pods. Can assign dedicated ENI to Pod. Install method:
  Replace Network and access_key/access_secret in terway.yml with your cluster pod subnet and aliyun openapi credentials. Then use kubectl apply -f terway.yml to install Terway into kubernetes cluster.

• ENI Secondary IP Mode

  ENI Secondary IP Mode, Using Aliyun ENI's secondary ip to connect the pods. This mode not limited by VPC route tables quotation. Install method:
  Replace access_key/access_secret and security_group/vswitches in terway-multiip.yml with your aliyun openapi credentials and resources id. Then use kubectl apply -f terway-multiip.yml to install Terway into kubernetes cluster.

Terway requires the access_key have following RAM Permissions

{
  "Version": "1",
  "Statement": [{
      "Action": [
        "ecs:CreateNetworkInterface",
        "ecs:DescribeNetworkInterfaces",
        "ecs:AttachNetworkInterface",
        "ecs:DetachNetworkInterface",
        "ecs:DeleteNetworkInterface",
        "ecs:DescribeInstanceAttribute",
        "ecs:DescribeInstanceTypesNew",
        "ecs:AssignPrivateIpAddresses",
        "ecs:UnassignPrivateIpAddresses",
        "ecs:DescribeInstances"
      ],
      "Resource": [
        "*"
      ],
      "Effect": "Allow"
    },
    {
      "Action": [
        "vpc:DescribeVSwitches"
      ],
      "Resource": [
        "*"
      ],
      "Effect": "Allow"
    }
  ]
}

Using kubectl get ds terway -n kube-system to watch plugin launching. Plugin install completed while terway daemonset available pods equal to nodes.

Terway network plugin usage

Vpc network container

On VPC installation mode, Terway will config pod's address using node's podCidr when pod not have any special config. eg:

[root@iZj6c86lmr8k9rk78ju0ncZ ~]# kubectl run -it --rm --image busybox busybox
If you don't see a command prompt, try pressing enter.
/ # ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
3: eth0@if7: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue
    link/ether 46:02:02:6b:65:1e brd ff:ff:ff:ff:ff:ff
/ # ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
3: eth0@if7: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue
    link/ether 46:02:02:6b:65:1e brd ff:ff:ff:ff:ff:ff
    inet 172.30.0.4/24 brd 172.30.0.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::4402:2ff:fe6b:651e/64 scope link
       valid_lft forever preferred_lft forever

Using ENI network interface to get the performance equivalent to the underlying network

On VPC installation mode, Config eni request aliyun/eni: 1 in one container of pod. The following example will create an Nginx Pod and assign an ENI:

apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
    resources:
      limits:
        aliyun/eni: 1

[root@iZj6c86lmr8k9rk78ju0ncZ ~]# kubectl exec -it nginx sh
# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
3: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UNKNOWN qlen 1000
    link/ether 00:16:3e:02:38:05 brd ff:ff:ff:ff:ff:ff
    inet 172.31.80.193/20 brd 172.31.95.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::216:3eff:fe02:3805/64 scope link
       valid_lft forever preferred_lft forever
4: veth1@if8: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue state UP
    link/ether 1e:60:c7:cb:1e:0e brd ff:ff:ff:ff:ff:ff
    inet6 fe80::1c60:c7ff:fecb:1e0e/64 scope link
       valid_lft forever preferred_lft forever

ENI Secondary IP Pod：

On ENI secondary IP installation mode, Terway will create & allocate ENI secondary IP for pod. The IP of pod will in same IP Range:

[root@iZj6c86lmr8k9rk78ju0ncZ ~]# kubectl get pod -o wide
NAME                     READY   STATUS    RESTARTS   AGE   IP              NODE                                 NOMINATED NODE
nginx-64f497f8fd-ckpdm   1/1     Running   0          4d    192.168.0.191   cn-hangzhou.i-j6c86lmr8k9rk78ju0nc   <none>
[root@iZj6c86lmr8k9rk78ju0ncZ ~]# kubectl get node -o wide cn-hangzhou.i-j6c86lmr8k9rk78ju0nc
NAME                                 STATUS   ROLES    AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION              CONTAINER-RUNTIME
cn-hangzhou.i-j6c86lmr8k9rk78ju0nc   Ready    <none>   12d   v1.11.5   192.168.0.154   <none>        CentOS Linux 7 (Core)   3.10.0-693.2.2.el7.x86_64   docker://17.6.2
[root@iZj6c86lmr8k9rk78ju0ncZ ~]# kubectl exec -it nginx-64f497f8fd-ckpdm bash
root@nginx-64f497f8fd-ckpdm:/# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
3: eth0@if106: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
    link/ether 4a:60:eb:97:f4:07 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.0.191/32 brd 192.168.0.191 scope global eth0
       valid_lft forever preferred_lft forever

Using network policy to limit accessible between containers

The Terway plugin is compatible with NetworkPolicy in the standard K8S to control access between containers, for example:

1. Create and expose an deployment for test

   [root@iZbp126bomo449eksjknkeZ ~]# kubectl run nginx --image=nginx --replicas=2
   deployment "nginx" created
   [root@iZbp126bomo449eksjknkeZ ~]# kubectl expose deployment nginx --port=80
   service "nginx" exposed
   

2. Run busybox to test connection to deployment:

   [root@iZbp126bomo449eksjknkeZ ~]# kubectl run busybox --rm -ti --image=busybox /bin/sh
   If you don't see a command prompt, try pressing enter.
   / # wget --spider --timeout=1 nginx
   Connecting to nginx (172.21.0.225:80)
   / #
   

3. Config network policy，only allow pod access which have run: nginx label:

   kind: NetworkPolicy
   apiVersion: networking.k8s.io/v1
   metadata:
     name: access-nginx
   spec:
     podSelector:
       matchLabels:
         run: nginx
     ingress:
     - from:
       - podSelector:
           matchLabels:
             access: "true"
   

4. The Pod access service without the specified label is rejected, and the container of the specified label can be accessed normally.

   [root@iZbp126bomo449eksjknkeZ ~]# kubectl run busybox --rm -ti --image=busybox /bin/sh
   If you don't see a command prompt, try pressing enter.
   / # wget --spider --timeout=1 nginx
   Connecting to nginx (172.21.0.225:80)
   wget: download timed out
   / #
   
   [root@iZbp126bomo449eksjknkeZ ~]# kubectl run busybox --rm -ti --labels="access=true" --image=busybox /bin/sh
   If you don't see a command prompt, try pressing enter.
   / # wget --spider --timeout=1 nginx
   Connecting to nginx (172.21.0.225:80)
   / #
   

Limit container in/out bandwidth

The Terway network plugin can limit the container's traffic via limit policy in pod's annotations. For example:

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  annotations:
    k8s.aliyun.com/ingress-bandwidth: 1m
    k8s.aliyun.com/egress-bandwidth: 1m
spec:
  nodeSelector:
    kubernetes.io/hostname: cn-shanghai.i-uf63p6s96kf4jfh8wpwn
  containers:
  - name: nginx
    image: nginx:1.7.9
    ports:
    - containerPort: 80

Build Terway

Prerequisites:

• Docker >= 17.05 with multi-stage build

docker build -t acs/terway:latest .

Test

unit test:

git clone https://github.com/AliyunContainerService/terway.git
docker run -i --rm \
  -v $(pwd)/terway:/go/src/github.com/AliyunContainerService/terway \
  -w /go/src/github.com/AliyunContainerService/terway \
  sunyuan3/gometalinter:v1 bash -c "go test -race ./..."

function test:

cd terway/tests
./test.sh --cluster-id ${clusterid} \
    --access-key ${ACCESS_KEY_ID} --access-secret ${ACCESS_KEY_SECRET} \
    --region ${region} --category vpc \
    --image ${terwayimage}

example:

./test.sh --cluster-id c05ef31ec40754f6c99c995963e2e01ed \
    --access-key ******** --access-secret ******** \
    --region cn-huhehaote --category vpc \
    --image registry.cn-hongkong.aliyuncs.com/sunyuan/terway:45

Contribute

You are welcome to make new issues and pull requests.

Built With

Felix: Terway's NetworkPolicy is implemented by integrating ProjectCalico's Felix components. Felix watch NetworkPolicy configuration and config ACL rules on container veth.

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