Cello CNI Network Plugin

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Overview

Cello is a kubernetes CNI plugin based on the Volcengine VPC network. By using the Cello plugin, the intercommunication of the internal network of the kubernetes cluster can be realized in the VPC network environment on the cloud. The kubernetes cluster can natively access to other resources under the same VPC when the access is allowed by security group. Cello uses secondary ENI to build the Pod network, and supports shared ENI mode and ENI multi-IP mode. In both modes, the following basic communication scenarios are supported:

• Pod to Pod communication
• Pod to Node communication

Cello replaces kube-proxy with Cilium to implement kubernetes services to achieve better performance and richer features. It supports the following types of services:

• ClusterIP
• NodePort
• LoadBalancer

Cello mode

ENI-Multi-IP

In the ENI-Multi-IP mode, Cello assigns multiple secondary private IPs under the secondary ENI to multiple Pods to achieve higher deployment density. The number of Pods on ECS depends on instance type (limit). Since each Pod is assigned an address within the VPC, all Pods and Nodes are almost the same in the VPC perspective. In addition to communicating through VPC, Pod can communicate with its Node through local fast path.

Exclusive-ENI

In exclusive mode, Cello assigns the secondary ENI directly to the Pod, pulls the secondary ENI into the Pod's NetNs and uses the primary IP of the secondary ENI for communication. From the perspective of VPC, all Pods and Nodes are the same. Limited by the number of secondary ENIs that can be attached on the ECS, the Pod deployment density in this mode is much lower. In addition to communicating through VPC, Pod also can communicate with its Node through the local veth-pair.

ENI Allocation

Cello is deployed on each node in the form of daemonset, and each Cello instance will independently apply for secondary ENIs and use them to configure pod network. Each ENI will select one of the subnets configured by the user and all security groups configured by the user.

• In eni_exclusive mode, eni is used directly, the number of pods that can be scheduled on the node is equal to eni_quota-1.
• In eni_shared mode, the number of pods that can be scheduled on the node is equal to (eni_quota-1)*ip_quota_per_eni.

ENI created by Cello will carry some tags to indicate the creator, and Cello will periodically check and recycle its own leaked ENI according to the tags if it is alive. Deploying an operator in the cluster to reclaim the detached ENI when deleting nodes can further avoid ENI leaks, and user intervention is required while cluster is deleted.

Scheduling Perception

Regardless of the mode, Cello will report the number of available network resources by device plugin so that the scheduler can schedule pods to nodes with resources. Users can use this mechanism by adding following requests and limits fields to the first container of pod.

# eni_shared mode:
resources:
  limits:
    vke.volcengine.com/eni-ip: "1"
  requests:
    vke.volcengine.com/eni-ip: "1"
# eni_exclusive mode:
resources:
  limits:
    vke.volcengine.com/eni: "1"
  requests:
    vke.volcengine.com/eni: "1"

Build

Required

• protobuf
• go 1.20+
• docker [option]

Bin

git clone [todo]
cd cello
go mod download
make bin

After make, all the programs and configuration files required for deployment are located in the output directory.

Image

git clone [todo]
cd cello
go mod download
make image 

Docker is used by default, and can be compiled with podman through ARG ENGINE.

You also can specify image name by ARG IMAGE_NAME and specify image tag by ARG IMAGE_TAG.

IMAGE_NAME=k8s.com/cello IMAGE_TAG=v1.0.0 make image

Installation

Install Kubernetes

• Prepare the Volcengine ECS instance (ECS instance kernel version 4.19+ is required, and the tested OS is veLinux 1.0 with 5.10 kernel).
• Install Kubernetes, kubeadm is recommended.

Install Cello

• Make sure the credentialAccessKeyId or ramRole passed to Cello has associated the required IAM policy.
• Refer to config.md to prepare the configuration.
• Install using helm (helm 3.0 is required).

  helm install cello chart

Test

Unit Test

git clone [todo]
cd cello
go mod download
make test

Function Test

Make sure the cluster has installed Cello correctly and kubectl can connect to the cluster.

git clone [todo]
cd cello
./tests/test.sh

Built With

Cilium: Cello integrate Cilium components to support NetworkPolicy and optimize the Service performance. Cilium watch NetworkPolicy and Service configuration and inject ebpf program into pod's primary device.

Community

Contributing

See the CONTRIBUTING.md file for details.

Contact

If you have any questions or want to contribute, you are welcome to communicate most things via GitHub issues or pull requests. Or Contact to Maintainers via email or Feishu group below.

License

Cello is under the Apache 2.0 license. See the LICENSE file for details.