https://github.com/cybozu-go/coil
CNI plugin for Kubernetes designed for scalability and extensibility
https://github.com/cybozu-go/coil
cni kubernetes nat
Last synced: 4 months ago
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CNI plugin for Kubernetes designed for scalability and extensibility
- Host: GitHub
- URL: https://github.com/cybozu-go/coil
- Owner: cybozu-go
- License: apache-2.0
- Created: 2018-10-04T05:12:32.000Z (over 6 years ago)
- Default Branch: main
- Last Pushed: 2024-08-09T09:49:31.000Z (7 months ago)
- Last Synced: 2024-08-10T10:19:26.342Z (7 months ago)
- Topics: cni, kubernetes, nat
- Language: Go
- Homepage:
- Size: 9.76 MB
- Stars: 160
- Watchers: 14
- Forks: 19
- Open Issues: 8
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
[][releases]
[](https://pkg.go.dev/github.com/cybozu-go/coil/v2?tab=subdirectories)
[](https://goreportcard.com/report/github.com/cybozu-go/coil)
Coil
====
**Coil** is a [CNI][]-based network plugin for Kubernetes.
Coil is designed with respect to the UNIX philosophy. You can combine
Coil with any routing software and/or any network policy implementation.
Coil allows to define multiple IP address pools. You can define a pool of
global IPv4 addresses for a small number of pods and another pool of
private IPv4 addresses for the remaining pods.
There are blog articles about Coil: https://blog.kintone.io/archive/category/Coil
## Status
Version 2 is generally available (GA). It conforms to [CNI spec 1.1.0](https://github.com/containernetworking/cni/blob/spec-v1.1.0/SPEC.md).
## Dependencies
- Kubernetes Version: 1.25, 1.26, 1.27
- Other versions are likely to work, but not tested.
- (Optional) Routing software
- Coil has a simple routing software for flat L2 networks.
- If your network is not flat, use BIRD or similar software to advertise the routes.
## Features
- Address pools
Coil can have multiple pools of IP addresses for different purposes.
By setting a special annotation to a namespace, you can specify a pool
for the pods in that namespace.
- IPv4/IPv6 dual stack
In addition to IPv4-only and IPv6-only stacks, Coil can define dual stack
address pools.
- Running with any routing software
Coil provides a simple router for clusters where all the nodes are in
a flat L2 network. This router, called `coil-router`, is optional.
For more complex networks, Coil exports routing information to an
unused kernel routing table. By importing the routes from the table,
any routing software can advertise them.
- On-demand NAT for egress traffics
Coil can implement SNAT _on_ Kubernetes. You can define SNAT routers
for external networks as many as you want.
Only selected pods can communicate with external networks via SNAT
routers.
- Auto MTU configuration
Coil detects the optimal MTU and configures MTU for container networks.
Refer to [the design document](./docs/design.md) for more information on these features.
## Quick start
Coil can run on [kind][] clusters using Docker.
Prepare a recent Ubuntu and install Docker and Go, then run:
```console
$ cd v2
$ make certs
$ make image
$ cd e2e
$ make start
$ make install-coil
$ ../bin/kubectl apply -f manifests/default_pool.yaml
```
Now you can play with Coil.
## Usage examples
[Project Neco](https://blog.kintone.io/entry/neco) uses Coil with these software:
- [BIRD][] to advertise routes over BGP,
- [MetalLB][] to implement [LoadBalancer] Service, and
- [Calico][] to implement [NetworkPolicy][].
Coil can work with [Cilium][] through its [generic veth chaining](https://docs.cilium.io/en/v1.8/gettingstarted/cni-chaining-generic-veth/) feature.
## Documentation
Installation procedures are described in [docs/setup.md](./docs/setup.md).
The user manual is [docs/usage.md](./docs/usage.md).
[docs](docs/) directory contains other documents about designs and specifications.
### Upgrade from v1
See [coil-migrator.md](https://github.com/cybozu-go/coil/blob/v2.0.11/docs/coil-migrator.md)
## License
Coil is licensed under the Apache License, Version 2.0.
[releases]: https://github.com/cybozu-go/coil/releases
[CNI]: https://kubernetes.io/docs/concepts/extend-kubernetes/compute-storage-net/network-plugins/
[BIRD]: https://bird.network.cz/
[LoadBalancer]: https://kubernetes.io/docs/concepts/services-networking/service/#loadbalancer
[NetworkPolicy]: https://kubernetes.io/docs/concepts/services-networking/network-policies/
[MetalLB]: https://metallb.universe.tf
[Calico]: https://www.projectcalico.org
[Cilium]: https://cilium.io/
[kind]: https://kind.sigs.k8s.io/