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https://github.com/munnerz/keepalived-cloud-provider

kube-keepalived-vip cloud provider for Kubernetes 1.6+
https://github.com/munnerz/keepalived-cloud-provider

Last synced: 3 months ago
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kube-keepalived-vip cloud provider for Kubernetes 1.6+

Host: GitHub
URL: https://github.com/munnerz/keepalived-cloud-provider
Owner: munnerz
License: mit
Created: 2017-03-23T03:17:51.000Z (almost 8 years ago)
Default Branch: master
Last Pushed: 2017-11-02T17:31:09.000Z (about 7 years ago)
Last Synced: 2024-10-14T14:32:49.934Z (4 months ago)
Language: Go
Size: 5.02 MB
Stars: 153
Watchers: 15
Forks: 22
Open Issues: 4
Metadata Files:
- Readme: README.md
- License: LICENSE

Awesome Lists containing this project

awesome-repositories - munnerz/keepalived-cloud-provider - kube-keepalived-vip cloud provider for Kubernetes 1.6+ (Go)

README

# keepalived-cloud-provider [![Build Status](https://travis-ci.org/munnerz/keepalived-cloud-provider.svg?branch=master)](https://travis-ci.org/munnerz/keepalived-cloud-provider)

> This project is in alpha state, and should be used with caution. Whilst it is quite simple, there
> are currently minimal unit tests and no integration tests. Contributions are very welcome.

keepalived-cloud-provider is an out-of-tree Kubernetes cloud provider implementation ([more info](https://github.com/wlan0/kubernetes.github.io/blob/c0f3aa4abe99ad0528c6ec168e8fbf14fdaf49ac/docs/getting-started-guides/running-cloud-controller.md)).
It will manage and automatically update a ConfigMap for [kube-keepalived-vip](https://github.com/kubernetes/contrib/tree/master/keepalived-vip), which will then
automatically create load balanced IP addresses in the specified CIDR.
This allows users in bare-metal environments to use services with `type: LoadBalancer` set.

This is perfect if you want to run Kubernetes in network in which you have a routable CIDR
that you want to expose your services in.

## Getting started

To use the cloud provider, we'll need to do a few things:

- Install `kube-keepalived-vip`
- Set `--cloud-provider=external` on our kube-controller-manager master component
- Deploy `keepalived-cloud-provider`
- Create a service with `type: LoadBalancer`!

### Install kube-keepalived-vip

Full instructions are available in the `kube-keepalived-vip` [repository](https://github.com/kubernetes/contrib/tree/master/keepalived-vip).

Briefly, we simply need to create a DaemonSet:

```bash
$ kubectl create -f vip-daemonset.yaml
```

```yaml
apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
name: kube-keepalived-vip
namespace: kube-system
spec:
template:
metadata:
labels:
name: kube-keepalived-vip
spec:
hostNetwork: true
containers:
- image: gcr.io/google_containers/kube-keepalived-vip:0.9
name: kube-keepalived-vip
imagePullPolicy: Always
securityContext:
privileged: true
volumeMounts:
- mountPath: /lib/modules
name: modules
readOnly: true
- mountPath: /dev
name: dev
# use downward API
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
# to use unicast
args:
- --services-configmap=kube-system/vip-configmap
# unicast uses the ip of the nodes instead of multicast
# this is useful if running in cloud providers (like AWS)
#- --use-unicast=true
volumes:
- name: modules
hostPath:
path: /lib/modules
- name: dev
hostPath:
path: /dev
nodeSelector:
# type: worker # adjust this to match your worker nodes
---
## We also create an empty ConfigMap to hold our config
apiVersion: v1
kind: ConfigMap
metadata:
name: vip-configmap
namespace: kube-system
data:
```

### Configure kube-controller-manager

In order to use the currently alpha external cloud provider functionality, we need to set a
flag on the `kube-controller-manager` component. How to do this depends on how
you deployed your cluster, but if deployed with `kubeadm` you should edit
`/etc/kubernetes/manifests/kube-controller-manager.yaml`. and add
`--cloud-provider external` to the command section.

If you are using the `kubeadm` config file, then the following fragment will
enable the external cloud provider.

```yaml
controllerManagerExtraArgs:
cloud-provider: external
```

### Deploy keepalived-cloud-provider

`keepalived-cloud-provider` can be deployed with a simple Kubernetes Deployment, and performs
leader election like other kubernetes master components. It is therefore safe to run multiple
replicas of the `keepalived-cloud-provider` pod.

```yaml
apiVersion: apps/v1beta1
kind: Deployment
metadata:
labels:
app: keepalived-cloud-provider
name: keepalived-cloud-provider
namespace: kube-system
spec:
replicas: 1
revisionHistoryLimit: 2
selector:
matchLabels:
app: keepalived-cloud-provider
strategy:
type: RollingUpdate
template:
metadata:
annotations:
scheduler.alpha.kubernetes.io/critical-pod: ""
scheduler.alpha.kubernetes.io/tolerations: '[{"key":"CriticalAddonsOnly", "operator":"Exists"}]'
labels:
app: keepalived-cloud-provider
spec:
containers:
- name: keepalived-cloud-provider
image: quay.io/munnerz/keepalived-cloud-provider:0.0.1
imagePullPolicy: IfNotPresent
env:
- name: KEEPALIVED_NAMESPACE
value: kube-system
- name: KEEPALIVED_CONFIG_MAP
value: vip-configmap
- name: KEEPALIVED_SERVICE_CIDR
value: 10.210.38.100/26 # pick a CIDR that is explicitly reserved for keepalived
volumeMounts:
- name: certs
mountPath: /etc/ssl/certs
resources:
requests:
cpu: 200m
livenessProbe:
httpGet:
path: /healthz
port: 10252
host: 127.0.0.1
initialDelaySeconds: 15
timeoutSeconds: 15
failureThreshold: 8
volumes:
- name: certs
hostPath:
path: /etc/ssl/certs
```

### Create a service

Once `keepalived-cloud-provider` is up and running, you should be able to create service with `type: LoadBalancer`:

```bash
$ kubectl expose deployment example-com --name=example-com --type=LoadBalancer
```

`keepalived-cloud-provider` will also honour the `loadBalancerIp` field in a `service.spec`, and will configure
a load balancer with the provided IP regardless whether it is within the `KEEPALIVED_SERVICE_CIDR`

```bash
$ kubectl get services
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
test 10.98.31.230 10.210.38.66 80:31877/TCP 3s
test2 10.107.177.153 10.210.38.65 80:31261/TCP 12m
```

#### Advanced: Configure forwarding method for the service

The `kube-keepalived-vip` service supports both the `NAT` and `DR` methods of
IPVS forwarding for the service traffic. The default forwarding method is `NAT`.
Depending on your network topology, you may need to change that to `DR` (direct
routing). To change this globally, you can set the environment variable
`KEEPALIVED_DEFAULT_FORWARD_METHOD` to `NAT` or `DR`. To change it on a per
service basis, then specify the method via the
`k8s.co/keepalived-forward-method` annotation on the service as shown
below:

```yaml
---
apiVersion: v1
kind: Service
metadata:
name: nginx
labels:
k8s-app: nginx
annotations:
k8s.co/keepalived-forward-method: DR
spec:
type: LoadBalancer
ports:
- port: 443
targetPort: 8080
protocol: TCP
name: http
selector:
k8s-app: nginx
```

More information on the differences between `NAT` and `DR` methods can be found
in the [Keepalived
documentation](http://keepalived.readthedocs.io/en/latest/load_balancing_techniques.html)