kops/docs/addons.md

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Markdown

## Installing Kubernetes Addons
With kops you manage addons by using kubectl.
(For a description of the addon-manager, please see [addon_manager.md](addon_manager.md).)
Addons in Kubernetes are traditionally done by copying files to `/etc/kubernetes/addons` on the master. But this
doesn't really make sense in HA master configurations. We also have kubectl available, and addons are just a thin
wrapper over calling kubectl.
The command `kops create cluster` does not support specifying addons to be added to the cluster when it is created. Instead they can be added after cluster creation using kubectl. Alternatively when creating a cluster from a yaml manifest, addons can be specified using `spec.addons`.
```yaml
spec:
addons:
- manifest: kubernetes-dashboard
- manifest: s3://kops-addons/addon.yaml
```
This document describes how to install some common addons and how to create your own custom ones.
### Custom addons
The docs about the [addon manager](addon_manager.md) describe in more detail how to define a addon resource with regards to versioning.
Here is a minimal example of an addon manifest that would install two different addons.
```yaml
kind: Addons
metadata:
name: example
spec:
addons:
- name: foo.addons.org.io
version: 0.0.1
selector:
k8s-addon: foo.addons.org.io
manifest: foo.addons.org.io/v0.0.1.yaml
- name: bar.addons.org.io
version: 0.0.1
selector:
k8s-addon: bar.addons.org.io
manifest: bar.addons.org.io/v0.0.1.yaml
```
In this this example the folder structure should look like this;
```
addon.yaml
foo.addons.org.io
v0.0.1.yaml
bar.addons.org.io
v0.0.1.yaml
```
The yaml files in the foo/bar folders can be any kubernetes resource. Typically this file structure would be pushed to S3 or another of the supported backends and then referenced as above in `spec.addons`. In order for master nodes to be able to access the S3 bucket containing the addon manifests, one might have to add additional iam policies to the master nodes using `spec.additionalPolicies`, like so;
```yaml
spec:
additionalPolicies:
master: |
[
{
"Effect": "Allow",
"Action": [
"s3:GetObject"
],
"Resource": ["arn:aws:s3:::kops-addons/*"]
},
{
"Effect": "Allow",
"Action": [
"s3:GetBucketLocation",
"s3:ListBucket"
],
"Resource": ["arn:aws:s3:::kops-addons"]
}
]
```
The masters will poll for changes changes in the bucket and keep the addons up to date.
### Dashboard
The [dashboard project](https://github.com/kubernetes/dashboard) provides a nice administrative UI:
Install using:
```
kubectl create -f https://raw.githubusercontent.com/kubernetes/kops/master/addons/kubernetes-dashboard/v1.10.0.yaml
```
And then navigate to `https://api.<clustername>/ui`
(`/ui` is an alias to `https://<clustername>/api/v1/proxy/namespaces/kube-system/services/kubernetes-dashboard`)
The login credentials are:
* Username: `admin`
* Password: get by running `kops get secrets kube --type secret -oplaintext` or `kubectl config view --minify`
#### RBAC
For k8s version > 1.6 and [RBAC](https://kubernetes.io/docs/admin/authorization/rbac/) enabled it's necessary to add your own permission to the dashboard. Please read the [RBAC](https://kubernetes.io/docs/admin/authorization/rbac/) docs before applying permissions.
Below you see an example giving **full access** to the dashboard.
```
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: kubernetes-dashboard
labels:
k8s-app: kubernetes-dashboard
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: cluster-admin
subjects:
- kind: ServiceAccount
name: kubernetes-dashboard
namespace: kube-system
```
### Monitoring with Heapster - Standalone
Monitoring supports the horizontal pod autoscaler.
Install using:
```
kubectl create -f https://raw.githubusercontent.com/kubernetes/kops/master/addons/monitoring-standalone/v1.11.0.yaml
```
Please note that [heapster is retired](https://github.com/kubernetes/heapster/blob/master/docs/deprecation.md). Consider using [metrics-server](https://github.com/kubernetes-incubator/metrics-server) and a third party metrics pipeline to gather Prometheus-format metrics instead.
### Monitoring with Prometheus Operator + kube-prometheus
The [Prometheus Operator](https://github.com/coreos/prometheus-operator/) makes the Prometheus configuration Kubernetes native and manages and operates Prometheus and Alertmanager clusters. It is a piece of the puzzle regarding full end-to-end monitoring.
[kube-prometheus](https://github.com/coreos/prometheus-operator/blob/master/contrib/kube-prometheus) combines the Prometheus Operator with a collection of manifests to help getting started with monitoring Kubernetes itself and applications running on top of it.
```console
kubectl apply -f https://raw.githubusercontent.com/kubernetes/kops/master/addons/prometheus-operator/v0.26.0.yaml
```
### Route53 Mapper
Please note that kops installs a Route53 DNS controller automatically (it is required for cluster discovery).
The functionality of the route53-mapper overlaps with the dns-controller, but some users will prefer to
use one or the other.
[README for the included dns-controller](https://github.com/kubernetes/kops/blob/master/dns-controller/README.md)
route53-mapper automates creation and updating of entries on Route53 with `A` records pointing
to ELB-backed `LoadBalancer` services created by Kubernetes. Install using:
The project is created by wearemolecule, and maintained at
[wearemolecule/route53-kubernetes](https://github.com/wearemolecule/route53-kubernetes).
[Usage instructions](https://github.com/kubernetes/kops/blob/master/addons/route53-mapper/README.md)
```
kubectl apply -f https://raw.githubusercontent.com/kubernetes/kops/master/addons/route53-mapper/v1.3.0.yml
```