https://github.com/wish/nodetaint

https://github.com/wish/nodetaint

daemonsets k8s kubernetes-controller

Last synced: 2 days ago
JSON representation

• Host: GitHub
• URL: https://github.com/wish/nodetaint
• Owner: wish
• License: mit
• Created: 2020-07-06T22:03:55.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2023-10-10T10:55:42.000Z (about 1 year ago)
• Last Synced: 2024-03-08T03:36:22.437Z (8 months ago)
• Topics: daemonsets, k8s, kubernetes-controller
• Language: Go
• Homepage:
• Size: 72.3 KB
• Stars: 37
• Watchers: 2
• Forks: 15
• Open Issues: 11
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-devops - nodetaint - Controller to manage taints for nodes in a k8s cluster. (Kubernetes)

README

        
# nodetaint

Controller to manage taints for nodes in a k8s cluster.

## What the problem is

Usually there are some system critical daemonsets (e.g. CNI, DNS, etc.) that needs to be running on a node before it can run any other pods. However k8s doesn't guarantee any ordering for pod scheduling in node startup, meaning your workload pods may start before the critical daemonsets have started!

## How it works

The controller solves this problem by removing a pre-configured taint from a node after annotated daemonsets are running on the node. To achieve this, you need to configure your cluster to launch nodes with the desired taint: configure `kubelet` to start with `--register-with-taints` option.

 The controller then determines, through annotation, which daemonsets should be running on a node prior to workload pods. It monitors for these daemonset pods to be Ready before removing the configured taint.

Note: If you are using the k8s cluster autoscaler you should align the [`ignore-taint`](https://github.com/kubernetes/autoscaler/blob/8ba18537807fb15a074d3587528157d441ac4389/cluster-autoscaler/main.go#L181) option with the same taints as registered on the kubelet. This will ensure the cluster autoscaler considers those nodes as "ready" for the purposes of scaling up/down.

## Configuration

### Command-line

`nodetaint` can be configured by the following command-line options:

Flag | Environment Variable | Type | Default | Required | Description

---- | -------------------- | ---- | ------- | -------- | -----------

`log-level` | `LOG_LEVEL` | `string` | `info` | no | The level of log detail.

`bind-address` | `BIND_ADDRESS` | `string` | `:9797` | no | The address for binding listener.

`node-taint` | `NODE_TAINT` | `string` | | yes |  The startup taint to put on node.

`daemonset-annotation` | `DAEMONSET_ANNOTATION` | `string` | | yes | The annotation of required daemonset.