https://github.com/philipn/kubernetes-sticky-node-scheduler

A custom Kubernetes scheduler that places variants of a pod on the same node
https://github.com/philipn/kubernetes-sticky-node-scheduler

Last synced: 10 days ago
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A custom Kubernetes scheduler that places variants of a pod on the same node

• Host: GitHub
• URL: https://github.com/philipn/kubernetes-sticky-node-scheduler
• Owner: philipn
• Created: 2016-08-01T12:48:38.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2017-08-15T06:33:40.000Z (over 7 years ago)
• Last Synced: 2024-06-10T02:35:30.610Z (7 months ago)
• Language: Python
• Homepage:
• Size: 20.5 KB
• Stars: 31
• Watchers: 4
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
`sticky-node-scheduler` is a custom [Kubernetes](http://kubernetes.io/)

scheduler that schedules all variants of a given pod on the same node.

If a pod variant isn't running on any nodes, we pick a node to schedule on to

based on which node is running the least amount of our sticky-scheduled pods.

If any varients of a pod *are* running, then we place all copies of the pod

on the same node.

If you're using e.g. EBS volumes, which can only be attached to a single node

at a time, and need seamless updates of your stateful Deployments, this might

be useful to you.

This scheduler only works with Kubernetes >= 1.6, which support custom

schedulers as a beta feature.

NOTE: This is **not** ready for production usage.

How to use

----------

First, deploy the scheduler into your cluster:

    $ kubectl apply -f deployment.yml

Then, for each Deployment or ReplicationController you want to schedule

using this scheduler, add:

    schedulerName: stickToExistingNodeScheduler

to the pod spec.  For instance:

    apiVersion: extensions/v1beta1

    kind: Deployment

    metadata:

      name: my-stateful-service

    spec:

      replicas: 2

      template:

        metadata:

          labels:

            app: my-stateful-service

        spec:

          schedulerName: stickToExistingNodeScheduler

          containers:

            - name: my-stateful-service

              image: stateful-service-image

The scheduler identifies 'variants' of your pods based on the

`metadata.labels` entry in your pod template.

Options

-------

The `NODE_FILTER_QUERY` environment variable controls which nodes are

selected for scheduling.  By default, it is set to

`labelSelector=kubernetes.io/role=node`, which will filter only nodes (e.g.

we won't schedule on to your master nodes).

The `POLL_FREQUENCY` environment variable controls how often we poll the

Kubernetes API for changes, per second.  The default is `0.5`.

License

-------

Copyright (c) 2016, 2017 Shotwell Labs, Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of

this software and associated documentation files (the "Software"), to deal in

the Software without restriction, including without limitation the rights to

use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies

of the Software, and to permit persons to whom the Software is furnished to do

so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all

copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

SOFTWARE.