120 lines
4.7 KiB
Markdown
120 lines
4.7 KiB
Markdown
---
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title: Portable Multi-Node Cluster
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---
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* TOC
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{:toc}
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## Prerequisites
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The only thing you need is a linux machine with **Docker 1.10.0 or higher**
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## Overview
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This guide will set up a 2-node Kubernetes cluster, consisting of a _master_ node which hosts the API server and orchestrates work
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and a _worker_ node which receives work from the master. You can repeat the process of adding worker nodes an arbitrary number of
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times to create larger clusters.
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Here's a diagram of what the final result will look like:
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### Bootstrap Docker
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This guide uses a pattern of running two instances of the Docker daemon:
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1) A _bootstrap_ Docker instance which is used to start `etcd` and `flanneld`, on which the Kubernetes components depend
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2) A _main_ Docker instance which is used for the Kubernetes infrastructure and user's scheduled containers
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This pattern is necessary because the `flannel` daemon is responsible for setting up and managing the network that interconnects
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all of the Docker containers created by Kubernetes. To achieve this, it must run outside of the _main_ Docker daemon. However,
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it is still useful to use containers for deployment and management, so we create a simpler _bootstrap_ daemon to achieve this.
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### Versions supported
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v1.2.x and v1.3.x are supported versions for this deployment.
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v1.3.0 alphas and betas might work, but be sure you know what you're doing if you're trying them out.
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### Multi-arch solution
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Yeah, it's true. You may run this deployment setup seamlessly on `amd64`, `arm`, `arm64` and `ppc64le` hosts.
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See this tracking issue for more details: https://github.com/kubernetes/kubernetes/issues/17981
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v1.3.0 ships with support for amd64, arm and arm64. ppc64le isn't supported, due to a bug in the Go runtime, `hyperkube` (only!) isn't built for the stable v1.3.0 release, and therefore this guide can't run it. But you may still run Kubernetes on ppc64le via custom deployments.
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hyperkube was pushed for ppc64le at versions `v1.3.0-alpha.3` and `v1.3.0-alpha.4`, feel free to try them out, but there might be some unexpected bugs.
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### Options/configuration
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The scripts will output something like this when starting:
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```shell
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+++ [0611 12:50:12] K8S_VERSION is set to: v1.3.0
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+++ [0611 12:50:12] ETCD_VERSION is set to: 2.2.5
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+++ [0611 12:50:12] FLANNEL_VERSION is set to: 0.5.5
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+++ [0611 12:50:12] FLANNEL_IPMASQ is set to: true
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+++ [0611 12:50:12] FLANNEL_NETWORK is set to: 10.1.0.0/16
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+++ [0611 12:50:12] FLANNEL_BACKEND is set to: udp
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+++ [0611 12:50:12] RESTART_POLICY is set to: unless-stopped
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+++ [0611 12:50:12] MASTER_IP is set to: 192.168.1.50
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+++ [0611 12:50:12] ARCH is set to: amd64
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+++ [0611 12:50:12] NET_INTERFACE is set to: eth0
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```
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Each of these options are overridable by `export`ing the values before running the script.
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## Setup the master node
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The first step in the process is to initialize the master node.
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Clone the `kube-deploy` repo, and run `master.sh` on the master machine _with root_:
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```shell
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$ git clone https://github.com/kubernetes/kube-deploy
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$ cd kube-deploy/docker-multinode
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$ ./master.sh
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```
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First, the `bootstrap` docker daemon is started, then `etcd` and `flannel` are started as containers in the bootstrap daemon.
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Then, the main docker daemon is restarted, and this is an OS/distro-specific tasks, so if it doesn't work for your distro, feel free to contribute!
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Lastly, it launches `kubelet` in the main docker daemon, and the `kubelet` in turn launches the control plane (apiserver, controller-manager and scheduler) as static pods.
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## Adding a worker node
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Once your master is up and running you can add one or more workers on different machines.
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Clone the `kube-deploy` repo, and run `worker.sh` on the worker machine _with root_:
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```shell
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$ git clone https://github.com/kubernetes/kube-deploy
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$ cd kube-deploy/docker-multinode
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$ export MASTER_IP=${SOME_IP}
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$ ./worker.sh
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```
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First, the `bootstrap` docker daemon is started, then `flannel` is started as a container in the bootstrap daemon, in order to set up the overlay network.
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Then, the main docker daemon is restarted and lastly `kubelet` is launched as a container in the main docker daemon.
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## Addons
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kube-dns and the dashboard are deployed automatically with v1.3.0
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### Deploy DNS manually for v1.2.x
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Just specify the architecture, and deploy via these commands:
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```shell
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# Possible options: amd64, arm, arm64 and ppc64le
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$ export ARCH=amd64
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# If the kube-system namespace isn't already created, create it
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$ kubectl get ns
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$ kubectl create namespace kube-system
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$ sed -e "s/ARCH/${ARCH}/g;" skydns.yaml | kubectl create -f -
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```
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### Test if DNS works
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Follow [this link](https://releases.k8s.io/release-1.2/cluster/addons/dns#how-do-i-test-if-it-is-working) to check it out.
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