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Merge pull request #1420 from luxas/update_kubeadm_arm 

Update and refactor the kubeadm documentation + add HypriotOS instructions as well
pull/1507/head
Lucas Käldström 2016-10-26 00:19:08 +03:00 committed by GitHub
parent 8f02f91f53 519ceca719
commit 50f4c84265
1 changed files with 76 additions and 44 deletions
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docs/getting-started-guides/kubeadm.md
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@ -1,4 +1,10 @@
---
assignees:
- mikedanese
- luxas
- errordeveloper
- jbeda
---
<style>
@ -19,7 +25,7 @@ See the full [`kubeadm` reference](/docs/admin/kubeadm) for information on all `
## Prerequisites
1. One or more machines running Ubuntu 16.04 or CentOS 7
1. One or more machines running Ubuntu 16.04, CentOS 7 or HypriotOS v1.0.1
1. 1GB or more of RAM per machine (any less will leave little room for your apps)
1. Full network connectivity between all machines in the cluster (public or private network is fine)
@ -35,24 +41,26 @@ See the full [`kubeadm` reference](/docs/admin/kubeadm) for information on all `
You will install the following packages on all the machines:
* `docker`: the container runtime, which Kubernetes depends on.
* `docker`: the container runtime, which Kubernetes depends on. v1.11.2 is recommended, but v1.10.3 and v1.12.1 are known to work as well.
* `kubelet`: the most core component of Kubernetes.
It runs on all of the machines in your cluster and does things like starting pods and containers.
* `kubectl`: the command to control the cluster once it's running.
You will only use this on the master.
You will only need this on the master, but it can be useful to have on the other nodes as well.
* `kubeadm`: the command to bootstrap the cluster.
For each host in turn:
* SSH into the machine and become `root` if you are not already (for example, run `sudo su -`).
* If the machine is running Ubuntu 16.04, run:
* If the machine is running Ubuntu 16.04 or HypriotOS v1.0.1, run:
# curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
# cat <<EOF > /etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF
# apt-get update
# apt-get install -y docker.io kubelet kubeadm kubectl kubernetes-cni
# # Install docker if you don't have it already.
# apt-get install -y docker.io
# apt-get install -y kubelet kubeadm kubectl kubernetes-cni
If the machine is running CentOS 7, run:
@ -80,6 +88,8 @@ Note: `setenforce 0` will no longer be necessary on CentOS once [#33555](https:/
The master is the machine where the "control plane" components run, including `etcd` (the cluster database) and the API server (which the `kubectl` CLI communicates with).
All of these components run in pods started by `kubelet`.
Right now you can't run `kubeadm init` twice without turning down the cluster in between, see [Turndown](#turndown).
To initialize the master, pick one of the machines you previously installed `kubelet` and `kubeadm` on, and run:
# kubeadm init
@ -87,6 +97,10 @@ To initialize the master, pick one of the machines you previously installed `kub
**Note:** this will autodetect the network interface to advertise the master on as the interface with the default gateway.
If you want to use a different interface, specify `--api-advertise-addresses=<ip-address>` argument to `kubeadm init`.
If you want to use [flannel](https://github.com/coreos/flannel) as the pod network; specify `--pod-network-cidr=10.244.0.0/16` if you're using the daemonset manifest below. _However, please note that this is not required for any other networks, including Weave, which is the recommended pod network._
Please refer to the [kubeadm reference doc](/docs/admin/kubeadm/) if you want to read more about the flags `kubeadm init` provides.
This will download and install the cluster database and "control plane" components.
This may take several minutes.
@ -127,7 +141,31 @@ If you want to be able to schedule pods on the master, for example if you want a
This will remove the "dedicated" taint from any nodes that have it, including the master node, meaning that the scheduler will then be able to schedule pods everywhere.
### (3/4) Joining your nodes
### (3/4) Installing a pod network
You must install a pod network add-on so that your pods can communicate with each other.
In the meantime, the kubenet network plugin doesn't work. Instead, CNI plugin networks are supported, those you see below.
**It is necessary to do this before you try to deploy any applications to your cluster, and before `kube-dns` will start up.**
Several projects provide Kubernetes pod networks.
You can see a complete list of available network add-ons on the [add-ons page](/docs/admin/addons/).
By way of example, you can install [Weave Net](https://github.com/weaveworks/weave-kube) by logging in to the master and running:
# kubectl apply -f https://git.io/weave-kube
daemonset "weave-net" created
If you prefer [Calico](https://github.com/projectcalico/calico-containers/tree/master/docs/cni/kubernetes/manifests/kubeadm) or [Canal](https://github.com/tigera/canal/tree/master/k8s-install/kubeadm), please refer to their respective installation guides.
If you are on another architecture than amd64, you should use the flannel overlay network as described in [the multi-platform section](#kubeadm-is-multi-platform)
NOTE: You can install **only one** pod network per cluster.
Once a pod network has been installed, you can confirm that it is working by checking that the `kube-dns` pod is `Running` in the output of `kubectl get pods --all-namespaces`.
And once the `kube-dns` pod is up and running, you can continue by joining your nodes.
### (4/4) Joining your nodes
The nodes are where your workloads (containers and pods, etc) run.
If you want to add any new machines as nodes to your cluster, for each machine: SSH to that machine, become root (e.g. `sudo su -`) and run the command that was output by `kubeadm init`.
@ -151,28 +189,12 @@ For example:
A few seconds later, you should notice that running `kubectl get nodes` on the master shows a cluster with as many machines as you created.
**YOUR CLUSTER IS NOT READY YET!**
### (Optional) Control your cluster from machines other than the master
Before you can deploy applications to it, you need to install a pod network.
In order to get a kubectl on your laptop for example to talk to your cluster, you need to copy the `KubeConfig` file from your master to your laptop like this:
### (4/4) Installing a pod network
You must install a pod network add-on so that your pods can communicate with each other when they are on different hosts.
**It is necessary to do this before you try to deploy any applications to your cluster.**
Several projects provide Kubernetes pod networks.
You can see a complete list of available network add-ons on the [add-ons page](/docs/admin/addons/).
By way of example, you can install [Weave Net](https://github.com/weaveworks/weave-kube) by logging in to the master and running:
# kubectl apply -f https://git.io/weave-kube
daemonset "weave-net" created
If you prefer [Calico](https://github.com/projectcalico/calico-containers/tree/master/docs/cni/kubernetes/manifests/kubeadm) or [Canal](https://github.com/tigera/canal/tree/master/k8s-install/kubeadm), please refer to their respective installation guides.
You should only install one pod network per cluster.
Once a pod network has been installed, you can confirm that it is working by checking that the `kube-dns` pod is `Running` in the output of `kubectl get pods --all-namespaces`.
**This signifies that your cluster is ready.**
# scp root@<master ip>:/etc/kubernetes/admin.conf .
# kubectl --kubeconfig ./admin.conf get nodes
### (Optional) Installing a sample application
@ -204,19 +226,7 @@ In the example above, this was `31869`, but it is a different port for you.
If there is a firewall, make sure it exposes this port to the internet before you try to access it.
### Explore other add-ons
See the [list of add-ons](/docs/admin/addons/) to explore other add-ons, including tools for logging, monitoring, network policy, visualization &amp; control of your Kubernetes cluster.
## What's next
* Learn more about [Kubernetes concepts and kubectl in Kubernetes 101](/docs/user-guide/walkthrough/).
* Install Kubernetes with [a cloud provider configurations](/docs/getting-started-guides/) to add Load Balancer and Persistent Volume support.
* Learn about `kubeadm`'s advanced usage on the [advanced reference doc](/docs/admin/kubeadm/)
## Cleanup
## Tear down
* To uninstall the socks shop, run `kubectl delete namespace sock-shop` on the master.
@ -232,18 +242,43 @@ See the [list of add-ons](/docs/admin/addons/) to explore other add-ons, includi
If you wish to start over, run `systemctl start kubelet` followed by `kubeadm init` or `kubeadm join`.
<!-- *syntax-highlighting-hack -->
## Explore other add-ons
See the [list of add-ons](/docs/admin/addons/) to explore other add-ons, including tools for logging, monitoring, network policy, visualization &amp; control of your Kubernetes cluster.
## What's next
* Learn about `kubeadm`'s advanced usage on the [advanced reference doc](/docs/admin/kubeadm/)
* Learn more about [Kubernetes concepts and kubectl in Kubernetes 101](/docs/user-guide/walkthrough/).
## Feedback
* Slack Channel: [#sig-cluster-lifecycle](https://kubernetes.slack.com/messages/sig-cluster-lifecycle/)
* Mailing List: [kubernetes-sig-cluster-lifecycle](https://groups.google.com/forum/#!forum/kubernetes-sig-cluster-lifecycle)
* [GitHub Issues](https://github.com/kubernetes/kubernetes/issues): please tag `kubeadm` issues with `@kubernetes/sig-cluster-lifecycle`
## kubeadm is multi-platform
kubeadm deb packages and binaries are built for amd64, arm and arm64, following the [multi-platform proposal](https://github.com/kubernetes/kubernetes/blob/master/docs/proposals/multi-platform.md).
deb-packages are released for ARM and ARM 64-bit, but not RPMs (yet, reach out if there's interest).
Anyway, ARM had some issues when making v1.4, see [#32517](https://github.com/kubernetes/kubernetes/pull/32517) [#33485](https://github.com/kubernetes/kubernetes/pull/33485), [#33117](https://github.com/kubernetes/kubernetes/pull/33117) and [#33376](https://github.com/kubernetes/kubernetes/pull/33376).
However, thanks to the PRs above, `kube-apiserver` works on ARM from the `v1.4.1` release, so make sure you're at least using `v1.4.1` when running on ARM 32-bit
The multiarch flannel daemonset can be installed this way. Make sure you replace `ARCH=amd64` with `ARCH=arm` or `ARCH=arm64` if necessary.
# ARCH=amd64 curl -sSL https://raw.githubusercontent.com/luxas/flannel/update-daemonset/Documentation/kube-flannel.yml | sed "s/amd64/${ARCH}/g" | kubectl create -f -
And obviously replace `ARCH=amd64` with `ARCH=arm` or `ARCH=arm64` depending on the platform you're running on.
## Limitations
Please note: `kubeadm` is a work in progress and these limitations will be addressed in due course.
1. The cluster created here doesn't have cloud-provider integrations, so for example won't work with (for example) [Load Balancers](/docs/user-guide/load-balancer/) (LBs) or [Persistent Volumes](/docs/user-guide/persistent-volumes/walkthrough/) (PVs).
To easily obtain a cluster which works with LBs and PVs Kubernetes, try [the "hello world" GKE tutorial](/docs/hellonode) or [one of the other cloud-specific installation tutorials](/docs/getting-started-guides/).
1. The cluster created here doesn't have cloud-provider integrations by default, so for example it doesn't work automatically with (for example) [Load Balancers](/docs/user-guide/load-balancer/) (LBs) or [Persistent Volumes](/docs/user-guide/persistent-volumes/walkthrough/) (PVs).
To set up kubeadm with CloudProvider integrations (it's experimental, but try), refer to the [kubeadm reference](/docs/admin/kubeadm/) document.
Workaround: use the [NodePort feature of services](/docs/user-guide/services/#type-nodeport) for exposing applications to the internet.
1. The cluster created here has a single master, with a single `etcd` database running on it.
@ -255,9 +290,6 @@ Please note: `kubeadm` is a work in progress and these limitations will be addre
1. `kubectl logs` is broken with `kubeadm` clusters due to [#22770](https://github.com/kubernetes/kubernetes/issues/22770).
Workaround: use `docker logs` on the nodes where the containers are running as a workaround.
1. There is not yet an easy way to generate a `kubeconfig` file which can be used to authenticate to the cluster remotely with `kubectl` on, for example, your workstation.
Workaround: copy the kubelet's `kubeconfig` from the master: use `scp root@<master>:/etc/kubernetes/admin.conf .` and then e.g. `kubectl --kubeconfig ./admin.conf get nodes` from your workstation.
1. If you are using VirtualBox (directly or via Vagrant), you will need to ensure that `hostname -i` returns a routable IP address (i.e. one on the second network interface, not the first one).
By default, it doesn't do this and kubelet ends-up using first non-loopback network interface, which is usually NATed.