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independent: update CoreDNS mentions for kubeadm (#8753)
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Give CoreDNS instead of kube-dns examples in:
- docs/setup/independent/create-cluster-kubeadm.md
- docs/setup/independent/troubleshooting-kubeadm.md
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@neolit123
neolit123 authored and Misty Stanley-Jones committed Jun 20, 2018
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96 changes: 85 additions & 11 deletions content/en/docs/setup/independent/create-cluster-kubeadm.md
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Expand Up @@ -20,7 +20,54 @@ kubeadm's simplicity means it can serve a wide range of use cases:
- Users familiar with Kubernetes can spin up clusters with kubeadm and test their applications.
- Larger projects can include kubeadm as a building block in a more complex system that can also include other installer tools.

kubeadm's overall feature state is **Beta**.
kubeadm is designed to be a simple way for new users to start trying
Kubernetes out, possibly for the first time, a way for existing users to
test their application on and stitch together a cluster easily, and also to be
a building block in other ecosystem and/or installer tool with a larger
scope.

You can install _kubeadm_ very easily on operating systems that support
installing deb or rpm packages. The responsible SIG for kubeadm,
[SIG Cluster Lifecycle](https://github.com/kubernetes/community/tree/master/sig-cluster-lifecycle), provides these packages pre-built for you,
but you may also on other OSes.


### kubeadm Maturity

| Area | Maturity Level |
|---------------------------|--------------- |
| Command line UX | beta |
| Implementation | beta |
| Config file API | alpha |
| Self-hosting | alpha |
| kubeadm alpha subcommands | alpha |
| CoreDNS | GA |
| DynamicKubeletConfig | alpha |


kubeadm's overall feature state is **Beta** and will soon be graduated to
**General Availability (GA)** during 2018. Some sub-features, like self-hosting
or the configuration file API are still under active development. The
implementation of creating the cluster may change slightly as the tool evolves,
but the overall implementation should be pretty stable. Any commands under
`kubeadm alpha` are by definition, supported on an alpha level.


### Support timeframes

Kubernetes releases are generally supported for nine months, and during that
period a patch release may be issued from the release branch if a severe bug or
security issue is found. Here are the latest Kubernetes releases and the support
timeframe; which also applies to `kubeadm`.

| Kubernetes version | Release month | End-of-life-month |
|--------------------|----------------|-------------------|
| v1.6.x | March 2017 | December 2017 |
| v1.7.x | June 2017 | March 2018 |
| v1.8.x | September 2017 | June 2018 |
| v1.9.x | December 2017 | September 2018   |
| v1.10.x | March 2018 | December 2018   |
| v1.11.x | June 2018 | March 2019   |

{{% /capture %}}

Expand Down Expand Up @@ -99,11 +146,38 @@ is ready to run Kubernetes. These prechecks expose warnings and exit on errors.
then downloads and installs the cluster control plane components. This may take several minutes.
The output should look like:

```
```none
[init] Using Kubernetes version: vX.Y.Z
[preflight] Running pre-flight checks
... (log output of initialization workflow) ...
[kubeadm] WARNING: starting in 1.8, tokens expire after 24 hours by default (if you require a non-expiring token use --token-ttl 0)
[certificates] Generated ca certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] apiserver serving cert is signed for DNS names [kubeadm-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 10.138.0.4]
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated sa key and public key.
[certificates] Generated front-proxy-ca certificate and key.
[certificates] Generated front-proxy-client certificate and key.
[certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[kubeconfig] Wrote KubeConfig file to disk: "admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "scheduler.conf"
[controlplane] Wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/manifests/kube-apiserver.yaml"
[controlplane] Wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/manifests/kube-controller-manager.yaml"
[controlplane] Wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/manifests/kube-scheduler.yaml"
[etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/manifests/etcd.yaml"
[init] Waiting for the kubelet to boot up the control plane as Static Pods from directory "/etc/kubernetes/manifests"
[init] This often takes around a minute; or longer if the control plane images have to be pulled.
[apiclient] All control plane components are healthy after 39.511972 seconds
[uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[markmaster] Will mark node master as master by adding a label and a taint
[markmaster] Master master tainted and labelled with key/value: node-role.kubernetes.io/master=""
[bootstraptoken] Using token: <token>
[bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstraptoken] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
Your Kubernetes master has initialized successfully!
Expand Down Expand Up @@ -156,9 +230,8 @@ created, and deleted with the `kubeadm token` command. See the
You must install a pod network add-on so that your pods can communicate with
each other.

The network must be deployed before any applications. An
internal helper service, kube-dns, will not start up before a network is installed. kubeadm
supports only Container Network Interface (CNI) based networks. It does not support kubenet.
**The network must be deployed before any applications. Also, CoreDNS will not start up before a network is installed.
kubeadm only supports Container Network Interface (CNI) based networks (and does not support kubenet).**

Several projects provide Kubernetes pod networks using CNI, some of which also
support [Network Policy](/docs/concepts/services-networking/networkpolicies/). See the [add-ons page](/docs/concepts/cluster-administration/addons/) for a complete list of available network add-ons.
Expand Down Expand Up @@ -263,11 +336,12 @@ kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl versio
{{% /tab %}}
{{< /tabs >}}

Once you install a pod network, you can confirm that it works by
checking that the kube-dns pod is Running in the output of `kubectl get pods --all-namespaces`.
Once the kube-dns pod is up and running, you can continue by joining your nodes.

If your network is not working or kube-dns is not in the Running state, check
Once a pod network has been installed, you can confirm that it is working by
checking that the CoreDNS pod is Running in the output of `kubectl get pods --all-namespaces`.
And once the CoreDNS pod is up and running, you can continue by joining your nodes.

If your network is not working or CoreDNS is not in the Running state, check
out our [troubleshooting docs](/docs/setup/independent/troubleshooting-kubeadm/).

### Master Isolation
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13 changes: 8 additions & 5 deletions content/en/docs/setup/independent/troubleshooting-kubeadm.md
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Expand Up @@ -101,14 +101,17 @@ Right after `kubeadm init` there should not be any pods in these states.
until you have deployed the network solution.
- If you see Pods in the `RunContainerError`, `CrashLoopBackOff` or `Error` state
after deploying the network solution and nothing happens to `coredns` (or `kube-dns`),
it's very likely that the Pod Network solution that you installed is somehow broken.
You might have to grant it more RBAC privileges or use a newer version. Please file
it's very likely that the Pod Network solution and nothing happens to the DNS server, it's very
likely that the Pod Network solution that you installed is somehow broken. You
might have to grant it more RBAC privileges or use a newer version. Please file
an issue in the Pod Network providers' issue tracker and get the issue triaged there.

#### `coredns` (or `kube-dns`) is stuck in the `Pending` state

kubeadm does not install a [pod network solution](https://kubernetes.io/docs/concepts/cluster-administration/addons/)
by default. You have to install a Pod Network before `coredns` (or `kube-dns`) pods will be scheduled.
This is **expected** and part of the design. kubeadm is network provider-agnostic, so the admin
should [install the pod network solution](/docs/concepts/cluster-administration/addons/)
of choice. You have to install a Pod Network
before CoreDNS may deployed fully. Hence the `Pending` state before the network is set up.

#### `HostPort` services do not work

Expand Down Expand Up @@ -140,7 +143,7 @@ services](/docs/concepts/services-networking/service/#type-nodeport) or use `Hos

The following error indicates a possible certificate mismatch.

```sh
```none
# kubectl get pods
Unable to connect to the server: x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kubernetes")
```
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