Home Kubernetes cluster in 15 minutes

Categories: Kubernetes

Description

This guide will let you install Kubernetes 1.8 with RBAC enabled on so called “baremetal” along with Calico network plugin. Although there is nothing specific to baremetal, that’s what I will use to install it. This cluster can be then used for small projects, once exposed to the Internet. That’s excatly what I use it for :)

Requirements

Spare machine with Ubuntu installed and at least a few GB of RAM. I used my spare HP laptop with 32GB RAM on Ubuntu 16.04 LTS.

Install kubeadm and kubectl

Follow the guide here: https://kubernetes.io/docs/setup/independent/install-kubeadm/

Disable SWAP

#Disable running swap
swapoff -a
#Disable swap parttion after system restart
sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab</pre>
# Setup Kubernetes cluster

Run kubeadm init.

sudo kubeadm init

The result will be long text, similar to:

[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[init] Using Kubernetes version: v1.8.5
[init] Using Authorization modes: [Node RBAC]
[preflight] Running pre-flight checks
[preflight] Starting the kubelet service
[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 [mike-hp-elitebook-8760w kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.16$.1.10]
[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 38.503774 seconds
[uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[markmaster] Will mark node mike-hp-elitebook-8760w as master by adding a label and a taint
[markmaster] Master mike-hp-elitebook-8760w tainted and labelled with key/value: node-role.kubernetes.io/master=""
[bootstraptoken] Using token: ff16e2.2114f554fcbd742d
[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] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstraptoken] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: kube-dns
[addons] Applied essential addon: kube-proxy

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run (as a regular user):

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

You should now deploy a pod network to the cluster. Run “kubectl apply -f [podnetwork].yaml” with one of the options listed at: http://kubernetes.io/docs/admin/addons/

You can now join any number of machines by running the following on each node as root:

kubeadm join --token ff16e2.2114f554fcbd742d 192.168.2.20:6443 --discovery-token-ca-cert-hash sha256:53fc49503ea6d4dab1220d4f3f49786c71cce891aeffc8df9896d9ed5b0a6dc8

Then, run suggested commands:

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Check that kubectl works properly with the cluster:

kubectl get nodes

Result:

NAME STATUS ROLES AGE VERSION
mike-hp-elitebook-8760w NotReady master 2m v1.8.4

Install network plugin - Calico

The node won’t become ready until we deploy network CNI plugin. As this is the Kubernetes 1.8 cluster, the RBAC is also enabled by default. Therefore we need to create RBAC resources as well. You can use this script to deploy Calico network plugin along with Roles, ClusterRoles and ClusterRoleBindings. It should work out of the box. Save the gist below on the server as calico.yaml and then run: kubectl apply -f calico.yaml

# Calico Version v2.4.1
# https://docs.projectcalico.org/v2.4/releases#v2.4.1
# This manifest includes the following component versions:
# calico/node:v2.4.1
# calico/cni:v1.10.0
# calico/kube-policy-controller:v0.7.0

# This ConfigMap is used to configure a self-hosted Calico installation.
kind: ConfigMap
apiVersion: v1
metadata:
name: calico-config
namespace: kube-system
data:
# The location of your etcd cluster. This uses the Service clusterIP
# defined below.
etcd_endpoints: "http://10.96.232.136:6666"

# Configure the Calico backend to use.
calico_backend: "bird"

# The CNI network configuration to install on each node.
cni_network_config: |-
{
"name": "k8s-pod-network",
"cniVersion": "0.1.0",
"type": "calico",
"etcd_endpoints": "__ETCD_ENDPOINTS__",
"log_level": "info",
"mtu": 1500,
"ipam": {
"type": "calico-ipam"
},
"policy": {
"type": "k8s",
"k8s_api_root": "https://__KUBERNETES_SERVICE_HOST__:__KUBERNETES_SERVICE_PORT__",
"k8s_auth_token": "__SERVICEACCOUNT_TOKEN__"
},
"kubernetes": {
"kubeconfig": "/etc/cni/net.d/__KUBECONFIG_FILENAME__"
}
}

---
# This manifest installs the Calico etcd on the kubeadm master. This uses a DaemonSet
# to force it to run on the master even when the master isn't schedulable, and uses
# nodeSelector to ensure it only runs on the master.
apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
name: calico-etcd
namespace: kube-system
labels:
k8s-app: calico-etcd
spec:
template:
metadata:
labels:
k8s-app: calico-etcd
annotations:
# Mark this pod as a critical add-on; when enabled, the critical add-on scheduler
# reserves resources for critical add-on pods so that they can be rescheduled after
# a failure. This annotation works in tandem with the toleration below.
scheduler.alpha.kubernetes.io/critical-pod: ''
spec:
# Only run this pod on the master.
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
# Allow this pod to be rescheduled while the node is in "critical add-ons only" mode.
# This, along with the annotation above marks this pod as a critical add-on.
- key: CriticalAddonsOnly
operator: Exists
nodeSelector:
node-role.kubernetes.io/master: ""
hostNetwork: true
containers:
- name: calico-etcd
image: quay.io/coreos/etcd:v3.1.10
env:
- name: CALICO_ETCD_IP
valueFrom:
fieldRef:
fieldPath: status.podIP
command: ["/bin/sh","-c"]
args: ["/usr/local/bin/etcd --name=calico --data-dir=/var/etcd/calico-data --advertise-client-urls=http://$CALICO_ETCD_IP:6666 --listen-client-urls=http://0.0.0.0:6666 --listen-peer-urls=http://0.0.0.0:6667"]
volumeMounts:
- name: var-etcd
mountPath: /var/etcd
volumes:
- name: var-etcd
hostPath:
path: /var/etcd

---

# This manifest installs the Service which gets traffic to the Calico
# etcd.
apiVersion: v1
kind: Service
metadata:
labels:
k8s-app: calico-etcd
name: calico-etcd
namespace: kube-system
spec:
# Select the calico-etcd pod running on the master.
selector:
k8s-app: calico-etcd
# This ClusterIP needs to be known in advance, since we cannot rely
# on DNS to get access to etcd.
clusterIP: 10.96.232.136
ports:
- port: 6666

---

# This manifest installs the calico/node container, as well
# as the Calico CNI plugins and network config on
# each master and worker node in a Kubernetes cluster.
kind: DaemonSet
apiVersion: extensions/v1beta1
metadata:
name: calico-node
namespace: kube-system
labels:
k8s-app: calico-node
spec:
selector:
matchLabels:
k8s-app: calico-node
template:
metadata:
labels:
k8s-app: calico-node
annotations:
# Mark this pod as a critical add-on; when enabled, the critical add-on scheduler
# reserves resources for critical add-on pods so that they can be rescheduled after
# a failure. This annotation works in tandem with the toleration below.
scheduler.alpha.kubernetes.io/critical-pod: ''
spec:
hostNetwork: true
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
# Allow this pod to be rescheduled while the node is in "critical add-ons only" mode.
# This, along with the annotation above marks this pod as a critical add-on.
- key: CriticalAddonsOnly
operator: Exists
serviceAccountName: calico-cni-plugin
containers:
# Runs calico/node container on each Kubernetes node. This
# container programs network policy and routes on each
# host.
- name: calico-node
image: quay.io/calico/node:v2.4.1
env:
# The location of the Calico etcd cluster.
- name: ETCD_ENDPOINTS
valueFrom:
configMapKeyRef:
name: calico-config
key: etcd_endpoints
# Enable BGP. Disable to enforce policy only.
- name: CALICO_NETWORKING_BACKEND
valueFrom:
configMapKeyRef:
name: calico-config
key: calico_backend
# Cluster type to identify the deployment type
- name: CLUSTER_TYPE
value: "kubeadm,bgp"
# Disable file logging so `kubectl logs` works.
- name: CALICO_DISABLE_FILE_LOGGING
value: "true"
# Set Felix endpoint to host default action to ACCEPT.
- name: FELIX_DEFAULTENDPOINTTOHOSTACTION
value: "ACCEPT"
# Configure the IP Pool from which Pod IPs will be chosen.
- name: CALICO_IPV4POOL_CIDR
value: "192.168.0.0/16"
- name: CALICO_IPV4POOL_IPIP
value: "always"
# Disable IPv6 on Kubernetes.
- name: FELIX_IPV6SUPPORT
value: "false"
# Set MTU for tunnel device used if ipip is enabled
- name: FELIX_IPINIPMTU
value: "1440"
# Set Felix logging to "info"
- name: FELIX_LOGSEVERITYSCREEN
value: "info"
- name: FELIX_HEALTHENABLED
value: "true"
# Auto-detect the BGP IP address.
- name: IP
value: ""
securityContext:
privileged: true
resources:
requests:
cpu: 250m
livenessProbe:
httpGet:
path: /liveness
port: 9099
periodSeconds: 10
initialDelaySeconds: 10
failureThreshold: 6
readinessProbe:
httpGet:
path: /readiness
port: 9099
periodSeconds: 10
volumeMounts:
- mountPath: /lib/modules
name: lib-modules
readOnly: true
- mountPath: /var/run/calico
name: var-run-calico
readOnly: false
# This container installs the Calico CNI binaries
# and CNI network config file on each node.
- name: install-cni
image: quay.io/calico/cni:v1.10.0
command: ["/install-cni.sh"]
env:
# The location of the Calico etcd cluster.
- name: ETCD_ENDPOINTS
valueFrom:
configMapKeyRef:
name: calico-config
key: etcd_endpoints
# The CNI network config to install on each node.
- name: CNI_NETWORK_CONFIG
valueFrom:
configMapKeyRef:
name: calico-config
key: cni_network_config
volumeMounts:
- mountPath: /host/opt/cni/bin
name: cni-bin-dir
- mountPath: /host/etc/cni/net.d
name: cni-net-dir
volumes:
# Used by calico/node.
- name: lib-modules
hostPath:
path: /lib/modules
- name: var-run-calico
hostPath:
path: /var/run/calico
# Used to install CNI.
- name: cni-bin-dir
hostPath:
path: /opt/cni/bin
- name: cni-net-dir
hostPath:
path: /etc/cni/net.d

---

# This manifest deploys the Calico policy controller on Kubernetes.
# See https://github.com/projectcalico/k8s-policy
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: calico-policy-controller
namespace: kube-system
labels:
k8s-app: calico-policy
spec:
# The policy controller can only have a single active instance.
replicas: 1
strategy:
type: Recreate
template:
metadata:
name: calico-policy-controller
namespace: kube-system
labels:
k8s-app: calico-policy-controller
annotations:
# Mark this pod as a critical add-on; when enabled, the critical add-on scheduler
# reserves resources for critical add-on pods so that they can be rescheduled after
# a failure. This annotation works in tandem with the toleration below.
scheduler.alpha.kubernetes.io/critical-pod: ''
spec:
# The policy controller must run in the host network namespace so that
# it isn't governed by policy that would prevent it from working.
hostNetwork: true
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
# Allow this pod to be rescheduled while the node is in "critical add-ons only" mode.
# This, along with the annotation above marks this pod as a critical add-on.
- key: CriticalAddonsOnly
operator: Exists
serviceAccountName: calico-policy-controller
containers:
- name: calico-policy-controller
image: quay.io/calico/kube-policy-controller:v0.7.0
env:
# The location of the Calico etcd cluster.
- name: ETCD_ENDPOINTS
valueFrom:
configMapKeyRef:
name: calico-config
key: etcd_endpoints
# The location of the Kubernetes API. Use the default Kubernetes
# service for API access.
- name: K8S_API
value: "https://kubernetes.default:443"
# Since we're running in the host namespace and might not have KubeDNS
# access, configure the container's /etc/hosts to resolve
# kubernetes.default to the correct service clusterIP.
- name: CONFIGURE_ETC_HOSTS
value: "true"
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: calico-cni-plugin
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: calico-cni-plugin
subjects:
- kind: ServiceAccount
name: calico-cni-plugin
namespace: kube-system
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: calico-cni-plugin
namespace: kube-system
rules:
- apiGroups: [""]
resources:
- pods
- nodes
verbs:
- get
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: calico-cni-plugin
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: calico-policy-controller
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: calico-policy-controller
subjects:
- kind: ServiceAccount
name: calico-policy-controller
namespace: kube-system
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: calico-policy-controller
namespace: kube-system
rules:
- apiGroups:
- ""
- extensions
resources:
- pods
- namespaces
- networkpolicies
verbs:
- watch
- list
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: calico-policy-controller
namespace: kube-system

After a few minutes you will see that node becomes ready:

kubectl get nodes

Result:

NAME STATUS ROLES AGE VERSION
mike-hp-elitebook-8760w Ready master 8m v1.8.4

We still, though, cannot schedule work on this node as it’s master. By default it is tainted with NoSchedule. We can see this by runnig kubectl describe node, like this:

kubectl describe node mike-hp-elitebook-8760w | grep Taint

Result:

Taints: node-role.kubernetes.io/master:NoSchedule

Let’s remove this taint:

kubectl taint nodes --all node-role.kubernetes.io/master-

Now we can schedule workloads inside the cluster:

kubectl run nginx --image nginx
sleep 30
kubectl get pods

And we shall see

NAME READY STATUS RESTARTS AGE
nginx-7c87f569d-cvlfc 1/1 Running 0 36s

Copy kubectl config over to your machine so that you don’t need to SSH anytime you want to deploy something.

The only thing that is left to do is copy the ~/.kube/config to your own machine in order to use it outside of the server.

Next steps

You can also setup DDNS (Dynamic DNS) and use port-forwarding on your home-grade router to have publicly avaialble cluster.

See also

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