Manually install Kubernetes cluster on Oracle Linux 7 VirtualBox on your laptop 💻 in minutes and with few commands with Vagrant
- Install Oracle VM VirtualBox
- Install Vagrant
- An account in Oracle Container Registry
- https://blogs.oracle.com/scoter/oracle-vm-virtualbox-get-kubernetes-cluster-running-in-minutes
- https://kubernetes.io/docs/reference/kubectl/cheatsheet/
We are going to build a cluster with 3 nodes: 1 master and 2 workers.
$ git clone https://github.com/oracle/vagrant-boxes
$ cd vagrant-boxes/Kubernetes
Start a new VirtualBox named master using vagrant and ssh into it:
$ vagrant up master; vagrant ssh master
Within the master guest, run the command below to run a shell with root privileges as root:
$ sudo -s;
master: [ERROR] Please allow iptables default FORWARD rule to ACCEPT
master: the way to do it:
master: # /sbin/iptables -P FORWARD ACCEPT
master: /tmp/vagrant-shell: Worker node ready
Welcome to Oracle Linux Server release 7.5 (GNU/Linux 4.14.35-1818.0.9.el7uek.x86_64)run the command below as the terminal says:
$ /sbin/iptables -P FORWARD ACCEPT
You will be asked to log in to the Oracle Container Registry when you run the command below:
$ /vagrant/scripts/kubeadm-setup-master.sh
After some minutes you should have something like:
[root@master vagrant]# /vagrant/scripts/kubeadm-setup-master.sh
/vagrant/scripts/kubeadm-setup-master.sh: Login to container-registry.oracle.com
Username: [email protected]
Password:
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
Login Succeeded
/vagrant/scripts/kubeadm-setup-master.sh: Setup Master node -- be patient!
/vagrant/scripts/kubeadm-setup-master.sh: Copying admin.conf for vagrant user
/vagrant/scripts/kubeadm-setup-master.sh: Copying admin.conf into host directory
/vagrant/scripts/kubeadm-setup-master.sh: Saving token for worker nodes
I1213 23:15:37.969880 3427 version.go:236] remote version is much newer: v1.17.0; falling back to: stable-1.12
/vagrant/scripts/kubeadm-setup-master.sh: Master node ready, run
/vagrant/scripts/kubeadm-setup-worker.sh
on the worker nodes
[root@master vagrant]# On a new terminal, start a new VirtualBox named worker1 using vagrant and ssh into it:
$ vagrant up worker1; vagrant ssh worker1
Within the worker1 guest, run the command below to run a shell with root privileges as root:
$ sudo -s;
worker1: [ERROR] Please allow iptables default FORWARD rule to ACCEPT
worker1: the way to do it:
worker1: # /sbin/iptables -P FORWARD ACCEPT
worker1: /tmp/vagrant-shell: Worker node ready
Welcome to Oracle Linux Server release 7.5 (GNU/Linux 4.14.35-1818.0.9.el7uek.x86_64)run the command below as the terminal says:
$ /sbin/iptables -P FORWARD ACCEPT
You will be asked to log in to the Oracle Container Registry when you run the command below:
$ /vagrant/scripts/kubeadm-setup-worker.sh
After some minutes you should have something like:
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the master to see this node join the cluster.
/vagrant/scripts/kubeadm-setup-worker.sh: Worker node ready
[root@worker1 vagrant]# In master machine, run as vagrant user (and NOT root user):
$ kubectl get nodes
$ kubectl cluster-info
Output:
[vagrant@master ~]$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
master.vagrant.vm Ready master 60m v1.12.7+1.2.3.el7
worker1.vagrant.vm Ready <none> 2m43s v1.12.7+1.2.3.el7
worker2.vagrant.vm Ready <none> 77s v1.12.7+1.2.3.el7
[vagrant@master ~]$ kubectl cluster-info
Kubernetes master is running at https://192.168.99.100:6443
KubeDNS is running at https://192.168.99.100:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.Within the master guest, run the command below to run a shell with root privileges as root:
$ sudo -s;
cat this file:
$ cat /etc/kubernetes/admin.conf
Select all the content of the file, and copy it.
In the host machine, create a new file, paste the content on it and save.
My file is located in /home/wfranchi/k8s.conf. Then you need to export it, run:
$ export KUBECONFIG=~/k8s.conf
After this, you are able to access the k8s cluster using kubectl from your host computer.
Try the following commands:
$ kubectl config view
$ kubectl get pods --all-namespaces
Output:
wfranchi@computer:~$ kubectl config view
apiVersion: v1
clusters:
- cluster:
certificate-authority-data: DATA+OMITTED
server: https://192.168.99.100:6443
name: kubernetes
contexts:
- context:
cluster: kubernetes
user: kubernetes-admin
name: kubernetes-admin@kubernetes
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:
- name: kubernetes-admin
user:
client-certificate-data: REDACTED
client-key-data: REDACTED
wfranchi@computer:~$ kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system coredns-b7df4d4c4-kkks7 1/1 Running 0 93m
kube-system coredns-b7df4d4c4-xvtkp 1/1 Running 0 93m
kube-system etcd-master.vagrant.vm 1/1 Running 0 92m
kube-system kube-apiserver-master.vagrant.vm 1/1 Running 0 93m
kube-system kube-controller-manager-master.vagrant.vm 1/1 Running 0 93m
kube-system kube-flannel-ds-fjsp5 1/1 Running 0 34m
kube-system kube-flannel-ds-llds8 1/1 Running 0 36m
kube-system kube-flannel-ds-r6hbm 1/1 Running 0 93m
kube-system kube-proxy-4dxxr 1/1 Running 0 93m
kube-system kube-proxy-9f4f8 1/1 Running 0 34m
kube-system kube-proxy-k6fkm 1/1 Running 0 36m
kube-system kube-scheduler-master.vagrant.vm 1/1 Running 0 93m
kube-system kubernetes-dashboard-669df9cb5d-x5hgk 1/1 Running 0 93m
This section demostrates how to deploy nginx in the new k8s.
Run the commands below separately:
$ kubectl create namespace test
$ kubectl create deployment nginx --image=nginx --namespace test
$ kubectl get pods --namespace test
$ kubectl get deployment nginx --namespace test
$ kubectl scale --current-replicas=1 --replicas=10 deployment/nginx --namespace test
$ kubectl get pods --namespace test
$ kubectl delete deployment nginx --namespace test
$ kubectl delete namespace test
Output:
wfranchi@computer:~$ kubectl create namespace test
namespace/test created
wfranchi@computer:~$ kubectl create deployment nginx --image=nginx --namespace test
deployment.apps/nginx created
wfranchi@computer:~$ kubectl get pods --namespace test
NAME READY STATUS RESTARTS AGE
nginx-55bd7c9fd-8hm29 0/1 ContainerCreating 0 17s
wfranchi@computer:~$ kubectl get deployment nginx --namespace test
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
nginx 1 1 1 1 39s
wfranchi@computer:~$ kubectl scale --current-replicas=1 --replicas=10 deployment/nginx --namespace test
deployment.extensions/nginx scaled
wfranchi@computer:~$ kubectl get pods --namespace test
NAME READY STATUS RESTARTS AGE
nginx-55bd7c9fd-25xk9 1/1 Running 0 29s
nginx-55bd7c9fd-428vm 0/1 ContainerCreating 0 29s
nginx-55bd7c9fd-4wrjh 0/1 ContainerCreating 0 29s
nginx-55bd7c9fd-8hm29 1/1 Running 0 83s
nginx-55bd7c9fd-cn799 1/1 Running 0 29s
nginx-55bd7c9fd-fdxpv 0/1 ContainerCreating 0 29s
nginx-55bd7c9fd-nnlcp 1/1 Running 0 29s
nginx-55bd7c9fd-nzkkq 1/1 Running 0 29s
nginx-55bd7c9fd-w4pg6 0/1 ContainerCreating 0 30s
nginx-55bd7c9fd-zcr4d 0/1 ContainerCreating 0 29s
wfranchi@computer:~$ kubectl get pods --namespace test
NAME READY STATUS RESTARTS AGE
nginx-55bd7c9fd-25xk9 1/1 Running 0 47s
nginx-55bd7c9fd-428vm 1/1 Running 0 47s
nginx-55bd7c9fd-4wrjh 1/1 Running 0 47s
nginx-55bd7c9fd-8hm29 1/1 Running 0 101s
nginx-55bd7c9fd-cn799 1/1 Running 0 47s
nginx-55bd7c9fd-fdxpv 1/1 Running 0 47s
nginx-55bd7c9fd-nnlcp 1/1 Running 0 47s
nginx-55bd7c9fd-nzkkq 1/1 Running 0 47s
nginx-55bd7c9fd-w4pg6 1/1 Running 0 48s
nginx-55bd7c9fd-zcr4d 1/1 Running 0 47s
wfranchi@computer:~$ kubectl delete deployment nginx --namespace test
deployment.extensions "nginx" deleted
wfranchi@computer:~$ kubectl delete namespace test
namespace "test" deletedTo destroy the VMs, on the host machine, cd into the folder you cloned before vagrant-boxes/Kubernetes and run:
$ vagrant destroy
Output:
wfranchi@computer:~/vagrant-boxes/Kubernetes$ vagrant destroy
worker2: Are you sure you want to destroy the 'worker2' VM? [y/N] y
==> worker2: Forcing shutdown of VM...
==> worker2: Destroying VM and associated drives...
worker1: Are you sure you want to destroy the 'worker1' VM? [y/N] y
==> worker1: Forcing shutdown of VM...
==> worker1: Destroying VM and associated drives...
master: Are you sure you want to destroy the 'master' VM? [y/N] y
==> master: Forcing shutdown of VM...
==> master: Destroying VM and associated drives...
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