Working with Ansible and Docker

As shown in the diagram, we are trying to provision, docker container in remote host using a intermediate docker container (Docker-Ansible) which has been installed Ansible.

So Ansible playbook will run inside the docker container which is in local host.

By this way you don't have to install Ansible in local machine.

Also we can execute multiple playbook at the same time.

Please note, for this demonstration I am using single machine. You can use two virtual machines instead of single machine with different IP address.

Steps.

1. Install Open-SSH server in Ubuntu.

Please follow below article for this.

https://www.cyberciti.biz/faq/ubuntu-linux-install-openssh-server/

2. Setup SSH keys in Ubuntu.

Please follow below article for this

https://www.digitalocean.com/community/tutorials/how-to-set-up-ssh-keys-on-ubuntu-1604

https://www.ssh.com/ssh/copy-id

3. Install Docker

https://dhanuka84.blogspot.com/2019/02/install-docker-in-ubuntu.html

4. Install Python

https://tecadmin.net/install-python-2-7-on-ubuntu-and-linuxmint/

5. Clone below two github projects

git clone https://github.com/dhanuka84/docker-ansible.git



git clone https://github.com/dhanuka84/docker-ansible-playbook.git

6. Build each project

cd   docker-ansible/master-ubuntu16.04

docker-ansible/master-ubuntu16.04$   docker build -t ansible-docker:master-ubuntu16.04 .

cd   docker-ansible-playbook

docker-ansible-playbook$   docker build -t docker-ansible-intermediate:latest .

7. Provisioning the container using intermediate container

cd   docker-ansible-playbook



docker-ansible-playbook$  ./start.sh

Explanation

1. Docker image ansible-docker:master-ubuntu16.04

If you look at the Dockerfile, you can see it has setup up all the things mentioned in the diagram as Docker-Ansible. This will be the generic Ubuntu based image.

2. docker-ansible-intermediate:latest

We use previous image as parent image in here. Mainly what we do with this image is setup SSH keys and hosts

Though define ssh-keyscan 192.168.0.114  > /root/.ssh/known_hosts in the image level is not the best approach for this just for demo purpose we did like this.

Best approach is do the same in container level  (start.sh) instead of image level.

3. docker-ansible-playbook$ vim docker.yml  playbook

---

- hosts: docker

#  gather_facts: no

  tasks:



  - name: Create container

    docker_container:

     name: docker-test

    # docker_host: "tcp://localhost:22"

    # This is a pre-built ubuntu based image. Also it has been installed python-pip as explain in the #diagram.

   #We use this image as provisioned container

     image: nitincypher/docker-ubuntu-python-pip:latest

    # image: ansible:ubuntu16.04

     command: sleep 1d

     detach: true

     interactive: true

     tty: true

    # tls_hostname: localhost




     tls_verify: yes

References:

https://developer.ibm.com/tutorials/cl-provision-docker-containers-ansible/

Setup Kubernetes Cluster with Virtualbox

Steps

1. Install Oracle Virtualbox & Extension pack

Download from here - https://www.virtualbox.org/wiki/Download_Old_Builds_5_2

2. Download Ubuntu ISO( ubuntu-18.04.3-desktop-amd64.iso )  image from below link

https://ubuntu.com/download/desktop

3. Create virtual machine in virtual box.  

Minimum Requirement is : 2 GB RAM, 1 VCPU

You can follow below blog for more details.

https://www.wikihow.com/Install-Ubuntu-on-VirtualBox

4. Sample virtual machine

After successfully setup virtual machine, you need to install guest additions as described below.
https://www.virtualbox.org/manual/ch04.html

5. Key points when creating a virtual machine

Network Settings:

• You need to connect to internet so we have to use NAT network adapter
• Also we are using bridged adapter as the cluster communication network, and it's IP as static IP
• Configure the adapters as mentioned in the image

6. Once you setup virtual machine you need to install Docker and disable swap

7. Setup the virtual machine. Execute following commands in a terminal

sudo apt-get update

sudo apt install net-tools

Change hostname

sudo hostnamectl set-hostname "k8s-master"

exec bash

8. Install Docker

sudo dpkg --configure -a

Install relevant packages

sudo apt install apt-transport-https ca-certificates curl software-properties-common

sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu bionic stable"

sudo apt update

apt-cache policy docker-ce

sudo apt install docker-ce

Use Docker as normal user

sudo usermod -aG docker ${USER}

su - ${USER}

sudo systemctl start docker

sudo systemctl enable docker

9. Create a static IP

Type below command and select enp0s9 entry

ifconfig -a

enp0s9: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500

        inet 192.168.0.166  netmask 255.255.255.0  broadcast 192.168.0.255

        inet6 fe80::a00:27ff:fe7c:faba  prefixlen 64  scopeid 0x20<link>

        ether 08:00:27:7c:fa:ba  txqueuelen 1000  (Ethernet)

        RX packets 21115  bytes 8269767 (8.2 MB)

        RX errors 0  dropped 0  overruns 0  frame 0

        TX packets 14770  bytes 1610853 (1.6 MB)

        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

sudo vim /etc/network/interfaces

insert below code block to above file

auto enp0s9

iface enp0s9 inet static

address 192.168.0.166

netmask 255.255.255.0

Change /etc/hosts file with below IP entries

sudo vim /etc/hosts

192.168.0.166      k8s-master

192.168.0.178      k8s-worker-node2

10. Install Kubernetes

Install relevant packages

sudo apt install apt-transport-https ca-certificates curl software-properties-common

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add

sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"

sudo apt update

Disable swap

sudo swapoff -a

vim /etc/fstab

comment out lines which indicate about swap

example :

#/swapfile                                 none            swap    sw              0       0

sudo apt-get install kubeadm -y

11. Cloning virtual machine as worker/slave node

Use below link but clone this as FULL clone

https://protechgurus.com/clone-virtual-machine-virtualbox/

12. Setup Kubernetes Master

sudo kubeadm init  --apiserver-advertise-address=192.168.0.166 --pod-network-cidr=192.168.0.0/24

mkdir -p $HOME/.kube

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

sudo chown $(id -u):$(id -g) $HOME/.kube/config

Save below out put to a file

kubeadm join 192.168.0.166:6443 --token pa36ca.1e073aktjf9rac6m \

    --discovery-token-ca-cert-hash sha256:b850d754741005a6d7f2a096441d3c229dd23bc3a0078157c5d815a22216bc34 

13. Setup Kubernetes in Slave node

Do step 9 and  10. Then execute below command to join slave node to cluster
Then change hostname

sudo kubeadm join 192.168.0.166:6443 --token pa36ca.1e073aktjf9rac6m \

    --discovery-token-ca-cert-hash sha256:b850d754741005a6d7f2a096441d3c229dd23bc3a0078157c5d815a22216bc34

14. Deploy Flannel as Pod Network in both master and slave nodes

sudo kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

15. Verify the cluster from master node

kubanetes@k8s-master:~$ kubectl get pods --all-namespaces

NAMESPACE     NAME                                 READY   STATUS    RESTARTS   AGE

kube-system   coredns-5644d7b6d9-vwnfx             0/1     Running   0          8m37s

kube-system   coredns-5644d7b6d9-zwgvn             0/1     Running   0          8m37s

kube-system   etcd-k8s-master                      1/1     Running   0          7m59s

kube-system   kube-apiserver-k8s-master            1/1     Running   0          8m1s

kube-system   kube-controller-manager-k8s-master   1/1     Running   0          7m51s

kube-system   kube-flannel-ds-amd64-wk5s6          1/1     Running   0          27s

kube-system   kube-proxy-xgcjh                     1/1     Running   0          8m37s

kube-system   kube-scheduler-k8s-master            1/1     Running   0          7m56s

kubanetes@k8s-master:~$ kubectl get nodes

NAME               STATUS   ROLES    AGE    VERSION

k8s-master         Ready    master   26m    v1.16.3

k8s-worker-node2   Ready    <none>   114s   v1.16.3

References:

https://www.linuxtechi.com/install-configure-kubernetes-ubuntu-18-04-ubuntu-18-10/

https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet/