This guide would help you create a 3 node cluster with docker engine running on each. This is useful to learn advanced docker concepts such as orchestration, overlay networking spanning multiple nodes, troubleshooting techniques etc.
Following are the softwares required to setup VMs locally on a desktop/laptop.
- Virtualbox
- Vagrant
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To setup the lab, as participants, we would create Virtual Machines with VirtualBox and setup the learning environment. Vagrant is a tool which allows us to build, configure and setup portable virtual machines automatically, and it works with multitude of hypervisors, Virtualbox included. We would also need a sophisticated editor with chef plugin, which would help us write code fast, with auto completion and syntax highlighting features etc. Thats where Atom comes in handy.
On windows systems, utilities such as ssh do not come installed by default. To install a bash shell and create a remote terminal, Git and ConEmu are effective tools.
In order to run 64bit VMs, systems need to be enabled with hardware virtualization extensions. On a Mac OSX, this is typically enabled by default. However, on many Windows Laptops/Desktops, VT-x needs to be manually enabled.
Enable Hardware Virtualization Technology(VT -x) from BIOS
These instructions different from system to system, bases on the BIOS provided with your laptop/desktop. For a lot of systems, Virtualization options are found in Security tab.
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Install software with specific version by clicking on link provided in below table
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Additional software need for windows system are git & ConEmu
| Software | Windows Installer | OS X Installer |
|---|---|---|
| Virtualbox | 5.2.10 | 5.2.10 |
| Vagrant | 2.1.1 | 2.1.1 |
All softwares except Virtualbox on Windows need no additional instructions while installing. Download, launch installer and follow through the default steps. Installing Virtualbox on Windows however needs special instructions due to NDIS/Network driver caveat.
Following are the instructions on installing VirtualBox on Windows and on Mac
Installing VirtualBox on Windows 10
Installing VirtualBox on Mac OSX
The newer version of Virtualbox installs NDIS6 driver by default, which creates conflicts with vagrant while bringing up the virtual machines and network interfaces. Description of this problem and solution is here. To avoid this, participants need to install Virtualbox with NDIS5 with the following instructions.
Note: this issue is specific to Windows only. Same version of Virtualbox on Mac/OSX works flawlessly.
Open a command line terminal /git bash, change directory to where you have downloaded the installer and run it as
VirtualBox-x.x.x-yyyyy-Win.exe -msiparams NETWORKTYPE=NDIS5
Above command will launch Virtualbox installer as usual, however, it will use NDIS5, which works without flaws while configuring network interfaces.
To setup the VM cluster, first you should clone the code containing vagrant specs.
git clone https://github.com/schoolofdevops/lab-setup.git
Change into the directory which contains the Vagrantfile for setting up a 3 node docker cluster.
cd lab-setup/vagrant-docker-cluster
Observe the Vagrantfile and the configuration that it does. To launch all the nodes (3VMs) run the following command.
vagrant up
This should bring up all 3 nodes.
Open three different terminals to login to 3 nodes created with above command
Terminal 1
vagrant ssh docker-01
sudo su
Terminal 2
vagrant ssh docker-02
sudo su
Terminal 3
vagrant ssh docker-03
sudo su
docker version
docker run hello-world