If we launch a browser on the host machine and access the URL http://localhost:8080, we should the browser render as follows:
Host Browser
Introduction to Vagrant - Part 2
| Bhaskar S | 01/21/2017 |
Hands-on with Vagrant - Continued
When a virtual environment is booted up using a specified Box, it will not have the necessary software setup for development use. One could manually install software after sshing into the virtual environment.
Could we not automate the installation and setup of the necessary software as well ???
The process of installing software in a newly booted virtual environment using Vagrant is called Provisioning.
One could use any of the configuration management tools like Ansible, Chef, Puppet, or even Shell scripts to automate the provisioning process. In our demonstration, we will use Shell scripts for software provisioning.
Now we will create a virtual environment by automatically provisioning the open source webserver nginx.
Three important points before we get started:
Vagrant automatically shares the current folder from which the vagrant commands are executed as the folder /vagrant in the virtual environment guest machine
In Vagrant, one can forward network ports from the virtual environment guest machine to a network port on the host machine
Vagrant executes a Shell script as a root user
Create an html file called index.html as shown below:
<html>
<head>
<title>index.html</title>
</head>
<style>
h2 {
color: blue;
font-style: bold;
text-align: center;
}
</style>
<body>
<br/>
<h2>Welcome to Web Programming using NGINX !!!</h2>
</body>
</html>
Next, create a Shell script called setup-web.sh in the current directory as shown below:
#!/bin/bash
echo 'Ready to install NGINX .....'
agt-get update > /dev/null 2>&1
apt-get install -y nginx
cp /vagrant/index.html /usr/share/nginx/html/
echo 'Install and setup of NGINX completed !!!'
Finally, update the Vagrantfile in the current directory as shown below:
Vagrant.configure(2) do |config|
config.vm.box = "ubuntu/trusty64"
config.vm.provider "virtualbox" do |vb|
vb.memory = "1024"
end
config.vm.provision "shell", path: "setup-web.sh"
config.vm.network "forwarded_port", guest: 80, host: 8080
end
Now, let us create and configure the virtual environment by executing the following command:
$ vagrant up
The following would be a typical output:
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Importing base box 'ubuntu/trusty64'...
==> default: Matching MAC address for NAT networking...
==> default: Checking if box 'ubuntu/trusty64' is up to date...
==> default: A newer version of the box 'ubuntu/trusty64' is available! You currently
==> default: have version '20170110.0.0'. The latest is version '20170112.0.0'. Run
==> default: `vagrant box update` to update.
==> default: Setting the name of the VM: Vagrant_default_1485053881499_9345
==> default: Clearing any previously set forwarded ports...
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
default: Adapter 1: nat
==> default: Forwarding ports...
default: 80 (guest) => 8080 (host) (adapter 1)
default: 22 (guest) => 2222 (host) (adapter 1)
==> default: Running 'pre-boot' VM customizations...
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
default: SSH address: 127.0.0.1:2222
default: SSH username: vagrant
default: SSH auth method: private key
default:
default: Vagrant insecure key detected. Vagrant will automatically replace
default: this with a newly generated keypair for better security.
default:
default: Inserting generated public key within guest...
default: Removing insecure key from the guest if it's present...
default: Key inserted! Disconnecting and reconnecting using new SSH key...
==> default: Machine booted and ready!
==> default: Checking for guest additions in VM...
default: The guest additions on this VM do not match the installed version of
default: VirtualBox! In most cases this is fine, but in rare cases it can
default: prevent things such as shared folders from working properly. If you see
default: shared folder errors, please make sure the guest additions within the
default: virtual machine match the version of VirtualBox you have installed on
default: your host and reload your VM.
default:
default: Guest Additions Version: 4.3.36
default: VirtualBox Version: 5.0
==> default: Mounting shared folders...
default: /vagrant => /home/bswamina/MyProjects/Vagrant
==> default: Running provisioner: shell...
default: Running: /tmp/vagrant-shell20170121-21785-blxglw.sh
==> default: stdin: is not a tty
==> default: Ready to install NGINX .....
==> default: Reading package lists...
==> default: Building dependency tree...
==> default: Reading state information...
==> default: The following extra packages will be installed:
==> default: libxslt1.1 nginx-common nginx-core
==> default: Suggested packages:
==> default: fcgiwrap nginx-doc
==> default: The following NEW packages will be installed:
==> default: libxslt1.1 nginx nginx-common nginx-core
==> default: 0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded.
==> default: Need to get 494 kB of archives.
==> default: After this operation, 1,798 kB of additional disk space will be used.
==> default: Get:1 http://archive.ubuntu.com/ubuntu/ trusty/main libxslt1.1 amd64 1.1.28-2build1 [145 kB]
==> default: Get:2 http://archive.ubuntu.com/ubuntu/ trusty-updates/main nginx-common all 1.4.6-1ubuntu3.7 [19.0 kB]
==> default: Get:3 http://archive.ubuntu.com/ubuntu/ trusty-updates/main nginx-core amd64 1.4.6-1ubuntu3.7 [325 kB]
==> default: Get:4 http://archive.ubuntu.com/ubuntu/ trusty-updates/main nginx all 1.4.6-1ubuntu3.7 [5,352 B]
==> default: dpkg-preconfigure: unable to re-open stdin: No such file or directory
==> default: Fetched 494 kB in 0s (649 kB/s)
==> default: Selecting previously unselected package libxslt1.1:amd64.
==> default: (Reading database ... 63025 files and directories currently installed.)
==> default: Preparing to unpack .../libxslt1.1_1.1.28-2build1_amd64.deb ...
==> default: Unpacking libxslt1.1:amd64 (1.1.28-2build1) ...
==> default: Selecting previously unselected package nginx-common.
==> default: Preparing to unpack .../nginx-common_1.4.6-1ubuntu3.7_all.deb ...
==> default: Unpacking nginx-common (1.4.6-1ubuntu3.7) ...
==> default: Selecting previously unselected package nginx-core.
==> default: Preparing to unpack .../nginx-core_1.4.6-1ubuntu3.7_amd64.deb ...
==> default: Unpacking nginx-core (1.4.6-1ubuntu3.7) ...
==> default: Selecting previously unselected package nginx.
==> default: Preparing to unpack .../nginx_1.4.6-1ubuntu3.7_all.deb ...
==> default: Unpacking nginx (1.4.6-1ubuntu3.7) ...
==> default: Processing triggers for ufw (0.34~rc-0ubuntu2) ...
==> default: Processing triggers for ureadahead (0.100.0-16) ...
==> default: Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
==> default: Setting up libxslt1.1:amd64 (1.1.28-2build1) ...
==> default: Setting up nginx-common (1.4.6-1ubuntu3.7) ...
==> default: Processing triggers for ufw (0.34~rc-0ubuntu2) ...
==> default: Processing triggers for ureadahead (0.100.0-16) ...
==> default: Setting up nginx-core (1.4.6-1ubuntu3.7) ...
==> default: Setting up nginx (1.4.6-1ubuntu3.7) ...
==> default: Processing triggers for libc-bin (2.19-0ubuntu6.9) ...
==> default: Install and setup of NGINX completed !!!
From the above output, we see that the virtual environment guest network port 80 is forwarded to the host network port 8080.
If we launch a browser on the host machine and access the URL http://localhost:8080, we should the browser render as follows:
A typical production application involves multiple tiers with different software stack(s) running on different hosts. For example, a 3-tier web application may involve a webserver reverse proxying to an application server, which in turn, accessing data on a database server.
Ideally, we want the development environment emulate the production environment as much as possible.
We will now demonstrate how to start-up and provision a virtual development environment with two guest machines - one running an nginx webserver and another running a Python Flask service. The nginx webserver acts as a reverse proxy for the Python Flask service.
An important point to keep in mind when dealing with multiple guest machines - networking using port forwarding will not work. As each of the guest machines as well as the host machine need to communicate with each other, we need to leverage private host networking. We will pick two unused IP addresses from the private subnet 192.168.x.x - 192.168.100.10 for guest machine running nginx and 192.168.100.20 for guest machine running Python Flask service.
For nginx to acts as a reverse proxy, we need to make changes to the file called default located in the directory /etc/nginx/sites-available/ as shown below:
server {
listen 80 default_server;
listen [::]:80 default_server ipv6only=on;
root /usr/share/nginx/html;
index index.html index.htm;
location / {
try_files $uri $uri/ =404;
}
location /app {
proxy_pass http://192.168.100.20:5000/;
}
}
Modify the Shell script called setup-web.sh in the current directory as shown below:
#!/bin/bash
echo 'Ready to install NGINX .....'
agt-get update > /dev/null 2>&1
apt-get install -y nginx
cp /vagrant/index.html /usr/share/nginx/html/
cp /vagrant/default /etc/nginx/sites-available/
/etc/init.d/nginx reload
echo 'Install and setup of NGINX completed !!!'
Create a new Shell script called setup-app.sh in the current directory as shown below:
#!/bin/bash
echo 'Ready to install Flask .....'
agt-get update > /dev/null 2>&1
apt-get install -y python-flask
mkdir /home/flask
cp /vagrant/MyFlaskApp.py /home/flask/
echo 'Install and setup Flask completed !!!'
python /home/flask/MyFlaskApp.py &
echo 'Started the Flask service !!!'
Create a simple Python Flask webservice script called MyFlaskApp.py as shown below:
Finally, modify the Vagrantfile in the current directory as shown below:
Vagrant.configure(2) do |config|
config.vm.box = "ubuntu/trusty64"
config.vm.provider "virtualbox" do |vb|
vb.memory = "1024"
end
config.vm.define "app" do |app|
app.vm.hostname = 'node-app'
app.vm.network "private_network", ip: "192.168.100.20"
app.vm.provision "shell", path: "setup-app.sh"
end
config.vm.define "web" do |web|
web.vm.hostname = 'node-web'
web.vm.network "private_network", ip: "192.168.100.10"
web.vm.provision "shell", path: "setup-web.sh"
end
end
Now, let us create and configure the multi-node virtual environment by executing the following command:
$ vagrant up
The following would be a typical output:
Bringing machine 'app' up with 'virtualbox' provider...
Bringing machine 'web' up with 'virtualbox' provider...
==> app: Importing base box 'ubuntu/trusty64'...
==> app: Matching MAC address for NAT networking...
==> app: Checking if box 'ubuntu/trusty64' is up to date...
==> app: A newer version of the box 'ubuntu/trusty64' is available! You currently
==> app: have version '20170110.0.0'. The latest is version '20170123.0.0'. Run
==> app: `vagrant box update` to update.
==> app: Setting the name of the VM: Vagrant_app_1485627550242_33702
==> app: Clearing any previously set forwarded ports...
==> app: Clearing any previously set network interfaces...
==> app: Preparing network interfaces based on configuration...
app: Adapter 1: nat
app: Adapter 2: hostonly
==> app: Forwarding ports...
app: 22 (guest) => 2222 (host) (adapter 1)
==> app: Running 'pre-boot' VM customizations...
==> app: Booting VM...
==> app: Waiting for machine to boot. This may take a few minutes...
app: SSH address: 127.0.0.1:2222
app: SSH username: vagrant
app: SSH auth method: private key
app:
app: Vagrant insecure key detected. Vagrant will automatically replace
app: this with a newly generated keypair for better security.
app:
app: Inserting generated public key within guest...
app: Removing insecure key from the guest if it's present...
app: Key inserted! Disconnecting and reconnecting using new SSH key...
==> app: Machine booted and ready!
==> app: Checking for guest additions in VM...
app: The guest additions on this VM do not match the installed version of
app: VirtualBox! In most cases this is fine, but in rare cases it can
app: prevent things such as shared folders from working properly. If you see
app: shared folder errors, please make sure the guest additions within the
app: virtual machine match the version of VirtualBox you have installed on
app: your host and reload your VM.
app:
app: Guest Additions Version: 4.3.36
app: VirtualBox Version: 5.0
==> app: Setting hostname...
==> app: Configuring and enabling network interfaces...
==> app: Mounting shared folders...
app: /vagrant => /home/bswamina/MyProjects/Vagrant
==> app: Running provisioner: shell...
app: Running: /tmp/vagrant-shell20170128-8321-vtcc9a.sh
==> app: stdin: is not a tty
==> app: Ready to install Flask .....
==> app: Reading package lists...
==> app: Building dependency tree...
==> app: Reading state information...
==> app: The following extra packages will be installed:
==> app: python-blinker python-itsdangerous python-jinja2 python-markupsafe
==> app: python-pyinotify python-werkzeug
==> app: Suggested packages:
==> app: python-flask-doc python-jinja2-doc python-pyinotify-doc ipython
==> app: python-genshi python-lxml python-greenlet python-redis python-pylibmc
==> app: python-memcache python-werkzeug-doc
==> app: The following NEW packages will be installed:
==> app: python-blinker python-flask python-itsdangerous python-jinja2
==> app: python-markupsafe python-pyinotify python-werkzeug
==> app: 0 upgraded, 7 newly installed, 0 to remove and 0 not upgraded.
==> app: Need to get 529 kB of archives.
==> app: After this operation, 2,987 kB of additional disk space will be used.
==> app: Get:1 http://archive.ubuntu.com/ubuntu/ trusty/main python-blinker all 1.3.dfsg1-1ubuntu2 [29.8 kB]
==> app: Get:2 http://archive.ubuntu.com/ubuntu/ trusty-updates/main python-werkzeug all 0.9.4+dfsg-1.1ubuntu2 [236 kB]
==> app: Get:3 http://archive.ubuntu.com/ubuntu/ trusty/main python-markupsafe amd64 0.18-1build2 [14.3 kB]
==> app: Get:4 http://archive.ubuntu.com/ubuntu/ trusty/main python-jinja2 all 2.7.2-2 [161 kB]
==> app: Get:5 http://archive.ubuntu.com/ubuntu/ trusty/main python-itsdangerous all 0.22+dfsg1-1build1 [11.5 kB]
==> app: Get:6 http://archive.ubuntu.com/ubuntu/ trusty/main python-flask all 0.10.1-2build1 [51.7 kB]
==> app: Get:7 http://archive.ubuntu.com/ubuntu/ trusty/main python-pyinotify all 0.9.4-1build1 [24.5 kB]
==> app: dpkg-preconfigure: unable to re-open stdin: No such file or directory
==> app: Fetched 529 kB in 0s (556 kB/s)
==> app: Selecting previously unselected package python-blinker.
==> app: (Reading database ... 63025 files and directories currently installed.)
==> app: Preparing to unpack .../python-blinker_1.3.dfsg1-1ubuntu2_all.deb ...
==> app: Unpacking python-blinker (1.3.dfsg1-1ubuntu2) ...
==> app: Selecting previously unselected package python-werkzeug.
==> app: Preparing to unpack .../python-werkzeug_0.9.4+dfsg-1.1ubuntu2_all.deb ...
==> app: Unpacking python-werkzeug (0.9.4+dfsg-1.1ubuntu2) ...
==> app: Selecting previously unselected package python-markupsafe.
==> app: Preparing to unpack .../python-markupsafe_0.18-1build2_amd64.deb ...
==> app: Unpacking python-markupsafe (0.18-1build2) ...
==> app: Selecting previously unselected package python-jinja2.
==> app: Preparing to unpack .../python-jinja2_2.7.2-2_all.deb ...
==> app: Unpacking python-jinja2 (2.7.2-2) ...
==> app: Selecting previously unselected package python-itsdangerous.
==> app: Preparing to unpack .../python-itsdangerous_0.22+dfsg1-1build1_all.deb ...
==> app: Unpacking python-itsdangerous (0.22+dfsg1-1build1) ...
==> app: Selecting previously unselected package python-flask.
==> app: Preparing to unpack .../python-flask_0.10.1-2build1_all.deb ...
==> app: Unpacking python-flask (0.10.1-2build1) ...
==> app: Selecting previously unselected package python-pyinotify.
==> app: Preparing to unpack .../python-pyinotify_0.9.4-1build1_all.deb ...
==> app: Unpacking python-pyinotify (0.9.4-1build1) ...
==> app: Setting up python-blinker (1.3.dfsg1-1ubuntu2) ...
==> app: Setting up python-werkzeug (0.9.4+dfsg-1.1ubuntu2) ...
==> app: Setting up python-markupsafe (0.18-1build2) ...
==> app: Setting up python-jinja2 (2.7.2-2) ...
==> app: Setting up python-itsdangerous (0.22+dfsg1-1build1) ...
==> app: Setting up python-flask (0.10.1-2build1) ...
==> app: Setting up python-pyinotify (0.9.4-1build1) ...
==> app: Install and setup Flask completed !!!
==> app: Started the Flask service !!!
==> web: Importing base box 'ubuntu/trusty64'...
==> web: Matching MAC address for NAT networking...
==> web: Checking if box 'ubuntu/trusty64' is up to date...
==> web: A newer version of the box 'ubuntu/trusty64' is available! You currently
==> web: have version '20170110.0.0'. The latest is version '20170123.0.0'. Run
==> web: `vagrant box update` to update.
==> web: Setting the name of the VM: Vagrant_web_1485627602622_53522
==> web: Clearing any previously set forwarded ports...
==> web: Fixed port collision for 22 => 2222. Now on port 2200.
==> web: Clearing any previously set network interfaces...
==> web: Preparing network interfaces based on configuration...
web: Adapter 1: nat
web: Adapter 2: hostonly
==> web: Forwarding ports...
web: 22 (guest) => 2200 (host) (adapter 1)
==> web: Running 'pre-boot' VM customizations...
==> web: Booting VM...
==> web: Waiting for machine to boot. This may take a few minutes...
web: SSH address: 127.0.0.1:2200
web: SSH username: vagrant
web: SSH auth method: private key
web:
web: Vagrant insecure key detected. Vagrant will automatically replace
web: this with a newly generated keypair for better security.
web:
web: Inserting generated public key within guest...
web: Removing insecure key from the guest if it's present...
web: Key inserted! Disconnecting and reconnecting using new SSH key...
==> web: Machine booted and ready!
==> web: Checking for guest additions in VM...
web: The guest additions on this VM do not match the installed version of
web: VirtualBox! In most cases this is fine, but in rare cases it can
web: prevent things such as shared folders from working properly. If you see
web: shared folder errors, please make sure the guest additions within the
web: virtual machine match the version of VirtualBox you have installed on
web: your host and reload your VM.
web:
web: Guest Additions Version: 4.3.36
web: VirtualBox Version: 5.0
==> web: Setting hostname...
==> web: Configuring and enabling network interfaces...
==> web: Mounting shared folders...
web: /vagrant => /home/bswamina/MyProjects/Vagrant
==> web: Running provisioner: shell...
web: Running: /tmp/vagrant-shell20170128-8321-1fhn3xh.sh
==> web: stdin: is not a tty
==> web: Ready to install NGINX .....
==> web: Reading package lists...
==> web: Building dependency tree...
==> web: Reading state information...
==> web: The following extra packages will be installed:
==> web: libxslt1.1 nginx-common nginx-core
==> web: Suggested packages:
==> web: fcgiwrap nginx-doc
==> web: The following NEW packages will be installed:
==> web: libxslt1.1 nginx nginx-common nginx-core
==> web: 0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded.
==> web: Need to get 494 kB of archives.
==> web: After this operation, 1,798 kB of additional disk space will be used.
==> web: Get:1 http://archive.ubuntu.com/ubuntu/ trusty/main libxslt1.1 amd64 1.1.28-2build1 [145 kB]
==> web: Get:2 http://archive.ubuntu.com/ubuntu/ trusty-updates/main nginx-common all 1.4.6-1ubuntu3.7 [19.0 kB]
==> web: Get:3 http://archive.ubuntu.com/ubuntu/ trusty-updates/main nginx-core amd64 1.4.6-1ubuntu3.7 [325 kB]
==> web: Get:4 http://archive.ubuntu.com/ubuntu/ trusty-updates/main nginx all 1.4.6-1ubuntu3.7 [5,352 B]
==> web: dpkg-preconfigure: unable to re-open stdin: No such file or directory
==> web: Fetched 494 kB in 0s (659 kB/s)
==> web: Selecting previously unselected package libxslt1.1:amd64.
==> web: (Reading database ... 63025 files and directories currently installed.)
==> web: Preparing to unpack .../libxslt1.1_1.1.28-2build1_amd64.deb ...
==> web: Unpacking libxslt1.1:amd64 (1.1.28-2build1) ...
==> web: Selecting previously unselected package nginx-common.
==> web: Preparing to unpack .../nginx-common_1.4.6-1ubuntu3.7_all.deb ...
==> web: Unpacking nginx-common (1.4.6-1ubuntu3.7) ...
==> web: Selecting previously unselected package nginx-core.
==> web: Preparing to unpack .../nginx-core_1.4.6-1ubuntu3.7_amd64.deb ...
==> web: Unpacking nginx-core (1.4.6-1ubuntu3.7) ...
==> web: Selecting previously unselected package nginx.
==> web: Preparing to unpack .../nginx_1.4.6-1ubuntu3.7_all.deb ...
==> web: Unpacking nginx (1.4.6-1ubuntu3.7) ...
==> web: Processing triggers for ufw (0.34~rc-0ubuntu2) ...
==> web: Processing triggers for ureadahead (0.100.0-16) ...
==> web: Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
==> web: Setting up libxslt1.1:amd64 (1.1.28-2build1) ...
==> web: Setting up nginx-common (1.4.6-1ubuntu3.7) ...
==> web: Processing triggers for ufw (0.34~rc-0ubuntu2) ...
==> web: Processing triggers for ureadahead (0.100.0-16) ...
==> web: Setting up nginx-core (1.4.6-1ubuntu3.7) ...
==> web: Setting up nginx (1.4.6-1ubuntu3.7) ...
==> web: Processing triggers for libc-bin (2.19-0ubuntu6.9) ...
==> web: * Reloading nginx configuration nginx
==> web: ...done.
==> web: Install and setup of NGINX completed !!!
Launch a browser on the host machine and access the URL http://192.168.100.10/app, we should the browser render as follows:
Hooray !!! We have successfully demonstrated the automatic provisioning and setup of multi-node virtual development environment using Vagrant.
To login to the VirtualBox guest machine running nginx, execute the following command:
$ vagrant ssh web
The following would be a typical output:
Welcome to Ubuntu 14.04.5 LTS (GNU/Linux 3.13.0-107-generic x86_64)
* Documentation: https://help.ubuntu.com/
System information disabled due to load higher than 1.0
Get cloud support with Ubuntu Advantage Cloud Guest:
http://www.ubuntu.com/business/services/cloud
0 packages can be updated.
0 updates are security updates.
New release '16.04.1 LTS' available.
Run 'do-release-upgrade' to upgrade to it.
vagrant@node-web:~$
Similarly, to login to the VirtualBox guest machine running Python Flask service, execute the following command:
$ vagrant ssh app
This concludes the topic on Vagrant.
References