Skip to content

Commit 0854970

Browse files
HelgeCPHHelgeCPH
committed
Automatic release of teaching material.
1 parent d33434b commit 0854970

File tree

1 file changed

+180
-0
lines changed

1 file changed

+180
-0
lines changed

‎sessions/session_03/README_PREP.md

+180
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,180 @@
1+
# Preparation Material for Session 03
2+
3+
Install VirtualBox and Vagrant on your computer.
4+
5+
6+
### Vagrant & VirtualBox
7+
8+
In case you are running MacOS or Windows you might find helpful [installation instructions for your host operating system in the linked guide](https://www.itu.dk/people/ropf/blog/vagrant_install.html). Note, Vagrant cannot be run in a VirtualBox VM. This means that you should install Vagrant and related plugins in your host OS (Windows/MacOS) if you are running Linux in a virtual box already. This is because vagrant creates VMs, and creating VMs from a VM can cause problems.
9+
10+
Install Virtualbox:
11+
12+
```bash
13+
sudo apt install virtualbox virtualbox-ext-pack
14+
```
15+
16+
Since the packaged Vagrant in the linked repositories is in a bit buggy version we install it directly from the package provided by the tool vendor:
17+
18+
```bash
19+
wget -O- https://apt.releases.hashicorp.com/gpg | gpg --dearmor | sudo tee /usr/share/keyrings/hashicorp-archive-keyring.gpg
20+
echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list
21+
sudo apt update && sudo apt install vagrant
22+
```
23+
24+
After installing Vagrant, we need to install a Vagrant plugin that we will need later:
25+
26+
```bash
27+
vagrant plugin install vagrant-digitalocean
28+
vagrant plugin install vagrant-scp
29+
vagrant plugin install vagrant-vbguest
30+
vagrant plugin install vagrant-reload
31+
```
32+
33+
Save the following into a file called `Vagrantfile` in your current directory:
34+
35+
```ruby
36+
# -*- mode: ruby -*-
37+
# vi: set ft=ruby :
38+
39+
Vagrant.configure("2") do |config|
40+
41+
config.vm.box = "bento/ubuntu-22.04"
42+
43+
config.vm.provider "virtualbox" do |vb|
44+
# Customize the amount of memory on the VM:
45+
vb.memory = "1024"
46+
end
47+
end
48+
```
49+
50+
Now, try to run from your current directory (the one in which you saved the `Vagrantfile`):
51+
52+
```bash
53+
vagrant up
54+
```
55+
56+
The command downloads the OS image `bento/ubuntu-22.04` and brings up a virtual machine on your computer (with Virtualbox as backend).
57+
It will take some time since the corresponding OS image has to be downloaded first. That image will be cached on your disk, i.e., following VM instantiations of the same image will be faster.
58+
Observe that no error message is displayed. If so, and in case you cannot find a solution for it, we will look at it in class.
59+
60+
61+
In case you did not receive any error message, for now, you can run:
62+
63+
```bash
64+
vagrant destroy
65+
```
66+
67+
### Intro to VMs with Vagrant
68+
69+
> Vagrant is a tool for building and managing virtual machine environments in a single workflow. With an easy-to-use workflow and focus on automation, Vagrant lowers development environment setup time, increases production parity, and makes the "works on my machine" excuse a relic of the past.
70+
>
71+
> Vagrant provides easy to configure, reproducible, and portable work environments built on top of industry-standard technology and controlled by a single consistent workflow to help maximize the productivity and flexibility of you and your team.
72+
>
73+
> https://www.vagrantup.com
74+
75+
In case you are in doubt about anything in the following quick intro, check the [brief and really good documentation](https://www.vagrantup.com/docs/).
76+
77+
#### Initialize & Start a VM
78+
79+
You can start your setup by creating a `Vagrantfile`. The argument to `vagrant init` is the name of the *box*. That is,
80+
81+
```bash
82+
$ mkdir vm
83+
$ cd vm
84+
$ vagrant init bento/ubuntu-22.04
85+
$ vagrant up
86+
```
87+
88+
> After running the above commands, you will have a fully functional VM in VirtualBox running Ubuntu 22.04 LTS 64-bit. You can SSH into this machine with `vagrant ssh`, and when you are done playing around, you can terminate the virtual machine with `vagrant destroy`.
89+
90+
91+
#### Accessing a VM
92+
93+
You log onto a VM with SSH as in the following.
94+
95+
```bash
96+
$ vagrant ssh
97+
```
98+
99+
You can leave the guest VM with:
100+
101+
```bash
102+
$ vagrant@vagrant: exit
103+
```
104+
105+
#### Teardown
106+
107+
A running VM can be ...
108+
109+
* put to sleep
110+
111+
```bash
112+
$ vagrant suspend
113+
```
114+
115+
* turned off
116+
117+
```bash
118+
$ vagrant halt
119+
```
120+
121+
* removed completely
122+
123+
```bash
124+
$ vagrant destroy
125+
```
126+
127+
#### State of VMs
128+
129+
The following command will display a list of all VMs and their respective states, i.e., `saved`, `poweroff`, `active`, etc.
130+
131+
```bash
132+
$ vagrant global-status
133+
```
134+
135+
#### VMs with other Operating Systems
136+
137+
That is, you can quickly setup development environments for many operating systems. For example, in the following the initialization and use of a FreeBSD and Windows VM.
138+
139+
```bash
140+
$ mkdir vm_freebsd
141+
$ cd vm_freebsd
142+
$ vagrant init freebsd/FreeBSD-12.3-STABLE
143+
$ vagrant up
144+
```
145+
146+
```bash
147+
$ mkdir vm_win
148+
$ cd vm
149+
$ vagrant init senglin/win-10-enterprise-vs2015community
150+
$ vagrant up
151+
```
152+
153+
You can find a catalog of available boxes at https://app.vagrantup.com/boxes/search
154+
155+
<img src="images/vm_catalogue.png" width="80%">
156+
157+
158+
### Vagrant for **local** development setup
159+
160+
At last, apply `vagrant` for a usual scenario: reproduction of development environments.
161+
162+
The branch [`VMify_local`](https://github.com/itu-devops/flask-minitwit-mongodb/tree/VMify_local) of repository https://github.com/itu-devops/flask-minitwit-mongodb contains an _ITU-MiniTwit_ application similar to the one you took over last week. It was refactored to use a MongoDB database instead of an SQLite3 database.
163+
164+
The application is a two-layered application with a frontend server (called `webserver`) and a database server (called `dbserver`).
165+
With the VM setup from the [`VMify_local`](https://github.com/itu-devops/flask-minitwit-mongodb/tree/VMify_local) branch, you have a complete running setup of the entire application that you can recreate on you computer, e.g., for local development.
166+
167+
To do so, clone the repository, switch to the right branch, check and try to develop a feeling for the contents of the [`Vagrantfile`](https://github.com/itu-devops/flask-minitwit-mongodb/blob/VMify_local/Vagrantfile), and start-up the VMs.
168+
169+
```bash
170+
$ git clone https://github.com/itu-devops/flask-minitwit-mongodb.github
171+
$ cd flask-minitwit-mongodb
172+
$ git checkout VMify_local
173+
$ vagrant up
174+
Bringing machine 'dbserver' up with 'virtualbox' provider...
175+
Bringing machine 'webserver' up with 'virtualbox' provider...
176+
...
177+
```
178+
179+
If everything starts error-free, you will find the running _ITU-MiniTwit_ at http://192.168.20.3:5000. With `vagrant ssh webserver` you can access the machine with the frontend code.
180+

0 commit comments

Comments
 (0)