So first, we log on to our cloud. There is a user named demo that has
already been provisioned by the deployment tool that I used.
I'll go directly to the Network section, and here the Network
Topology, which is a graphical representation of my network.
And you can see there are already two networks, public, which is for
the outside network outside of the cloud, and private connected by a router.
Let me launch an instance on the private network, that's my first-tier network.
So this is a web server, I'll call it webserver1.
I need to provision it from somewhere, I'll have to provide a provisioning source.
Several types of sources are available. I'll select Image,
and I specify that I don't want a volume.
The lower half of the screen shows all the images.
Right now there is only one, and I'm going to select it.
The last thing I have to specify is the size of my server, and that is
called a Flavor. I will make the tiny server with 1 CPU, 0.5 GB of
RAM, and a 1 GB root disk. And with that, I have filled in all the
mandatory parts, and I can launch the instance.
Great. The next step is to add a networking tier for my application
servers, so I'll create a network. That will be my appnet, and I also
have to provide an IP address range, that is called a subnet in OpenStack terminology.
It requires a name, and the address range, I can select whatever I want.
The third and final screen shows that by default, a DHCP server is
enabled on each network, and I will leave it like that.
Alright, appnet was created, but it's a bit isolated right now.
I want to connect it to private, to my first tier, so I need a router.
I'll just give it a name, and I will not connect this router to an external network.
I could do that, but in this case, the router connects to internal
networks to each other. Here's our router, next step is to connect it
to the two networks, first appnet. I'm going to click on that router,
and I will add an interface. This interface is the interface to
appnet, and I will ask OpenStack to provide a default IP address.
The router also needs to be connected to private.
So again, I click on the router, let me move that to the side,
and then add interface. And there is only one subnet left,
namely the private subnet. Here I have to specify the IP address,
the default IP address is already taken by router1 unfortunately,
so I have to do that manually. With that, I have created my second
network tier and connected it to the first tier.
Last but not least, let's also run a server on the second tier.
Since it is the appnet, it will be the appserver or appserver1.
Same source as before, and the same flavor as before.
And here I have to select the network, because we have two networks now.
And of course I'm going to select appnet.
And here we have it, a 2-tier application, a 2-tier networking with
two servers connected to the networks made in about 5 minutes.
That was your first glimpse at an OpenStack cloud.
What did you see? A cloud is a little bit like a physical data
center with servers, networks, and storage systems.
The main difference to a real data center, it takes almost no effort
to create servers, networks, and LANS, and connect them together
without the inconvenience of hauling heavy equipment and stringing cables.
There are many things we haven't touched yet in this discovery tour,
for example, how can we connect to an instance from the outside world,
how can we protect an instance from unauthorized access, and of course
we just saw the cloud from a user's perspective, not from a cloud operator's.
In a few minutes, you will have the opportunity to discover a cloud for yourself.