Are you looking for cloud architect interview questions or solution architect interview
questions?
If so, this video is for you.
Hi, my name is Michael Gibbs and I'm the founder and CEO of Go Cloud Architects and we're an
organization dedicated towards building high-performance cloud computing and networking careers.
I've been working in tech now for over 25 years and coaching and mentoring others to
get their first tech job or get promoted in tech for two decades now.
And I've loved every last moment of it.
Today we're going to talk about cloud architect interview questions or solutions to architect
interview questions.
And when we describe these, we're going to describe them in a little bit of depth.
See what happens when you go on a cloud architect interview or a solutions architect interview.
We're asking these questions to gauge a few things.
One and primarily is your technical competence, but two is how well you communicate that technology.
And three is how well you can actually listen to the question and respond to it.
See, these are real critical architecture skills.
So we're going to ask them in these interviews and we're going to do this by asking open-ended
questions.
So for example, if I were to give someone a question of what is object storage and they
answer S3, that is not a winning answer.
And if they describe object storage, what it is, how it works and why an organization
would use it, that's going to be a winning answer.
And then they can also say after you know that, here's an AWS implementation of S3,
here's a Microsoft Azure implementation called Blob.
But really what it's about is just knowing, can you describe the technology?
Because that's, what's you're going to be dealing with an architect constantly, describing
technology to executives, engineers, and architects.
So let's go with the question.
The first question will be, what is a firewall, how does it work and why does an organization
use it?
And really what we're looking to hear is that a firewall is an appliance that keeps bad
guys out or intruders out.
And it also lets internal users behind the firewall be secure.
So let's look at it this way.
Think of a firewall as a big wall around a castle protecting people from coming in, think
of the firewall.
But if you had walls around the castle, you wouldn't be able to get out of the castle.
So at some point you'd have to open the door to get out and open the door to get in.
But if you open the door to get out, it would be open for intruders to get in.
So you can't just do that.
So firewalls use something called stateful packet inspection.
And what does this mean?
A firewall which blocks the perimeter, looks and watches everything that's going on.
So by default, firewalls block all incoming traffic that's generated externally, but firewalls
allow internal traffic to traverse the firewall and come back.
So how do they do that?
Firewalls are what's called stateful.
So here's what that actually means.
Here's my firewall, here's me.
I want to go to www.gocloudcareers.com.
I go from my PC through the firewall, to the internet.
It then it gets routed to the web server that's handling my system.
And then it comes back.
The web server answers my request and yet the firewall miraculously let's my traffic
in, so why?
See what's going on is the firewall is watching my connection.
As soon as I pierced through the firewall, it knows my source address and destination
IP address protocols and port number and it tracks that and it puts it into a table.
So then when I traverse that, say I send a SNI to an external web server to open a connection,
a TCP connection.
And the web server responds to my SNI with an arc and then generates a SNI to open the
connection on the other end, the firewall watched it, the firewall knows because the
firewall is stateful.
So that's what we mean by stateful packet inspection.
It's watching what's going on and then it allows you to return.
So organizations use firewalls to protect the perimeter for the network.
Firewalls are configured by default to block all incoming traffic, except that you enable.
So by policy, you determine what you allow in, if any, and the firewall lets your outbound
traffic return.
So organizations use it to protect the perimeters of the network to enhance their security using
the network needs and data center unused in the cloud.
Now, you know what is a firewall, how it works and why you would use them.
Now, this next question pops up a lot.
When you use an application load balancer versus a network load balancer, and people
struggle with it and there's really no reason.
We find that people that come from an application development background automatically think
of an application load balancer.
And we find that people like me, they're used to defining high performance networks, use
network bouncers, but let's break it down into something more than that.
An application load balancer and a network load balancer are similar and different in
certain ways in that they're both similar and that they load balance between certain
things.
They are dissimilar with regards to the intelligence and their speed and performance.
So an application load balancer is really, really smart.
It's looking at layer seven of the OSI model it's looking at things in the header.
And it is very intelligent because it'll look at all parts of an HTTP or HTTPS header and
it can do some very intelligent routing.
So if your performance needs are low and you're trying to route between say microservices
or certain containers that are small, use an application load balancer, it's super smart.
Now what happens when you ask something to do a lot of work, it's slow?
What happens if you ask something to do something very minimal, it's fast.
So if you need performance, for example, you use a network a load balance, a network load
balancer, which operate at layer four are very fast because all they do is they map
the flows for the most part.
So that's destination address protocol, port number boom in and out, in and out, in and
out.
And because of that, they're really fast.
So routing between microservices, needing a lot of intelligence, use an application
load balancer, high performance routing high-performance movement of your data, share it with a network
load balancer.
Now, you know which one to use.
This next question pops up on all kinds of certification exam, but it's also something
that we may ask to see if someone's actually worked with the network before.
The question is, how long does it take to transfer an organization's data over the WAN
connection?
See, let's say you want to migrate to the cloud.
You need to take your data from your data center and move it to the cloud.
And there's lots of ways you can do it.
You can use it with transfer appliances, send your files directly over.
You can basically receive a hard drive and send a hard drive over, or you can receive
a ruggedized computer plus hard drive and send it over.
Or you can just use your network.
So let's talk about how long it's going to take over the network because the time that
you have, and the speed that you have will determine whether you can use the network
or whether you need something different, like an AWS snowmobile, snowball for example, where
a huge environment an AWS snowmobile, so let's calculate it out.
So here's what you do.
Let's say you have a gigabit per second WAN length.
That means you can transfer a gigabit per second, but wait data is actually bytes, not
bit.
So now the first thing you need to do is take your 1,000 megabit and divide by eight, because
there's eight bit to a byte.
Now that gets you your megabit per second rate.
So now take your megabit per second rate, multiply that by 60 because there's 60 seconds
in a minute.
Now again, multiply that to by 60 again because there's 60 minutes in an hour and then multiply
that by 24.
Now, guess what?
You know exactly how much data you can transfer in one day, very simply.
Now that you know this, let's say you have a certain amount of data.
Take the amount of data you have divided by the amount of data per day.
And you will know how many days it will take to get your data from point A to point B.
That's it, that's how you know how long it will take to transfer your data.
So if you're ever posed an exam question or an interview question that says, you've got
a certain amount of data and a certain amount of time, what should you do?
You now know how to calculate it, so wonderful.
Now let's talk about the non transitive routing.
What is non-transitive routing and why I'm asking these questions.
When you're dealing with IBGP in the networking world, you're dealing with a lot of non-transitive
routing, but when you're in cloud computing, you're also dealing with non-transitive routing.
Why is this?
The cloud providers want to work hard to make sure that you don't make your organization
transit to the entire world?
So here's what non-transitive routing is.
Let's say B, router B, or organization B in the middle.
Organization A to the left of me.
Organization B to the right of me.
And of course this may be actually flipped because of the camera, but where my left hand
is actually at, see, this is organization A organization B and where my right hand is
that we'll call this organization C. In order for A to reach me and C, I need to make sure
that each person knows each other's routing information.
So if C gives me it's routing information and I pass C's routing information to A, A
knows how to reach C. Now if A sends his information to me, to B me and I send it to C, now they
can both reach each other, that is fully transitive routing.
What is non-transitive routing?
If I take in As routes and I take an C's routes, and I know how to reach A, because I have
A's routes and A has mine and C knows how to reach me because it has his routes and
mine, but A and C don't know each other's routes, that's non transitive routing.
Which means I can talk to A and I can talk to C, but A can't talk to C through me that
is non-transitive routing.
So let's look about what you could do about these kinds of things.
In BGP, that traditional environment IBGP, we use something called a route reflector.
And what was the route reflector?
Something that broke the rules of non-transitive routing.
So A would send a route out to me B, B would send it to C, C would send it to B and B would
send it to A. And all of a sudden, everybody can talk to everybody.
Now that's great when you want them to, but if you don't want them to, that's a problem
because you become transit for people.
So when you're dealing with the cloud providers and you're connecting multiple, VPCs, what
they do is they prevent them from exchanging each other's routing information for both
security purposes, as well as to make sure you don't become transit for multiple partner
organizations.
So how do you do that in the cloud?
Let's say you're on AWS, for example, and you've got a VPC peer to multiple organizations,
and of course you could fully match them, just like you did with IBGP.
And with IBGP, we came up with a solution called a route reflector.
And when you're dealing with cloud providers, let's take AWS they have things like cloud
hub and transit gateway.
What is cloud hub and transit gateway?
Almost effectively the same route reflector technology, all the implementations and what
they support are different.
Basically it means that if C, VPC C sends me VPC B it's routing information, and I pass
it to VPC A its routing information, then they can all reach each other.
So what happens with these transit gateways and cloud hubs, is they permit transitive
routing, they break the rules of non-transitive abruptly and by allowing it to go through
and everybody has reachability, which enables you to create a hub-and-spoke routing environment
with VPC peering in the club.
Now, since we're talked about the routing and the complexities of this, what is VPC
peering?
Well, we're going to tell you right now.
So when we ask someone what is VPC peering, we're trying to find out if they actually
know first, what is a VPC and why organizations would peer that with other organizations or
themselves?
So what VPC peering is, is you take an organization's virtual, private cloud, and you connect it
to another organization's virtual, private cloud, and you exchange routing information
and services between them and in the process, you enable them to talk to each other.
So let's look at why you might want to do VPC peering.
Let's say for an example, you are a retail store.
Let's say you have a partner organization that you buy your supplies from, and they
also purchase certain things from you.
You could peer your organization with somebody else's virtual, private cloud ride over the
AWS network for example, leveraged the high performance network that AWS has and communicate
to each other in a private and secure.
So what is VPC peering?
VPC peering is used to one organization to another organization, leveraging the benefits
of the network supported by the cloud provider in a rapid and secure and fast manner.
I hope you've enjoyed these AWS solutions, architect, interview questions, or cloud architect,
interview questions.
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We will bring you in, you will interview me.
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Thank you and take care.