Are you looking for AWS 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 careers. Today, we're going
to be talking about AWS interview questions. Now, at Go Cloud Architects, we spend a lot
of time teaching you how to interview and we teach you the leadership skills, we can
teach you the verbal skills, and we teach you the interview skills, but that's for your
generic interviews, but there's still a technical interview for the cloud architect. The point
of the technical interview is to ascertain what your level of technical competency is,
but also determine how well you can explain the technology, how well you understand the
technology, and if you can design the technology. So, let's help you out, let's give you some
more cloud architect questions, so you can learn from the questions, be prepared for
a year interview, and get hired. That's the ultimate goal of all this training is to help
you have a fantastic cloud architect career.
The first question we're going to ask you today is what is a load balancer and why would
you use it? Really what we're trying to determine is not if you know the name of an AWS service
or a Google service, that's not important from an architecture perspective. What is
important is that you know what a low balancer is and why you would use it. Let's talk about
first, what is a load balancer? A load balancer is a type of device, it's typically a server
or a piece of specific hardware, that will determine which server to send traffic to.
If you desire to load share between five servers, you're going to use a load balancer to share
the load across from five servers.
Why would we do all of this? Why wouldn't we just use a big server? Well, in reality,
you could in many cases just use a really big server as opposed to five small servers,
but you've got a problem. What if a single server fails? You've got nothing, you've got
no redundancy, so when you're designing a high-performance web application that also
requires high availability, you're going to use a load balancer. A load balancer is a
device to increase the availability and performance of your systems. That's what a load balancer
is and that's really what you need to know.
Now, when we look at load balancers, we can further break them down into either a network
load balancers or application load balancers and they're a little bit different. Network
load balancers are really fast. Network low balancers work at layer four, so basically
they're looking at, say, what's going on in the TCP header and they're pushing it across
the other side and they're very fast because all they're looking at is layer four information.
All they're looking at is layer four information so they're really fast, they don't have a
lot to do. When you're using a load balancer and you need extreme performance, you're going
to use a network load balancer.
The other type of load balancer is something called an application load balancer and an
application load balancer works instead of layer four of the OSI model, like the network
load balancer, at layer seven or the OSI model, and an application load balancer looks at
the application. If you need an incredible amount of application intelligence and application
routing, you're going to use an application load balancer because it can look in things
of, say, the HTTP header and it can do very detailed routing based upon what's going on.
Application load balancer, if you're going to, say, route between microservices or you
need intelligence in your routing, network load balancer, if you need speed.
Now, of course, when you deal with AWS or GCP, they have their version of an elastic
load balancer for network and elastic load balancer for application, but realistically
speaking, it's just a network or application load balancer. In your architecture you need
to know what to use, which is going to be a network load balancer or an application
load balancer and then on the cloud provider, you can pick the service that matches it.
The next question I'm going to ask you is what is a Firewall? The reason we ask this
is a Firewall is an absolutely critical component to security but when we ask people questions,
we find that many just don't know. Let's talk about it. A Firewall protects the perimeter
of the edge of your network. It is a security appliance that's basically standing guard
saying, "You're not allowed in. You're not allowed in. You're not allowed in." What a
Firewall does is it looks for traffic based upon policy. Firewalls by default will block
all external traffic from coming in. They want to come in it's block, block, block,
block, because unless you allow it in, the Firewall will block everything. By comparison,
a Firewall will all your internal network out on the internet and it will allow all
your return traffic back through the Firewall. How?
Firewalls are what's called stateful. What we mean by stateful is stateful actually tracks
what's going on, so if I'm behind the Firewall and I am behind a Firewall while making this
video, and if I want to send my traffic to the internet, I send my traffic through the
Firewall. Now my Firewall's smart, it's stateful, it's watching and it says, "Okay, Mike started
the session, let his return traffic come back because I know it's destined for Mike and
I know it's related to the same session where Mike requested the web content," because it's
stateful so it's watching it.
What does a Firewall do? It blocks traffic, the edge of your network, it keeps your network
secure, it blocks all traffic denied by policy, and it miraculously lets your outbound traffic
back if it's coming from you. That is a Firewall, how it works, and you would use it to enhance
security.
The next question and we're starting to get into the financial implications of cloud computing.
The question is how does cloud computing affect an organization's cost? Well, it affects it
in a lot of different ways. Let's first look at it from the first perspective of normal
costs. Typically in a data center, you have a large amount of capital cost, you're purchasing
servers, you're purchasing networks, you're purchasing all the devices that go on servers,
workstations, Firewalls, load balancers, routers, switches, air conditioning, power distribution
units, they're the things that you must purchase, which means capital. It costs something to
maintain this data and that's called your operational costs. In a traditional data center,
you have extremely high capital costs and your operational costs are related to things
like electric, your network connections, and the people that staff your network. Typically
speaking, super high capital costs, moderately high on ongoing costs.
Now, when you move to the cloud, there's nothing to buy. Since there's nothing to buy, the
shift to the cloud substantially decreases your capital expenditures or your capital
costs. But every time you do anything on the cloud, you're going to pay for it. You're
going to pay for data being sent. You're going to pay for every second your systems are up.
You're going to pay for every day that your network connections are up and you're going
to pay for data sent on your network. In a cloud computing environment, while capital
costs are really low, your operational costs are extremely high. The cloud competing environment
causes a shift from capital expenses effectively to operational expenses. In a cloud computing
environment, it is much more expensive operationally, but much cheaper capital-wise. Is it cheaper
on the cloud? It may be, it may not be, and that's going to be based upon how well the
architecture is done, how well it's planned, and whether there really is a benefit for
this customer. But what there will always be is an agility benefit, meaning if it took
me a month to buy a server from Dell and have it delivered and installed, and I can spin
up an EC2 instance, for example, on the AWS cloud in seconds, that level of agility is
incredible and that level of agility is one of the main reasons we move to the cloud,
speed, agility.
The next question we're going to ask you today are what our VPC flow logs and why we'd use
them? Now, this is a bit of a networking/AWS question and the reason we're asking it is
we want to see if you understand traffic flows and traffic management and why you would use
them. For people from the networking world, they're pretty familiar with something called
Cisco NetFlow. What Cisco NetFlow did is it would examine the traffic, they would cross
Cisco routers, and you could say, "Hmm, the traffic's all going from here to point B,"
and the reason you were doing this, as you were looking for security violations, you
were looking for areas of congestion in your network, and it would enable you to better
plan what's going on in your network and troubleshoot. Fantastic. AWS did the same thing. They created
something called the flow log and the flow log basically lets you see the traffic that
goes across your VPC. VPC flow logs give you lots of information about your traffic flows,
but they are excellent for troubleshooting, especially in security.
For example, the VPC flow logs will tell you the source and destination. It will tell you
the protocols and the port numbers of things going on the wire. For example, you can see
that something's being accepted by your ACL, but rejected by the security group. If you've
got traffic that's supposed to go to a web server and it's accepted by the ACL, but blocked
by the security group and you want it there, now you know what to fix. VPC flow logs give
you a lot of information about your traffic and they help you set up your proper flows
and they help you debug things when things are broken so they're very effective and the
troubleshooting environment.
Now this next question is an architecture question and you have a web server in a data
center and you want to move it to the cloud. What do you need to know before you move it
to the cloud? Server in the data center, you want to bring it to the cloud, but do you
need to know? Well, I'll tell you. First thing we need to know is the power of the server.
How many cores, how much DRAM, how much storage? Because guess what? We need the same thing
for the cloud. We need a virtual machine that's going to have a similar number of cores, a
similar amount of DRAM, and provide the appropriate storage. In this particular environment, you
just lift a server to the cloud, just know the basics of your virtual machine. Have your
server on one end, match it up with an instance which is a virtual machine on the other end,
and there you go, completely done.
I'm going to give you one more question for the day and this question is DNS question
and what is the difference between latency based routing and geolocation based routing?
Now, what we're looking for, because you could think of both of these as latency based, but
in some ways they are, but in some ways they're not. Latency based routing determines the
lowest latency and sends you to the web server with the lowest latency so you get the best
experience. Geolocation routing is something different. Geo-location routing actually looks
at the source IP address and determines what's closest to you.
Let's say for example, I'm in Canada and I know that this province is French and this
province is English. I might look at the user's source address and say, "Route the French
province to the French website. Route the English province to the English website."
That's when you would use geolocation routing. Geolocation routing enables you to take users
based upon their source address and send them to a different destination. What's great when
you're dealing with a multinational company, for which they have multiple languages, they
need multiple websites. Latency routing is for speed and performance, geo-location routing,
while will also optimize speed and performance, what it really will do will send people to
the appropriate website based upon their locations.
What have we talked about today? We talked about what a load balancer was, what a Firewall
was, how does cloud computing affect an organization's cost, what are VPC flow logs and why would
you use them? How to do a simple lift and shift of a server from the data center to
the cloud, and we talked about the difference between latency based routing and geolocation
routing.
Let's talk about some things that we can do to help you in your cloud computing career.
Every Monday and every Thursday, we have a free how to get your first cloud job webinar
and on this webinar, we teach you everything you need to know to get your first job, things
that could be on your resume, how to be the perfect interview, exactly what hiring managers
are looking for, and the types of certifications that you need. Then after that, we spend an
hour answering any cloud architecture questions you may have. We do this for free on Mondays
and Thursdays.
Now on every Tuesday, what we do is we have a cloud architect experience webinar and on
this webinar, we talk about it from a technology perspective, what is it going to take to get
the real world experience of a cloud architect so you can get hired? On Mondays we do how
do you build your career and on Tuesdays we talk about technology and it's all free.
Now most Wednesdays, not all, but most Wednesdays we hold a free YouTube Live, where you can
bring us any cloud architect career question, and we will answer them live in real time.
Typically we do these, we get lots of people, it's typically a fun experience. We love to
coach the world and we do it completely for free. We do it [inaudible 00:12:18] so please
subscribe to our channel and check out.
We have just instituted the Ask Cloud Mike email address program. I'll drop the link
in the description below. If you have any questions about your cloud computing career
and you can't make it to one of the free webinars, send us an email to askcloudmike, the link
is in the description below, and ask a questions related to your career and we will do everything
we can to try and produce a video on our YouTube channel to answer your questions, especially
if you don't live in a time zone where you can attend one of our free webinars.
A few more things that we have, we provide a free AWS certified solution architect associate
e-book, the link is in the description below. If you're working on the AWS certified solution
architect associate, we also have a completely free AWS certified solution architect training
program. I'll leave the link in the description below. Our team is currently authoring an
AWS advanced security and an AWS advanced networking e-book and they're going to be
released in approximately eight weeks. I'll leave the links in the description below.
You can preregister and they will be delivered to you via email completely free when they
are released.
Thank you so much for allowing me to be part of your career by watching these videos. It's
an honor and a privilege to be part of this cloud architect community. I've been in technology
now for 25 years, and I absolutely love this community, so thank you for the privilege
to be able to work with you all. I look forward to seeing you in another video next week.
Take care. I'll talk to you soon.