Are you looking to start your cloud architect career? Do you desire to
learn AWS solutions architect interview questions? Well if so, this video is for you.
Hi, my name is Michael Gibbs and I am the founder and CEO of GoCloud Architects,
and we're an organization dedicated towards building elite cloud computing careers.
And today we're going to talk about some interview questions. In fact, we're going to cover
six of them. And the point of these questions is to help you build your technical competency,
because [inaudible 00:00:33] interview, we actually ask these questions to
gauge your levels of technical competency, communication skills,
and ability to present complex technical materials. So let's get to our questions.
The first question we're going to ask is going to be related to storage. And we're going to ask you
the difference of what is the difference between IOPS and THROUGHPUT? We ask this because we find
that a lot of people are confused by this and if you're going to build storage architectures,
you must know, because different applications require different levels of latency versus
different levels of THROUGHPUT. So let's talk about what IOPS is versus THROUGHPUT. IOPS, or
input and output operations per second, determines how frequently you can read and write to the disc,
back and forth as fast as you can. That's the speed of disk access. IOPS is related to latency.
The higher the IOPS, meaning the more read/write operations per second, the lower the latency.
So NVME drives and SSD drives tend to have relatively low latency because
the rewrite operations are very fast or the IOPS are very fast.
Magnetic drives by comparison typically have much higher latencies and much lower IOPS.
But when you put a bunch of magnetic drives together in a RAID environment,
you can still get great THROUGHPUTs. So we'll talk a little bit more about that in a moment.
But latency is measured in IOPS, and there's an inverse relationship between the amount of IOPS
and the actual latency on the network. THROUGHPUT by comparison is the amount of stuff and data that
can be moved at any one period of time. So if we were going to compare IOPS to speed,
and it's not exactly the case, and let's say we had a car that could drive at 55 miles an hour.
Now, the car's THROUGHPUT would be whatever it could stuff in the trunk, or the boot,
whichever country you're in. By comparison, if you had a tractor trailer or a freight train, and you
had this giant space and it was still traveling at 55 miles per hour, you could carry a lot more
stuff. And the stuff is the THROUGHPUT. So input operations per second is the amount of latency.
THROUGHPUT is the amount of stuff. So for example, video editors need drives that have
very high THROUGHPUT because they're working with large file sizes. But they can tolerate a little
more latency. A database, for example, that needs extreme speed in terms of read and write
operations per second, but is not moving large amounts of data, needs a higher IOPS. So now you
know the difference between IOPS and THROUGHPUT, you know what hiring managers are looking for.
Now, let's ask a very specific AWS question.
What's the difference between a network ACL and a Security group? I'll tell you,
when we interview people, this is a point of confusion, so let's clarify that.
A network ACL quite simply keeps traffic outside of a sub-net. It's just like an access list on
a router, keeps traffic outside of a subnet. The security group keeps traffic out of a host. So if
this is your server and you apply a security group to it, the traffic that you don't permit will be
denied and not be able to enter the server. So the real differences between a network ACL and
a security group is the network ACL protects the subnet, the security group protects the server.
Now, there is other one salient difference to know as well. And that is that network ACL's
are stateless. And by stateless, and this is important to know, it means that nothing is
tracking the state of the connection. Which means traffic that's allowed in is not being monitored,
so therefore you don't know a lot of return traffic. So network ACL's need to be applied in
both directions. By comparison, a security group is stateful. It's like a stateful firewall. So you
only have to enable it on the inbound direction. Why? Because it's stateful and by stateful
[inaudible 00:04:06] can see that the data coming in here to this host is destined to the host and
the return traffic is allowed out. Only the return traffic is allowed out because it's stateful,
and stateful [inaudible 00:04:16] watch the state of the connection. So now you know the difference
between a network ACL and a security group. Now, this actually starts to give us some knowledge
of the person's data center knowledge, as well as their cloud knowledge, as it pertains to storage.
I always ask people to describe the difference between RAID zero, RAID one, RAID five and RAID
10. And I ask for people to talk about the strengths and weaknesses of each approach,
because as an architect, you're going to be dealing with this constantly.
So let's talk about the level of RAID. RAID zero, or the most basic kind of RAID,
is basically called striping. So basically, if you have three discs, disc one, disc two, disc three,
data gets sent to disk one, disc two, disc three, disc one, disc two, disc three, disc one,
disc two, disc three. And the advantage of this is when you have three drives, if you have three
two terabyte drives and a RAID zero array, you have six total terabytes. And the speed that
you get is equivalent to three times each drive, because you're using all three drives in series.
Right, right, right. Right, right, right. Right, right, right. And you get lots of
speed and you get lots of capability. Now here's the drawback, or the weakness with RAID zero. It
has zero redundancy. So if you have three drives in a RAID array and one of the drives fails,
you lose everything because your data is spread across the drives.
So RAID zero gives you phenomenal speed and performance, but it's got no redundancy.
Now, let's talk about RAID one. RAID one is mirroring. And what RAID one is, if you've got a
10 terabyte drive in your computer or your server, you have a second 10 terabyte drive, and the data
is copied from one drive to the other drive in real time, so if one of the drives is lost,
the other drive still has all the data. You just break the mirror and you run with it.
So RAID one has the advantage of you always have an identical ready to use copy of your data,
which is fantastic. The downsides of RAID one is you don't get any increase in capacity. If
you have two 10 terabyte drives, you only have 10 terabytes of capacity because one
is being used for backup at all times, you don't have any speed improvement
because everything is being written to one disc, and the speed limitation is the disc,
is going to be written to the next disc at the same speed limitation on that disc,
so you've got no speed performance. So you don't get any speed and you don't get any more capacity,
but you do get wonderful, wonderful, wonderful availability and redundancy.
Now let's talk about RAID five. RAID five is the most common form of RAID in the enterprise
environment. And what RAID five is it's striping with parody. Now, AWS typically doesn't recommend
it on their network, but the entire enterprising world is running it. And I bet you, they're
probably running it on their internal RAID arrays for which they sell as [inaudible 00:06:48] as
well as S3. So RAID five is, let's say you have three disks. Disc one, disc two, disc three.
Data gets written on all three discs, but they also send what's called parody data
on all three desks. So let's say you have disc one gets data, disc two gets data, disc three gets
parody. The next time disc one gets parody, disco two gets data, disc three gets data.
Ultimately what's going on is you're taking one of the discs and you're using it for recovery.
So if you've got four discs, you've got the capacity of three, because one of them is
going to be used for recovery or parody data. If you have four drives in a RAID five array,
you'll have three that'll get used. But if you have six drives,
five out of the six will be used and one will be used for parody. RAID five generally speaking
has some very good performance in terms of THROUGHPUT, but RAID five can actually add
some latency, because writing this parody data definitely adds latency into the environment.
But RAID five gives you fantastic THROUGHPUT. It gives you great redundancy,
because if anything happens, basically you remove the bad drive, you pop a new drive in and you
basically ask your RAID array to rebuild the data from the parody data from the other drives and you
are good to go. So RAID five gives you a good blend of speed, performance, and redundancy.
Now for people that need more performance and lower latency than you could possibly get with
RAID five, there is another option. The option is RAID zero. So we talked about RAID zero basically
being super fast because you're running from drive to drive to drive. And we also talked about RAID
one being the perfect backup, have one drive here, it gets copied to another drive. So what
if you could combine them? And that's what RAID [inaudible 00:08:27]. So if you have four drives
in the first RAID array and in RAID zero, you get four times the capacity and four times the speed.
Now, if you made another RAID zero array, you'd have again the same speed and capacity. Now,
if you mirrored the first RAID array to the second RAID array, you'd have effectively one RAID array
in terms of capacity and the other RAID array in terms of backup and redundancy. So RAID 10
is really just taking the speed of RAID zero and it's blending it with the recovery abilities of
RAID one and combining them together. And it is a fantastic way for high performance. The downside
of this, because it requires double the number of disks and it gets very expensive very quickly.
The next question we're going to ask is another AWS question. And we're
going to ask the client to describe the AWS shared responsibility model.
Really what we're looking for is does the client actually understand what is the things that the
organization would manage versus what are the things that AWS would manage? And what we're
really looking for is the cloud is nothing more than a virtualized network in a data center. And
as an underlying technology, it's just a network and a data center. So as it stands as a rule,
AWS is going to manage the network and they're going to manage all their data center things.
So what does that mean? It means the servers, the servers, they're going to keep them patched with
their bios updates, operating system updates, hypervisor updates. They're going to take care
of that. They're going to make sure that their physical network, the kind that you're riding
underneath is secure and locked down. They're going to make sure that their network itself has
good capacity, good availability, good redundancy, and can survive cable cuts and breaks and failures
They're going to take care of all that for you. If it's a serverless environment,
they're going to manage all the servers that are doing the serverless environment. And basically
they're going to secure the cloud and you're going to secure your VPC and all your applications and
services. So that's the shared security model. AWS manages the data center and you manage your stuff.
But we like to ask that to see if people actually understand it because it's very important.
Now these next two questions are actually very important questions. They pop up in interviews.
I'm going to include them here because lots of organizations, especially big organizations like
AWS, are inclined to ask these kinds of questions. The first question of this non-technical bunch
we're going to talk about is, tell me about a major contribution you made to your last employer.
Why are we asking this? We want to know, are you the kind of person that goes above and beyond?
So we've told you in the past what hiring managers desire is someone that goes above and beyond,
someone that communicates well, someone that's energetic, someone that's enthusiastic and
someone who likes to bring out the best in others. Someone that's a problem solver. Do you know who
does this? People that make big contributions, because people that make these contributions
make big contributions to their employer. So that's what they're looking to find out.
So tell them about a big project that you had and you took the lead on the project and you
brought resources from this department, this department, this department, this department.
Talk about how you met with the customer, how you found the great customer requirements.
Talk about how you designed something for the customer, with the help of this large team.
And it delighted the customer so much, not only they purchased the solution, but they
decided to use many more of your solutions in the future, or something to that effect.
Show them about something that you did that made a difference. That's why work hard,
and when you're working hard, communicate with others, always try to bring out the best in
others, develop your emotional intelligence, all these things matter, because when you can
make a big contribution, your contributions will be known. Not only will you be hireable,
you'll be paid a lot more. And what you did in one company directly carries over to another company,
so make sure you've got a good list of major contributions you've made in your career.
The last question that we're going to ask in the same genre is to tell me about a major challenge
at work and what you did to get past it. Now there's lots of opportunities here. You can talk
about a technology problem that the organization faced and an architecture that you designed to
make it better. You could talk about a person that was on your team maybe that did not have the
skills for the job and how you mentored them. And in the process of mentoring them, they were able
to do their job and you made a great team, for example. Give them an example of something that
was really challenging, not your average ordinary things, and show them what you did to surmount
that challenge. See, we want winners, and winners are people that basically have had challenges and
they overcome the challenges, they surmount the challenge and they move on to the next great
thing. So if the employer asked about a major challenge, tell them about a major challenge and
then show them how you rose to the occasion, solve the problem and how great it was for everyone.
Let me tell you about some free services from the GoCloud architects community.
We have twice per week a how to get your first cloud architect webinar.
I will leave the link in the description below. We do this every Monday and every Thursday.
And we will tell you how to get your first job. We will tell you what employers desire, how to
interview, what your resume should look like, the types of certifications that will get you hired
and much more. And of course you will have at least 60 minutes to ask us questions so we can do
any kind of career coaching. And we do it free on these calls. We have them on Monday and Thursday.
Every Tuesday at 9:00 AM, we have a how to get real hands on cloud experience webinar.
And in this webinar, we talk about what you can do from the comfort of your own home to
develop real hands-on cloud architect experience, so you can be technically
competent and get hired. I highly recommend you do that. We have that every Tuesday at 9:00 AM.
Many weeks and most weeks, what we actually try to do is we try to do a YouTube live on Wednesday.
So please subscribe, look out for these YouTube lives and you'll be notified, but we do this
on most Wednesdays where we basically make it a free cloud architect career question and answer
session. We love answering your questions. We love guiding you. I'd rather you ask us a question,
we give you some consulting and in the process save you three years of a waste of time and
effort. So anything we can do to help you in your career, we absolutely do it.
We are actually going to introduce a new program and it's going to be called the Ask Mike program.
And what we'll do is we'll make a link and you'll be able to find the link off of our LinkedIn page
as well as our Facebook page. And we'll be posting it to YouTube at some point in the future. And you
can ask us questions. And what we'll do is we'll make YouTube videos answering your questions.
We want to know we're doing everything we can to help you in your cloud architect careers.
If you are not certified, we have a free AWS certified solution
architect [inaudible 00:14:50] associate e-course. It's completely free. I'll leave the link in the
description below. And if you're going to take an AWS certified solution architect training program,
please read our book too. So we have a free AWS certified solution architect associate e-book,
and I will leave the link in the description below. Thank you so much for watching this
video. We look forward to seeing you in another video very soon. Thank you.