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Build Your Own Data Pipeline

Season 4, episode 2 of the DataTalks.Club podcast with Andreas Kretz

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The transcripts are edited for clarity, sometimes with AI. If you notice any incorrect information, let us know.

Alexey: Today we'll talk about learning how to build data pipelines for data scientists. One of the most frequent questions I get is, “I'm a data scientist and I want to build data pipelines. How do I do this?” Finally, today, I'll know how to answer this question. The guest we have today, Andreas, knows this better than anyone. Andreas is data engineer and calls himself “the plumber of data science”. He writes and talks about platform architecture, as well as the tools and techniques that are used to build modern data science platforms. Welcome, Andreas. (1:56)

Andreas: Thanks for having me. (2:33)

Alexey: So why “the plumber of data science”? Do you have a story behind this? (2:37)

Andreas: Well, I call data engineering “the plumbing of data science” because when you look at data science, you usually see what the data scientists do, like the algorithms and so on, but in the background there is a platform that you have to run on – pipelines that you have to build. Basically an infrastructure that needs to support what the data scientists do. Usually it's invisible, but it's a huge mess when done wrong, a bit like plumbing. Also this analogy fits very well with “pipelines”. (2:42)

Andreas’s background

Alexey: Indeed. Before we go into our main topic of plumbing and building pipelines, let's start with your background. Can you tell us about your career journey so far? (3:19)

Andreas: Sure. My name is Andreas Kretz. I come from Germany and I've been involved with computer science my entire life. I’ve always loved computers. I started, like many people, by playing computer games. Then I got into actual computer science and studied it. After that, I made a quick detour towards SAP consulting, but that wasn't my thing. I came back into the computer science realm where I started as a software engineer in an industrial IoT project. We were working on getting and analyzing machine data, and that's where I got into the topic of big data. (3:29)

Andreas: Big data was a popular thing back then – everybody was talking about it and we were doing it. But I actually had the problem with so much data coming in, because the standard tools didn't work anymore. I needed to find different solutions to actually work this out. Back then I started with Hadoop. Hadoop was really a big thing back then as well, so that turned out really good. That's how I got into the field – through big data.

Andreas: Now I’m in data engineering and data science. I switched to a data engineer role – specifically, I became a team lead for data engineering. This year I started leading a data lab. But since this month, I went full time with teaching data engineering with my Academy at LearnDataEngineering.com.

Alexey: We will talk a bit about your course as well. It seems like there is a lot of interest in data engineering these days. Since you said that you worked with Hadoop, I think you’ve been in this area for quite a while. I think nowadays, there is a lot more interest in data engineering then even a couple of years ago. Now, I talk to some data scientists and they say that they want to get into data engineering and start building data pipelines. Not just learn to build the pipelines, but switch to data engineering entirely. Do you have an idea of while this is happening? (5:43)

Andreas: When you look back a few years, the thing that generally happened was – and I've seen this everywhere – people were starting with data science and hired data scientists. They had some data lying around and the data scientists analyzed this data. They had a few business ideas, “We could do this. We could do that.” And then they get to the data science track and they solved these problems. But at some point, one that we’re rapidly approaching these days, the people realized, “Okay, I have these analytics methods. I solved the problem. But now I need to automate it. Now I need to build something around it. How do I actually bring this into production?” That's why we see a lot more engineering today. People leave the stage of ‘proof of concept’ and they get more into the stage of “Okay, now we need to build something. We want to make money. We want to build a platform.” That's what I currently see. (6:27)

Alexey: So data science becomes more mature and companies realize “Okay. This is not just a one-time thing, where we do something in Jupyter Notebook and throw it away. We need to automate it. We need to build data pipelines.” That's why people realized that, “Okay, this is what data engineers do.” (7:33)

Andreas: From a data scientist’s perspective, usually you would think “Okay, why should the scientist actually do that? The scientist should work on designs, right? He shouldn't work on the engineering.” But it also depends on the structure of the project. Or it can depend on the structure of the company. If you're in a small startup – most likely, they start small. They have a data scientist and that data scientist needs set something up. There is no engineer. So once it works, then they bring it to the engineers and they make everything nice and beautiful. But that's why also the data scientists are getting more into this. (7:56)

Who to hire first – a data engineer or a data scientist?

Alexey: Do you think a company should first hire a data scientist, and then a data engineer? Or the other way around? (8:40)

Andreas: I personally think companies should hire both. But they don’t need a huge engineering team to start. If you want to start really small – hire one scientist and one engineer. The scientist can focus on the actual science and the engineer can think of “Okay, how can we turn this into a product later down the road?” That's usually a big hurdle. “Once the proof of concept is finished, how can we make this into a product?” “How can we build a platform around it?” If you can get a data engineer early, then you are already ahead of the game. But generally, I would say the science part starts with the scientist. That's the main thing. They have some one-off data, which usually lies around somewhere. Somewhere, somebody has the right CSV, the right database - hopefully. Most likely. (8:46)

How can I, as a data scientist, learn to build pipelines?

Alexey: So a company hires a data scientist and this data scientist works on a proof of concept. Then they need to productionize it. If the company doesn’t realize that they need a data engineer, this data scientist implements the whole thing himself. What we usually end up with is a lot of code that is difficult to maintain, because data scientists are usually not the best engineers. I think this is where the question actually comes from. (9:47)

Alexey: The question that I mentioned in the beginning, “How can I, as a data scientist, improve my data engineering skills?” Sometimes it happens that data scientists need to do this. So I’ll come back to this question – “I am a data scientist. I want to learn how to build data pipelines. How can I do this?”

Andreas: I think the problem isn't actually the coding. The coding is usually fairly simple. Nowadays, in engineering, you can do most stuff with Python if you're a good developer, which you should be as a data scientist. This shouldn't be a problem. The actual problem that data scientists tend to have or what they should look into is thinking ahead to “How can I deploy this? How can I bring this into a uniformed platform?” What a lot of data scientists tend to do is choose too many tools for their platform. They choose the packages that they use in Python – “I’ll take this. Take that and try this out here.” But actually, in engineering, that doesn't work. You can't introduce 20 different tools. You need to figure out which few things you need to select and then build everything around them. The actual conceptual part is actually the problematic part, which is what the scientist needs to understand. (10:44)

Don’t use too many tools

Alexey: Why can't we take 20 different tools and make a platform from them? You said it doesn't work like this – data scientists tend to take many different packages and just put them into one thing and do the data science. Why can’t we do this with the platform? Why can't we take 20 different tools? (12:03)

Andreas: The problem is the operations part. Somebody needs to take care of it all at some point, even if it's the data scientists themselves. Say you have one data scientist and he needs to set something up. He uses 20 different tools. Then the data scientist needs to take care of it himself if there are no more people available. This will be problematic because there are so many things to keep afloat. Very often, some pipeline gets stuck somewhere, something quits, and you need to look up what the problem is. If you're using an open source tool here or there, you need to optimize the configuration. Therefore, it gets more and more complicated to actually have everything up and running as opposed to focusing on a few areas and using a few tools. That's very important. (12:22)

What is a data pipeline and why do we need it?

Alexey: You mentioned data pipelines and our talk is about data pipelines. Maybe we can talk a bit about this. What is a data pipeline? Why do we need a data pipeline? Why is my Jupyter Notebook, with all the coordinates, not enough? (13:25)

Andreas: Well, from an analytic standpoint, it's enough. You don't need to set up huge pipelines for the actual analytics stuff in most cases. In other cases, if it gets more complicated, you need to split up your notebook and create Docker containers out of it or whatever and deploy it. But let's forget about the analytics. When you think about the pipelines or the platforms, somehow, somewhere – you have ingestion. The data needs to come from somewhere. At the other end, you have the analytics and the visualization behind it, or storage. So you need to actually build something for that. For instance, I always put it into a few parts. One part is ingestion. Another part is our buffers, like message queues. The next part is processing frameworks, storage, and visualization. These are the different areas that you need to look at. If you think about ingestion – how could you ingest the data later? For instance, you set up an API or you set up an ETL job that pulls the data in. You can have different types of processing frameworks. (13:39)

What is ingestion?

Alexey: To clarify on what ingestion is – let's say we have a website and the user can do a bunch of things on it. These events that we track need to end up in our database. The process of getting these events and putting them someplace – this is called ingestion. Is that right? (15:11)

Andreas: You could say it another way. Say you have your website where the user is clicking something and you want to track the clicks. The website would actually shoot the event and the event would go into a message queue, like Apache Kafka, or Kinesis on AWS. Then it lies around there somewhere. Then you need to process it further, so you would introduce a processing framework that actually takes this message, processes it, and stores it somewhere. The next step would be the visualization. In between there somewhere, you use the analytics to actually access the data, do the analytics, and put the data back. That’s just an example. (15:29)

Alexey: To recap, the process is as follows. First, the user makes an event. This goes to some message queue. From the message queue it gets into some storage. I think this is what is usually called a Data Lake these days, right? (16:11)

Andreas: It could be a data lake. It could also be a noSQL database. (16:23)

Alexey: So, just some storage. Then these are raw events, and we need to process them. So then there is a job that takes the events and processes them, does some transformation, and it ends up in some visualization – some dashboard, maybe, for analytics. Or maybe this is something I, as a data scientist, can also take and use it for building my models. Is that right? (16:29)

Andreas: Yeah. It depends a bit on what you're doing. Are you doing event processing? Are you doing streaming – where you're immediately reacting to the data that's coming in? Or are you taking the data in a batch processing way? Because when you do streaming, you are going to take the data immediately from the message queue, take it, process it, analyze it, make a forecast, and push the data further. Or if you're doing a batch process, you would store it first, then take it out, process it and put it back in. (16:51)

Alexey: In both cases, we refer to this sequence of things as a data pipeline, right? (17:26)

Andreas: Yes, I would call this a data pipeline – a complete pipeline, where you have a beginning and an end. You could argue, “Where's the end? Is the end at the storage? Or is the end at the visualization?” It depends. But the important part is that there are just a few tools, or a few parts, that interact with each other. It's not something that comes and gets stored and then at some point you take it out or use a CSV file that you download from somewhere. That's not a pipeline. (17:33)

Can just one person build a data pipeline?

Alexey: That seems like a lot of work. Something that a data scientist – just one person – probably cannot really implement on his or her own, so it needs multiple people and a data engineer, at the very least. (18:14)

Andreas: It depends where you are. If you're in a private cloud or an on-premise setup, where you have to install everything with open source tools and run everything on them, that can be annoying. If you're on a cloud platform like AWS, Azure, or GCP, it's fairly simple to actually set up a message queue or a no-SQL database. As I said before, the problem is understanding “Which tools make sense in the case that I currently have?” Also, another thing that is always a problem is the actual schema design. Not in terms of a relational database, but the fact that you have to design how the data looks. How do you process the data? It's important to understand, “Okay, in this step, I need to do that. Then I need to do that. And the final result that comes in my documents story looks like this. So where can the problems come up there?” (18:27)

Approaches to building data pipelines for data scientists

Alexey: Maybe we can simplify this a bit. Let's say I work at a company as a data scientist and we have data engineers. The data engineers take care of the ingestion part – they track the events, put them into these message queues, and then eventually these events end up in our data lake or some other form of storage. We need to then use these events to build our pipelines for our machine learning models. The data engineers focus on this lake, so they're not really helping us. Maybe they can help a bit, but basically, we're on our own here. We have access to this data lake and we need to build a model. (19:47)

Alexey: Usually data scientists know Python pretty well and some SQL. They know all these GitBash things. And when it comes to Python, they also usually know a so-called Py Data Stack – SciKit Learn or NumPy, Pandas. With this knowledge, how do we approach this process of building a pipeline to get our events from the data lake?

Andreas: You mentioned in the beginning, you're more alone in this as a scientist? Hopefully not. Hopefully, the engineer speaks to you or you speak with the engineer to turn it all in a way that the data gets stored somewhere in a form that you can already work with. That's one of the main things that you need to look at. As a scientist, I would start very simple. I would focus on Python. If you know Python, don't go spread yourself thin with another language. Don't go for something like Scala or Java. Use what you already know best. Let’s say I like working with Git, and Docker for writing Python code. In this case I would focus on what tools there are available to me. What processing frameworks could I use to apply my Python skills and build something up with that? You would then use it for API building. You wouldn't use something with Java, you would most likely look at something like Flask or fast API, which I like a lot for prototyping. You would likely need to go in that direction. (21:05)

Processing frameworks

Alexey: So what are these processing frameworks? (22:31)

Andreas: Processing frameworks. When I coach in my Academy, I try to show my students that “Okay, there is this section called processing frameworks, which is everything that actually takes some data, does something with it, analyzes or modifies it, and then gives the output.” So you could think of the processing framework as, “Okay, what does some processing? A Python script that runs in a Docker container.” I already count this as processing. Apache Spark, Apache Flink, or if you're on the cloud, you could say, “Okay, AWS lambda functions or Azure Functions.” These things or perhaps I would use AWS Glue for that. These are frameworks that are doing the processing for you, you just need to code them right. That's one area that you need to decide on. (22:36)

Andreas: Back to what we talked about before – it wouldn't make sense to do a part in Spark, then a part in Flink, and then introduce some Lambda functions here and there, and then run a Jupyter Notebook, where you do some processing. [groans] It almost gets too complicated to actually run with a small team.

Alexey: So, basically, this is a thing that gets some data in and produces data out, right? It might convert something or…? (24:04)

Andreas: The processing framework, I would say is what you train your algorithms with. It's what you apply your algorithms with. It's where you, as a data scientist, do the pre-processing. These are the kinds of things where you filter out the data. (24:14)

Alexey: I think most of the time we can do plain SQL for most of these things, except model training. Like data transformation. (24:34)

Andreas: It depends on what you're working with. If you're working with some kind of a no-SQL database, running simple SQL queries might be a problem. If you're doing a more relational-orient or relation database, then yeah – you most likely would use SQL to get the data or just simple files from a data lake. But within your framework, it could be that you use SQL to build data frames, and then access these data frames via SQL. SQL is still a big part in engineering and in science. Everybody knows it. All the tools support it. It's one of the big things in data science. (24:44)

Common setup for data pipelines — car price prediction

Alexey: So what are the most common setups that you see? Or a setup that you would recommend? Let's say we have these tasks – we have data in our S3 bucket, for example, or some Google Storage bucket. Let's say these are parquet files that the engineers prepared for us. For those who don't know – parquet is a special format for files that is optimized for storing data. So we have that – what would we use to actually process this data? (25:36)

Andreas: Giving general recommendations is always a bit problematic because you don't know what people are working on. There are a lot of ways of actually processing this data. As I said before, you could say, “Okay. This data is just lying around. I'm just using Docker containers on-house called ECS to actually trigger ECS jobs and read the data from the data lake, process it, and then put it somewhere else.” (26:09)

Andreas: You could even schedule this. AWS, for instance, has a as a scheduling service, which is basically Airflow in the cloud. I just forgot how they call it – “Manage Data Flows” or something like that. You could set up something like this. You could also build something within SageMaker – using SageMaker notebook. I use that as well. The possibilities are endless. I don't want to cheap out of this question, but there are so many things you could do. It’s difficult to answer.

Alexey: It may be a problem as well. Because when you have so many tools for doing your job, you can get lost. Maybe we can make it a bit more concrete. Let's say I want to build a model for predicting car prices. Suppose we have a website with cars, their prices, and other different characteristics for cars. We want to build the pipeline for training our model – for predicting prices – and a pipeline for applying this model. To make it more concrete, let’s say the data is stored in MySQL. The engineers copy all the data to an S3 bucket, so we don't need to touch the production MySQL database. So we have a replica of the data set and we need to build a model for that. I don't know if you have any preferences for the cloud, so let's say we use S3, as I already mentioned it. (27:22)

Andreas: I like AWS the most. I work with AWS the most, so I'm always thinking in AWS. (28:37)

Alexey: Alright, we can take AWS as an example. I think they're the most popular cloud provider right now – for seven years already or something close to it. (28:49)

Andreas: Yeah. By far the most popular. (28:56)

Alexey: I imagine that for most of our listeners, the chances that they use AWS are pretty high. (28:58)

Andreas: That depends, by the way. It depends on the on the actual industry. It also depends on the actual location. I have students from northern European countries where they looked at job descriptions, and it turns out Azure is more prevalent for some industries. Then in others, like in the US, most of the things have AWS in them. So there are actually differences. (29:09)

Andreas: To your example. I'm not sure if I understood it correctly. Is there data coming in from two sides? From the website and from the from the SQL database?

Alexey: Yeah. Let’s say we have a product. We have a website with cars. We own it as a company. What we want to do is help our users when they are not sure what price to put. We want to build the model for them when they enter the car make, model, etc., we help them by suggesting a price. This is a simple model. For this website, it's backed by MySQL – there is a MySQL database with all the data for all the listings. But as data scientists, we cannot really go and access this MySQL database, because it's a production database. So what engineers made for us is some sort of snapshot replica, just for us to access the data. And now we need to build this model. (29:54)

Andreas: Well, first you need to think about “Okay, how do I apply this from the analytic standpoint?” You most likely want to apply it so that when the customer searches, he already gets the predictions, or the recommendations, right? So would you do that live or would you put that into the categories? The end result of your analytics - is it always getting generated live, or are you doing some predictions and storing them somewhere? (30:51)

Alexey: I know it's going to complicate things, but let's say when a user creates a new listing, fills everything in and once that’s done, we suggest the price. So they get a prediction when they create a new listing - it’s a live thing. (31:33)

Andreas: Okay. There are a few methods you could apply. You could take the listing that has just been created and send it into a message queue. That’s how you would stay in the streaming lane. At the other side of that is where the algorithm is listening. Once something comes in, most likely it will come from the website as a JSON, the algorithm takes the listing, does the recommendation part, and then either stores it somewhere or offers it over an API. I'm not sure how you would want to do that. If the listing already stored, then you could say, “Okay, I'm putting that to the stored listing.” I mean, what you see is that people actually apply or supply the analytics as an API. The website would actually call an API and it would run your script in the background. The API would then return the recommendations. (31:50)

Productionizing the model with the help of a data pipeline

Alexey: What you described is the process when we already have a model and we want to deploy it. So this how we would use it. But what I meant is – we don't have model yet, we need to do build it, right? So what can I do as a data scientist? I can pull this data in, save it on my laptop, open Jupyter Notebook. You know, do stuff with Pandas, do stuff with NumPy, SciKit Learn. Train this model and I have this pickle file. (33:17)

Alexey: Then two months after that, things change – the prices are different – and we need to retrain it. I don't want to do this every month. I don't want to pull in new data and execute cells in a particular order in my Jupyter Notebook, because maybe in half a year I will forget that I need to execute this cell before this cell because I accidentally messed with the order. So we need to somehow productionize it.

Andreas: That's what I meant – with the Jupyter notebook, sometimes it's good. For this, to create a proof of concept or the first version of your analytics, you would set up in a Jupyter notebook so that you can see that it works. The next part would be productionizing it. Most likely, if you're already in a Jupyter Notebook and working with this stuff, you could just go and take your Python code, put it in a Docker container, schedule this container to run on the data, every day, every week. And then just retrain the models to see if you find something better – to see if you find some different results for the current ones. This way, you keep training your models and then you store the model somewhere and apply them. Most likely you can store the model conflicts on S3. When you apply the model in your pipeline, you will actually have your script, and that script would pull the pull the information from S3 and then just apply it. (34:16)


Alexey: So, we take our Jupyter notebook, we put it in a Python file, we put this Python file in some Docker container and we go to our cloud and find a way how we can schedule this script. And that's pretty much it. Right? (35:27)

Andreas: Depends on how you want to run it. For the training - yeah. The actual scheduling can be really easy. You could use something like Airflow. But if you have something real simple, you could use Cloudwatch and then schedule the bit with AWS. You need to schedule a lambda function, which then starts your container. You could very easily set this up without having the whole framework running like Airflow. That's what I meant before. Does the data scientists need to look into this to actually figure out? Is it worth it? Because it's one more thing to manage. Or can I can he live right now with something that is less complicated? (35:46)

Alexey: You said Cloudwatch. As far as I remember, in Amazon, there are multiple ways of deploying a Docker container. You have ECS, AWS Batch, and SageMaker, right? So you can just take any of these, put your Docker container there with your script, and then use Cloudwatch to schedule it to run every week, for example. (36:44)

Andreas: I remember I think we talked about the fact that SageMaker can get quite expensive. That's why I'm always hesitant to say “Use SageMaker for everything.” [laughs] (37:14)

Alexey: Well, at least you can use AWS Batch. I think it’s four times cheaper, if I remember correctly. (37:27)

Andreas: That I don't know. (37:32)

Alexey: So in SageMaker, they have the same instances – instance types – but they have ML in front of them. And just having ML in front of them makes them more expensive. But in the end, it’s the same types of instances. (37:36)

Andreas: Oh, well. That's logical. (37:49)

Andreas: The cool thing I like about that is what I mentioned before. Deploying your algorithm as a service – what you could do is deploy your algorithm as an endpoint with SageMaker that you have running. You can send the data to the endpoint and it will send you some predictions. That’s something that is really, really cool and now makes it a bit easier to do the management of the pipelines. (37:53)

Alexey: Let's make our example a bit more complex. So let's say we have this [laughs] (38:24)

Andreas: Usually I do this with boards – where we draw on the board, so I get the picture. Yeah, let's make it more complicated. (38:29)


Alexey: Let's say to get the data from this storage that we have, we need to write a couple of SQL queries. And we need to execute the SQL queries one after another. We have a lot of fraud data. So the first query would get us a smaller data set with only the data we need. Let's say this second query would do some extra aggregation or cleaning. So we have two queries that do something and then at the end, this is what we use for training in our model. We take the output of the second query and, again, do some simple stuff with Pandas, train our model, and we get this pickle file. (38:39)

Alexey: Now we need to schedule this – to somehow run the whole thing in a sequence. We need to run the first query, then the second query that gets the results of the first query and produces some other results. Then the third job gets the results from the second query and trains model and produces the pickle file. So how do we orchestrate this whole thing?

Andreas: I feel like I say always ‘it depends’ but it depends on how complicated you want to make it. (39:52)

Alexey: Let’s say the simplest possible. (40:00)

Andreas: You could do something really simple where you build up a message queue. Once the first script is ready, it fires up a message into the message queue. Then on the other side, there’s a listener that basically takes this message, and in the message, you say, “Okay, what part of the job already ran? Where is the data stored?” Then the second part can take the data, process it, and then writes back to the message queue. This way you can use your message queue in a streaming manner, where one job takes the information out, “Okay, I need to do something. Where is the data lying around? Do it. I'm finished. Write back.” So it’s often very easy to use queues for this kind of job. (40:01)

Start simple

Alexey: I think I implemented something like this a couple of companies ago. When I left, what they ended up doing this discovery and all that, and then moved into Airflow. (40:55)

Andreas: Yeah. Airflow – these things are really strong, and really good, so it makes sense to use them. But if this is a one-off thing and you need to build something quick, you need to start somewhere. What is good enough? Most likely, for this company, you build this, it ran for some time, and it was good enough while you build it. At some point, it grew over. They needed to have more logging behind it, more insight. Then you move to something like Airflow or something. You don't need to go all out in the beginning. (41:06)

Alexey: So, for the first model, if it's just the first data science project in the company, you don't need to go with Airflow, Kubernetes, and all these big things. (41:54)

Andreas: It depends a bit on your timeline. What the goal of the company? Where does the company want to move? Is the company unsure where to move? Or is this going to be a platform where a lot of projects are going to work? Then it's good to have help – then I would set up everything already. Otherwise, start small. Start Agile and you can always build something or add something to it after afterwards. That's also what I usually tell my coaching students. “Build something first. Build it simple. And then, at some point, add more stuff to it. Start with a Lambda function and then use Spark streaming for that. And then take the next step.” In every area you can always escalate and make it more complicated down the road. (42:07)

Learning DevOps to implement data pipelines

Alexey: We have a related question from Chetna. I think we already discussed how we can do this from a Jupyter Notebook like our data scientists can start their journey towards picking up data engineering skills. That part we discussed, but the second part of the question is “How do you learn the DevOps and software engineering skills that you need to actually to be able to implement this?” (43:05)

Andreas: DevOps skills – that's where the tool selection comes in. You need to understand, “Okay, how can I actually bring this into production? How do I manage my code? There are certain tools that I see around all the time, something like GitLab. A lot of people use GitLab as their code repository, as well as for building and deploying their code in production. That's something I see a lot. Generally, there are many tools out there. It's the same most of the time. If you use Jenkins for building and so on, most likely there's the same stuff. (43:36)

Alexey: So your recommendation would be to just pick any tool and try to learn it? (44:36)

Andreas: I would pick something that fits to the rest of what I just built. That's what I meant in the beginning. You need to understand what tools you actually want to use so you don't go overboard and so that everything fits together. You need to know that you're actually using the right tool to manage and deploy your code so that it that fits into your actual production environment. (44:41)

How to choose the right tool

Alexey: If I'm a data scientist and I don't have experience with these kinds of things, I would need to talk to a data engineer or somebody who's dealing with infrastructure to actually help me and guide me for that. Because how do I know if this is the right tool if I haven't used it previously? (45:13)

Andreas: Yeah. There are a few options of what you can do. First of all, how I always go about this – this may sound very lame, but I look at the documentation of the tool. What can this tool actually do? Then I search for examples where people already did that what I envision doing. If you can find some examples out there – like on Google – examples where they did this, this, and this, specifically. You can also find some quick to-do lists or tutorials. If you can do all that, then you are most likely already on the right track. If it's an open source tool, or whatever, just set it up in a dev environment and test it out. If that works, that already looks good – you're most likely on the right track. (45:31)

Alexey: Coming back to our example of ‘building a model for price prediction’. Let's say we decided to go with AWS Batch and Lambda and whatnot. What we can do is go to our favorite search engine, put the queries there, like ‘model training pipeline’, and the name of the tool ‘AWS batch lambda’, and hit enter. Maybe adding ‘tutorial’ at the end might help as well. We see what the results are. You may end up on ‘towards data science’ or some other similar website, where there is nearly a step-by-step tutorial with all the steps that you need to do. (46:37)

Andreas: Very often you can find something be entering, like in your case, ‘how to use AWS batch to analyze S3 data’ or something along those lines. Most likely, you’ll find 10 blog posts that already do the exact thing that you want to do. Then you just insert your code. Of course, you need to write it, but the frame around it is there – how to get the data and where to write the data. Most likely, you can already extract what you need from this. (47:22)

Alexey: Yeah, so I guess the short answer to this question “How to learn DevOps?” is just “Do stuff. If you don't know how, Google them.” (47:54)

Andreas: Use the search to find out what different tools there are. What capabilities do they have? How does that fit to the rest of the platform? And then just try it out. I always go for the “Okay, let's try this” approach. Because usually, when you actually do it, you find the holes in the whole thing. “This doesn't work that way. This doesn't work that way.” It's always the same. Unfortunately. (48:02)

Are Hadoop, Docker, Cloud necessary for a first job/internship?

Alexey: Another question, “Do you think data engineering skills like Hadoop, Docker, Cloud, are necessary for students who are looking for internship? Do they need to have these skills to get their first job?” (48:36)

Andreas: No. I think for an internship, if you can code Python and know your way around SQL – that should be enough. You should have learned this during your studies. If you have a bit of an idea of how computer networking works, like DNS, IP networking, that’s also good. If you have an idea about these things, you're good to go for an internship. For becoming a junior data engineer, I think you need some experience on some kind of a platform. Most likely it makes sense to use AWS. I would start by using AWS. That's why in the academy I build the AWS capstone project first, because I think that's the most important thing. We use that most often in the coaching as well. (48:55)

Andreas: The second important part, in my opinion, is the open source tools. Just use a few open source tools like Kafka, Spark, MongoDB –that’s some stuff that is around everywhere. It makes sense to know them. If you don't get a junior role after that, I don't know… I would most likely hire someone who has that on a resume. The important part is documenting it. That's what I always say to my students – document your stuff. Never just do an AWS certification, or whatever – never just do the certification. Always create a GitHub, put up some information, put up interesting stuff that you have learned. You need a track record. You need to have a track record. You need to have a professional profile. Not just a LinkedIn page, but a professional profile that has some experience.

Is Hadoop still relevant or necessary?

Alexey: In this question, there is a bunch of things mentioned under ‘data engineering skills’, which are Hadoop, Docker, Cloud. So Docker and cloud – I don't think you would argue that these are important things to learn. What about Hadoop? Do people still need it or use it? (20:56)

Andreas: It depends. [laughs] I see the trend that Hadoop isn't what it used to be. The cloud platforms got so strong and they innovated so fast, most companies nowadays use the cloud platform. Yes, you still have stuff lying around that’s still working on Hadoop – very often in bigger companies where they’re running private clouds. And of course, they're running Hadoop. I think learning it to get a role can make sense, but it's not one of the primary things. The cool thing I’ve noticed coming from Hadoop, I see that everything on the cloud platform, is basically the same stuff that you do on Hadoop. You're running on a Hadoop platform, it just has different name and works a bit differently. It's very, very interesting how these tools fit together. (51:14)

Data engineering academy

Alexey: We have a question from Julian. The question is about your academy. You mentioned it a couple of times. First of all, “What is the link to the academy? How can people find it?” (52:21)

Andreas: LearnDataEngineering.com (52:39)

Alexey: It’s one word, right? (52:41)

Andreas: One word. That's where I have the Academy and where I do the coaching. I started with YouTube, I don't know how many years ago – four years, three years? When did we talk Alexey? Do you know how many years ago? (52:46)

Alexey: I think two years. (53:01)

Andreas: Maybe two and a half years ago, I started with YouTube. On YouTube, you make videos, but you can’t put up a journey. You can say, “Okay, learn this, this, this, and this and then it will work out.” So last year, I actually decided to “Okay, let's try to build a curriculum for actually learning data engineering.” It turns out that it's harder than I thought. What we talked about before –there are so many tools and you need to focus on some stuff. But in the academy, (53:03)

Andreas: I created a step-by-step course that gives you the fundamentals of what data engineering is and what you need to actually start. Then we go through basics of platform pipeline design. Then the fundamental tools. Then capstone projects – like the AWS project. We have one more coming next week about Azure – an Azure course. I'm currently working on another one, as I said before, with open source tools, MongoDB, Kafka, Spark, and so on. If somebody is interested in data engineering, check that out. Or check out one of my 300 videos on YouTube. I don't know how many there are currently.

Alexey: I think if you Google ‘the plumbers of data science’, the first link should be your channel. (54:32)

Andreas: Could be. Yeah. (54:46)

Alexey: Or your name. (54:44)

Andreas: Yeah. My name is well. My name and data engineering most likely would bring something up. (54:46)

How to pick up Cloud skills

Alexey: What I understood by talking to you now is that one of the most important skills data scientists need to have in order to pick up data engineering is cloud skills. But ‘cloud skills’ is such a broad term, right? But there are a couple of tools that are useful for data processing. I'm wondering if it’s possible to give a good recommendation on how to approach learning this? I usually suggest learning things by doing projects. Maybe you can recommend a project that people can build in order to pick up these cloud skills? (54:52)

Andreas: A project? Well, I don't want this to be a sales thing. One project you can do is ecommerce data on AWS. I think the general approach is the more important approach. On my website, you can find a link to the data engineering cookbook. Also on my YouTube, I have videos about my data science platform blueprint. This will help you a lot to actually see the areas that I talked about before – connect, buffer, processing, framework, store, visualize. Then actually choose some select tools for each of these and build a pipeline. Just start by using this. Use a data set from Kaggle or wherever – you don't need to go really big. Use a small data set, 40 megabytes, whatever. Just start applying this in a building a platform and building some pipelines on it. (55:36)

Alexey: I think there are a couple of competitions on Kaggle, where it's not just one CSV file, but they have multiple CSV files. Then you would need to actually join four or five different files. Then to actually build this final table you need to do multiple joins. I think this kind of dataset would be most interesting, because this is what we usually do at work. So it's not just data that’s already prepared, but we need to do a couple of joins and couple of things on top of that. I think one of the competitions was, I think, Outbrain Click Prediction. There are a couple of them. These click prediction competitions are quite interesting, because they have a lot of data there. But 40 megabytes, I think is also a good start. (56:43)

Avoid huge datasets when learning

Andreas: The thing is, for learning it, you don't need the huge data sets. When you use huge data sets, first of all, the loading times are going to be terrible. Everything runs long. You cannot easily look into the data. Because it's big, the cloud platforms are going to cost more because you need bigger systems and everything. Don't need that. Very often in the academy or in the coaching, we use a simple ecommerce datasets from Kaggle. Even there you can understand some things like, “Would you go the no-SQL route and not the standard route of building a relational database?” and so on. It doesn't need to be complicated to actually start. If you're listening to this, you only need to remember one thing – start simple and use a simple data set. Don't go all out. You will only get frustrated. Most likely, use the cloud for beginning. (57:33)

Alexey: So don’t start with Kubernetes, Airflow and one terabyte of data, right? (58:48)

Andreas: No. [laughs] (58:55)

Convincing your employer to do data science

Alexey: Good advice. So it's almost time for us to finish. But there is one interesting question. Maybe we can take a couple of minutes to answer it. Maybe it's a tough one. Let's try. “I'm trying to convince my company to start a data science department. What is the best tool set to show results with my current $0 budget?” (58:56)

Andreas: Well… I don't want to discourage people, so I’m being careful with what I say. If you need to convince somebody to actually use data science, it's already a bit of a problem. I would go the route of just doing it. If you don't have money and you can spend some time. Just build something locally. Don't build a platform. Don't build pipelines. Do a proof of concept. As we said, use a notebook, get some data, and show what analytics can actually do – what analytics can deliver. Put a number on it. “How much money will this bring?” People don't care about data, like “How much data we processed for that.” or “How long it took.” (59:23)

Andreas: “How much money will this bring in?” is even better than “How much money will be saved through that.” Most likely, revenue counts. So if you can show a good result, if you can show a rough timeline, and how much revenue this can generate in the future, then most likely, something will move if you talk to the right people. Otherwise, forget it.

Alexey: So you need to turn this $0 budget into something greater than zero. (1:00:58)

Andreas: Yeah. The cool thing nowadays is, if you have if you have a MacBook or whatever, you can already start doing data science. It's not like you need that a big machine – a $10,000 analytics PC. You can start small. (1:01:03)

Alexey: In AWS, there is this thing called ‘free tier’. Right? Which allows you to do some lambda stuff for free. You can get EC2 for free. (1:01:19)

Andreas: Yeah, but how much does that help you? Most likely, you are going to run tests for a few days or train models for a few days, and the feature is over. You have a computer at work, use that. Start a training at the end of the day, let it run throughout the night or over the weekend. And hope that something comes up on Monday. (1:01:30)

How to find Andreas

Alexey: That's interesting. Last question – how can people find you? (1:02:05)

Andreas: You can find me by just Googling my name – Andreas Kretz – or “plumbers of data science’ or ‘learn data engineering’. On LinkedIn, on YouTube, on Instagram. (1:02:10)

Alexey: Instagram? (1:02:23)

Andreas: Instagram as well. Andreas Kretz. I have 1400 followers. Wow. Trying so hard on Instagram. Instagram is terrible. You can contact me there as well. We have a Telegram chat group. If you go to LearnDataEngineering.com, on the bottom is a telegram chat group – “Team Data Science” I call it. (1:02:24)

Alexey: I’ll put a link in the description. Do you have any last words? (1:02:51)

Andreas: Thanks for inviting me. It was really fun talking to you, Alexey. I hope I a few people will get into engineering now. It's really a cool profession. And I love it. (1:02:58)

Alexey: I'll put all these links, maybe not right now, in a couple of hours. So check the description. We have a couple of more talks tomorrow and on Friday. Check them out. Thanks for joining us today. Thanks a lot, Andreas, for sharing your experience with us. Now, the next time when somebody asks, “How can I build a data pipeline?” I will share this video with them and hopefully they will not start with Kubernetes and other stuff but something simple. (1:03:11)

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