The cloud workflow doesn't come with a scheduling feature. Apart from that, what are all the differences between these two services in terms of features? In which use case should we prefer the workflow over composer or vice versa?
There are some key differences to consider when choosing between the two solutions :
A Composer instance needs to be in a running state to trigger DAGs and you'll also need to size your Cloud Composer instance based on your usage, You do not need to do this in Cloud Workflows as it is a Serverless service and you pay for anytime a workflow is triggered
Another key difference is that Cloud Composer is really convenient for writing and orchestrating data pipelines because of it's internal scheduler and also because of the provided Operators, You can interact with any Data services inside of GCP.
However, Cloud Workflows interacts with Cloud Functions, wich is a task that Composer cannot do really well.
Both Composer and Workflows support orchestrating multiple services and can handle long running workflows. Despite there being some overlap in the capabilities of these products, each has differentiators that make them well suited to particular use cases.
Composer is most commonly used for orchestrating the transformation of data as part of ELT or data engineering. Workflows, in contrast, is focused on the orchestration of HTTP-based services built with Cloud Functions, Cloud Run, or external APIs.
Composer is designed for orchestrating batch workloads that can handle a delay of a few seconds between task executions. It wouldn’t be suitable if low latency was required in between tasks, whereas Workflows is designed for latency sensitive use cases.
While you don’t have to worry about maintaining Airflow deployments in Composer, you do need to specify how many workers you need for a given Composer environment. Workflows is completely serverless; there is no infrastructure to manage or scale.
For further information refer to this google blog article and this one.
Related
I need to run a pipeline of data transformation that is composed of several scripts in distinct projects = Python repos.
I am thinking of using Compute Engine to run these scripts in VMs when needed as I can manage resources required.
I need to be able to orchestrate these scripts in the sense that I want to run steps sequentially and sometimes asyncronously.
I see that GCP provides us with a Worflows components which seems to suit this case.
I am thinking of creating a specific project to orchestrate the executions of scripts.
However I cannot see how I can trigger the execution of my scripts which will not be in the same repo as the orchestrator project. From what I understand of GCE, VMs are only created when scripts are executed and provide no persistent HTTP endpoints to be called to trigger the execution from elsewhere.
To illustrate, let say I have two projects step_1 and step_2 which contain separate steps of my data transformation pipeline.
I would also have a project orchestrator with the only use of triggering step_1 and step_2 sequentially in VMs with GCE. This project would not have access to the code repos of these two former projects.
What would be the best practice in this case? Should I use other components than GCE and Worflows for this or there is a way to trigger scripts in GCE from an independent orchestration project?
One possible solution would be to not use GCE (Google Compute Engines) but instead create Docker containers that contain your task steps. These would then be registered with Cloud Run. Cloud Run spins up docker containers on demand and charges you only for the time you spend processing a request. When the request ends, you are no longer charged and hence you are optimally consuming resources. Various events can cause a request in Cloud Run but the most common is a REST call. With this in mind, now assume that your Python code is now packaged in a container which is triggered by a REST server (eg. Flask). Effectively you have created "microservices". These services can then be orchestrated by Cloud Workflows. The invocation of these microservices is through REST endpoints which can be Internet addresses with authorization also present. This would allow the microservices (tasks/steps) to be located in separate GCP projects and the orchestrator would see them as distinct callable endpoints.
Other potentials solutions to look at would be GKE (Kubernetes) and Cloud Composer (Apache Airflow).
If you DO wish to stay with Compute Engines, you can still do that using shared VPC. Shared VPC would allow distinct projects to have network connectivity between each other and you could use Private Catalog to have the GCE instances advertize to each other. You could then have a GCE instance choreograph or, again, choreograph through Cloud Workflows. We would have to check that Cloud Workflows supports parallel items ... I do not believe that as of the time of this post it does.
This is a common request, to organize automation into it's own project. You can setup service account that spans multiple projects.
See a tutorial here: https://gtseres.medium.com/using-service-accounts-across-projects-in-gcp-cf9473fef8f0
On top of that, you can also think to have Workflows in both orchestrator and sublevel project. This way the orchestrator Workflow can call another Workflow. So the job can be easily run, and encapsuled also under the project that has the code + workflow body, and only the triggering comes from other project.
I am trying to build an app where the user is able to upload a file to cloud storage. This would then trigger a model training process (and predicting later on). Initially I though I could do this with cloud functions/pubsub and cloudml, but it seems that cloud functions are not able to trigger gsutil commands which is needed for cloudml.
Is my only option to enable cloud-composer and attach GPUs to a kubernetes node and create a cloud function that triggers a dag to boot up a pod on the node with GPUs and mounting the bucket with the data? Seems a bit excessive but I can't think of another way currently.
You're correct. As for now, there's no possibility to execute gsutil command from a Google Cloud Function:
Cloud Functions can be written in Node.js, Python, Go, and Java, and are executed in language-specific runtimes.
I really like your second approach with triggering the DAG.
Another idea that comes to my mind is to interact with GCP Virtual Machines within Cloud Composer through the Python operator by using the Compute Engine Pyhton API. You can find more information in automating infrastructure and taking a deep technical dive into the core features of Cloud Composer here.
Another solution that you can think of is Kubeflow, which aims to make running ML workloads on Kubernetes. Kubeflow adds some resources to your cluster to assist with a variety of tasks, including training and serving models and running Jupyter Notebooks. Please, have a look on Codelabs tutorial.
I hope you find the above pieces of information useful.
I am learning GCP, and came across Kuberflow and Google Cloud Composer.
From what I have understood, it seems that both are used to orchestrate workflows, empowering the user to schedule and monitor pipelines in the GCP.
The only difference that I could figure out is that Kuberflow deploys and monitors Machine Learning models. Am I correct? In that case, since Machine Learning models are also objects, can't we orchestrate them using Cloud Composer? How does Kubeflow help in any way, better than Cloud Composer when it comes to managing Machine Learning models??
Thanks
Kubeflow and Kubeflow Pipelines
Kubeflow is not exactly the same as Kubeflow Pipelines. The Kubeflow project mostly develops Kubernetes operators for distributed ML training (TFJob, PyTorchJob). On the other hand the Pipelines project develops a system for authoring and running pipelines on Kubernetes. KFP also has some sample components, by the main product is the pipeline authoring SDK and the pipeline execution engine
Kubeflow Pipelines vs. Cloud Composer
The projects are pretty similar, but there are differences:
KFP use Argo for execution and orchestration. Cloud Composer uses Apache Airflow.
KFP/Argo is designed for distributed execution on Kubernetes. Cloud Composer/Apache Airflow are more for single-machine execution.
KFP/Argo are language-agnostic - components can use any language (components describe containerized command-line programs). Cloud Composer/Apache Airflow use Python (Airflow operators are defined as Python classes).
KFP/Argo have concept of data passing. Every component has inputs and outputs and pipleine connects them into a data passing graph. Cloud Composer/Apache Airflow do not really have data passing (Airflow has global variable storage and XCom, but it's not the same thing as explicit data passing) and the pipeline is a task dependency graph rather than mostly data dependency graph (KFP can also have task dependencies, but usually they're not needed).
KFP supports execution caching feature that skips execution of tasks that have already been executed before.
KFP records all artifacts produced by pipeline runs in ML Metadata database.
KFP has experimental adapter which allows using Airflow operators as components.
KFP has large fast-growing ecosystem of custom components.
Kubeflow is a platform for developing and deploying a machine learning (ML) systems. Its components are focused on creating workflows aimed to build ML systems.
Cloud Composer provides the infraestructure to run Apache Airflow worflows. Its components are known as Airflow Operators and the workflows are connections between these operators that are known as DAGs.
Both services run on Kubernetes, but they are based on different programming frameworks; therefore, you are correct, Kuberflow deploys and monitors Machine Learning models. See below the answer for your questions:
In that case, since Machine Learning models are also objects, can't we orchestrate them using Cloud Composer?
You would need to find an operator that meet your needs, or create a custom operator with the structure required to create a model, see this example. Even when it can be performed, this could be more difficult that using Kubeflow.
How does Kubeflow help in any way, better than Cloud Composer when it comes to managing Machine Learning models??
Kubeflow hides complexity as it is focused on Machine Learninig models. The frameworks specialized on machine learning makes those things easier than using Cloud Composer which in this context can be considered as a general purpose tool (focused on linking existing services supported by the Airflow Operators).
Taking this straight from kubeflow.org
The Kubeflow project is dedicated to making deployments of machine
learning (ML) workflows on Kubernetes simple, portable and scalable.
Our goal is not to recreate other services, but to provide a
straightforward way to deploy best-of-breed open-source systems for ML
to diverse infrastructures. Anywhere you are running Kubernetes, you
should be able to run Kubeflow.
And as you can see it is a suite made of many software that are useful in the life cycle of a ML model. It comes with tensorflow, jupiter, etc.
Now the real deal, when it comes to Kubeflow is "easy deploy of a ML model at scale on a Kubernetis cluster".
However on GCP you already a ML suite in cloud, datalab, cloud build etc. So I don't know how much efficient will be sinning up a kubernetis cluster if you don't need the "portability" factor.
Cloud Composer is the real deal while taking about orchestration of a workflow. It is a "managed" version of Apache Airflow and it is ideal for any "simple" workflow that changes a lot, since you can change it via a visual UI and with python.
It is also ideal to automate infrastructure operations:
I am currently studying for the GCP Data Engineer exam and have struggled to understand when to use Cloud Scheduler and whe to use Cloud Composer.
From reading the docs, I have the impression that Cloud Composer should be used when there is interdependencies between the job, e.g. we need the output of a job to start another whenever the first finished, and use dependencies coming from first job. You can then chain flexibly as many of these "workflows" as you want, as well as giving the opporutnity to restart jobs when failed, run batch jobs, shell scripts, chain queries and so on.
For the Cloud Scheduler, it has very similar capabilities in regards to what tasks it can execute, however, it is used more for regular jobs, that you can execute at regular intervals, and not necessarily used when you have interdependencies in between jobs or when you need to wait for other jobs before starting another one. Therefore, seems to be more tailored to use in "simpler" tasks.
These thoughts came after attempting to answer some exam questions I found. However, I was surprised with the "correct answers" I found, and was hoping someone could clarify if these answers are correct and if I understood when to use one over another.
Here are the example questions that confused me in regards to this topic:
Question 1
You are implementing several batch jobs that must be executed on a schedule. These jobs have many interdependent steps that must be executed in a specific order. Portions of the jobs involve executing shell scripts, running Hadoop jobs, and running queries in BigQuery. The jobs are expected to run for many minutes up to several hours. If the steps fail, they must be retried a fixed number of times.
Which service should you use to manage the execution of these jobs?
A. Cloud Scheduler
B. Cloud Dataflow
C. Cloud Functions
D. Cloud Composer
Correct Answer: A
Question 2
You want to automate execution of a multi-step data pipeline running on Google Cloud. The pipeline includes Cloud Dataproc and Cloud Dataflow jobs that have multiple dependencies on each other. You want to use managed services where possible, and the pipeline will run every day.
Which tool should you use?
A. cron
B. Cloud Composer
C. Cloud Scheduler
D. Workflow Templates on Cloud Dataproc
Correct Answer: D
Question 3
Your company has a hybrid cloud initiative. You have a complex data pipeline that moves data between cloud provider services and leverages services from each of the cloud providers.
Which cloud-native service should you use to orchestrate the entire pipeline?
A. Cloud Dataflow
B. Cloud Composer
C. Cloud Dataprep
D. Cloud Dataproc
Correct Answer: D
Any insight on this would be greatly appreciated. Thank you !
Your assumptions are correct, Cloud Composer is an Apache Airflow managed service, it serves well when orchestrating interdependent pipelines, and Cloud Scheduler is just a managed Cron service.
I don't know where you have got these questions and answers, but I assure you(and I just got the GCP Data Engineer certification last month), the correct answer would be Cloud Composer for each one of them, just ignore this supposed correct answers and move on.
Cloud Scheduler is essentially Cron-as-a-service. All you need is to enter a schedule and an endpoint (Pub/Sub topic, HTTP, App Engine route). Cloud Scheduler has built in retry handling so you can set a fixed number of times and doesn't have time limits for requests. The functionality is much simpler than Cloud Composer.
Cloud Composer is managed Apache Airflow that "helps you create, schedule, monitor and manage workflows. Cloud Composer automation helps you create Airflow environments quickly and use Airflow-native tools, such as the powerful Airflow web interface and command line tools, so you can focus on your workflows and not your infrastructure."(https://cloud.google.com/composer/docs/)
Airflow is aimed at data pipelines with all the needed tooling.
I am using Google Data Flow to implement an ETL data ware house solution.
Looking into google cloud offering, it seems DataProc can also do the same thing.
It also seems DataProc is little bit cheaper than DataFlow.
Does anybody know the pros / cons of DataFlow over DataProc
Why does google offer both?
Yes, Cloud Dataflow and Cloud Dataproc can both be used to implement ETL data warehousing solutions.
An overview of why each of these products exist can be found in the Google Cloud Platform Big Data Solutions Articles
Quick takeaways:
Cloud Dataproc provides you with a Hadoop cluster, on GCP, and access to Hadoop-ecosystem tools (e.g. Apache Pig, Hive, and Spark); this has strong appeal if you are already familiar with Hadoop tools and have Hadoop jobs
Cloud Dataflow provides you with a place to run Apache Beam based jobs, on GCP, and you do not need to address common aspects of running jobs on a cluster (e.g. Balancing work, or Scaling the number of workers for a job; by default, this is automatically managed for you, and applies to both batch and streaming) -- this can be very time consuming on other systems
Apache Beam is an important consideration; Beam jobs are intended to be portable across "runners," which include Cloud Dataflow, and enable you to focus on your logical computation, rather than how a "runner" works -- In comparison, when authoring a Spark job, your code is bound to the runner, Spark, and how that runner works
Cloud Dataflow also offers the ability to create jobs based on "templates," which can help simplify common tasks where the differences are parameter values
Here are three main points to consider while trying to choose between Dataproc and Dataflow
Provisioning
Dataproc - Manual provisioning of clusters
Dataflow - Serverless. Automatic provisioning of clusters
Hadoop Dependencies
Dataproc should be used if the processing has any dependencies to tools in the Hadoop ecosystem.
Portability
Dataflow/Beam provides a clear separation between processing logic and the underlying execution engine. This helps with portability across different execution engines that support the Beam runtime, i.e. the same pipeline code can run seamlessly on either Dataflow, Spark or Flink.
This flowchart from the google website explains how to go about choosing one over the other.
https://cloud.google.com/dataflow/images/flow-vs-proc-flowchart.svg
Further details are available in the below link
https://cloud.google.com/dataproc/#fast--scalable-data-processing
Same reason as why Dataproc offers both Hadoop and Spark: sometimes one programming model is the best fit for the job, sometimes the other. Likewise, in some cases the best fit for the job is the Apache Beam programming model, offered by Dataflow.
In many cases, a big consideration is that one already has a codebase written against a particular framework, and one just wants to deploy it on the Google Cloud, so even if, say, the Beam programming model is superior to Hadoop, someone with a lot of Hadoop code might still choose Dataproc for the time being, rather than rewriting their code on Beam to run on Dataflow.
The differences between Spark and Beam programming models are quite large, and there are a lot of use cases where each one has a big advantage over the other. See https://cloud.google.com/dataflow/blog/dataflow-beam-and-spark-comparison .
Cloud Dataflow is a serverless data processing service that runs jobs written using the Apache Beam libraries. When you run a job on Cloud Dataflow, it spins up a cluster of virtual machines, distributes the tasks in your job to the VMs, and dynamically scales the cluster based on how the job is performing. It may even change the order of operations in your processing pipeline to optimize your job.
So use cases are ETL (extract, transfer, load) job between various data sources / data bases. For example load big files from Cloud Storage into BigQuery.
Streaming works based on subscription to PubSub topic, so you can listen to real time events (for example from some IoT devices) and then further process.
Interesting concrete use case of Dataflow is Dataprep. Dataprep is cloud tool on GCP used for exploring, cleaning, wrangling (large) datasets. When you define actions you want to do with your data (like formatting, joining etc), job is run under the hood on Dataflow.
Cloud Dataflow also offers the ability to create jobs based on "templates," which can help simplify common tasks where the differences are parameter values.
Dataproc is a managed Spark and Hadoop service that lets you take advantage of open source data tools for batch processing, querying, streaming, and machine learning. Dataproc automation helps you create clusters quickly, manage them easily, and save money by turning clusters off when you don't need them. With less time and money spent on administration, you can focus on your jobs and your data.
Super fast — Without using Dataproc, it can take from five to 30
minutes to create Spark and Hadoop clusters on-premises or through
IaaS providers. By comparison, Dataproc clusters are quick to start,
scale, and shutdown, with each of these operations taking 90 seconds
or less, on average. This means you can spend less time waiting for
clusters and more hands-on time working with your data.
Integrated — Dataproc has built-in integration with other Google
Cloud Platform services, such as BigQuery, Cloud Storage, Cloud
Bigtable, Cloud Logging, and Cloud Monitoring, so you have more than
just a Spark or Hadoop cluster—you have a complete data platform.
For example, you can use Dataproc to effortlessly ETL terabytes of
raw log data directly into BigQuery for business reporting.
Managed — Use Spark and Hadoop clusters without the assistance of an
administrator or special software. You can easily interact with
clusters and Spark or Hadoop jobs through the Google Cloud Console,
the Cloud SDK, or the Dataproc REST API. When you're done with a
cluster, you can simply turn it off, so you don’t spend money on an
idle cluster. You won’t need to worry about losing data, because
Dataproc is integrated with Cloud Storage, BigQuery, and Cloud
Bigtable.
Simple and familiar — You don’t need to learn new tools or APIs to
use Dataproc, making it easy to move existing projects into Dataproc
without redevelopment. Spark, Hadoop, Pig, and Hive are frequently
updated, so you can be productive faster.
If you want to migrate from your existing Hadoop/Spark cluster to the cloud, or take advantage of so many well-trained Hadoop/Spark engineers out there in the market, choose Cloud Dataproc; if you trust Google's expertise in large scale data processing and take their latest improvements for free, choose DataFlow.
Here are three main points to consider while trying to choose between Dataproc and Dataflow
Provisioning
Dataproc - Manual provisioning of clusters
Dataflow - Serverless. Automatic provisioning of clusters
Hadoop Dependencies
Dataproc should be used if the processing has any dependencies to tools in the Hadoop ecosystem.
Portability
Dataflow/Beam provides a clear separation between processing logic and the underlying execution engine. This helps with portability across different execution engines that support the Beam runtime, i.e. the same pipeline code can run seamlessly on either Dataflow, Spark or Flink.
Cloud Dataproc and Cloud Dataflow can both be used for data processing, and there’s overlap in their batch and streaming capabilities. You can decide which product is a better fit for your environment.
Cloud Dataproc is good for environments dependent on specific Apache big data components:
- Tools/packages
- Pipelines
- Skill sets of existing resources
Cloud Dataflow is typically the preferred option for green field environments:
- Less operational overhead
- Unified approach to development of batch or streaming pipelines
- Uses Apache Beam
- Supports pipeline portability across Cloud Dataflow, Apache Spark, and Apache Flink as runtimes.
See more details here https://cloud.google.com/dataproc/
Pricing comparision:
DataProc
Dataflow
If you want to calculate and compare cost of more GCP resources, please refer this url https://cloud.google.com/products/calculator/
One of the other important difference is:
Cloud Dataproc:
Data mining and analysis in datasets of known size
Cloud Dataflow:
Manage datasets of unpredictable size
see
Cloud Dataflow
Is a serverless data processing service that runs jobs written using
the Apache Beam libraries.
When you run a job on Cloud Dataflow it gets operated like this:
It spins up a cluster of virtual machines
Distributes the tasks in your job to the VMs, and dynamically scale the cluster based on how the job is performing
Dataflow may even change the order of operations in your processing pipeline to optimize your job.
It supports both batch and streaming Jobs. So use cases are ETL (extract, transfer, load) jobs between various data sources/databases.
For example, load big files from Cloud Storage into Big Query.
Streaming works based on subscription to Pub-Sub topic, so you can listen to real-time events (for example from some IoT devices) and then further process the data.
An interesting concrete use case of Dataflow is Data prep.
Data prep is a cloud tool on GCP used for exploring, cleaning, and wrangling (large) datasets. When you define the actions you want to perform on your data (like formatting, joining etc.), the job run under the hood on Dataflow.
Cloud Dataflow also offers the ability to create jobs based on "templates" which can help simplify common tasks where the differences are parameter values.
Data proc
Is a managed Spark and Hadoop service that lets you take advantage of
open-source data tools for batch processing, querying, streaming, and
machine learning.
Data proc automation helps you create clusters quickly, manage them easily, and save money by turning clusters off when you don't need them. With less time and money spent on administration, you can focus on your jobs and your data.