I know there is information worth 10 google pages on this but, all of them tell me to just put --master yarn in the spark-submit command. But, in cluster mode, how can my local laptop even know what that means? Let us say I have my laptop and a running dataproc cluster. How can I use spark-submit from my laptop to submit a job to this cluster?
Most of the documentation on running a Spark application in cluster mode assumes that you are already on the same cluster where YARN/Hadoop are configured (e.g. you are ssh'ed in), in which case most of the time Spark will pick up the appropriate local configs and "just work".
This is same for Dataproc: if you ssh onto the Dataproc master node, you can just run spark-submit --master yarn. More detailed instructions can be found in the documentation.
If you are trying to run applications locally on your laptop, this is more difficult. You will need to set up an ssh tunnel to the cluster, and then locally create configuration files that tell Spark how to reach the master via the tunnel.
Alternatively, you can use the Dataproc jobs API to submit jobs to the cluster without having to directly connect. The one caveat is that you will have to use properties to tell Spark to run in cluster mode instead of client mode (--properties spark.submit.deployMode=cluster). Note that when submitting jobs via the Dataproc API, the difference between client and cluster mode is much less pressing because in either case the Spark driver will actually run on the cluster (on the master or a worker respectively), not on your local laptop.
Related
I'm trying to figure out which is the best way to work with Airflow and Spark/Hadoop.
I already have a Spark/Hadoop cluster and I'm thinking about creating another cluster for Airflow that will submit jobs remotely to Spark/Hadoop cluster.
Any advice about it? Looks like it's a little complicated to deploy spark remotely from another cluster and that will create some file configuration duplication.
You really only need to configure a yarn-site.xml file, I believe, in order for spark-submit --master yarn --deploy-mode client to work. (You could try cluster deploy mode, but I think having the driver being managed by Airflow isn't a bad idea)
Once an Application Master is deployed within YARN, then Spark is running locally to the Hadoop cluster.
If you really want, you could add a hdfs-site.xml and hive-site.xml to be submitted as well from Airflow (if that's possible), but otherwise at least hdfs-site.xml files should be picked up from the YARN container classpath (not all NodeManagers could have a Hive client installed on them)
I prefer submitting Spark Jobs using SSHOperator and running spark-submit command which would save you from copy/pasting yarn-site.xml. Also, I would not create a cluster for Airflow if the only task that I perform is running Spark jobs, a single VM with LocalExecutor should be fine.
There are a variety of options for remotely performing spark-submit via Airflow.
Emr-Step
Apache-Livy (see this for hint)
SSH
Do note that none of these are plug-and-play ready and you'll have to write your own operators to get things done.
I just created a Google Cloud cluster (1 master and 6 workers) and by default Spark is configured.
I have a pure python code that uses NLTK to build the dependency tree for each line from a text file. When I run this code on the master spark-submit run.py I get the same execution time when I run it using my machine.
How to make sure that the master is using the workers in order to reduce the execution time ?
You can check the spark UI. If its running on top of yarn, please open the yarn UI and click on your application id which will open the spark UI. Check under the executors tab it will have the node ip address also.
could you please share your spark submit config.
Your command 'spark-submit run.py' doesn't seem to send your job to YARN. To do such thing, you need to add the --master parameter. For example, a valid command to execute a job in YARN is:
./bin/spark-submit --master yarn python/pi.py 1000
If you execute your job from the master, this execution will be straightforward. Anyway, check this link for another parameter that spark-submit accept.
For a Dataproc cluster (Hadoop Google cluster) you have two options to check the job history including the ones that are running:
By command line from the master: yarn application -list, this option sometimes needs additional configuration. If you have troubles, this link will be useful.
By UI. Dataproc enables you to access the Spark Web UI, it improves monitoring tasks. Check this link to learn how to access the Spark UI and other Dataproc UIs. In summary, you have to create a tunnel and configure your browser to use socks proxy.
Hope the information above help you.
TL;DR: In a Spark Standalone cluster, what are the differences between client and cluster deploy modes? How do I set which mode my application is going to run on?
We have a Spark Standalone cluster with three machines, all of them with Spark 1.6.1:
A master machine, which also is where our application is run using spark-submit
2 identical worker machines
From the Spark Documentation, I read:
(...) For standalone clusters, Spark currently supports two deploy modes. In client mode, the driver is launched in the same process as the client that submits the application. In cluster mode, however, the driver is launched from one of the Worker processes inside the cluster, and the client process exits as soon as it fulfills its responsibility of submitting the application without waiting for the application to finish.
However, I don't really understand the practical differences by reading this, and I don't get what are the advantages and disadvantages of the different deploy modes.
Additionally, when I start my application using start-submit, even if I set the property spark.submit.deployMode to "cluster", the Spark UI for my context shows the following entry:
So I am not able to test both modes to see the practical differences. That being said, my questions are:
1) What are the practical differences between Spark Standalone client deploy mode and cluster deploy mode? What are the pro's and con's of using each one?
2) How to I choose which one my application is going to be running on, using spark-submit?
What are the practical differences between Spark Standalone client
deploy mode and cluster deploy mode? What are the pro's and con's of
using each one?
Let's try to look at the differences between client and cluster mode.
Client:
Driver runs on a dedicated server (Master node) inside a dedicated process. This means it has all available resources at it's disposal to execute work.
Driver opens up a dedicated Netty HTTP server and distributes the JAR files specified to all Worker nodes (big advantage).
Because the Master node has dedicated resources of it's own, you don't need to "spend" worker resources for the Driver program.
If the driver process dies, you need an external monitoring system to reset it's execution.
Cluster:
Driver runs on one of the cluster's Worker nodes. The worker is chosen by the Master leader
Driver runs as a dedicated, standalone process inside the Worker.
Driver programs takes up at least 1 core and a dedicated amount of memory from one of the workers (this can be configured).
Driver program can be monitored from the Master node using the --supervise flag and be reset in case it dies.
When working in Cluster mode, all JARs related to the execution of your application need to be publicly available to all the workers. This means you can either manually place them in a shared place or in a folder for each of the workers.
Which one is better? Not sure, that's actually for you to experiment and decide. This is no better decision here, you gain things from the former and latter, it's up to you to see which one works better for your use-case.
How to I choose which one my application is going to be running on,
using spark-submit
The way to choose which mode to run in is by using the --deploy-mode flag. From the Spark Configuration page:
/bin/spark-submit \
--class <main-class>
--master <master-url> \
--deploy-mode <deploy-mode> \
--conf <key>=<value> \
... # other options
<application-jar> \
[application-arguments]
Let's say you are going to perform a spark submit in EMR by doing SSH to the master node.
If you are providing the option --deploy-mode cluster, then following things will happen.
You won't be able to see the detailed logs in the terminal.
Since driver is not created in the Master itself, you won't be able to terminate the job from the terminal.
But in case of --deploy-mode client:
You will be able to see the detailed logs in the terminal.
You will be able to terminate the job from the terminal itself.
These are the basic things that I have noticed till now.
I'm also having the same scenario, here master node use a standalone ec2 cluster. In this setup client mode is appropriate. In this driver is launched directly with in the spark-submit process which acts as a client to the cluster. The Input & output of the application is attached to the console.Thus, this mode is especially suitable for applications that involve REPL.
Else if your application is submitted from a machine far from the worker machines then it is quite common to use cluster mode to minimize the network latency b/w driver & executor.
I read an answer from What conditions should cluster deploy mode be used instead of client?,
(In client mode) You could run spark-submit on your laptop, and the Driver Program would run on your laptop.
Also, the Spark Doc says,
In client mode, the driver is launched in the same process as the client that submits the application.
Does it mean that I can submit spark tasks from any machine, as long as it can be reachable from master and has Spark environment?
Or in other words, can driver process run outside of the Spark cluster?
Yes, the driver can run on your laptop. Keep in mind though:
The Spark driver will need the Hadoop configuration to be able to talk to YARN and HDFS. You could copy it from the cluster and point to it via HADOOP_CONF_DIR.
The Spark driver will listen on a lot of ports and expect the executors to be able to connect to it. It will advertise the hostname of your laptop. Make sure it can be resolved and all ports accessed from the cluster environment.
Yes, I'm running spark-submit jobs over the LAN using option --deploy-mode cluster. Currently running into this issue however: the server response (json object) isn't very descriptive.
My team is deploying a new Big Data architecture on Amazon Cloud. We have Mesos up and running Spark jobs.
We are submitting Spark jobs (i.e.: jars) from a bastion host inside the same cluster. Doing so, however, the bastion host is the driver program and this is called the client mode (if I understood correctly).
We would like to try the cluster mode, but we don't understand where to start the dispatcher process.
The documentation says to start it in the cluster, but I'm confused since our masters don't have Spark installed and we use Zookeeper for master election. Starting it on a slave node is not a vailable option, since slave can fail and we don't want to expose a slave ip or public DNS to the bastion host.
Is it correct to start the dispatcher on the bastion host?
Thank you very much
Documentation is not very detailed.
However, we are quite happy with what we discovered:
according to the documentation, cluster mode is not supported for Mesos clusters (and for Python applications).
However, we started the dispatcher using --master mesos://zk://...
For submitting applications, you need the following:
spark-submit --deploy-mode cluster <other options> --master mesos://<dispatcher_ip>:7077 <ClassName> <jar>
If you run this command from a bastion machine, it won't work, because the Mesos master will look for the submitable jar in the same path as the bastion. We ended exposing the file as a downloadable URL.
Hope this helps
I haven't used cluster mode in Mesos and the cluster mode description is not very detailed. There isn't even a --help option on the script, like there should be, IMHO. However, if you don't pass the --master argument, it errors out with a help message and it turns out there is a --zk option for specifying the Zookeeper URL.
What might work is to launch this script on the bastion itself with the appropriate --master and --zk options. Would that work for you?
You could use a docker image with spark and your application.jar instead of uploading the jar to s3. I didn't try yet, but I think it should work. The environment variable is SPARK_DIST_CLASSPATH in spark-env.sh. I use spark distribution compiled without hadoop with apache hadoop 2.7.1
export SPARK_DIST_CLASSPATH=$(/opt/hadoop/bin/hadoop classpath):/opt/hadoop/share/hadoop/tools/lib/*:/opt/application.jar