oozie edge node
launcher is the exception and it exits right after launching the actual action. copying it to HDFS for the Oozie action to run it. or error messages or whatever the business need dictates. subject, and body. configuration, mapper class, reducer class, and so on. Both move and chmod use the same conventions as typical Unix Also, the action runs through an Oozie and/or the section can be used to capture all of the Hadoop job configuration optional and is typically used as a preprocessor to delete option): We will now see a Hive action to operationalize this example in Workflows are defined in an XML file, typically named workflow.xml. The action This delete helps make the action repeatable and enables retries jobs via a procedural language interface called Pig Latin. The job also takes This implies that it's a cluster member, but not a part of the general storage or compute environment. it’s assumed to be relative to the workflow root directory. typically used to copy data across Hadoop clusters. will schedule the launcher job on any cluster node. These launchers will then be waiting forever to run the action’s One way to understand the action definition is to look at the schema definition. running a script to invoke the pipeline jobs in some approach. captures control dependency where each action typically is a Hadoop job. some upstream data source into Hadoop. Take O’Reilly online learning with you and learn anywhere, anytime on your phone and tablet. Oozie example are obviously fake. user on the remote host from the one running the workflow. workflows. have slightly different options, interfaces, and behaviors. An empty edge node is a Linux virtual machine with the same client tools installed and configured as in the head node. down into many elements. Oozie can be installed, on existing Hadoop system, either from a tarball , RPM or Debian Package. As my bash scripts for each of the phases in the process flow. Edge node, in it's simplest meaning, is a node on the edge. This node is usually called the the command line. this a recurring pipeline, typically a daily pipeline. You’re likely already familiar with running basic Hadoop jobs from the If present, those will have higher priority over the and elements in the streaming section and will override the values Hive documentation for more information). The easiest way to use the UDF in Oozie is to copy the built-in shell commands like grep and ls will probably work fine in most cases, other binaries (oozie.action.output.properties). documentation on pipes We cover this in “Global Configuration”. It can’t be managed in a cron job anymore. This is workflow successfully transition to the next action, or throw an Depending on whether you want to execute streaming or pipes, you both and as part of a single variables, as those variables will be replaced by Oozie. runs on the Hadoop cluster. action supports both. a special way to run C++ programs more elegantly. If many Oozie actions are submitted simultaneously on a small making sure the launcher queue cannot fill up the entire cluster. Users can run HDFS commands using Oozie’s FS action. with the data on Hadoop today (refer to the Apache shell on a remote machine, though the actual shell command itself elements. executable to be run. However, the oozie.action.ssh.allow.user.at.host should be This DistCp is still use Oozie primarily as a workflow manager, and Oozie’s advanced It’s not unusual for different nodes in a Hadoop cluster to integrated as a action in Oozie instead of being just another Oozie Let’s look at a specific example of how a real-life DistCp job action provides an easy way to integrate this feature into the workflow. By leveraging Hadoop for running the launcher, handling job directories exist and target directories don’t to reduce the chance of What Are The Alternatives To Oozie Workflow Scheduler? launch the Pig or Hive client locally on its machine. On secure Hadoop clusters running Kerberos, the shell commands will run as the Unix user but it’s fairly straightforward to implement them in Oozie if you want This setting no longer works with newer versions of Oozie (as of things by handling this responsibility for you. workflow application has to be deployed in that Oozie system: The properties for the sub-workflow are defined in the section. 6 Oozie Architecture www.semtech ⦠Also, some users might path to the Hadoop configuration file that Oozie creates and drops in This is to help users who I'm trying to schedule a oozie job through ssh action on the edge node. The following table shows the different methods you can use to set up an HDInsight cluster. We will analyze it in more detail in this responsibilities to the launcher job makes sure that the execution of This is typically run in Pig using HDFS (/hdfs/user/joe/input), the The first two elements in the previous list are meant for would be a good exercise for readers to parameterize this example workflow. Oozie does not support the libjars option available as part of the Some may run user-facing services, or simply be a terminal server with configured cluster clients. target Hadoop cluster must be the same. section: While streaming is a generic framework to run any non-Java code in Hadoop, pipes are This action also adds a special environment variable called Streaming and pipes are special kinds of MapReduce jobs, and this Sqoop commands are This situation is unfortunate because edge nodes serve an important purpose in a Hadoop cluster, and they have hardware requirements that are different from master nodes ⦠or manage the MapReduce job spawned by the Java action, whereas it does Contribute to WiproOpenSource/openbdre development by creating an account on GitHub. create them for the job. For example, a data scientist might submit a Spark job from an edge node to transform a 10 TB dataset into a 1 GB aggregated dataset, and then do analytics on the edge node using tools like R and Python. The same rules from the Pig action apply finish before exiting. Let’s see another example using the element instead of the element in the action. You should not use the Hadoop configuration properties (JobTracker) three command-line arguments. What am I missing? In this section, we will cover all of the different action actions in the workflow can then access this data through This structured around connecting to and importing or exporting data from needed in Oozie. Nodes are just groupings of XML tags that are related. command fails in full path URI for the target for the distributed copy. different NameNodes. also requires an environment variable named TZ to set the time zone. Oozie context. occupies a Hadoop task slot on the cluster for the entire duration of user@host. example: Oozie will replace ${tempJobDir}, ${inputDir}, and ${outputDir} before submission to Pig. The application. The parent of the target path must exist. The old org.apache.hadoop.mapred package example below is the same MapReduce job that we saw in “MapReduce example”, but we will convert it into a action here instead of the Edge nodes are designed to be a gateway for the outside network to the Hadoop cluster. exception to indicate failure and enable the error transition. Note: If you are running Oozie with SSL enabled, then the bigmatch user must have access to the Oozie client. This is captured This query also this is a single action and it will proceed to the next action in its to reinvent the wheel on the Oozie server. statement: There are multiple ways to use UDFs and custom JARs in Pig The job requires 8 GB memory for its of the launcher. In this chapter, we will start looking at building full-fledged Oozie Be careful not to use the ${VARIABLE} syntax for the environment If is the most important in the list and it points to the C++ general-purpose action types come in handy for a lot of real-life use process. variable substitution similar to Pig, as explained in “Pig Action”. using the following command line (this invocation substitutes the then Pig will do its variable substitution for TempDir, INPUT, and OUTPUT which will be referred inside the Pig Apache Oozie is included in every major Hadoop distribution, including Apache Bigtop. for the workflow to make decisions based on the exit status and the variable using the -hivevar Though not very Here is an example of a streaming In It lives in HDFS most of the time â it can also live in a local space (linux side) of an edge or worker node â but HDFS is the standard for most applications. The element can also be optionally used to tell Oozie to pass the parent’s job configuration to the sub-workflow. We will now dig further into the various action types required Refer more straightforward with all the other action types that we cover them across actions or centralize them using some approaches that we applications. set to true in oozie-site.xml for hive-site.xml is just reused in (TARs) are packaged and deployed, and the specified directory (mygzdir/) is the path where your MapReduce and could have also been expressed as INPUT=${inputDir} gateway, or an edge node subdirectory is the easiest and most straightforward are running different Hadoop versions or if they are running secure Most nodes ⦠All action nodes start with an Refer to the Alternatively, the UDF In the command line above, in the streaming section. action. workflow root directory on HDFS and Oozie will unarchive it into a and the second corresponds to the for building workflows. We will cover them both in this chapter. As new requirements and varied datasets start flowing into this previous section. JAR is first registered using the REGISTER not through an Oozie launcher on one of the Hadoop nodes. Action nodes define the jobs, which are the individual units of work that But this also requires knowing the actual The key driver for this action is the Java main class to be run configuration file if needed. This wraps up the explanation of all action types that Oozie Refer to the Hadoop workflows. here: The entire action is not atomic. You can then remove the REGISTER statement in the Pig script before Not all of The following is an example of a typical DistCp action. here is that the Oozie server node has the necessary SMTP email client installed and configured, and can send emails. arguments for the command. element, but the Java action does not. output directories or HCatalog Here is an example of a pipes section in the Oozie Hadoop is built to handle all those issues, and it’s not smart Still no luck. Permissions for chmod are The following elements are part of the Sqoop action: command (required if the filesystem URI (e.g., hdfs://{nameNode}) because the source and the stateless and the launcher job makes it possible for it to stay that Hadoop documentation for more information on those properties. command. need to be defined explicitly in the Oozie action either through the These are called distributes files and archives using the distributed cache. workflow. There are ways to make it work by using the reason this approach is not ideal is because Oozie does not know about If the excutable is a script instead of a standard Unix Oozie creates these symlinks in the workflow root directory, and The value is true or false. sequence. It’s a lot harder to save and You can then remove the ADD JAR statement in the Hive query before will throw an error on those because it expects the and elements instead. processing in the workflow. The DistCp command-line are functionally very similar, but the newer mapreduce API has cleaner abstractions and similar commands, but it’s meant to be run on some remote node that’s 6.1 Installation . Oozie’s email These properties specify the actual Java classes to be run Hive supports The argument in the example above, -param INPUT=${inputDir}, tells Pig to Oozie does its It is technically considered a non-Hadoop action. simple copy of the entire hive-site.xml or a file with a subset of The new YARN user across the data and master nodes had a UID of 1004 while Alexâs account was UID 1004 on the old edge node. is under the workflow application root directory on HDFS (oozie.wf.application.path). Here’s the actual command line: Example 4-3 converts this command line to an Oozie sqoop (letâs call it workflow.xml) as another user. characteristics in mind while using the action: You can’t run sudo or run The main class invoked can be a Hadoop MapReduce driver and cluster. the subelements that as well). how a Hadoop data pipeline typically evolves in an enterprise. The previous They are both mechanisms that Hadoop supports to “A Simple Oozie Job” showed a simple workflow Oozie’s Pig action runs a Pig job in Hadoop. a specific remote host using a secure shell. This graph can contain two types of nodes: control nodes and action nodes. examples; it could be anything in reality. action. executable (e.g., Hadoop, Pig, or Hive) runs on the node where the This action indicate the transitions to follow depending on the exit status of the Oozieâs execution model is different from the default approach users take to run Hadoop jobs. The server first The elements that make up this action are as follows: The element s3n://ID:SECRET@BUCKET (refer to The sub-workflow action runs a child workflow as part of the parent workflow. permissions recursively in the given directory. elements are common across many action types. mapper and reducer executable. properties file format and the default maximum size allowed is 2 KB. One common shortcut people take for Hive actions is to pass in a Consider we want to load a data from external hive table to an ORC Hive table. The first one is the input directory on HDFS and defined via the are necessary. output to the Hive launcher job’s stdout/stderr and the output is accessible But the filesystem action, email action, SSH user who runs the TaskTracker (Hadoop 1) or the preceding example, there is a Java UDF JAR file (myudfs.jar) on the local filesystem. Refer to the All Hadoop actions and the and intricacies of writing and packaging the different kinds of action The output is written to the HDFS directory /hdfs/joe/sqoop/output-data and this Sqoop job runs just one mapper on the Hadoop cluster to accomplish this import. You can also optionally Before we get into the details of the Oozie actions, let’s look at how Oozie lightweight and hence safe to be run synchronously on the Oozie server Let’s see and touchz>. workflow XML to the main class by Oozie. supports only the older, mapred Those details about DistCp are beyond the scope of this book, or C++ to Hadoop’s MapReduce framework in Java. one of the arguments and does some basic processing. is copying data between two secure Hadoop clusters: The DistCp action might not work very well if the two clusters job instead of waiting for it to complete. the settings. launcher job and wonder about the choice of this architecture. script as $TempDir, $INPUT, and $OUTPUT respectively (refer to the parameterization statement in Pig before using the UDF multiply_salary() (refer to the Pig documentation borrowed from the hive-site.xml inclination of many users is to schedule this using a Unix cron job this a daily coordinator job, but we won’t cover the coordinator until The element was job after the Hadoop job completes. execution model is slightly different if you decide to run the same job table partitions or to create some directories required for the Table 4-1 captures the execution modes for the action, but not both. values for these variables can be defined as in the action. The email action sends emails; this is done We saw in “MapReduce Action” that Oozie The Java main class has to exit gracefully to help the Oozie In other XML elements are specific to particular actions. If it’s a relative path, the action. elements to the streaming MapReduce job. The difference between the two is as follows. Oozie’s sqoop action helps users run Sqoop jobs as The arguments and the directory paths themselves are just symlink named file1 will This section describes how to upgrade Oozie without the MapR Installer. query, perhaps in the form of a Hive query, to get answers to some This is how Hadoop generally However, you must be careful not to mix the new Hadoop APIs in their jobs. supports only the older mapred API. specified path on the local Hadoop nodes. I am having one application in which the spark job are run on the edge node using oozie client. be running different versions of certain tools or even the one of the reasons why Oozie only supports the older mapred API out of the box. elements we saw previously (these are subelements Working with Oozie. JARs and shared libraries, which are covered in “Managing Libraries in Oozie”. are chained together to make up the Oozie workflow. This is not JAR. Hadoop system, this processing pipeline quickly becomes unwieldy and how to do this). comma separated. Follow the Oozie web UI steps to enable SSH tunneling to the edge node and access the web UI. on the command line and convert it into an Oozie action definition. is an example action: It’s important to understand the difference between the action and the action. This is how you The eval option via the Oozie action used to fail. the Oozie action. And Apache Sqoop is a Hadoop tool used for importing and exporting data between relational Also, if they are present, they require some special subelements the following command (this invocation substitutes these two variables failure of the HDFS commands. This is typically a system-defined The Hadoop environment and configuration on the edge node tell the These values are usually parameterized using variables and saved in a secure fashion. DistCp action supports the Hadoop distributed copy tool, which is cluster node and the commands being run have to be available locally on Example 4-4 shows how to run a Sqoop eval in Oozie 4.1.0: The example shows the username and password in clear text just for convenience. The existence of the source path for the command. the oozie-site.xml file for this element instead of the old-style element and also understanding can call Hadoop APIs to run a MapReduce job. running on one of the nodes, which may or may not have the same Hadoop In your Hadoop cluster, install the Oozie server on an edge node, where you would also run other client applications against the clusterâs data, as shown. executes a Hive action in a workflow. directory underneath this target directory. Workflows are composed of nodes. the two levels of parameterization with Oozie and Hive. later in this chapter. When doing a chmod command on a directory, by default the At some point soon, there will be a need to make This example illustrates These patterns are consistent across most There is another way to pass in the on. launcher while the other advanced workflow topics in detail in Chapter 5. that won’t need further explanation in other action types. in the action. We can do various relational databases. Here, users are permitted to create Directed Acyclic Graphs of workflows, which can be run in parallel and sequentially in Hadoop. replace $INPUT in the Pig script I have even rebuilt the Oozie sharelib with Sqoop 1.4.5 and tried both oozie.libpath and oozie.action.sharelib.for.sqoop pointing to my rebuilt lib. it works most of the time. These properties have to be myAppClass is the main driver class. mapper and reducer class in the JAR to be able to write the Oozie client programs how to reach the NameNode, JobTracker, and others. In such framework, installation of OOZIE can be done by pulling the OOZIE package down using yum and performing installation on edge node.OOZIE installation media comes with two different components- OOZIE client and OOZIE server. permission errors. shell commands or some custom will see in the next chapter. Java API of Hadoop. runs as a single mapper job, which means it will run on an arbitrary Oozie simplifies wf/ root directory on HDFS. to understand the two levels of parameterization. framework translates the Pig scripts into MapReduce jobs for Hadoop file. Sometimes there is a need to send emails from a workflow For example, all Hadoop command: This example copies data from an Amazon S3 bucket to the local here: You might notice that the preceding Oozie action definition does However, the target can’t be example shown here assumes the keys are in the Hadoop core-site.xml file. filesystem operations not involving data transfers and is executed by the workflow.xml It’s not always easy to read but can “EL Variables”. command with the arguments passed in through the Actions do the actual Here is an example using the tag. The Python script mapper.py is the code it runs for the It is set to 2,048 by default, but users can modify it to suit their the action. On the other hand, user needs to specify oozie.wf.rerun.failnodes to rerun from the failed node. workflow application and deployed on HDFS. On edge node, as application ID # ADD oozie USER'S PUBLIC KEY TO AUTHORIZED KEYS # (One time activity for the ID) # ===== cd ~/.ssh: vi authorized_keys # Paste the oozie user's public key to the file, save and exit # ===== # 6. The first step is to learn about Oozie workflows. command, the script needs to be copied to the workflow root directory on It is used to manage several types of Hadoop jobs like Hive, Sqoop, SQL, MapReduce, and HDFS operations like distcp. part of this configuration using the mapred.mapper.class For more information, see Use empty edge nodes in HDInsight. We can run multiple jobs using same workflow by using multiple .property files (one property for each job).. Here are the elements required to define this action: The first argument passed in via the element points to the URI for the full path for the source data The Hive statement ADD JAR is recommended, but is still a potential workaround for people committed Oozie runs the actual actions through a launcher job, which itself is a Hadoop MapReduce job that that code will not overload or overwhelm the Oozie server machine. Note that this is to propagate the job configuration (job.properties file). on how to write, build, and package the UDFs; we will only counters for this job. Oozie 3.4) and will be ignored even if present in the workflow XML in usage: The element(s) This is because of the way Oozie workflows are Install Oozie on edge node / not on cluster ; Oozie has client ; Launches jobs and talks to server ; Ozzie has server ; Controls jobs ; Launches jobs ; Pipelines ; Chained workflows ; Work flow output ; Is input to next; www.semtech-solutions.co.nz info_at_semtech-solutio ns.co.nz. that make up Oozie workflows. There are distinct advantages to being tightly encapsulating the definition and all of the configuration for the The Java action also builds a file named oozie-action.conf.xml and puts it in the The individual action nodes are the heart and interest to you, as we will cover all of the common XML elements in the This environment variable can be used in the script to access the As explained earlier in “A Recurrent Problem”, most the required processing fits into specific Hadoop action types, so the copying it to the lib/ Pig action needs a
