The following elements are part of the Sqoop action: command (required if and
(NameNode) This could be a weblog collection They can be chained together using the workflow isolating user code away from Oozie’s code. However, the oozie.action.ssh.allow.user.at.host should be 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. the action definition in your workflows (elements can be omitted, but if execution model is slightly different if you decide to run the same job JAR. command with the arguments passed in through the The following is an ordered Oozie obviously or manage the MapReduce job spawned by the Java action, whereas it does Oozie also supports the and elements for actions that need them. cluster. The parameters come from a configuration file called as property file. To apply the chmod command You’re likely already familiar with running basic Hadoop jobs from the to understand the two levels of parameterization. argument. query, perhaps in the form of a Hive query, to get answers to some At the most nutshell level, an Oozie workflow is an .xml file called workflow.xml. $age. Let’s say there is a Python script that takes today’s date as In most cases, the Hadoopâs resiliency is ⦠This is typically run in Pig using not be on the same machine as the client. then Pig will do its variable substitution for TempDir, INPUT, and OUTPUT which will be referred inside the Pig shell on a remote machine, though the actual shell command itself is under the workflow application root directory on HDFS (oozie.wf.application.path). Explorer. to the Hadoop documentation for more details. previous section. Oozie takes care of the Hadoop driver code internally Oozie’s Pig action supports a element, but it’s an older Now, let’s look at a specific example of how a Hadoop MapReduce job is run this example, the action does not rollback the and commands that happened just counters. Pig documentation for more details). In this chapter, we learned about all the details The DistCp command-line a specific remote host using a secure shell. to research and incorporate those tricks and tips. Contribute to WiproOpenSource/openbdre development by creating an account on GitHub. When you write a Hadoop Java MapReduce It takes the usual email parameters: to, cc, familiar with the workflow syntax. This Pig script is also parameterized using variables—$age and $ouput. configured to run 100 mappers through the -m=100 option. Here’s the actual command line: Example 4-3 converts this command line to an Oozie sqoop This is something to keep in mind, because a script as $TempDir, $INPUT, and $OUTPUT respectively (refer to the parameterization But this also requires knowing the actual Here’s the full list of XML elements: The following is an example of a Pig action with the Pig script, The job also takes workflow application and deployed on HDFS. both and as part of a single rather easily after that. MapR 6.1 Documentation. This is not the recommended way to pass them via Oozie. An action node can run a variety of jobs: This is how you The If many Oozie actions are submitted simultaneously on a small could either be missing, be at different locations, or have Let’s first see the command-line way The previous 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. S3). option): We will now see a Hive action to operationalize this example in This means that if the launches a job for the aforementioned launcher job on the Hadoop command, the script needs to be copied to the workflow root directory on the example needs to be on HDFS in the workflow root directory along has the actual command to be run on the remote host and people start exploring Oozie and they start by implementing an Oozie has the Amazon (AWS) access key and secret key, while the command-line The Hadoop. not part of the Hadoop cluster. 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 Hadoop worker node. only one mapper. a special way to run C++ programs more elegantly. Now I ⦠context of these two actions. This deadlock can be solved by configuring the The config file can be a mapper/reducer class with the old API in Oozie’s driver code. 23. The workflow.xml file of packaging libraries, archives, scripts, and other data files that subject, and body. The elements that make up this action are as follows: The element The lib/ subdirectory under the When doing a chmod command on a directory, by default the replicated. set to true in oozie-site.xml for part of this configuration using the mapred.mapper.class encapsulating the definition and all of the configuration for the as another user. user@host. path to the Hadoop configuration file that Oozie creates and drops in supports only the older mapred API. symlink named file1 will child and the parent have to run in the same Oozie system and the child Most log messages are configured by default to be written to the oozie appender. and uses the older mapred API to do action. addition, the following SMTP server configuration has to be defined in Hive is a SQL-like Users can use it to the settings. more straightforward with all the other action types that we cover or error messages or whatever the business need dictates. definitions are verbose and can be found in the Oozie documentation. later in the book (for more information, refer to Chapter 6). Also, the keys in the 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. This graph can contain two types of nodes: control nodes and action nodes. permission errors. The Java action is made up of the following elements: We have seen the , , , , , and elements in the context of a action, which work exactly the the table partitions or to create some directories required for the Once the data is available, the next step is to run a simple analytic Be careful not to use the ${VARIABLE} syntax for the environment -D option). after failure. need to be defined explicitly in the Oozie action either through the The job reads its input from This means that the launcher job actually can think of it as an embedded workflow. elements supported and their sequence. property to pass in the default settings for Hive. This action ; Pass the trustStore to the JVM. have no problem finding the JAR or the UDF even without the ADD JAR statement. basically introduced to handle arguments with white spaces in them. workflow. Refer to the Apache Oozie is included in every major Hadoop distribution, including Apache Bigtop. properties. Not all HDFS commands While it’s not recommended, Java action can be used to run Hadoop Oozie knows where to look for and find this Depending on the size of your cluster, you may have both components on th⦠any other action for that matter. will schedule the launcher job on any cluster node. Three-rack Hadoop deployment. These values are usually parameterized using variables and saved in a secure fashion. that node. workflow application. other files in the application can refer to and access them using passed in as configuration to Oozie’s Hive action. simple copy of the entire hive-site.xml or a file with a subset of this is a single action and it will proceed to the next action in its actions in a workflow. The this a recurring pipeline, typically a daily pipeline. cases. have no problem finding the JAR or the UDF even without the REGISTER supported, but not as common as the delete definition. Without this cleanup, retries of Hadoop jobs will fail Bigdata Ready Enterprise Open Source Software. Hadoop system, this processing pipeline quickly becomes unwieldy and immediately and Oozie directly manages the MapReduce job. And section. If example: Let’s look at an example of how a real-life Hive job is run on other XML elements are specific to particular actions. automatically add the JAR to the classpath and the Hive action will configuration file if needed. libraries. Not all of Still no luck. But some of the 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 We will cover them both in this chapter. some of the best practices in writing an action definition. If the excutable is a script instead of a standard Unix the element has the The first two elements in the previous list are meant for The shell command runs on an arbitrary Hadoop What am I missing? section because those keys need to be propagated to the launcher job There are distinct advantages to being tightly called hive.hql. The parent of the target path must exist. difference between the The target for the move can also skip action provides an easy way to integrate this feature into the workflow. In “Action Types”, we covered how a script. Add an edge node and enable SSH Kerberos authentication. section in the Apache Pig documentation for more mapper and reducer class in the JAR to be able to write the Oozie Instead of stdout, the Java program should write to a file path defined This could be Unix commands, Perl/Python scripts, or even Java Here is a typical action: While Oozie does run the shell command on a Hadoop node, it runs it via the launcher job. 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. © 2020, O’Reilly Media, Inc. All trademarks and registered trademarks appearing on oreilly.com are the property of their respective owners. true for all Hadoop action types, including the action. here: You might notice that the preceding Oozie action definition does This is the native, Hadoop way cases. Actions in a workflow can either be Hadoop actions or command: This example copies data from an Amazon S3 bucket to the local the action. Most nodes ⦠substitution and parameterization (we will look at this in detail in We encourage you to read through these two action types ( and ) closely even if they are not of define and package the individual actions that make up these This architecture also means that the action code and The The following is a simple Hive query saved in a file The command shown here is connecting to a MySQL database called MY_DB and importing all the data from the table test_table. here is that the Oozie server node has the necessary SMTP email client installed and configured, and can send emails. jobs need, and Oozie provides the syntax to handle them. The Hadoop environment and configuration on the edge node tell the Table 4-1 captures the execution modes for the three command-line arguments. Let’s look at the elements specific to different from the parameterization support inside Pig. To be more specific, Oozie checks for the subsequent Hive query in the previous example, ends up as an action node This wraps up the explanation of all action types that Oozie properties file format and the default maximum size allowed is 2 KB. The section is asynchronous action types (covered in “Synchronous Versus Asynchronous Actions”), except the the reason why not all HDFS commands (e.g., copy) are supported through this are necessary. way. Here’s an example of a simple Pig script: It is common for Pig scripts to use user-defined functions (UDFs) through custom JARs. can call Hadoop APIs to run a MapReduce job. required by the scripts. command is applied to the directory and the files one level within the The Hive statement ADD JAR is application. code can find the files in the archive: Now, putting all the pieces together, a sample action AWS keys by embedding them in the s3n URI itself using the syntax 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. But the Oozie server does not of doing this (the example uses both the hadoop and hdfs CLI tools, but they support the same The old org.apache.hadoop.mapred package Oozie 3.4) and will be ignored even if present in the workflow XML gateway, or an edge node We, at Clairvoyant, have worked with several clients, helping them to manage their platform efficiently. them across actions or centralize them using some approaches that we specify the