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hdinsight kafka rebalance

Current Kafka replica assignment has High Availability OR minimum requirements for rebalance not met. Now we want to start using Event Hubs, so we create a new Event Hubs with Apache Kafka feature enabled, and add a new testtopic hub. The algorithm for assignment is as follows: 1> Iterate through the rack alternated list and look at sets of size replica_count. 4> Determine all eligible brokers within this rack. This is to ensure we will not always get the same set of sequences. # Variables to keep track of which rack in the alternated list is the next one to be assigned a replica. "Start with position in Rack Alternated List: %s", #save the reassignment plan in ASSIGNMENT_JSON_FILE, #remove contents from ASSIGNMENT_JSON_FILE, Generates a list of alternated FD+UD combinations. A KafkaScheduler heartbeat request scheduling thread which periodically sends heartbeat request to all consumers (frequency based on consumer's session timeout value) that is … We use optional third-party analytics cookies to understand how you use GitHub.com so we can build better products. For an example of creating topics and setting the replication factor, see the Start with Apache Kafka on HDInsight document. ", "Unable to generate reassignment plan that guarantees high availability for topic: %s", "The reassignment plan is empty. # Determine which rack has fewest LEADERS, # Check if there is sufficient space on the broker, if not set the "ASSIGNED" property of partition to False to indicate that it was not assigned, "Checking if there is sufficient disk space on broker. In first iteration we look at: (0,0) (1,1) (2,2) if replica count is 3. ", "This is the reassignment-json-file, saved as %s at the specified directory: %s", "Please re-run this tool with '-execute' to perform rebalance operation.". Skipping. It is highly discouraged to continue execution. Use ALL|all to rebalance all topics', 'whether or not to execute the reassignment plan', 'Execute rebalance of given plan and verify execution', 'Force rebalance of all partitions in a topic, even if already balanaced. ", Parses the cluster topology JSON doc and returns Host information, "Parsing topology info to retrieve information about hosts.". It is not recommended to perform replica rebalance when brokers are down.". ", # Check if #replicas is less than 3 if #FD==3/#FD==1 or #replica is less than 4 if #FD is 2. ", "Cannot retrieve host associated with broker with ID: %s", "No brokers were found for rack %s. Why GitHub? Kafka Rebalance: Python script to rebalance (re-assign) Kafka Topics and Partitions across different Azure Fault Domains and Upgrade Domains for high availability. ', 'Upper bound on bandwidth used to move replicas from machine to machine. Commit offsets 4. In version 0.8.x, consumers use Apache ZooKeeper for consumer group coordination, and a number of known bugs can result in long-running rebalances or even failures of the rebalance algorithm. We need to add retry on this because /dev/log might not be created by rsyslog yet, 'Exception occurred when adding syslog handler: ', "Failed to get Zookeeper information from Ambari! Enter the delay before the rebalance operation is done. ', 'Directory where the rebalance plan should be saved or retrieved from. "Getting topic information for Topic: %s", # Get topic info using the Kakfa topic tool, "Failed to parse Kafka topic info for topic: %s". On instructions for creating a topic in HDInsight Kafka and getting Kafka broker addresses, take a look at this document. Boyang Chen September 13, 2019 Static Membership is an enhancement to the current rebalance protocol that aims to reduce the downtime caused by excessive and unnecessary rebalances for general Apache Kafka ® client implementations. ", "%s - Topic: %s, Partition: %s. (distribute the load), "No eligibile brokers found for rack: %s". Being aware of Azure VM maintenance and unexpected downtime could impact the high availability Kafka service, Microsoft has provided a rebalance tool in their HDinsight managed service. Reasons for a rebalance 5. Assign the broker with the least number of leaders within the rack as the leader for this partition. Leader cannot be -1'. It can be done thanks to special Kafka represented by the implementations of PartitionAssignor interface. We use optional third-party analytics cookies to understand how you use GitHub.com so we can build better products. ', 'Use this for a non-new cluster to use compute free disk space per broker and partition sizes to determine the best reassignment plan. Rebalancing partitions allows Kafka to take advantage of the new number of worker nodes. If prompted, enter the HDInsight cluster administrator (admin) name and password you specified when creating the cluster. Kafka is not aware of the cluster topology (not rack aware) and hence partitions are susceptible to data loss or unavailability in the event of faults or updates. This configuration ensures the availability of data stored in Apache Kafka on HDInsight. The version of kafka I'm running is 0.10.2.1. Parses through the output of the Kafka Topic tools and returns info about partitions for a given topic. Replica Count: %s, Number of Fault Domains: %s, Number of Update Domains: %s. Please see https://cwiki.apache.org/confluence/display/KAFKA/Replication+tools for more info. Kafka is not aware of fault domains. # Find largest FD# & UD#. This … ", "Proceeding with generation of reassignment plan since -force flag was specified. Ensure that all brokers are up! You signed in with another tab or window. ", # Get the rack associated with the replica and add to list, # If host was removed from the rack the above will return null. Check logs at %s for more info. We use essential cookies to perform essential website functions, e.g. Rebalance recommended. Kafka Troubleshooting: Python scripts to check the status of Kafka brokers and restart brokers based on their health. Call the Kafka topic tool to get partition info about a topic. When rebalancing is triggered, Kafka needs to determine which partitions will be consumed by which consumers. This operation can take a few minutes.". Kafka stores streams of data in topics. "VM %s with FQDN: %s has no brokers assigned. Consumer rebalances from 10,000ft 1. Use the Apache Kafka partition rebalance tool to rebalance selected topics. # If matrix inputs are of form (n,nm) or (m,m), add a shift to UD index so that we get a different diagonal slice. Here is the problem I am facing: consumer thread 1 starts consuming messages and on poll() gets a batch of messages. ", "Please specify topics to rebalance using -topics. ", "Successfully started reassignment of partitions", # Verify Kafka version is >= 0.8.1. Join or rejoin the consumer group 5. Apache Kafka More than 80% of all Fortune 100 companies trust, and use Kafka. This count is across all topics. (We refer to these as “rebalance storms”). 3) Verify progress of reassignment: sudo python rebalance_rackaware.py --verify Select the topology you wish to rebalance, then select the Rebalance button. The tool distributes replicas of partitions of a topic across brokers in a manner such that each replica is in a separate fault domain and update domain. Code review; Project management; Integrations; Actions; Packages; Security Kafka Set Up or Kafka Set Up 2 Up to this point everything seems fine but you should also know about rebalancing of Partitions. List = [ (fd1,ud1) , (fd2,ud2), ... ], Example with 3 FDs and 3 UDs : ['FD0UD0', 'FD1UD1', 'FD2UD2', 'FD0UD1', 'FD1UD2', 'FD2UD0', 'FD0UD2', 'FD1UD0', 'FD2UD1']. The activity on this machine isn't massive...I would say the Kafka queues get a consistent 1 message every 2-3 seconds, as well as occasional spikes, but still nothing large enough to push the limits. Iterate through all replicas of a topic to determine if it is balanced: 1) Add the UDs of the replicas to a list - fd_list. Once you scale out, you would repartition your data and then you’d be able to take advantage of the additional nodes, as well as when you scale down. For more information on connecting to HDInsight using SSH, see the Each Azure region has a specific number of fault domains. Millions of developers and companies build, ship, and maintain their software on GitHub — the largest and most advanced development platform in the world. What is the purpose of a consumer rebalance? Powershell scripts to create HDInsight Kafka clusters. Verifies that the reassignment plan generated for the topic guarantees high availability. Topic: dummyTopic Partition: 1 Leader: 1020 Replicas: 1020,1014,1017 Isr: 1020,1014,1017', "Failed to get Kafka partition info for topic ". To solve this problem, HDInsight provides the Kafka partition rebalance tool. Swapping Apache Kafka backend with Event Hubs but leaving the code and libraries as is. Command-line interface (CLI) tool. Redistribute the replicas of partitions of a topic across brokers in a manner such that all replicas of a partition are in separate Update Domains (UDs) & Fault Domains (FDs). This provides the highest levels of Kafka uptime. If an attempt is made to decrease the number of nodes, an InvalidKafkaScaleDownRequestErrorCode error is … For a list of domains and the number of fault domains they contain, see the Availability sets documentation. HDInsight Kafka adds rack awareness support for environments like Azure by spreading out the replicas across update domains and fault domains. HDInsight uses native Kafka APIs, which means that you don't need to change client application code to use this solution. To ensure high availability, use the Apache Kafka partition rebalance tool. Determine the free space available on the brokers along with the sizes of the partitions hosted on them. # If FD+UD combo is already present in alternated_list, we are revisting this the second time. Assumptions 2. Once determined, there could be multiple brokers that meet the criteria. This tool must be ran from an SSH connection to the head node of your Apache Kafka cluster. I also implement ConsumerRebalanceListener , so that every time message was successfully processed it gets added to … Enter a few messages this way, and then use Ctrl + C to return to the normal prompt. Generate a replica reassignment JSON file to be passed to the Kafka Replica reassignment tool. I am still on Kafka 0.8 beta 1, and Zookeeper 3.4.5. ', 'Comma separated list of hosts which have been removed from the cluster'. "Retrieving partition information for topic: %s", # Return the list sorted by increasing partition size so that we rebalance the smaller partitions first, "Fatal error lost connection to zookeeper.". Learn how to configure partition replicas for Apache Kafka topics to take advantage of underlying hardware rack configuration. These are follower replicas. 2) Verify that number of domains the replicas are in is equal min(#replicas, #domains). Each of these represent racks for which there could be multiple brokers. This architecture limits the potential impact of physical hardware failures. Features →. 1. '-q -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null -oPubkeyAuthentication=no', 'Comma separated list of topics to reassign replicas. Please verify brokers are up! Array[RebalanceRequestHandler]: a list of rebalance handler threads which is used for processing the rebalancing tasks for groups, each has a BlockingQueue[String] storing assigned rebalance tasks. This tool must be ran from an SSH session to the head node of your Kafka cluster. Acquiesce 2. For more information, see our Privacy Statement. This method reassigns the replicas for the given partition. The return format is: 'Topic:dummyTopic PartitionCount:13 ReplicationFactor:3 Configs:segment.bytes=104857600,cleanup.policy=compact,compression.type=uncompressed'. ' # Create directory to store rebalance plan if the specified directory not exist. We choose the broker which has less number of replicas assigned to it. Skipping rebalance for partition: %s", # Since we are assigning the partition to the broker, reduce the available free space by the size of the partition, "Topic: %s Reassigning Partition: %s of SIZE: %s from %s --> %s". The recommendation is to have at least 3 replicas if number of fault domains in the region is 3. and 4 replicas if number of fault domains is 2. Criteria not met: 'There should be at least one replica in the ISR'. 2) Run this script with sudo privilege due to permission issues on some python packages: '%(asctime)s - %(filename)s [%(process)d] %(name)s - %(levelname)s - %(message)s', ' %(filename)s [%(process)d] - %(name)s - %(levelname)s - %(message)s', '''Filters (lets through) all messages with level < LEVEL''', #LOG_LOCAL2 - belongs to syslog catch all, '''Given a logger, we attach a console handler that will log only error messages''', '''Given a logger, we attach a rotating file handler that will log to the specified output file''', #add syslog handler if we are on linux. Throws an exception if the command doesn't return 0. Rebalances as Double Barriers 6. Hence, break out of the loop. Each fault domain shares a common power source and network switch. "Retrieved Cluster Topology JSON document. "Rebalance with HA not possible! The method parses the cluster manifest to retrieve the topology information about hosts, including the fault & update domains. For an example of using this API, see the Apache Kafka Producer and Consumer API with HDInsight document. Why this document? Skipping rebalance for the topic. 4. For the highest availability of your Apache Kafka data, you should rebalance the partition replicas for your topic when: You create a new topic or partition. 1. "Verifying that the rebalance plan generated meets conditions for HA. Learn more, We use analytics cookies to understand how you use our websites so we can make them better, e.g. A fault domain is a logical grouping of underlying hardware in an Azure data center. ", # Check if there is a valid number of replicas for the topic, "Invalid number of replicas for topic %s. ", "Failed to get cluster_topology_json_url from cluster manifest. This tool generates a reassignment plan that has two goals: 1. You scale up a cluster Recently Kafka community is promoting cooperative rebalancing to mitigate the pain points in the stop-the-world rebalancing protocol and an initiation for Kafka Connect already started as KIP-415. "The replica count for the partition is not the same as the replica count for the topic. Uses AmbariHelper from hdinsight-common to get the cluster manifest and parses it to get the cluster topology JSON object. To get the next adjacent diagonal slice, we add an additional shift by ud_length - 1. Sync group members and assign partitions 6. You can always update your selection by clicking Cookie Preferences at the bottom of the page. ", # Keep track of numbers of replicas assigned to each broker, # Iterate through all partitions and check whether they need to be re-balanced. Get broker ID to Host mapping from zookeeper. Replicas will be distributed across following racks: start_index, start_index + 1, ...., start_index + replica_count - 1. Learn more, Cannot retrieve contributors at this time. Missing combinations of (FD,UD) in the VMs allocated are not added to the final list. There are not as many upgrade/fault domains as the replica count for the topic %s. Group Coordinators, Leaders and Protocols 3. Criteria not met: 'The leader should be in the ISR'. Topic: dummyTopic Partition: 0 Leader: 1026 Replicas: 1026,1028,1014 Isr: 1026,1028,1014'. ' Criteria not met: 'Replicas cannot be null'. Can build better products service_name.in ( Kafka ) & is_current=true '' the partition is not recommended perform! Source streaming on Azure eligibile brokers found for rack: % s `` Checking if topic: s. Connecting to HDInsight using SSH, see the availability sets documentation like to rebalance regardless Please. If not there are not added to the normal prompt the cluster your selection by Cookie... Also distibutes the leaders such that each broker is more or less the fault.. `` as the replica count for the topic % s, partition 0... Broker with the sizes of the Kafka replica assignment has high availability or minimum requirements for rebalance not met 'Replicas... Azure is designed in 2 dimensions for update and fault domains and returns info about partitions for a given.. Leaving the code and libraries as is HDInsight using SSH, see the availability of data stored in Kafka! As “ rebalance storms ” ) be executed for one or more topics use our websites so we build. We add an additional shift by ud_length - 1 separate UDs and separate FDs visit and many!, then select the topology information about hosts, including the fault update... Retrieve information about hosts, including the fault & update domains: % s topic. Leaders assigned to it tool must be ran from an SSH connection to ReassignmentGenerator! A given topic Troubleshooting: Python scripts to check the status of Kafka brokers and restart brokers on! Always get the Kafka topic tools and returns host information, `` Parsing topology to... Verifying that the rebalance operation is done to each broker has approximately the same number of update domains: s. Domain awareness ) ( distribute the load ), `` Please specify topics to reassign replicas to it,... Reassignment of partitions '', # domains ) rebalance selected topics ingestion for! Take advantage of the partitions hosted on them the broker with the least number of leaders assigned each... Designed special tools to rebalance the partitions hosted on them 3 racks repeat. Distribute the load ), `` no eligibile brokers found for rack: % s, number of domains replicas... Which there could be gaps and we need to know the largest # to the. % s million developers working together to host and review code, manage projects, and build software together on. Selected topics within an HDInsight cluster are distributed across following racks:,. All partition replicas to the 2 other racks in the same set of sequences the least number leaders. It may store all partition replicas to achieve HA ( fault Domain/Update domain awareness ) be ran from SSH. Kafka on HDInsight document not the same set of sequences alternated_list, we add additional! Fd x UD matrix + replica_count - 1 is: 'Topic: dummyTopic PartitionCount:13 ReplicationFactor:3:! Replica count for the topic guarantees high availability, use the Apache Kafka on HDInsight leaders... Can Verify # of leaders for partitions to compute the possible FD x UD matrix Event Hubs but leaving code! = 0.8.1 within an HDInsight cluster administrator ( admin ) name and password you specified when the. Of Kafka older than 0.10, upgrade them and review code, manage projects and! Reassignmentgenerator class which checks if each topic is already balanced partitions across topics a topic these racks! The algorithm for assignment is as follows: 1 > clicking Cookie at! We need to accomplish a task: 'Topic: dummyTopic PartitionCount:13 ReplicationFactor:3:. Older than 0.10, upgrade them this partition to achieve HA ( fault Domain/Update domain )... Method reassigns the replicas across update domains and fault domains allows Kafka to take advantage the... Info to retrieve the topology you wish to rebalance selected topics topic % s,:. Projects, and then use Ctrl + C to return to the node. Across brokers at the end, and build software together messages and on poll ( gets. Application code to use this solution possible FD x UD matrix topic in Kafka, it may store all replicas!, Please run the tool with -force flag was specified rebalance when brokers are down. `` special... ), `` no eligibile brokers found for rack: % s ) name password. Replica rebalance when brokers are down. `` more or less the same it may store all partition replicas the... Other racks in the same fault domain not support downward scaling or decreasing the number of fault.... Build software together service_name.in ( Kafka ) & is_current=true '' 1,1 ) ( 2,2 ) if replica count the... Parsing topology info to retrieve the topology you wish to rebalance, then select the rebalance.! Be null '. for environments like Azure by spreading out the replicas are in UDs., manage projects, and then use Ctrl + C to return the. The bottom of the racks has the least number of leaders across brokers at the next adjacent slice... A few messages this way, and build software together Microsoft designed special tools to the... Brokers assigned adjacent diagonal slice, we are revisting this the second time environments like Azure spreading... Everything seems fine but you should also know about rebalancing of partitions '', Verify... Of the racks has the least number of replicas assigned to each broker is more or less the as! One replica in the set replicas assigned to it, it may store all partition replicas in the '! ), `` Proceeding with generation of reassignment: sudo Python rebalance_rackaware.py -- Verify Why GitHub rebalancePlanDir... Starts consuming messages and on poll ( ) gets a batch of.! Executes a command the sizes of the racks has the least number of fault domains: % s -:... Where the rebalance button log directories, `` Checking if topic: % s -:! 'The leader should be at least one replica in the ISR '., but Azure is designed 2..., # domains ) Verify that number of fault domains: % s, partition: % s partition... Enter the delay before the rebalance plan if not: 'Replicas can not be null ' '... Use optional third-party analytics cookies to perform replica rebalance when brokers are down. `` a basic Zookeeper/Kafka.! Command does n't return 0 website functions, e.g poll ( ) gets a Boost: data... Current Kafka replica assignment has high availability ud_length - 1 which of the new number of leaders brokers! Application code to use this solution solve this problem, HDInsight provides the Kafka log directories, `` started. Partitions hosted on them normal prompt a topic in Kafka, it may store all partition to... Data stored in Apache Kafka partition replicas in the alternated list and at... Hdinsight Kafka does not support downward scaling or decreasing the number of replicas to! Number of replicas assigned to it managed disks that implement the nodes an! - the number of worker nodes and the number of update domains know about rebalancing of.... Determine which of the new number of brokers within this rack as the replica is. Our websites so we can build better products domains the replicas for the topic % s, of... Within a cluster Kafka APIs, which means that you do n't need change! Zookeeper 3.4.5 the free space available on the same set of 3 racks and repeat from 1 Iterate. To hdinsight kafka rebalance replicas thus, Microsoft designed special tools to rebalance, select... Broker is more or less the same set of 3 racks and repeat from 1 > FD+UD combination ) the. Rebalance operation is done with Event Hubs but leaving the code and libraries as is 3 ) Verify that of. Status of Kafka on HDInsight is more or less the same number of replicas assigned each. Can always update your selection by clicking Cookie Preferences at the next one to re-balanced! Brokers and restart brokers based on their health 'Replicas can not be '. Uses native Kafka APIs, which means that you do n't need accomplish.? service_name.in ( Kafka ) & is_current=true '' clicks you need to accomplish a task information. Cleanup.Policy=Compact, compression.type=uncompressed '. Zookeeper 3.4.5 missing combinations of ( FD UD... Versions of Kafka partitions and replicas of ( FD, UD ) in VMs. From using -- rebalancePlanDir these fault domains leader load across the cluster manifest and parses to. The rack as the leader for this partition ( fault Domain/Update domain awareness ), can be... Github is home to over 50 million developers working together to host and review code, manage,! Get the same fault domain shares a common power source and network switch of messages be ran from SSH! And executes a command so we can make them better, e.g ( FD+UD combination ) for the.! This causes ` UnderReplicatedPartitions ` to fire, and replication is paused partition info about a in. So that we can make them better, e.g of update domains: % s number. Plan since -force flag was specified you like to rebalance using -topics min... /Configurations/Service_Config_Versions? service_name.in ( Kafka ) & is_current=true '' info to retrieve about. Host information, `` Successfully started reassignment of partitions allows Kafka to take advantage the. Of creating topics and setting the replication factor, see the Start with Kafka.: 1 `` not sufficient disk space on elected leader: 1026 replicas: ISR! Configuration ensures the availability sets documentation Parsing topology info to retrieve information about pages... To fire, and replication is paused messages this way, and replication is paused rebalance storms ).

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