tillrohrmann commented on a change in pull request #11947: URL: https://github.com/apache/flink/pull/11947#discussion_r424988448
########## File path: docs/ops/memory/mem_setup_master.md ########## @@ -0,0 +1,94 @@ +--- +title: "Set up Master Memory" +nav-parent_id: ops_mem +nav-pos: 3 +--- +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +The Master is the controlling element of the Flink Cluster. +It consists of three distinct components: Flink Resource Manager, Flink Dispatcher and one Flink JobManager per running Flink Job. +This guide walks you through high level and fine-grained memory configurations for the Master. + +* toc +{:toc} + +The further described memory configuration is applicable starting with the release version *1.11*. If you upgrade Flink +from earlier versions, check the [migration guide](mem_migration.html) because many changes were introduced with the *1.11* release. + +<span class="label label-info">Note</span> This memory setup guide is relevant <strong>only for the Master</strong>! +The Master memory components have a similar but simpler structure compared to the [TaskManagers' memory configuration](mem_setup_tm.html). + +## Configure Total Memory + +The simplest way to set up the memory configuration is to configure the [total memory](mem_setup.html#configure-total-memory) for the process. +If you run the Master process using local [execution mode](#local-execution) you do not need to configure memory options, they will have no effect. + +## Detailed configuration + +The following table lists all memory components, depicted above, and references Flink configuration options which +affect the size of the respective components: + +| **Component** | **Configuration options** | **Description** | +| :------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | +| [Total Process Memory](mem_setup.html#configure-total-memory) | [`jobmanager.memory.process.size`](../config.html#jobmanager-memory-process-size) | The *total process memory* size for the job manager. This includes all the memory that a job manager JVM process consumes, consisting of the *total Flink memory*, *JVM metaspace* and *JVM overhead*. | +| [Total Flink Memory](mem_setup.html#configure-total-memory) | [`jobmanager.memory.flink.size`](../config.html#jobmanager-memory-flink-size) | The *total Flink memory* size for the job manager. This includes all the memory that a job manager consumes, except for *JVM metaspace* and *JVM overhead*. It consists of [JVM Heap](#configure-jvm-heap) and [Off-heap Memory](#configure-off-heap-memory) Memory. | +| [JVM Heap](#configure-jvm-heap) | [`jobmanager.memory.heap.size`](../config.html#jobmanager-memory-heap-size) | *JVM Heap* memory size for job manager. | +| [Off-heap Memory](#configure-off-heap-memory) | [`jobmanager.memory.off-heap.size`](../config.html#jobmanager-memory-off-heap-size) | *Off-heap* memory size for job manager. This option covers all off-heap memory usage including direct and native memory allocation. | +| [JVM metaspace](mem_setup.html#jvm-parameters) | [`jobmanager.memory.jvm-metaspace.size`](../config.html#jobmanager-memory-jvm-metaspace-size) | Metaspace size of the Flink JVM process | +| JVM Overhead | [`jobmanager.memory.jvm-overhead.min`](../config.html#jobmanager-memory-jvm-overhead-min) <br/> [`jobmanager.memory.jvm-overhead.max`](../config.html#jobmanager-memory-jvm-overhead-max) <br/> [`jobmanager.memory.jvm-overhead.fraction`](../config.html#jobmanager-memory-jvm-overhead-fraction) | Native memory reserved for other JVM overhead: e.g. thread stacks, code cache, garbage collection space etc, it is a [capped fractionated component](mem_setup.html#capped-fractionated-components) of the [total process memory](mem_setup.html#configure-total-memory) | +{:.table-bordered} +<br/> + +### Configure JVM Heap + +As mentioned before in the [total memory description](mem_setup.html#configure-total-memory), another way to set up the memory +for the Master is to specify explicitly the *JVM Heap* size ([`jobmanager.memory.heap.size`](../config.html#jobmanager-memory-heap-size)). +It gives more control over the available *JVM Heap* which contains: + +* Flink framework (e.g. *Job cache*) +* User code executed during job submission (e.g. for certain batch sources) or in checkpoint completion callbacks + +The required size of *JVM Heap* is mostly driven by the number of running jobs, their structure, and requirements for +the mentioned user code. + +The *Job cache* resides in the *JVM Heap*. It can be configured by +[`jobstore.cache-size`](../config.html#jobstore-cache-size) which must be less than the configured or derived *JVM Heap* size. + +<span class="label label-info">Note</span> If you have configured the *JVM Heap* explicitly, it is recommended to set +neither *total process memory* nor *total Flink memory*. Otherwise, it may easily lead to memory configuration conflicts. +The Flink scripts and CLI set the *JVM Heap* size via the JVM parameters *-Xms* and *-Xmx* when they start the Master process, see also [JVM parameters](mem_setup.html#jvm-parameters). + +### Configure Off-heap Memory + +The *Off-heap* memory component accounts for any type of *JVM direct memory* and *native memory* usage. Therefore, it +is also set via the corresponding JVM argument: *-XX:MaxDirectMemorySize*, see also [JVM parameters](mem_setup.html#jvm-parameters). + +The size of this component can be configured by [`jobmanager.memory.off-heap.size`](../config.html#jobmanager-memory-off-heap-size) +option. This option can be tuned e.g. if the Master process throws ‘OutOfMemoryError: Direct buffer memory’, see +the [the troubleshooting guide](mem_trouble.html#outofmemoryerror-direct-buffer-memory) for more information. Review comment: Will remove it. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
