azagrebin commented on a change in pull request #10999: [FLINK-15143] Docs for FLIP-49 TM memory model and configuration guide URL: https://github.com/apache/flink/pull/10999#discussion_r376447038
########## File path: docs/ops/memory/mem_migration.md ########## @@ -0,0 +1,234 @@ +--- +title: "Migration from old configuration (before 1.10 release)" +nav-parent_id: ops_mem +nav-pos: 5 +--- +<!-- +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 [memory setup of task managers](mem_setup.html) has changed a lot with the 1.10 release. Many configuration options +were removed or their semantics changed. This guide will help you to understand how to migrate the previous memory configuration to the new one. + +* toc +{:toc} + +<div class="alert alert-warning"> + <strong>Warning:</strong> It is important to review this guide because the legacy and new memory configuration can + result in different sizes of memory components. If you try to reuse your Flink configuration from the previous versions + before 1.10, it can result in changes to the behavior, performance or even configuration failures of your application. +</div> + +<span class="label label-info">Note</span> The previous memory configuration allows that no memory related options are set at all +as they all have default values. The [new memory configuration](mem_setup.html#configure-total-memory) requires +that at least one subset of the following options is configured explicitly, otherwise the configuration will fail: +* [`taskmanager.memory.flink.size`](../config.html#taskmanager-memory-flink-size) +* [`taskmanager.memory.process.size`](../config.html#taskmanager-memory-process-size) +* [`taskmanager.memory.task.heap.size`](../config.html#taskmanager-memory-task-heap-size) and [`taskmanager.memory.managed.size`](../config.html#taskmanager-memory-managed-size) + +The [default ‘flink-conf.yaml’](#default-configuration-in-flink-confyaml) shipped with Flink sets [`taskmanager.memory.process.size`](../config.html#taskmanager-memory-process-size) +to make the default memory configuration consistent. + +This [spreadsheet](https://docs.google.com/spreadsheets/d/1mJaMkMPfDJJ-w6nMXALYmTc4XxiV30P5U7DzgwLkSoE) can also help +to evaluate and compare the results of the legacy and new memory computations. + +## Changes in Configuration Options + +This chapter shortly lists all changes in the memory configuration options before the 1.10 release. +It also references other chapters for more details about the migration to the new configuration options. + +The following options are completely removed. If they are still used, they will be just ignored. + +<table class="table table-bordered"> + <thead> + <tr> + <th class="text-left">Removed option</th> + <th class="text-left">Note</th> + </tr> + </thead> + <tbody> + <tr> + <td><h5>taskmanager.memory.fraction</h5></td> + <td> + Check the description of the new option <a href="../config.html#taskmanager-memory-managed-fraction)">taskmanager.memory.managed.fraction</a>. + The new option has different semantics and the value of the deprecated option usually has to be adjusted. + See also <a href="#managed-memory">how to migrate managed memory</a>. + </td> + </tr> + <tr> + <td><h5>taskmanager.memory.off-heap</h5></td> + <td>On-heap <i>managed memory</i> is no longer supported, see also <a href="#managed-memory">how to migrate managed memory</a>.</td> + </tr> + <tr> + <td><h5>taskmanager.memory.preallocate</h5></td> + <td>Pre-allocation is no longer supported and <i>managed memory</i> is always allocated lazily, see also <a href="#managed-memory">how to migrate managed memory</a>.</td> + </tr> + </tbody> +</table> + +The following options are deprecated but if they are still used they will be interpreted as new options for backwards compatibility: + +<table class="table table-bordered"> + <thead> + <tr> + <th class="text-left">Deprecated option</th> + <th class="text-left">Interpreted as</th> + </tr> + </thead> + <tbody> + <tr> + <td><h5>taskmanager.heap.size</h5></td> + <td> + <ul> + <li><a href="../config.html#taskmanager-memory-flink-size">taskmanager.memory.flink.size</a> for <a href="../deployment/cluster_setup.html">standalone deployment</a></li> + <li><a href="../config.html#taskmanager-memory-process-size">taskmanager.memory.process.size</a> for containerised deployments</li> + </ul> + See also <a href="#total-memory-previously-heap-memory">how to migrate total memory</a>. + </td> + </tr> + <tr> + <td><h5>taskmanager.memory.size</h5></td> + <td><a href="../config.html#taskmanager-memory-managed-size">taskmanager.memory.managed.size</a>, see also <a href="#managed-memory">how to migrate managed memory</a>.</td> + </tr> + <tr> + <td><h5>taskmanager.network.memory.min</h5></td> + <td><a href="../config.html#taskmanager-memory-network-min">taskmanager.memory.network.min</a></td> + </tr> + <tr> + <td><h5>taskmanager.network.memory.max</h5></td> + <td><a href="../config.html#taskmanager-memory-network-max">taskmanager.memory.network.max</a></td> + </tr> + <tr> + <td><h5>taskmanager.network.memory.fraction</h5></td> + <td><a href="../config.html#taskmanager-memory-network-fraction">taskmanager.memory.network.fraction</a></td> + </tr> + </tbody> +</table> + +Although, the network memory configuration has not changed too much it is recommended to verify its configuration. +It can change if other memory components have new sizes, e.g. the total memory which the network can be a fraction of. +See also [new detailed memory model](mem_setup.html#detailed-memory-model). + +The container cut-off configuration options, [containerized.heap-cutoff-ratio](config.html#containerized-heap-cutoff-ratio) +and [containerized.heap-cutoff-min](config.html#containerized-heap-cutoff-min), have no effect for task manager processes anymore +but they still have the same semantics for the job manager process. See also [how to migrate container cut-off](#container-cut-off-memory). + +## Total Memory (previously Heap Memory) + +The previous options which were responsible for the total memory used by Flink are ‘taskmanager.heap.size’ or ‘taskmanager.heap.mb’. +Despite their naming, they included not only JVM heap but also other off-heap memory components. The options have been deprecated. + +The Mesos integration also had a separate option with the same semantics: ‘mesos.resourcemanager.tasks.mem’ which has also been deprecated. + +If the mentioned legacy options are used without specifying the corresponding new options, +they will be directly translated into the following new options: +* Total Flink memory ([`taskmanager.memory.flink.size`](../config.html#taskmanager-memory-flink-size)) for standalone deployments +* Total process memory ([`taskmanager.memory.process.size`](../config.html#taskmanager-memory-process-size)) for containerized deployments (Yarn or Mesos) + +It is also recommended to use these new options instead of the legacy ones as they might be completely removed in the following releases. + +See also [how to configure total memory now](mem_setup.html#configure-total-memory). + +## JVM Heap Memory + +JVM heap memory previously consisted of the managed memory (if configured to be on-heap) and the rest +which included any other usages of heap memory. This rest was always implicitly derived as the remaining part of the total memory, +see also [how to migrate managed memory](#managed-memory). + +Now, if only *total Flink memory* or *total process memory* is configured, then the JVM heap is also derived as the rest of +what is left after subtracting all other components from the total memory, see also [how to configure total memory](mem_setup.html#configure-total-memory). + +Additionally, you can now have more direct control over the JVM heap assigned to the operator tasks +([`taskmanager.memory.task.heap.size`](../config.html#taskmanager-memory-task-heap-size)), +see also [Task (Operator) Heap Memory](mem_setup.html#task-operator-heap-memory). +The same memory has to be accounted for the heap state backend ([MemoryStateBackend](../state/state_backends.html#the-memorystatebackend) +or [FsStateBackend](../state/state_backends.html#the-fsstatebackend) if it is chosen for streaming jobs. + +A part of the JVM heap is now always reserved for Flink framework +([`taskmanager.memory.framework.heap.size`](../config.html#taskmanager-memory-framework-heap-size)). +See also [Framework memory](mem_setup.html#framework-memory). + +## Managed Memory + +See also [how to configure managed memory now](mem_setup.html#managed-memory). + +### Explicit size + +The previous option to configure managed memory size (‘taskmanager.memory.size’) was renamed to +[`taskmanager.memory.managed.size`](../config.html#taskmanager-memory-managed-size) and deprecated. +It is recommended to use the new option because the legacy one can be removed in future releases. + +### Fraction + +If not set explicitly, the managed memory could be previously specified as a fraction (‘taskmanager.memory.fraction’) +of the total memory minus network memory and container cut-off (only for [Yarn](../deployment/yarn_setup.html) and +[Mesos](../deployment/mesos.html) deployments). This option has been completely removed and will have no effect if still used. +Please, use the new option [`taskmanager.memory.managed.fraction`](../config.html#taskmanager-memory-managed-fraction) instead. +This new option will set the [managed memory](mem_setup.html#managed-memory) to the specified fraction of the +[total Flink memory](mem_setup.html#configure-total-memory) if its size is not set explicitly by +[`taskmanager.memory.managed.size`](../config.html#taskmanager-memory-managed-size). + +### RocksDB state + +If the [RocksDBStateBackend](../state/state_backends.html#the-rocksdbstatebackend) is chosen for a streaming job, +its native memory consumption should now be accounted for in [managed memory](mem_setup.html#managed-memory). +The RocksDB memory allocation is limited by the [managed memory](mem_setup.html#managed-memory) size. +This should prevent the killing of containers on [Yarn](../deployment/yarn_setup.html) or [Mesos](../deployment/mesos.html). +See also [how to migrate container cut-off](#container-cut-off-memory). + +### Other changes + +Additionally, the following changes have been made: +* The [managed memory](mem_setup.html#managed-memory) is always off-heap now. The configuration option ‘taskmanager.memory.off-heap’ is removed and will have no effect anymore. +* The [managed memory](mem_setup.html#managed-memory) now uses native memory which is not direct memory. It means that the managed memory is no longer accounted for in the JVM direct memory limit. +* The [managed memory](mem_setup.html#managed-memory) is always lazily allocated now. The configuration option ‘taskmanager.memory.preallocate’ is removed and will have no effect anymore. + +## Container Cut-Off Memory + +For containerized deployments, you could previously specify a cut-off memory. This memory could accommodate for unaccounted memory allocations. +Dependencies which were not directly controlled by Flink were the main source of those allocations, e.g. RocksDB, internals of JVM etc. +This is no longer available and the related configuration options (`containerized.heap-cutoff-ratio` and `containerized.heap-cutoff-min`) +will have no effect on the task manager process anymore. The new memory model introduced more specific memory components, +described further, to address these concerns. + +In streaming jobs which use [RocksDBStateBackend](../state/state_backends.html#the-rocksdbstatebackend), the RocksDB +native memory consumption should be accounted for as a part of the [managed memory](mem_setup.html#managed-memory) now. +The RocksDB memory allocation is also limited by the configured size of the [managed memory](mem_setup.html#managed-memory). +See also [migrating managed memory](#managed-memory) and [how to configure managed memory now](mem_setup.html#managed-memory). + +The other specific consumption of direct or native off-heap memory can be now addressed by the following new configuration options: +* Task off-heap memory ([`taskmanager.memory.task.off-heap.size`](../config.html#taskmanager-memory-task-off-heap-size)) +* Framework off-heap memory ([`taskmanager.memory.framework.off-heap.size`](../config.html#taskmanager-memory-framework-off-heap-size)) +* JVM metaspace ([`taskmanager.memory.jvm-metaspace.size`](../config.html#taskmanager-memory-jvm-metaspace-size)) +* JVM overhead (see also [detailed new memory model](mem_setup.html#detailed-memory-model)) + +<span class="label label-info">Note</span> The job manager still has container cut-off memory configuration options. +The mentioned configuration options remain valid for the job manager in the same way as before. + +## Default Configuration in flink-conf.yaml + +This section describes the changes of the default ‘flink-conf.yaml’ shipped with Flink. + +The total memory (‘taskmanager.heap.size’) is replaced by [`taskmanager.memory.process.size`](../config.html#taskmanager-memory-process-size) +in the default ‘flink-conf.yaml’. The value is also increased from 1024Mb to 1568Mb. Review comment: and here ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services
