1 Yarn生产环境核心参数配置案例
1）需求：从1G数据中，统计每个单词出现次数。服务器3台，每台配置4G内存，4核CPU，4线程。
2）需求分析：
1G / 128m = 8个MapTask；1个ReduceTask；1个mrAppMaster
平均每个节点运行10个 / 3台 ≈ 3个任务（4 3 3）
3）修改yarn-site.xml配置参数如下：
<!-- 选择调度器，默认容量 -->
<property>
<description>The class to use as the resource scheduler.</description>
<name>yarn.resourcemanager.scheduler.class</name>
<value>org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler</value>
</property>
<!-- ResourceManager处理调度器请求的线程数量,默认50；如果提交的任务数大于50，可以增加该值，但是不能超过3台 * 4线程 = 12线程（去除其他应用程序实际不能超过8） -->
<property>
<description>Number of threads to handle scheduler interface.</description>
<name>yarn.resourcemanager.scheduler.client.thread-count</name>
<value>8</value>
</property>
<!-- 是否让yarn自动检测硬件进行配置，默认是false，如果该节点有很多其他应用程序，建议手动配置。如果该节点没有其他应用程序，可以采用自动 -->
<property>
<description>Enable auto-detection of node capabilities such as
memory and CPU.
</description>
<name>yarn.nodemanager.resource.detect-hardware-capabilities</name>
<value>false</value>
</property>
<!-- 是否将虚拟核数当作CPU核数，默认是false，采用物理CPU核数 -->
<property>
<description>Flag to determine if logical processors(such as
hyperthreads) should be counted as cores. Only applicable on Linux
when yarn.nodemanager.resource.cpu-vcores is set to -1 and
yarn.nodemanager.resource.detect-hardware-capabilities is true.
</description>
<name>yarn.nodemanager.resource.count-logical-processors-as-cores</name>
<value>false</value>
</property>
<!-- 虚拟核数和物理核数乘数，默认是1.0 -->
<property>
<description>Multiplier to determine how to convert phyiscal cores to
vcores. This value is used if yarn.nodemanager.resource.cpu-vcores
is set to -1(which implies auto-calculate vcores) and
yarn.nodemanager.resource.detect-hardware-capabilities is set to true. The number of vcores will be calculated as number of CPUs * multiplier.
</description>
<name>yarn.nodemanager.resource.pcores-vcores-multiplier</name>
<value>1.0</value>
</property>
<!-- NodeManager使用内存数，默认8G，修改为4G内存 -->
<property>
<description>Amount of physical memory, in MB, that can be allocated
for containers. If set to -1 and
yarn.nodemanager.resource.detect-hardware-capabilities is true, it is
automatically calculated(in case of Windows and Linux).
In other cases, the default is 8192MB.
</description>
<name>yarn.nodemanager.resource.memory-mb</name>
<value>4096</value>
</property>
<!-- nodemanager的CPU核数，不按照硬件环境自动设定时默认是8个，修改为4个 -->
<property>
<description>Number of vcores that can be allocated
for containers. This is used by the RM scheduler when allocating
resources for containers. This is not used to limit the number of
CPUs used by YARN containers. If it is set to -1 and
yarn.nodemanager.resource.detect-hardware-capabilities is true, it is
automatically determined from the hardware in case of Windows and Linux.
In other cases, number of vcores is 8 by default.</description>
<name>yarn.nodemanager.resource.cpu-vcores</name>
<value>4</value>
</property>
<!-- 容器最小内存，默认1G -->
<property>
<description>The minimum allocation for every container request at the RM in MBs. Memory requests lower than this will be set to the value of this property. Additionally, a node manager that is configured to have less memory than this value will be shut down by the resource manager.
</description>
<name>yarn.scheduler.minimum-allocation-mb</name>
<value>1024</value>
</property>
<!-- 容器最大内存，默认8G，修改为2G -->
<property>
<description>The maximum allocation for every container request at the RM in MBs. Memory requests higher than this will throw an InvalidResourceRequestException.
</description>
<name>yarn.scheduler.maximum-allocation-mb</name>
<value>2048</value>
</property>
<!-- 容器最小CPU核数，默认1个 -->
<property>
<description>The minimum allocation for every container request at the RM in terms of virtual CPU cores. Requests lower than this will be set to the value of this property. Additionally, a node manager that is configured to have fewer virtual cores than this value will be shut down by the resource manager.
</description>
<name>yarn.scheduler.minimum-allocation-vcores</name>
<value>1</value>
</property>
<!-- 容器最大CPU核数，默认4个，修改为2个 -->
<property>
<description>The maximum allocation for every container request at the RM in terms of virtual CPU cores. Requests higher than this will throw an
InvalidResourceRequestException.</description>
<name>yarn.scheduler.maximum-allocation-vcores</name>
<value>2</value>
</property>
<!-- 虚拟内存检查，默认打开，修改为关闭 -->
<property>
<description>Whether virtual memory limits will be enforced for
containers.</description>
<name>yarn.nodemanager.vmem-check-enabled</name>
<value>false</value>
</property>
<!-- 虚拟内存和物理内存设置比例,默认2.1 -->
<property>
<description>Ratio between virtual memory to physical memory when setting memory limits for containers. Container allocations are expressed in terms of physical memory, and virtual memory usage is allowed to exceed this allocation by this ratio.
</description>
<name>yarn.nodemanager.vmem-pmem-ratio</name>
<value>2.1</value>
</property>
2 容量调度器多队列提交案例
1）在生产环境怎么创建队列？
（1）调度器默认就1个default队列，不能满足生产要求。
（2）按照框架：hive /spark/ flink 每个框架的任务放入指定的队列（企业用的不是特别多）
（3）按照业务模块：登录注册、购物车、下单、业务部门1、业务部门2
2）创建多队列的好处？
（1）因为担心员工不小心，写递归死循环代码，把所有资源全部耗尽。
（2）实现任务的降级使用，特殊时期保证重要的任务队列资源充足。11.11 6.18
业务部门1（重要）=》业务部门2（比较重要）=》下单（一般）=》购物车（一般）=》登录注册（次要）
2.1 需求
需求1：default队列占总内存的40%，最大资源容量占总资源60%，hive队列占总内存的60%，最大资源容量占总资源80%。
需求2：配置队列优先级
2.2 配置多队列的容量调度器
1）在capacity-scheduler.xml中配置如下：
（1）修改如下配置
<!-- 指定多队列，增加hive队列 -->
<property>
<name>yarn.scheduler.capacity.root.queues</name>
<value>default,hive</value>
<description>
The queues at the this level (root is the root queue).
</description>
</property>
<!-- 降低default队列资源额定容量为40%，默认100% -->
<property>
<name>yarn.scheduler.capacity.root.default.capacity</name>
<value>40</value>
</property>
<!-- 降低default队列资源最大容量为60%，默认100% -->
<property>
<name>yarn.scheduler.capacity.root.default.maximum-capacity</name>
<value>60</value>
</property>
（2）为新加队列添加必要属性：
<!-- 指定hive队列的资源额定容量 -->
<property>
<name>yarn.scheduler.capacity.root.hive.capacity</name>
<value>60</value>
</property>
<!-- 用户最多可以使用队列多少资源，1表示 -->
<property>
<name>yarn.scheduler.capacity.root.hive.user-limit-factor</name>
<value>1</value>
</property>
<!-- 指定hive队列的资源最大容量 -->
<property>
<name>yarn.scheduler.capacity.root.hive.maximum-capacity</name>
<value>80</value>
</property>
<!-- 启动hive队列 -->
<property>
<name>yarn.scheduler.capacity.root.hive.state</name>
<value>RUNNING</value>
</property>
<!-- 哪些用户有权向队列提交作业 -->
<property>
<name>yarn.scheduler.capacity.root.hive.acl_submit_applications</name>
<value>*</value>
</property>
<!-- 哪些用户有权操作队列，管理员权限（查看/杀死） -->
<property>
<name>yarn.scheduler.capacity.root.hive.acl_administer_queue</name>
<value>*</value>
</property>
<!-- 哪些用户有权配置提交任务优先级 -->
<property>
<name>yarn.scheduler.capacity.root.hive.acl_application_max_priority</name>
<value>*</value>
</property>
<!-- 任务的超时时间设置：yarn application -appId appId -updateLifetime Timeout
参考资料：https://blog.cloudera.com/enforcing-application-lifetime-slas-yarn/ -->
<!-- 如果application指定了超时时间，则提交到该队列的application能够指定的最大超时时间不能超过该值。
-->
<property>
<name>yarn.scheduler.capacity.root.hive.maximum-application-lifetime</name>
<value>-1</value>
</property>
<!-- 如果application没指定超时时间，则用default-application-lifetime作为默认值 -->
<property>
<name>yarn.scheduler.capacity.root.hive.default-application-lifetime</name>
<value>-1</value>
</property>
2）分发配置文件
3）重启Yarn或者执行yarn rmadmin -refreshQueues刷新队列，就可以看到两条队列：
[atguigu@hadoop102 hadoop-3.1.3]$ yarn rmadmin -refreshQueues
2.4 任务优先级
容量调度器，支持任务优先级的配置，在资源紧张时，优先级高的任务将优先获取资源。默认情况，Yarn将所有任务的优先级限制为0，若想使用任务的优先级功能，须开放该限制。
1）修改yarn-site.xml文件，增加以下参数
<property>
<name>yarn.cluster.max-application-priority</name>
<value>5</value>
</property>
2）分发配置，并重启Yarn
[atguigu@hadoop102 hadoop]$ xsync yarn-site.xml [atguigu@hadoop103 hadoop-3.1.3]$ sbin/stop-yarn.sh [atguigu@hadoop103 hadoop-3.1.3]$ sbin/start-yarn.sh
3）模拟资源紧张环境，可连续提交以下任务，直到新提交的任务申请不到资源为止。
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop jar /opt/module/hadoop-3.1.3/share/hadoop/mapreduce/hadoop-mapreduce-examples-3.1.3.jar pi 5 2000000
4）再次重新提交优先级高的任务
[atguigu@hadoop102 hadoop-3.1.3]$ hadoop jar /opt/module/hadoop-3.1.3/share/hadoop/mapreduce/hadoop-mapreduce-examples-3.1.3.jar pi -D mapreduce.job.priority=5 5 2000000
5）也可以通过以下命令修改正在执行的任务的优先级。
yarn application -appID <ApplicationID> -updatePriority 优先级
[atguigu@hadoop102 hadoop-3.1.3]$ yarn application -appID application_1611133087930_0009 -updatePriority 5