Flink安装排坑指南

Flink依赖与java环境，请先安装jdk，最好1.8以上，配置好JAVA_HOME环境变量

首先我是在window上安装flink的，下载flink

下载之后解压到任意目录，进入bin目录运行start-cluster.bat脚本启动flink服务，但是Task Slots却为0，查看log发现是TaskManager没有初始化成功

2020-03-14 18:28:37,888 ERROR org.apache.flink.runtime.taskexecutor.TaskManagerRunner       - TaskManager initialization failed.
org.apache.flink.configuration.IllegalConfigurationException: Failed to create TaskExecutorResourceSpec
	at org.apache.flink.runtime.taskexecutor.TaskExecutorResourceUtils.resourceSpecFromConfig(TaskExecutorResourceUtils.java:72)
	at org.apache.flink.runtime.taskexecutor.TaskManagerRunner.startTaskManager(TaskManagerRunner.java:356)
	at org.apache.flink.runtime.taskexecutor.TaskManagerRunner.<init>(TaskManagerRunner.java:152)
	at org.apache.flink.runtime.taskexecutor.TaskManagerRunner.runTaskManager(TaskManagerRunner.java:308)
	at org.apache.flink.runtime.taskexecutor.TaskManagerRunner.lambda$runTaskManagerSecurely$2(TaskManagerRunner.java:322)
	at org.apache.flink.runtime.security.NoOpSecurityContext.runSecured(NoOpSecurityContext.java:30)
	at org.apache.flink.runtime.taskexecutor.TaskManagerRunner.runTaskManagerSecurely(TaskManagerRunner.java:321)
	at org.apache.flink.runtime.taskexecutor.TaskManagerRunner.main(TaskManagerRunner.java:287)
Caused by: org.apache.flink.configuration.IllegalConfigurationException: The required configuration option Key: 'taskmanager.cpu.cores' , default: null (fallback keys: []) is not set
	at org.apache.flink.runtime.taskexecutor.TaskExecutorResourceUtils.checkConfigOptionIsSet(TaskExecutorResourceUtils.java:90)
	at org.apache.flink.runtime.taskexecutor.TaskExecutorResourceUtils.lambda$checkTaskExecutorResourceConfigSet$0(TaskExecutorResourceUtils.java:84)
	at java.util.Arrays$ArrayList.forEach(Unknown Source)
	at org.apache.flink.runtime.taskexecutor.TaskExecutorResourceUtils.checkTaskExecutorResourceConfigSet(TaskExecutorResourceUtils.java:84)
	at org.apache.flink.runtime.taskexecutor.TaskExecutorResourceUtils.resourceSpecFromConfig(TaskExecutorResourceUtils.java:70)
	... 7 more
2020-03-14 18:28:37,892 INFO  org.apache.flink.runtime.blob.TransientBlobCache              - Shutting down BLOB cache
2020-03-14 18:28:37,892 INFO  org.apache.flink.runtime.blob.PermanentBlobCache              - Shutting down BLOB cache

以为是没有权限创建文件夹，用管理员权限试了也报一样的错

搞了半天也没个结果，最后果断放弃了window环境。

在vmware上弄了个centos7，在centos7上搭建了jdk和flink环境，推荐centos7最少给2G内存，不然后面启动flink时会被内存不够的问题折腾死。

flink最少需要192M的内存才能启动，jdk1.8之后堆内存采用的是元空间，元空间是根据内存大小自动分配的。如果元空间给的太小，flink将会启动不起来。

The derived from fraction jvm overhead memory (19.200mb (20132659 bytes)) is less than its min value 192.000mb (201326592 bytes), min value will be used instead

在启动flink时可以通过jvm参数指定元空间大小

-XX:MetaspaceSize，初始空间大小，达到该值就会触发垃圾收集进行类型卸载，同时GC会对该值进行调整：如果释放了大量的空间，就适当降低该值；如果释放了很少的空间，那么在不超过MaxMetaspaceSize时，适当提高该值。

flink的cofig/flink-conf.yaml配置的jobmanager.heap.size和taskmanager.memory.process.size也不能超过元空间大小。它们默认大小分别是：1024m和1568m

配置方法：env.java.opts: -XX:MetaspaceSize=512m，指定元空间为512m

如果电脑内存够大的话，推荐还是直接给centos弄个2G吧，能省很多事。

运行./bin/start-cluster.sh，在linux上顺利启动，在win10上通过浏览器访问

win10上启动不了不知道是不是因为权限太严格导致的，希望有路过的大佬能在评论区指点一二