ThreadPriorityPolicy = 42的Cassandra启动错误

问题描述

当我尝试启动Cassandra时，它向我显示了这样的错误，我已经在env.sh和conf文件中也对conf文件进行了更改.

When I am trying to start Cassandra it shows me error like this I already did changes in the conf file also in env.sh, the file also.

没有类似类型错误的选项可用于此目的.

No options of similar type error is working for this.

intx ThreadPriorityPolicy=42 is outside the allowed range [ 0 ... 1 ]
Improperly specified VM option 'ThreadPriorityPolicy=42'
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.

其他信息

java version "9.0.4"
Java(TM) SE Runtime Environment (build 9.0.4+11)
Java HotSpot(TM) 64-Bit Server VM (build 9.0.4+11, mixed mode)

推荐答案

这是Cassandra的已知问题- CASSANDRA-13107 .

This is a known issue of Cassandra - CASSANDRA-13107.

在Java 9 JVM接受ThreadPriorityPolicy的任何整数值之前，而0和1是唯一的有效值.

Before Java 9 JVM accepted any integer value for ThreadPriorityPolicy, while 0 and 1 were the only valid values.

ThreadPriorityPolicy=1允许提高线程优先级，但前提是该进程以root特权启动.当ThreadPriorityPolicy=1时，JVM显式检查 euid = 0:

ThreadPriorityPolicy=1 allows to raise thread priorities, but only if the process starts with root privileges. When ThreadPriorityPolicy=1, JVM explicitly checks that euid=0:

static int prio_init() {
  if (ThreadPriorityPolicy == 1) {
    // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
    // if effective uid is not root. Perhaps, a more elegant way of doing
    // this is to test CAP_SYS_NICE capability, but that will require libcap.so
    if (geteuid() != 0) {
      if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
        warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
      }
      ThreadPriorityPolicy = 0;
    }
  }

请注意上面代码中的错误(或后门):如果将ThreadPriorityPolicy设置为0或1以外的值，则会跳过euid检查，但仍将允许应用程序使用高于正常值的优先级. Cassandra使用此后门.

Note a bug (or backdoor) in the above code: if you set ThreadPriorityPolicy to something other than 0 or 1, euid check will be skipped, but the application will be still allowed to use priorities above normal. Cassandra uses this backdoor.

由于 JEP 245 的结果，JDK 9改进了命令行参数验证，因此不再接受0或1以外的值.

As a result of JEP 245 JDK 9 improved command line argument validation, and therefore ThreadPriorityPolicy does not accept values other than 0 or 1 anymore.

编辑%CASSANDRA_HOME%/conf/jvm.options文件:

• 如果您在Linux上的root下运行Cassandra，
  将-XX:ThreadPriorityPolicy=42替换为-XX:ThreadPriorityPolicy=1
• 否则，请完全删除-XX:ThreadPriorityPolicy=42行.

• If you run Cassandra under root on Linux,
  replace -XX:ThreadPriorityPolicy=42 with -XX:ThreadPriorityPolicy=1
• Otherwise remove -XX:ThreadPriorityPolicy=42 line altogether.

这篇关于ThreadPriorityPolicy = 42的Cassandra启动错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！