R h2o.init() 失败，但 h2o 服务器从终端启动答案

【问题标题】：R h2o.init() fails, but h2o server starts from terminalR h2o.init() 失败，但 h2o 服务器从终端启动
【发布时间】：2018-08-05 23:55:57
【问题描述】：

我在 R 中运行 h2o 时遇到问题。刚刚按照此页面上的 R 说明安装：http://h2o-release.s3.amazonaws.com/h2o/rel-wolpert/2/index.html。那么，

library(h2o)
h2o.init(nthreads = -1, max_mem_size = '2g', ip = "127.0.0.1")

h2o 服务器无法启动：

    H2O is not running yet, starting it now...

Note:  In case of errors look at the following log files:
    /var/folders/7y/p9rdbryd5zg5nvtjgdzyshx40000gt/T//RtmpvbbPTR/h2o_arman_started_from_r.out
    /var/folders/7y/p9rdbryd5zg5nvtjgdzyshx40000gt/T//RtmpvbbPTR/h2o_arman_started_from_r.err

java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)

Starting H2O JVM and connecting: ............................................................Cannot load library from path lib/osx_64/libxgboost4j_gpu.dylib
Cannot load library from path lib/libxgboost4j_gpu.dylib
Failed to load library from both native path and jar!
Cannot load library from path lib/osx_64/libxgboost4j_omp.dylib
Cannot load library from path lib/libxgboost4j_omp.dylib
Failed to load library from both native path and jar!
Found XGBoost backend with library: xgboost4j_minimal
Your system supports only minimal version of XGBoost (no GPUs, no multithreading)!
----- H2O started  -----
Build git branch: master
Build git hash: a0f976c49acfa9750b7887b1cda6408d298913f4
Build git describe: jenkins-master-4214
Build project version: 3.19.0.4215 (latest version: 3.18.0.2)
Build age: 16 hours and 15 minutes
Built by: 'jenkins'
Built on: '2018-02-26 07:35:56'
Watchdog Build git branch: (unknown)
Watchdog Build git hash: (unknown)
Watchdog Build git describe: (unknown)
Watchdog Build project version: (unknown)
Watchdog Built by: (unknown)
Watchdog Built on: (unknown)
XGBoost Build git branch: (unknown)
XGBoost Build git hash: (unknown)
XGBoost Build git describe: (unknown)
XGBoost Build project version: (unknown)
XGBoost Built by: (unknown)
XGBoost Built on: (unknown)
KrbStandalone Build git branch: (unknown)
KrbStandalone Build git hash: (unknown)
KrbStandalone Build git describe: (unknown)
KrbStandalone Build project version: (unknown)
KrbStandalone Built by: (unknown)
KrbStandalone Built on: (unknown)
Processed H2O arguments: [-name, H2O_started_from_R_arman_nbd116, -ip, 127.0.0.1, -port, 2341, -ice_root, /var/folders/7y/p9rdbryd5zg5nvtjgdzyshx40000gt/T//RtmpvbbPTR]
Java availableProcessors: 8
Java heap totalMemory: 245.5 MB
Java heap maxMemory: 1.78 GB
Java version: Java 1.8.0_111 (from Oracle Corporation)
JVM launch parameters: [-Xmx2g, -ea]
OS version: Mac OS X 10.13.1 (x86_64)
Machine physical memory: 16.00 GB
X-h2o-cluster-id: 1519649491546
User name: 'arman'
IPv6 stack selected: false
Network address/interface is not reachable in 150ms: /fe80:0:0:0:75d0:fa45:58ee:6f07%utun0/name:utun0 (utun0)
Network address/interface is not reachable in 150ms: /fe80:0:0:0:5448:2bff:fec7:2829%awdl0/name:awdl0 (awdl0)
Network address/interface is not reachable in 150ms: /fe80:0:0:0:1846:22ba:65a6:e16b%en0/name:en0 (en0)
Network address/interface is not reachable in 150ms: /192.168.0.9/name:en0 (en0)
Network address/interface is not reachable in 150ms: /fe80:0:0:0:0:0:0:1%lo0/name:lo0 (lo0)
Network address/interface is not reachable in 150ms: /0:0:0:0:0:0:0:1/name:lo0 (lo0)
Network address/interface is not reachable in 150ms: /127.0.0.1/name:lo0 (lo0)
IP address not found on this machine 
[1] "127.0.0.1"
[1] 2341
[1] TRUE
[1] -1
[1] "Failed to connect to 127.0.0.1 port 2341: Connection refused"
[1] 0
Error in h2o.init(nthreads = -1, max_mem_size = "2g", ip = "127.0.0.1",  : 
  H2O failed to start, stopping execution.

另一方面，我可以从终端运行服务器

java -jar /Users/arman/Library/R/3.4/library/h2o/java/h2o.jar
# Retrieved the location of jar file in R using  h2o:::.h2o.downloadJar()

上述命令有效。我可以继续从终端运行，但 h2o.init 提供了许多便利选项以及代码一致性。

任何想法为什么 h2o 无法从 R 初始化？此外，尝试从 Python 并有同样的问题。

操作系统：Mac OS X 版本 10.13.1

java 版本“1.8.0_111” Java(TM) SE 运行时环境 (build 1.8.0_111-b14) Java HotSpot(TM) 64 位服务器 VM（内部版本 25.111-b14，混合模式）

h2o 版本：3.19.0.4215

R 版本：3.4.3

【问题讨论】：

标签： h2o

【解决方案1】：

您的示例中非常奇怪的是您没有在 h2o.init() 中提及端口，但它却尝试在端口 2341 上启动。

要么：

您指定了端口，但没有在您的问题中显示
您已设置环境变量H2O_R_CMD_CHECK_DOC_EXAMPLES_PORT。

请尝试使用默认端口 (54321)。

通常，当 H2O 无法在某个端口上启动时，这是因为那里已经运行了某些东西，或者是因为防火墙问题。鉴于它可以从命令行运行，我的猜测是需要授予 R 应用程序访问您选择的端口上的 localhost 的权限。（在 Windows 上，您第一次尝试使用它时会弹出一个对话框；Mac 是否也在做类似的事情？）

【讨论】：

在我的示例中，我不小心粘贴了在端口 2341 上尝试的结果。但是在尝试默认端口 54321 时结果是相同的。关于授予访问 localhost 的权限，Mac 没有问我。我假设它是默认启用的。

【解决方案2】：

我意识到这是一篇旧帖子，但我在 Arch Linux 上遇到了类似的问题。问题是我的主机文件 (/etc/hosts) 不正确。我已经将它编写为使用以太网连接使用静态 IP 地址。但是在具有 DHCP 和非静态 IP 的 wifi 上，R 中的 h2o.init() 显然试图获取和使用静态（错误）IP 地址。将 /etc/hosts 更改为使用“localhost”而不是固定 IP 地址解决了该问题。

【讨论】：