作者:冉南阳
简介
Cloudera Data Science Workbench为从单个交互式会话中启动多个称为workers的引擎实例提供了基本支持。任何R或Python会话均可用于生成workers。这些工作程序可以配置为在启动时运行脚本(例如Python文件)或命令中。
可以使用 launch_workers函数。以及另外两个函数是list_workers 和 list_workers。来自所有工作程序的输出将显示在启动它们的会话的控制台中。会话退出时,这些workers将终止。
Python示例
Python分布式运算基本语法
import cdsw
workers=cdsw.launch_workers(n=2,cpu=0.2,memory=0.5,code="print('Hello from a CDSW Woker')")
list_workers
cdsw.list_workers()
stop_worker
cdsw.stop_workers()
编辑Python文件master.py;在Master引擎中,该脚本将启动三个工作程序并接受来自Workers的传入连接。
# master.py
import cdsw, socket
# Launch two CDSW workers. These are engines that will run in
# the same project, execute a given code or script, and exit.
workers = cdsw.launch_workers(n=3, cpu=0.2, memory=0.5, script="worker.py")
# Listen on TCP port 6000
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(("0.0.0.0", 6000))
s.listen(1)
# Accept two connections, one from each worker. Workers will
# execute worker.py.
conn, addr = s.accept()
for i in range(3):
# Receive a message from each worker and return a response.
data = conn.recv(20)
if not data: break
print("Master received:", data)
conn.send("Hello From Server!".encode())
conn.close()
编辑worker.py文件;Workers将执行脚本中的命令,并返回给Master。
# worker.py
import os, socket
# Open a TCP connection to the master.
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((os.environ["CDSW_MASTER_IP"], 6000))
# Send some data and receive a response.
s.send("Hello From Worker!".encode())
data = s.recv(1024)
s.close()
print("Worker received:", data)
执行master.py,可以看到执行了三次worker.py。
R语言示例
基本语法
library("cdsw")
workers <- launch.workers(n=2,cpu=0.2,memory=0.5, env="",code="print('Hello From a CDSW Workers')")
由于解析 launch.workers函数的bug,因此定义env 参数。如果未定义env 参数,env参数在内部序列化为与Cloudera Data Science Workbench不兼容的格式。此bug不会影响Python引擎。
编写master.r文件,在Master引擎中,该脚本将启动两个工作程序并接受来自Workers的传入连接。
# master.r
library("cdsw")
# Launch two CDSW workers. These are engines that will run in
# the same project, execute a given code or script, and exit.
workers <- launch.workers(n=2, cpu=0.2, memory=0.5, env="", script="worker.r")
# Accept two connections, one from each worker. Workers will
# execute worker.r.
for(i in c(1,2)) {
# Receive a message from each worker and return a response.
con <- socketConnection(host="0.0.0.0", port = 6000, blocking=TRUE, server=TRUE, open="r+")
data <- readLines(con, 1)
print(paste("Server received:", data))
writeLines("Hello from master!", con)
close(con)
}
编写worker.r文件;Workers将执行以下命令,并返回到Master。
# worker.r
print(Sys.getenv("CDSW_MASTER_IP"))
con <- socketConnection(host=Sys.getenv("CDSW_MASTER_IP"), port = 6000, blocking=TRUE, server=FALSE, open="r+")
write_resp <- writeLines("Hello from Worker", con)
server_resp <- readLines(con, 1)
print(paste("Worker received: ", server_resp))
close(con)
执行master.r,可以看到执行了两次worker.r
参考文档
https://docs.cloudera.com/documentation/data-science-workbench/1-6-x/topics/cdsw_parallel_computing.html