Using Python subprocess.Popen in Rmd Failed

I am using Rmd and reticulate python eval function, which aims at opening a file via Python subprocess.Popen command, however, it seems sub-threading is not available. BTW, it works very well in the terminal.

my code is

import subprocess

def getFilefromHDFS(path):
  args_list = ['hadoop', 'fs', '-ls', path]
  proc = subprocess.Popen(args_list, stdout=subprocess.PIPE,stderr=subprocess.PIPE)
  proc.communicate()
  print proc.returncode
  
getFilefromHDFS("/user/hive/warehouse/ai.db/xxx/")

The error is :

OSError: [Errno 2] No such file or directory

here is my session info:

R version 3.5.1 (2018-07-02)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 16.04.5 LTS

Matrix products: default
BLAS: /usr/local/lib/R/lib/libRblas.so
LAPACK: /usr/local/lib/R/lib/libRlapack.so

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods  
[7] base     

other attached packages:
[1] sp_1.3-1           leaflet_1.1.0.9000 crosstalk_1.0.0   
[4] mlflow_0.7.0       bindrcpp_0.2.2     dplyr_0.7.8       

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.0       lattice_0.20-35  forge_0.1.0     
 [4] tidyr_0.8.2      png_0.1-7        ps_1.1.0        
 [7] utf8_1.1.4       assertthat_0.2.0 rprojroot_1.3-2 
[10] digest_0.6.16    packrat_0.4.9-3  showimage_1.0.0 
[13] mime_0.5         plyr_1.8.4       R6_2.3.0        
[16] backports_1.1.2  evaluate_0.11    httr_1.3.1      
[19] pillar_1.3.0     rlang_0.3.0.1    lazyeval_0.2.1  
[22] rematch_1.0.1    curl_3.2         rstudioapi_0.7  
[25] callr_3.0.0      Matrix_1.2-14    DT_0.5          
[28] reticulate_1.10  rmarkdown_1.10   readr_1.1.1     
[31] stringr_1.3.1    htmlwidgets_1.3  munsell_0.5.0   
[34] shiny_1.1.0      compiler_3.5.1   pingr_1.1.2     
[37] httpuv_1.4.5     pkgconfig_2.0.2  base64enc_0.1-3 
[40] htmltools_0.3.6  openssl_1.0.2    tidyselect_0.2.5
[43] tibble_1.4.2     shinytest_1.3.0  fansi_0.3.0     
[46] crayon_1.3.4     withr_2.1.2      later_0.7.4     
[49] grid_3.5.1       jsonlite_1.5     xtable_1.8-3    
[52] git2r_0.23.0     magrittr_1.5     scales_1.0.0    
[55] geohash_0.4.0    cli_1.0.0        stringi_1.2.4   
[58] debugme_1.1.0    swagger_3.9.2    webdriver_1.0.5 
[61] fs_1.2.6         promises_1.0.1   testthat_2.0.1  
[64] parsedate_1.1.3  tools_3.5.1      glue_1.3.0      
[67] purrr_0.2.5      hms_0.4.2        processx_3.2.0  
[70] yaml_2.2.0       colorspace_1.3-2 knitr_1.20      
[73] bindr_0.1.1 

need help,
Thanks

Start by reproducing the Rmd call through reticulate's Python eval with the shown subprocess.Popen example, then compare it with the terminal execution and the supplied session information. The issue does not name project files or tests; done means identifying the cause of the OSError and establishing a working or clearly documented subprocess behavior.