Distributed Parallel Startup Methods
====================================

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.. toctree::
  :maxdepth: 1
  :hidden:

  dynamic_cluster
  mpirun
  rank_table

Startup Method
---------------

Currently GPU, Ascend and CPU support multiple startup methods respectively, three of which are dynamic cluster, \ ``mpirun`` and \ ``rank table``:

- `Dynamic cluster <https://www.mindspore.cn/tutorials/experts/en/r2.2/parallel/dynamic_cluster.html>`_: this method does not rely on third-party libraries, has disaster recovery function, good security, and supports three hardware platforms. It is recommended that users prioritize the use of this startup method.
- `mpirun <https://www.mindspore.cn/tutorials/experts/en/r2.2/parallel/mpirun.html>`_: this method relies on the open source library OpenMPI, and startup command is simple. Multi-machine need to ensure two-by-two password-free login. It is recommended for users who have experience in using OpenMPI to use this startup method.
- `rank table <https://www.mindspore.cn/tutorials/experts/en/r2.2/parallel/rank_table.html>`_: this method requires the Ascend hardware platform and does not rely on third-party library. After manually configuring the rank_table file, you can start the parallel program via a script, and the script is consistent across multiple machines for easy batch deployment.

The hardware support for the three startup methods is shown in the table below:

+-------------------------+--------------+-----------------+-------------+
|                         | GPU          | Ascend          | CPU         |
+=========================+==============+=================+=============+
|    Dynamic cluster      | Support      | Support         | Support     |
+-------------------------+--------------+-----------------+-------------+
|  \ ``mpirun``\          | Support      | Support         | Not support |
+-------------------------+--------------+-----------------+-------------+
|    \ ``rank table``\    | Not support  | Support         | Not support |
+-------------------------+--------------+-----------------+-------------+