brain initiation

20230607171316-openmpi.org

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+:PROPERTIES:
+:ID:       e56e90b1-ae5b-4344-97eb-993e5a81263e
+:END:
+#+title:  OpenMPI
+#+filetags: :CLUSTER:
+
+OpenMPI is a Message Passing Interface (MPI) library project combining technologies and resources from several other projects (FT-MPI, LA-MPI, LAM/MPI, and PACX-MPI).  It is used by many TOP500 supercomputers including Roadrunner, which was the world's fastest supercomputer from June 2008 to November 2009, and K computer, the fastest supercomputer from June 2011 to June 2012.
+
+Note: To use OpenMPI, [[id:422e07f8-c888-460f-849e-76d451946045][ssh]]-keys are created just like for [[id:56d784ed-a87c-441f-b819-73369760ca32][borg-backup]].
+
+* Configure the Host file
+Here map the IP adresses to the host names so that it is not requiered to type the ip adresses again and again...
+For that you need [[id:673d1cb1-536b-42f1-a046-40a8937c4283][root]] ([[id:dc54334e-afa9-4a53-be91-1e90bc6bf8d0][sudo]])
+#+begin_src bash
+  sudo nano /etc/hosts
+#+end_src
+
+* Example for map the IP adresses
+#+begin_src bash
+ # Standard host addresses
+ 127.0.0.1  localhost
+ ::1        localhost ip6-localhost ip6-loopback
+ ff02::1    ip6-allnodes
+ ff02::2    ip6-allrouters
+ # This host address
+ 127.0.1.1  <client1>
+ #MPI SETUP
+ <local IP adress of master>  <master>
+ <local IP adress of client>  <client1 but set annother name >
+#+end_src
+NOTE: Do this for all [[id:70899526-8b7d-4976-94fc-cc07c41e550a][clients]] and for the master.  The master must known all clients but the clients only there self and the master.
+
+* Setting up NFS
+NFS is used to share object file among all the systems and sharable datas in this [[id:408e8348-778a-4fbd-a14d-9f3d9c595b4a][cluster]].
+[[id:c69a77dc-f87f-418c-9870-eedddc43be37][Mounting]] the sharable folder:
+** NFS on Master
+#+begin_src bash
+  yay nfs-utils
+  mkdir <name of sharable folder>
+  cat /etc/exports #/home/<user>/<name of sharbel folder>* (rw,sync,no_root_squash,no_subtree_check)
+  exportfs -a
+  sudo systemctl enable nfs-utils && sudo systemctl start nfs-utils && sudo systemctl restart nfs-utils
+#+end_src
+
+** NFS on Clients
+#+begin_src bash
+  yay nfs-utils
+  mkdir <name of sharable folder>
+  sudo mount -t nfs <master>:/home/<user>/<name of sharable folder> ~/storage
+  df -h
+  sudo systemctl enable nfs-utils && sudo systemctl start nfs-utils && sudo systemctl restart nfs-utils 
+#+end_src
+
+** Add the entry to the file system table on clients
+#+begin_src bash
+  cat /etc/fstab
+  #MPI Cluster SetUP
+  <master>:/home/<smad>/<name of sharable folder> /home/<smad>/<name of sharable folder> nfs
+#+end_src
+
+** Write a program in C and compile the code
+- the file have to be a <name of file>.c on the Master-Node
+#+begin_src bash
+  cd <name of sharable folder>
+  pwd /home/<user>/<name of sharable folder>
+  mpicc <name of file>.c
+#+end_src
+
+** Run the C-Code on Master-Node
+#+begin_src bash
+  mpirund -np 4 -hosts <master>,<client1>,<client2> ./a.out
+#+end_src
+
+NOTE: The file.c can be every file from [[id:f2d9ff98-f926-442e-ae9b-fc1023e15b07][GMSH]], [[id:2d45175d-7fcc-4a55-b81c-14da72247eef][FEA-Tool]] or other c compatible program.