Merge branch '123-docs-software-virtual_machines-md' into 'preview'

Removed HTML syntax from code block

Closes #123

See merge request !374

doc.zih.tu-dresden.de/docs/software/virtual_machines.md

@@ -4,21 +4,21 @@ The following instructions are primarily aimed at users who want to build their
 [Singularity](containers.md) containers on ZIH systems.
 
 The Singularity container setup requires a Linux machine with root privileges, the same architecture
-and a compatible kernel. If some of these requirements can not be fulfilled, then there is
-also the option of using the provided virtual machines (VM) on ZIH systems.
+and a compatible kernel. If some of these requirements cannot be fulfilled, then there is also the
+option of using the provided virtual machines (VM) on ZIH systems.
 
-Currently, starting VMs is only possible on partitions `ml` and HPDLF. The VMs on the ML nodes are
+Currently, starting VMs is only possible on partitions `ml` and `hpdlf`. The VMs on the ML nodes are
 used to build singularity containers for the Power9 architecture and the HPDLF nodes to build
 Singularity containers for the x86 architecture.
 
 ## Create a Virtual Machine
 
-The `--cloud=kvm` Slurm parameter specifies that a virtual machine should be started.
+The Slurm parameter `--cloud=kvm` specifies that a virtual machine should be started.
 
 ### On Power9 Architecture
 
 ```console
-marie@login$ srun -p ml -N 1 -c 4 --hint=nomultithread --cloud=kvm --pty /bin/bash
+marie@login$ srun --partition=ml --nodes=1 --cpus-per-task=4 --hint=nomultithread --cloud=kvm --pty /bin/bash
 srun: job 6969616 queued and waiting for resources
 srun: job 6969616 has been allocated resources
 bash-4.2$
@@ -27,7 +27,7 @@ bash-4.2$
 ### On x86 Architecture
 
 ```console
-marie@login$ srun -p hpdlf -N 1 -c 4 --hint=nomultithread --cloud=kvm --pty /bin/bash
+marie@login$ srun --partition=hpdlf --nodes=1 --cpus-per-task=4 --hint=nomultithread --cloud=kvm --pty /bin/bash
 srun: job 2969732 queued and waiting for resources
 srun: job 2969732 has been allocated resources
 bash-4.2$
@@ -35,17 +35,17 @@ bash-4.2$
 
 ## Access a Virtual Machine
 
-Since the a security issue on ZIH systems, we restricted the filesystem permissions. Now you have to
-wait until the file `/tmp/${SLURM_JOB_USER}\_${SLURM_JOB_ID}/activate` is created, then you can try
+After a security issue on ZIH systems, we restricted the filesystem permissions. Now, you have to
+wait until the file `/tmp/${SLURM_JOB_USER}_${SLURM_JOB_ID}/activate` is created. Then, you can try
 to connect via `ssh` into the virtual machine, but it could be that the virtual machine needs some
-more seconds to boot and start the SSH daemon. So you may need to try the `ssh` command multiple
+more seconds to boot and accept the connection. So you may need to try the `ssh` command multiple
 times till it succeeds.
 
 ```console
 bash-4.2$ cat /tmp/marie_2759627/activate
 #!/bin/bash
 
-if ! grep -q -- "Key for the VM on the partition ml" "/home/rotscher/.ssh/authorized_keys" >& /dev/null; then
+if ! grep -q -- "Key for the VM on the partition ml" "/home/marie/.ssh/authorized_keys" > /dev/null; then
   cat "/tmp/marie_2759627/kvm.pub" >> "/home/marie/.ssh/authorized_keys"
 else
   sed -i "s|.*Key for the VM on the partition ml.*|ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC3siZfQ6vQ6PtXPG0RPZwtJXYYFY73TwGYgM6mhKoWHvg+ZzclbBWVU0OoU42B3Ddofld7TFE8sqkHM6M+9jh8u+pYH4rPZte0irw5/27yM73M93q1FyQLQ8Rbi2hurYl5gihCEqomda7NQVQUjdUNVc6fDAvF72giaoOxNYfvqAkw8lFyStpqTHSpcOIL7pm6f76Jx+DJg98sXAXkuf9QK8MurezYVj1qFMho570tY+83ukA04qQSMEY5QeZ+MJDhF0gh8NXjX/6+YQrdh8TklPgOCmcIOI8lwnPTUUieK109ndLsUFB5H0vKL27dA2LZ3ZK+XRCENdUbpdoG2Czz Key for the VM on the partition ml|" "/home/marie/.ssh/authorized_keys"
@@ -71,7 +71,7 @@ We provide [tools](virtual_machines_tools.md) to automate these steps. You may j
 The available space inside the VM can be queried with `df -h`. Currently the whole VM has 8 GB and
 with the installed operating system, 6.6 GB of available space.
 
-Sometimes the Singularity build might fail because of a disk out-of-memory error. In this case it
+Sometimes, the Singularity build might fail because of a disk out-of-memory error. In this case, it
 might be enough to delete leftover temporary files from Singularity:
 
 ```console
@@ -111,4 +111,4 @@ Bootstraps **shub** and **library** should be avoided.
 ### Transport Endpoint is not Connected
 
 This happens when the SSHFS mount gets unmounted because it is not very stable. It is sufficient to
-run `\~/mount_host_data.sh` again or just the SSHFS command inside that script.
+run `~/mount_host_data.sh` again or just the SSHFS command inside that script.