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This page is for all the users that are not used to manage linux environment.

Add/delete a user in your virtual machine

In order to add the user and set his/her password use following commands

sudo /usr/sbin/adduser <username>

sudo chage -d 0 <username>

After you need to modify the file /etc/ssh/sshd_config, enabling the PasswordAuthentication and then restart and check the SSH deamon:

Ubuntu:

sudo systemctl restart sshd.service

sudo systemctl status sshd.service

CentOS:

sudo systemctl restart sshd.service

sudo systemctl status sshd.service

In order to delete a user and his/her HOME directory just execute the command:

deluser --remove-home <username>

Grant a user root privileges in your virtual machine

It is possible to grant a user with root privileges using O the command adduser instead of useradd when the new user is created:
```
sudo /urs/sbin/adduser <username> sudo
```
Otherwise you can add the following line in the section #User privilege specification of the file /etc/sudoers:
<username> ALL=(ALL:ALL) ALL

How to mount remote filesystem with FUSE (Filesystem in USEr space) on CentOS or Ubuntu

On CentOS: - You will need to install a few packages that are not available in the standard CentOS repository. So, you must enable the EPEL repo:
```
yum install epel-release -y 
```
- Install FUSE (Filesystem in USEr space) and SSHFS packages
yum install fuse sshfs
- Load the FUSE module
```
modprobe fuse
```
- Confirm that the FUSE module is loaded
lsmod | grep fuse
fuse 84368 2
- Optionally, make sure the FUSE module is loaded upon a reboot
echo "modprobe fuse" >> /etc/rc.local
- Using SSHFS. Once the FUSE module is loaded, you can mount your remote partition using SSHFS:
sshfs user@remote_host:/remote_directory /local_mount_partition
If you have configured the login via ssh key authorization, you can use the following command:
```
sshfs user@remote_host:/remote_directory  /local_mount_partition -o IdentityFile=<absolute-path-with-key>
```
Note: If appear the following error
```
fuse: bad mount point `/local_mount_partition': Transport endpoint is not connected
```
execute: sudo fusermount -u /local_mount_partition

On Ubuntu: - First you have to install FUSE and SSHFS packages with the apt-get comand:

apt-get install fuse

apt-get install sshfs

Once the FUSE module is loaded, you can mount your remote partition using SSHFS:

sshfs user@remote_host:/remote_directory  /local_mount_partition

If you have configured the login via ssh key authorization, you can use the following command:

sshfs user@remote_host:/remote_directory  /local_mount_partition -o IdentityFile=<absolute-path-with-key>

Note: If appear the following error

fuse: bad mount point `/local_mount_partition': Transport endpoint is not connected

execute : sudo fusermount -u /local_mount_partition

How to use and configure Docker in your virtual machine

To use Docker in your virtual machine please set the MTU value at 1400 in the file /etc/docker/daemon.json. More in particular edit the file /etc/docker/daemon.json and then set

- - {
    "mtu" : 1400
    }

For any questions please write to superc@cineca.it .