Persistent Data¶

Overview¶

Kasm Workspaces allows administrators to configure folders to be mapped inside a Kasm each time it is provisioned. This is done by configuring the Volume Mappings field on the Kasm Image.

Configuring Volume Mappings on the Kasm Image¶

Volume Mappings may also be applied as a Group Setting . This may be useful if a certain set of users should have the mapping. When applied at the group level, all sessions created by members of this group will have the mapping applied.

Configuring Volume Mappings as a Group Setting¶

In this guide we will configure a folder on the host /var/kasm_user_share to be mapped inside the Kasm Desktop image to a folder named /share. This effectively will act as a file share. All users’s who have access to provision the image will have access to this folder.

Volume Mapping Config¶

bind

The path inside the Kasm where the volume will be mounted.

mode

rw for Read-Write , ro for Read-Only.

uid

The linux user id ownership that should be given to the volume. This permission is applied to the folder on the host. The uid must be 1000 in order for the Kasm container use to access the files.

gid

The linux group id ownership that should be given to the volume. This permission is applied to the folder on the host. The gid must be 1000 in order for the Kasm container use to access the files.

required

If true the volume must be accessible in order to provision the Kasm when requested. If false the system will allow the Kasm to be provision even if connectivity to the volume cannot be established. If not specified the default is true.

timeout

When a Kasm is provisioned , the system will attempt to establish connectivity to the volume specified. The system will wait the specified number of seconds before deeming the connectivity has failed. If not specified the default is 10 seconds

skip_check (optional)

When a Kasm is provisioned , the system will attempt to establish connectivity to the volume specified and ensure the ownership of that directory matches the uid:gid specified with a :code:’chown’. On some filesystems such as those mounted as read only, this check will fail or error. The administrator may choose to set this value to true so the system will skip the check. The default is false if not specified.

User Tokens¶

The volume mapping config supports the use of {user_id} and {username} tokens in the mapping name and bind attribute. This allows the administrator to create unique share locations per user.

{
   "/var/kasm_user_share/{user_id}":{
      "bind":"/share/{username}",
      "mode":"rw",
      "uid": 1000,
      "gid": 1000,
      "required": true,
      "skip_check": false
   }
}

Configuration Example¶

Create Host Directory¶

On the Kasm Workspaces server, create the directory and change the ownership to user and group 1000.

Note

If Kasm is installed in a multi-server deployment, /var/kasm_user_share in this example should reference a shared data storage solution (e.g NFS, HDFS, GFS, SMB, SSHFS) to ensure data continuity. Administrators must ensure this path is accessible from the hosts of all Agent services.

sudo mkdir /var/kasm_user_share
sudo chown 1000:1000 /var/kasm_user_share/
echo "test" > /var/kasm_user_share/test.txt

Configure Image Volume Mappings¶

Log into the Kasm UI as an administrator.
Select Images, and click edit (pencil) next to the Kasm Desktop image

In the Volume Mappings field, paste the following configuration and click Submit

{
   "/var/kasm_user_share":{
      "bind":"/share",
      "mode":"rw",
      "uid": 1000,
      "gid": 1000,
      "required": true,
      "skip_check": false
   }
}

Note

Although this guide demonstrate mapping a single volume, multiple volume mappings can be defined.

{
   "/var/kasm_user_share1":{
      "bind":"/share1",
      "mode":"rw",
      "uid": 1000,
      "gid": 1000,
      "required": true
   },
   "/var/kasm_user_share2":{
      "bind":"/share2",
      "mode":"rw",
      "uid": 1000,
      "gid": 1000,
      "required": true
   }
}

Verify Access¶

Launch the Kasm Desktop Image.
Verify the user can read and write to the /share location.

../_images/verification1.png — **Verifying Volume Access**¶

NFS Examples¶

This example assumes NFS Server and client software is installed on the respective servers.

NFS Server¶

Create the folder to host the share.

sudo mkdir /kasmdata
sudo chown -R 1000:1000 /kasmdata/

Add the entry to /etc/exports. In this example the IP of the NFS Client is 192.168.1.3. Note the use of all_squash, anonuid, and anongid settings to ensure that all files are accessed and written as the default Kasm session UID 1000. See https://linux.die.net/man/5/exports for more details.
/kasmdata 192.168.1.3(rw,sync,all_squash,anonuid=1000,anongid=1000,no_subtree_check)
Expose the new additions defined in the exports.
sudo exportfs -ar

NFS Client¶

Create a directory for the mount.
sudo mkdir -p /mnt/kasm-nfs
Add an entry to `/etc/fstab for the NFS mount. In this example the IP of the NFS Server is 192.168.1.2
192.168.1.2:/kasmdata /mnt/kasm-nfs nfs defaults 0 0
Mount the share.
sudo mount /mnt/kasm-nfs
Test creating a file.
sudo touch /mnt/kasm-nfs/example.txt

Inspect the file from the NFS Server to ensure the permissions are UID/GID 1000.

ls -la /kasmdata/
total 8
drwxr-xr-x  2 1000 1000 4096 Feb 24 08:39 .
drwxr-xr-x 20 root root 4096 Feb 23 16:00 ..
-rw-r--r--  1 1000 1000    0 Feb 24 08:39 example.txt

You can now reference the NFS share in volume mappings or persistent profile configurations.

{
   "/mnt/kasm-nfs":{
      "bind":"/share",
      "mode":"rw",
      "uid": 1000,
      "gid": 1000,
      "required": true,
      "skip_check": false
   }
}