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Commonly Asked Questions

RemoteLabZ Logs location

RemoteLabz's logs are located under /opt/remotelabz/var/log/ and RabbitMQ's log under /var/log/rabbitmq

Change password of phpmyadmin

sudo mysql -h localhost -u root -p
CREATE USER 'phpmyadmin'@'localhost' IDENTIFIED BY '<New-Password-Here>';
GRANT ALL PRIVILEGES ON *.* TO 'phpmyadmin'@'localhost' WITH GRANT OPTION;
FLUSH PRIVILEGES;
If you have finish with your modification, you have to go lab and delete the new lab created from the sandbox.

List the RabbitMQ messages waiting

On the RabbitMQ server To list the number of message in each queues 

sudo rabbitmqctl list_queues

How to modify the image of the device

To avoid a teacher or an user include a corrupted image, only the administrator can modify an existing default image. With the menu Device Sandbox, a new lab is created and after the export button is click, a new device template and new Operating Systems are created. To make an export, you have to :

  1. Click on Device Sandbox
  2. Click on the Modify button of the device whose image you wants to modify
  3. Start the device
  4. Make your modification
  5. Stopped the device
  6. Click on Export and choose a name for you new device template
  7. Leave the lab

How to increase size of disk on LVM virtual machines

  1. Shutdown the VM
  2. Right click the VM and select Edit Settings
  3. Select the hard disk you would like to extend
  4. On the right side, make the provisioned size as large as you need it and confirm
  5. Power on the VM and connect to it.
  6. Identify your disk name with sudo fdisk -l for example /dev/sda
  7. sudo fdisk /dev/sda
  8. Enter p to print the partition table
  9. Enter n to add a new partition
  10. Enter p again to make it a primary partition
  11. Enter the number of your new partition
  12. Pick the first cylinder which will most like come at the end of the last partition (this is the default value)
  13. Enter the amount of space (default is the rest of space available)
  14. Enter w to save these changes
  15. Restart the VM and log in
  16. Type sudo fdisk -l and check that a new partition is present
  17. Find your volume group with df -h.
    • Example: /dev/mapper/ubuntu--vg-root 15G 4.5G ...
    • Volume group is: ubuntu-vg
  18. Extend the volume group : sudo vgextend [volume group] /dev/sdaX
    • Example: sudo vgextend ubuntu-vg /dev/sda3
  19. Find the amount of free space available : sudo vgdisplay [volume group] | grep "Free"
  20. Expand the logical volume : sudo lvextend -L+[freespace]G /dev/[volgroup]/[volume]
    • Example 1: sudo lvextend -L+64G /dev/ubuntu-vg/root
    • Example 2: sudo lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu
  21. Expand the ext3 file system in the logical volume : sudo resize2fs /dev/[volgroup]/[volume]
    • Example: sudo resize2fs /dev/ubuntu-vg/root
  22. You can now run the df command to very that you have more space df -h

How to import a new image from an OVA

We assume your image has the name import_vm.ova in OVF format and in your home directory. 

cd ~
mkdir new_image
cd new_image
tar xvf ../import_vm.ova new_image.img -O qcow2
sudo mv Rocky_Linux.img /opt/remotelabz-worker/images/
As root, in operating system (OS), add a new operating system and in the Image filename parameter, give the name of your new image file. For our example, you have to type "new_image.img". finally, Create a new device which use this OS.

How to remove all bridge OVS on a worker manually

for i in $(sudo ovs-vsctl show | grep "Bridge" | grep "br-" | cut -d " " -f 6); do sudo ovs-vsctl del-br $i; done;

How to check the the queue and exchange with RabbitMQ

To list the queues 

rabbitmqadmin list queues

To list the exchange 

rabbitmqadmin list exchanges

To delete an exchange 

sudo rabbitmqadmin delete exchange name="worker"

To create an exchange with a specific type (direct or fanout) 

sudo rabbitmqadmin declare exchange name="worker" type="direct"

To clear a queue 

sudo rabbitmqadmin purge_queue queue_name

How to list all routes of the proxy

On the front 

curl http://localhost:8001/api/routes

Too many file opened

Many parameters have to be modify. Add following lines in /etc/sysctl.conf and execute a sysctl -p the system read this file.

fs.inotify.max_user_watches=60000
fs.inotify.max_user_instances=10000
fs.file-max=9793398

You can also modify the file /etc/security/limits.conf which is read on boot and use the command prlimit --nofile=300000:500000 --pid Process_Number (ulimit is obsolete) to change this value for a given process without reboot your server

*               soft    nofile          65535
*               hard    nofile          524288