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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 a device's image

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

Change the size of a partition on LVM

Add new hot plug physical disk to LVM

  1. Scan your host if the disk is not detected : (to execute in root) echo "- - -" > /sys/class/scsi_host/host2/scan
  2. Create partition on the new disk sudo fdisk /dev/sdb
    1. Enter p to print the partition table
    2. Enter n to add a new partition
    3. Enter p again to make it a primary partition
    4. Enter the number of your new partition
    5. Pick the first cylinder which will most like come at the end of the last partition (this is the default value)
    6. Change the label t and select type 8e
    7. Enter w to save these changes
  3. Extend your volume group sudo vgextend ubuntu-vg /dev/sdb1
  4. Extend your logical volume sudo lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
  5. Extend your filesystem sudo resize2fs /dev/ubuntu-vg/ubuntu-lv

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
    1. Enter p to print the partition table
    2. Enter n to add a new partition
    3. Enter p again to make it a primary partition
    4. Enter the number of your new partition
    5. Pick the first cylinder which will most like come at the end of the last partition (this is the default value)
    6. Enter the amount of space (default is the rest of space available)
    7. Enter w to save these changes
  8. Restart the VM and log in
  9. Type sudo fdisk -l and check that a new partition is present
  10. Find your volume group with df -h.
    • Example: /dev/mapper/ubuntu--vg-root 15G 4.5G ...
    • Volume group is: ubuntu-vg
  11. Extend the volume group : sudo vgextend [volume group] /dev/sdaX
    • Example: sudo vgextend ubuntu-vg /dev/sda3
  12. Find the amount of free space available : sudo vgdisplay [volume group] | grep "Free"
  13. 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
  14. Expand the ext3 file system in the logical volume : sudo resize2fs /dev/[volgroup]/[volume]
    • Example: sudo resize2fs /dev/ubuntu-vg/root
  15. You can now run the df command to very that you have more space df -h

Extend physical partition

If you have a difference between the size of your disk and the logical size of your part, perhaps, the partition does not use all your disk.

  1. sudo parted /dev/sda
  2. In parted, type the following command
    • (parted) print
    • (parted) resizepart 3 100%
    • (parted) quit
  3. sudo pvresize /dev/sda3
  4. sudo lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
  5. sudo resize2fs /dev/ubuntu-vg/ubuntu-lv

Shrink the size of a mounted partition

You cannot shrink an ext4 partition online. You have to use initramfs and reboot your system. Create the file /etc/initramfs-tools/hooks/resizefs 

#!/bin/sh
set -e
PREREQS=""
prereqs() { echo "$PREREQS"; }
case $1 in
   prereqs)
       prereqs
       exit 0
   ;;
esac
. /usr/share/initramfs-tools/hook-functions
copy_exec /sbin/e2fsck
copy_exec /sbin/resize2fs
exit 0
We make it executable sudo chmod +x /etc/initramfs-tools/hooks/resizefs

To decrease your logical volume ubuntu--vg-ubuntu--lv partition to 200G, for example, create the file /etc/initramfs-tools/scripts/local-premount/resizefs 

#!/bin/sh
set -e
PREREQS=""
prereqs() { echo "$PREREQS"; }
case "$1" in
   prereqs)
       prereqs
       exit 0
   ;;
esac
/sbin/e2fsck -yf /dev/mapper/ubuntu--vg-ubuntu--lv
/sbin/resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv 199G
/sbin/e2fsck -yf /dev/mapper/ubuntu--vg-ubuntu--lv
We make it executable sudo chmod +x /etc/initramfs-tools/scripts/local-premount/resizefs

You have now to update your initramfs with the command update-initramfs -u and reboot

After the reboot, you should see the modification and you can now change the size of the logical volume (LV) : lvreduce /dev/mapper/vg-root -L 200G. Now, you can adjust your partition to the size of your LV :resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv

You have finish to shrink you partition and so, you can delete the script 

sudo rm /etc/initramfs-tools/hooks/resizefs
sudo rm /etc/initramfs-tools/scripts/local-premount/resizefs
sudo update-initramfs -u

How to import a new image from an OVA (obsolete in version 2.5)

Note

From version 2.5, you can directly upload your OVA from the Operating system menu

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 
qemu-img convert import_vm.vmdk new_image.img -O qcow2
sudo mv new_image.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 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

Configure OpenVSwitch

Visualisation des configurations des ports 

ovs-vsctl list interface eth1

# Voir seulement les options configurées
ovs-vsctl get interface eth1 options

# Voir la vitesse configurée
ovs-vsctl get interface eth1 options:link-speed
ovs-vsctl get interface eth1 options:duplex

Liste des bridges et de ses ports 

ovs-vsctl list-br  # Liste des bridges
ovs-vsctl list-ports br0  # Ports d'un bridge spécifique

Configurer la vitesse d'un port et son duplex 

ovs-vsctl set interface eth1 options:link-speed=100
ovs-vsctl set interface eth1 options:duplex=full
Ou en une seule commande : 
ovs-vsctl set interface eth1 options:link-speed=100 options:duplex=full

Traffic Control 

tc qdisc add dev eth1 root handle 1: tbf rate 100mbit burst 32kbit latency 400ms

Delete a vlan tag 

ovs-vsctl remove port <port_name> tag X

Add a vlan tag 

ovs-vsctl set port <port_name> tag <vlan>

Delete a trunk 

ovs-vsctl set port <port_name> trunks=[]