Context

This post deals with how to increase a volume attached to a server instance on openstack. See openstack volume ressource.

Test database

To test everything goes well, a test database is setup:

sudo -u postgres
sudo -u postgres psql -c "create database webapp";
sudo -u postgres psql -d webapp -c "CREATE TABLE account(user_id serial PRIMARY KEY,username VARCHAR (50) UNIQUE NOT NULL,created_on TIMESTAMP NOT NULL);" ;
sudo -u postgres psql -d webapp -c "INSERT INTO account (username,created_on ) VALUES ('foo','2019-01-01') ;" ;
sudo -u postgres psql -d webapp -c "INSERT INTO account (username,created_on ) VALUES ('bar','2019-01-02') ;" ;

Check command:

sudo -u postgres psql -d webapp -c "SELECT * FROM account" ;

returns:

 user_id | username |     created_on      
---------+----------+---------------------
       1 | foo      | 2019-01-01 00:00:00
       2 | bar      | 2019-01-02 00:00:00
(2 rows)

Switch off automatic volume mount in /etc/fstab

ssh demo

Comment lines in /etc/fstab that concern the volume you want to increase:

sudo vim /etc/fstab 

#/dev/vdb1 /data ext4 defaults 0 0
#/data/pgsql /var/lib/postgresql none bind 0 0

sudo reboot

Check

ssh demo

Check that they are no more mount point that depend on the volume we are going to manipulate.

df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            992M     0  992M   0% /dev
tmpfs           201M  4,5M  197M   3% /run
/dev/vda1       4,9G  1,9G  2,9G  40% /
tmpfs          1003M  8,0K 1003M   1% /dev/shm
tmpfs           5,0M     0  5,0M   0% /run/lock
tmpfs          1003M     0 1003M   0% /sys/fs/cgroup

Stop your applications if needed

sudo service apache2 stop
sudo service postgresql stop

Increase our volume size

identify your target server and target volume with openstack volume list and openstack server list

TARGET_SERVER=ed864066-ed73-46e0-b551-5bfca9873af6
TARGET_VOLUME=1be3646a-3bb5-40fc-b9eb-6ab803b60d2c
VOLUME_SIZE=25

Detach volume from server

openstack server remove volume $TARGET_SERVER $TARGET_VOLUME

At this point, the device should NOT be visible when you execute: ls -l /dev/vd*.

Increase volume size

openstack volume set $TARGET_VOLUME --size $VOLUME_SIZE

Attach volume to server

openstack server add volume $TARGET_SERVER $TARGET_VOLUME --device /dev/vdb

At this point, the device should BE visible when you execute: ls -l /dev/vd*.

Manage partition on your openstack server

Let's configure the partition to use all the volume space.

ssh demo
sudo parted /dev/vdb resizepart 1 100%
sudo e2fsck -f /dev/vdb1
sudo resize2fs /dev/vdb1

Restore /etc/fstab

uncomment the lines:

/dev/vdb1 /data ext4 defaults 0 0
/data/pgsql /var/lib/postgresql none bind 0 0

reboot: sudo reboot

Check your fs

Check volume size and partition size

sudo fdisk -l

Disk /dev/vdb: 25 GiB, 26843545600 bytes, 52428800 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x0e1b27a4

Device     Boot Start      End  Sectors Size Id Type
/dev/vdb1        2048 52428799 52426752  25G 83 Linux

Check database

Use our test command to check our database:

ssh demo
sudo -u postgres psql -d webapp -c "SELECT * FROM account" ;

check data are ok:

 user_id | username |     created_on      
---------+----------+---------------------
       1 | foo      | 2019-01-01 00:00:00
       2 | bar      | 2019-01-02 00:00:00
(2 rows)

Purpose

Run GUI application inside a docker container using X11Forwarding.

source from github.

Create a container

DockerFile

FROM ubuntu
RUN apt update \
    && apt install -y firefox \
                      openssh-server \
                      xauth \
                      emacs \
    && mkdir /var/run/sshd \
    && mkdir /root/.ssh \
    && chmod 700 /root/.ssh \
    && ssh-keygen -A \
    && sed -i "s/^.*PasswordAuthentication.*$/PasswordAuthentication no/" /etc/ssh/sshd_config \
    && sed -i "s/^.*X11Forwarding.*$/X11Forwarding yes/" /etc/ssh/sshd_config \
    && sed -i "s/^.*X11UseLocalhost.*$/X11UseLocalhost no/" /etc/ssh/sshd_config \
    && grep "^X11UseLocalhost" /etc/ssh/sshd_config || echo "X11UseLocalhost no" >> /etc/ssh/sshd_config

RUN echo "CONTENT_OF_ID_RSA_PUB_KEY_HERE" >> /root/.ssh/authorized_keys

Build it

docker build -t benit/ubuntu-x11 . --build-arg http_proxy=$http_proxy

Run Container

docker run --name ubuntu-x11 --rm -d -p 2150:22 benit/ubuntu-x11

SSH client configuration

Edit ~/.ssh/config on the client, here my workstation is named lxdev:

Host ubuntuX11
     Hostname lxdev
     Port 2150
     user root
     ForwardX11 yes
     ForwardX11Trusted yes

Use it!

ssh -X ubuntu-x11 emacs     

Enjoy!

Purpose

This post deals with creating a multi linux iso live usb drive. source

Procedure

• format your drive to fat32
• download MultiBootUsb
• install it : dpkg -i python3-multibootusb_8.8.0-1_all.deb
• check if all python dependencies are satisfied, if not try install missing with sudo apt install python3-pyqt5 p7zip-full python3-pyudev
• enjoy : you can now burn several iso using the GUI. Great tool!