Aug 31, 2015

Install Docker under Ubuntu 14.04 (Trusty)

Docker supports Ubuntu versions:

  • Ubuntu Vivid 15.04 (64-bit)
  • Ubuntu Trusty 14.04 (LTS) (64-bit)
  • Ubuntu Precise 12.04 (LTS) (64-bit)
  • Ubuntu Raring 13.04 and Saucy 13.10 (64 bit) 

For both Vivid and Trusty you need nothing. It will work out of the box. Others will require some modifications. (Updating of some things, like kernel or installing with wget on 13.04)

1. To install docker from a repository do so:
sudo apt-get update
sudo apt-get install docker.io
sudo ln -sf /usr/bin/docker.io /usr/local/bin/docker
sudo sed -i '$acomplete -F _docker docker' /etc/bash_completion.d/docker.io

2. Now run it with:
sudo apt-get install lxc-docker

3. Make it run on system boot:
sudo update-rc.d docker.io defaults

4. Ready to go! Run container with an Ubuntu:
sudo docker run -i -t ubuntu /bin/bash

To disconnect, or detach, from the shell without exiting use the escape sequence Ctrl-p + Ctrl-q

Aug 27, 2015

Remi and EPEL repositories in CentOS

There are 2 common repositories that come nowdays for centos. They contain tasty things, while they are absent in official repositories.

CentOS 5:
wget http://dl.fedoraproject.org/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm
wget http://rpms.famillecollet.com/enterprise/remi-release-5.rpm
sudo rpm -Uvh remi-release-5*.rpm epel-release-5*.rpm

CentOS 6:
wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
sudo rpm -Uvh remi-release-6*.rpm epel-release-6*.rpm

You can check you are successful like so:
ls -1 /etc/yum.repos.d/epel* /etc/yum.repos.d/remi.repo
/etc/yum.repos.d/epel.repo
/etc/yum.repos.d/epel-testing.repo
/etc/yum.repos.d/remi.repo

Now you are only left to activate Remi repository:
sudo vi /etc/yum.repos.d/remi.repo

In [remi] section we need to change enabled=0 into enabled=1. It will look like so:
[remi]
name=Les RPM de remi pour Enterprise Linux 6 - $basearch
#baseurl=http://rpms.famillecollet.com/enterprise/6/remi/$basearch/
mirrorlist=http://rpms.famillecollet.com/enterprise/6/remi/mirror
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-remi

Only need to update now:
yum update -y

















Aug 25, 2015

Tmux quick start guide

Tmux is a handy terminal manager that allows you to switch between terminal sessions easily. Without losing history or windows upon ssh disconnects or similar. It is like screen, just better. (First of all because of using client-server based technology... )

Here is my minimal keyboard shortcuts guide that allows you to start using Tmux in a blink of an eye. Endless advanced commands and hotkey combinations you could always find by entering "man tmux" in a terminal.

Tmux is installed quite easily in most of common linux based systems. Just type:
Ubuntu:
$ sudo apt-get install tmux
CentOS:
$ sudo yum install tmux

This allows you to start using by starting it with
$ tmux a || tmux new
This command first tries to attach to existing running tmux instance and creates new in case it is not found.

Ctrl+b d - Will allow you to disconnect at any time. (This is also a way it is happening when you loose ssh session. How to connect - look earlier)


Each session can have many windows:
Ctrl+b c - Create a new window.
Ctrl+b 0...9 - switch to window #;
Ctrl+b p - switch to previous window;
Ctrl+b n - switch to next window;
Ctrl+b l - switch to next active window (to the one you have switched from to this window);
Ctrl+b & - close this window (Or just type exit in terminal.

One terminal can have multiple windows:
Ctrl+b % - splits current panel in part, vertically;
Ctrl+b " - splits current horizontally;
Ctrl+b →←↑↓ - switch between panels;
Ctrl+b x - close current panel (you could also type exit in a terminal window).

Minus is a scrolling behavior:
Ctrl+b PgUp - enters "copy mode", afterwards:
    PgUp, PgDown - scrolling;
    q - exit copy mode.

Good more complex gist of hotkeys also here:
HOTKEYS GIST