[ERROR] Unable to switch capabilities : Operation not permitted

Shut the VPS down, enter the host via SSH and enable needed capabilities for your VPS (where $VPS_ID is your VPS id, ie 101, 102…)

for CAP in CHOWN DAC_READ_SEARCH SETGID SETUID NET_BIND_SERVICE NET_ADMIN SYS_CHROOT SYS_NICE CHOWN DAC_READ_SEARCH SETGID SETUID NET_BIND_SERVICE NET_ADMIN SYS_CHROOT SYS_NICE; do vzctl set $VPS_ID --capability ${CAP}:on --save; done

That’s it :-)

Also, I am working in Ruby on Rails development since about 2 years ago. One of the things I have to do usually is to set up servers for hosting projects. And sometimes I have to set up a server for project development and tracking. These are the steps you can follow to set up a Ruby on Rails based server for development tracking.

1. Get a server

There are plenty of choices around the internet, some of them come completelly installed and prepared for deploying your app. They usually work the same way traditional LAMP hostings used to do, but using ssh key authentication instead of FTP sessions… some of them have also web based backend panels for deploying, migrating and managing your app gems.

I prefer to set up an empty GNU/Linux vanilla server, so that I can host everything I need, my way, no worries if PHP, Ruby or whatever. I can set up a relay mailserver, netfilter routing, traffic shaping, services for monitoring and differential backups that I can periodically rsync to my office local server. This is the way a sysadmin thinks, something that coders not always understand.

If you want to set up a development server I recomment you to take a look at most basic Linode VPS. Their control panel will let you run and destroy any Linux distro, setup and resize partitions, add failover addresses, disk space, processor and memory. And of course you’ll have full SSH root access. So I find it very useful and flexible for my needs.

Some considerations:

• You’ll have to set up a DNS name for the server IP, i.e: http://devel.somedomain.net
• You’ll need root access on the server. I’ll suppose you are working on a local computer, remotely logged via SSH to your server
• I usually build my servers using Debian (Lenny for now), but a basic knowledge of any other distro package system will let you adapt my guide to your preferred system
• I’ll suppose you’ve set up a specific environment for running your app on the development server (I usually call it beta)

2. Install screen

You may partially lose your work if for any reason your local computer hangs during the process. So it’s recommendable to install and use screen for working on a detachable console terminal. This way, if your computer shuts down, you’ll be able to boot again, ssh into your server and recover your screen session.

You’ll maybe want to set up your screen sessions to look nicer than withe on black, and give you some additional information of the remote system. I use a copy of the screenrc configuration file from my friend r0sk, it’s simple and nice and works sweet.

Enter screen

3. Base system

You’ll need an unprivileged user to host your web apps. I usually create a web user

Add contrib and non-free repositories to your Apt sources file (vim /etc/apt/sources.list)

Update your sources and then your system

Edit your SSH server config file to disallow root login and enable SSH key authentication (vim /etc/ssh/sshd_config)

Restart your SSH service

Install build-essentials for compiling and installing the environment dependencies

Install Postfix for using as MTA relay server, or MySQL Debian packages will install Exim (which I don’t really like)

4. Backports

Because of some software versions being old and deprecated on the APT sources, and some other not being present, an alternative repository can be set up for installing newer versions. The backports repository.

Edit your APT sources file (vim /etc/apt/sources.list)

Update your system again

5. MySQL

Install mysql service, and its ruby bindings package

Create a database for your project (mysql -uroot -p)

6. Ruby, Rubygems and Rails

Install the Ruby stuff, I prefer to use backports at this point to ensure latest versions.

Add unversioned links for the newly created binaries

Install Rubygems from source, so you can update it directly whenever you want. Otherwise the system will update it for you, only when new packages for your distro are available.

Link gem binary to an unversioned name

Update rubygems (not really needed, but just in case)

Install Rails

7. Image processing

Youll surelly want a plugin for cropping and thumbnailing images, maybe attachment_fu or paperclip. They both can work with Imagemagick.

8. Apache

There are different web server layouts for hosting your application. Some people likes Nginx+Mongrel, some other prefer Apache+Passenger, others prefer Nginx+Passenger… I love Apache. Maybe because its syntax simplicity, its flexibility or maybe simply because as a sysadmin I’ve been working for years with it.

Install Apache

Rename default virtualhost

Edit that virtualhost (vim /etc/apache2/sites-available/devel_somedomain_net)and configure it with the minimum options to work. I’m adding a basic HTTP authentication so only people you give the password can see your project (it’s a development server heheh).

Enable your new virtualhost

As the unprivileged user running the service, create the application directory and the HTTP Auth passwords file

Create the apache log directory for your app

Install Passenger

Create a file for loading passenger module into Apache (vim /etc/apache2/mods-available/passenger.load). Be careful with versions on the names as they may have changed.

Enable passenger module

Change the user and group executing Apache service to match your unprivileged user (vim /etc/apache2/envvars)

Restart Apache

9. Git and Gitosis

If you don’t want to pay a Github account and you don’t want your source to be visible to everyone, you’ll want to host your own Git server. There are different choices for that, but I like Gitosis because it’s simple and I can manage it from my command line, only editing a config file.

Install Git

Gitosis is written in Python, so you need to install python’s setup-tools in order to install Gitosis

Clone and install Gitosis

Create a new unprivileged user for hosting Gitosis and its repositories. It does not need a password (so it can’t log in) but it needs a shell as all management occours using an SSH session.

Upload your ssh public key to the server, leave it in /tmp/ and call it user@host.pub being user@host the final string specified into the file itself (ivan@mbp-local, or something similar)

Initialize Gitosis using the SSH key you just uploaded, which will be the Gitosis admin

In your local computer clone the Gitosis repository so you can manage it from now on

Enter the gitosis-admin directory and check the contents. It has to show a filename called gitosis.conf and a directory called keydir.

10. Add a repository for your app

Edit the Gitosis config (vim gitosis.conf) and add a new group, formed with one user (or more, separated with spaces), and its repository

Make sure to put user’s keyfiles into the keydir directory, following the previously mentioned format. Upload your changes.

In your local computer you can now create an application and add its files to the repo

11. Capistrano

You’ll want to deploy your software to your newly configured server. Capistrano is the best choice I know, since it creates versioned directories to let you roll back and forth, remotely run tasks on the hosted version of your app, place a custom “under maintenance” page, etc…

Install Capistrano

Capify your application

Create a recipe (vim config/deploy.rb)

12. SSH keys

In order to deploy your app without typing any password, you’ll have to set up a SSH key authentication between you and the unprivileged user of the server (web user).

Copy the content of your local ssh keyfile (commonly ~/.ssh/id_rsa.pub) and paste at the end of /home/web/.ssh/authorized_keys on the server. You’ll want to repeat this process for each developer so they can also deploy without typing a password.

You’ll also need to generate a SSH key for your web user on the server, and add it as a member of the repo in gitosis. Otherwise you won’t be able to deploy your app, because the server won’t let itself access to the repo for fetching.

13. Redmine

Redmine is one of those powerful tools that make your life easier when working with other developers, designers, webmasters and CEO’s… it helps you to keep tracking of issues, bugs, timings, files and documents, wikis and it also lets you graphically browse your repositories. If you’ve never tested it, now it’s your time.

NOTE: you’ll need to create a new entry on your DNS server. Set up a CNAME called redmine pointing to devel.somedomain.net

Redmine needs mod_rewrite support on Apache

You’ll need subversion to checkout the source code of Redmine

Su to your unprivileged user

Checkout the code

Create a database for redmine (mysql -uroot -p)

Edit Redmine’s database configuration file (vim config/database.yml)

Place a secret key for Redmine cookies on its environment file, inside the Initializer block (vim config/environment.rb)

Migrate the database

Edit the SMTP configuration for Redmine to be able to send notification emails (vim config/email.yml)

If you want to relay over Gmail or your domain’s email is hosted on Google apps, you’ll need to install a tls authentication plugin

Use this config for use with Gmail / Google apps

Exit su, and become root again

Create a new Apache virtualhost (vim /etc/apache2/sites-available/redmine_somedomain_net)

Create an Apache log directory for redmine

Enable your new virtualhost and restart Apache

14. Start writing Ruby on Rails

Here comes the funny part. Enjoy! ;-)

Here is the PDF for downloading.

Hoy tenía un problema con el proyecto en el que estoy trabajando, y pedí a Mauro que me echase un cable a ver si entre los dos conseguíamos solucionarlo. Él estaba en su casa, y yo en la mía. Los ingredientes para cocinar un pair programming realmente fluído en remoto:

• Port forwarding: un puerto para el acceso remoto por SSH y otro para el acceso al servidor de aplicaciones (acceso web)
• screen: Usando una versión ligeramente modificada del screenrc de r0sk. Usamos tres consolas: [0] log del servidor, [1] vim con el código, [2] una bash para hacer accesos de mysql u otras cosas que necesitemos
• vim: con los controles mapeados para trabajar con tabs, y el plugin de FuzzyFinderTextMate para buscar y abrir archivos… así se puede hacer todo en una sola consola
• Skype: Para hablar todo el rato durante la sesión de programación

Los programadores maceros que usan TextMate suelen hacer el pair programming usando VNC, pero aunque no lo he probado pongo las dos manos en el fuego a que tiene que ser una cagada. La pareja screen+vim es brutal por lo lightweight y lo flexible, y consume muy poquito ancho de banda con lo que la comunicación del conjunto (ssh + skype) es perfecta.

La experiencia ha sido GENIAL, y hemos resuelto el problema en aproximadamente 1 hora. Es como trabajar en pair programming en local, tocando el mismo código y comentando todo el rato. Ha sido una pasada, y lo recomiendo a todos los programadores que trabajen separados físicamente del resto del equipo.

• Mondo es una herramienta para crear imágenes del sistema autoarrancables (liveCD) y poderlas planchar en un CD o DVD (o en varios si es muy grande). Después se puede arrancar el sistema con ellas y restaurarlo así al estado en que se encontraba en el momento de sacar el backup.
• DAR, por su parte, es una herramienta de backup diferencial.
• Y rsync todos sabemos lo que es. Yo lo uso para hacer un mirror de los discos en lugar de usar RAID1, de esta forma tengo una ventana de tiempo de 24 horas para restaurar un backup en caso de fallo en el filesystem (ya que con un RAID1 se propaga al momento, y sí: lo he sufrido ya una vez, la primera y la última).

Todas estas herramientas las uso mediante un pequeño set de scripts, es muy sencillito y no tiene mucha complicación, así que he decidido liberarlos para que los podais usar si estais interesados.

He creado una página nueva (se ve en el menú lateral) llamada Mussol Scripts y lo he dejado ahí junto con un par más que había escrito anteriormente para otras cosas.

Espero que os sea de utilidad :-)

Un virtualhost habitual (atención al ==):

$HTTP["host"] == "www.something.net" {

Para que www.something.net, www.something.com o www.something.lo_que_sea apunten al mismo documentroot (atención al =~):

$HTTP["host"] =~ "www.something" {

Y para que www.something.net y www.otherthing.net apunten al mismo documentroot:

$HTTP["host"] =~ "(www.something.net|www.otherthing.net)" {

Aquí está el tuto. Como siempre, espero que sea de ayuda!

I have updated the mini-tutorial about installing ]Project-open[ on Debian ETCH. A guy called Martin Van Es sent me some emails with tips on making it work with Aolserver4 and PostgreSQL 8.1. I’ve tested it and works okay.

Here is the tutorial. I hope it helps!

Slackware tiene herramientas de gestión de paquetes, y son flexibles y funcionan perfectamente. Desde luego jamás he visto petar un paquete de slackware como he visto petar un paquete instalado con apt.
El sistema de paquetes de Slackware es muy sencillo: descomprimir el binario, copiar los contenidos a su sitio y guardar una base de datos de referencia para borrarlos cuando se desee. No falla. ¿Para qué más?

Ahora bien, no hay paquetes de slackware para todo lo que se desea. Así que aquí va una pequeña explicación de cómo crear paquetes para Slackware usando makepkg, una de las herramientas propias de la distribución.

1. Crear un área de trabajo para compilar el paquete

mkdir /work
mkdir /work/scripts
mkdir /work/builds

2. Descargar el fuente y compilarlo

cd /usr/local/src
tar zxvfp progname-progversion.tar.gz
cd progname-progversion/
./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
make

3. Instalarlo dentro del área de trabajo

make install DESTDIR=/work/builds
cp -Rp doc/ /work/builds/usr/
# copiar más cosas que se quieran incorporar al paquete

4. Crear el paquete

cd /work/builds
makepkg progname-progversion-arch-build.tgz
# contestar SI a la pregunta sobre enlaces y permisos

5. Mover el paquete a su sitio y limpiar los restos

mkdir -p /var/spool/packages
mv progname-progversion-arch-build.tgz /var/spool/packages/
rm -rf *

6. Instalar el paquete

cd /var/spool/packages
installpkg progname-progversion-arch-build.tgz

7. Praise Bob!

----

I've written a page with instructions and packages for installing ]Project-open[ on Debian ETCH. I’ve never built any debian package, so maybe they’re so primitive. But anyway they’re completely functional.
I’ve posted it on my company’s website too.
Comments will be appreciated :-)