The following commands dump a MySQL database from a remote server and create a corresponding database on the local computer.

The instructions have been tested on OSX and Linux (Ubuntu/Debian). On-line SSH compression is applied, so transferring SQL files, which are text content and compress well, should be around 6x faster than normal.

(Well… actually the script is six lines, but because this is my blog I’ll decide it doesn’t count)

The script

• Remotely runs mysqldump and puts the result to a local file
• Creates a MySQL database and corresponding user with full access to this database
• Reads the content of mysqldump to the newly created database

 ssh user@dserver.com -C -o CompressionLevel=9 mysqldump -u YOURDATABASEUSER --password=YOURDATABASEPASSWORD --skip-lock-tables --add-drop-table YOURDATABASENAME > YOURDATABASENAME.sql
mysql -uroot -p
create database YOURDATABASENAME;
connect YOURDATABASENAME;
source YOURDATABASENAME.sql
GRANT ALL ON YOURDATABASENAME.* TO 'YOURDATABASEUSER'@'localhost' identified by 'YOURDATABASEPASSWORD';

Leave out create database and GRANT for the subsequent runs – all data on the local computer will be replaced.

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eCrypfs makes one directory in a file-system crypted. Since it does not work on a partition level, you do not need to worry about extending or shrinking the encrypted partition inside the uncrypted partition. Instead, file system works normally and only the content of the files are encrypted. This should also add some more fault tolerance in the case of disk failure – it is less unlikely to loose the whole encrypted partition.

Here we create an encrypted directory on an external hard drive

• First format the drive with ext4 file-system (mkfs.ext4)

Prepare a passphrase in a .TXT file (you won’t be asked to type mistyped passphrase again).

Then go to the mounted disk

cd /media/fbf0a2c3-0631-4a00-ad1b-a34e449c8b2a/
mkdir crypted
chmod 700 crypted/
sudo mount -t ecryptfs crypted/ crypted/

Copy-paste in the passphrase and otherwise use the default settings given by ecryptfs.

Voilá. Now your encrypted folder is ready. It is not accessible if you do not mount it with eCryptfs and enter the passphrase.

We can test it with umount and mounting it again. It will ask passphrase and  format options again:

echo "foobar" > test.txt
umount /media/fbf0a2c3-0631-4a00-ad1b-a34e449c8b2a/crypted
cd crypted
cat test.txt

You will see garbled output instead of the file contents. But after you remount it it works again:

mount -t ecryptfs crypted/ crypted/

Just give the passphrase and hit enter to all options (again).

More info

• How to create encrypted directories using eCryptsfs

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Use cases

• You are running a backend servers behind Apache
• You need to make sure that the users are served from the same backend every time: the backend itself caches or stores user specific data and this data is not shared across the backends. For example, Plone 3 may have issues with content item creation if sticky sessions are not used.

The method described here works in every situation and does not rely on client IP address, etc. The only downside is that if one balancer member goes down all subsequent requests for it will die. So this method can be only used for load balancing, not for high availability (I am not sure if BALANCER_ROUTE_CHANGED environment variable is set when a balancer member is lost and would redirect the clients to a new balancer member).

This requests were tested on Ubuntu Linux, but may as well work in other environments.

Setting route configution in virtual host

Create a balancer

<Proxy balancer://yourlb>
 BalancerMember http://127.0.0.1:13001/ route=1
 BalancerMember http://127.0.0.1:13002/ route=2
 BalancerMember http://127.0.0.1:13003/ route=3
 BalancerMember http://127.0.0.1:13004/ route=4
</Proxy>

Set the cookie using mod_headers. Note that the cookie must be in format [session name].[route id] (the dot is required). It seems to be possible to leave session name empty.

Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED

Make ProxyPass  follow the cookie (Zope virtual host monster style with HTTPS)

ProxyPass / balancer://lbsits/http://localhost/VirtualHostBase/https/yoursite.org:443/yourplonesiteid/VirtualHostRoot/ stickysession=ROUTEID

Note: Hard restart is required. apache2ctl graceful is not enough to make new balancer rules effective.

Testing

Use wget

wget -S https://yoursite.org/

See that Set-Cookie: ROUTE_ID is present and it contains a valid value (is not empty)

HTTP/1.1 200 OK
 Date: Wed, 13 Apr 2011 15:21:52 GMT
 Server: Zope/(Zope 2.10.9-final, python 2.4.5, linux2) ZServer/1.1 Plone/3.3.3
 Content-Length: 23197
 Expires: Sat, 01 Jan 2000 00:00:00 GMT
 Content-Type: text/html;charset=utf-8
 Content-Language: en
 Set-Cookie: I18N_LANGUAGE="en"; Path=/
 Set-Cookie: ROUTEID=.1; path=/

More info

• Sticky sessions with Nginx
• mod_proxy_balancer example
• Misc. Apache docs for Plone

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We are going to use the following strategy

• Use cryptoloop kernel module. This is 100% open source software and the part of mainstream Linux (as opposite to TrueCrypt)
• No additional software installations needed – stock Ubuntu is fine
• These instructions work also on a server – no GUI needed
• We will create an encrypted file on the target hard-drive partition. The target partition can be even NTFS, so the hard disk acts normally in Windows, though you still need Linux to read encrypted files
• The encrypted file system will be Ext4 and mounted through a loop device

Prerequisites

• Ubuntu Linux
• Basic terminal / command-line know how

Creating an encrypted partition on an external driver

Plug-in the hard disk to Ubuntu Desktop – it will automount it over USB.

Install cryptoloop driver

    sudo modprobe cryptoloop

Check what mount point the new disk has – in your case it is /media/Elements:

ls /media
cdrom  cdrom0  Elements

Check how much space the disk contains

df -h
/dev/sdc1             932G   94M  932G   1% /media/Elements

Create a loopback file – don’t use the whole disk. In our case, allocate just 500 GB for the encrypted file system. Note that this may take time:

dd if=/dev/zero bs=1G count=500 of=/media/Elements/encrypted-fs

Now mount this file as a crypted loopback device. Note that need you to give separate password for sudo and the encryption. We use SHA-1 encryption. Don’t use password, use passphrase. SHA-1 has 160 bit key and to produce enough entropy, you need a latin sentence of at least 27 case-sensitive alphanumeric characters. We do this using losetup command.

sudo losetup -e sha1 /dev/loop0 /media/Elements/encrypted-fs

Then format this encrypted partition as ext4 file system.

mkfs.ext4 /dev/loop0

And now start using it

mkdir /media/encrypted
mount /dev/loop0 /media/encrypted

Usage

Later when you remount the encrypted partition you can simply do

sudo losetup -e sha1 /dev/loop0 /media/Elements/encrypted-fs
mount /dev/loop0 /media/encrypted

After usage always cleanly unmount the encrypted partition before unplugging the external hard-drive

umount /media/encrypted

More info

• https://help.ubuntu.com/community/EncryptedFilesystemHowto
• http://www.ppcnerds.org/index.php?name=News&file=article&sid=186&newlang=ita (see the new way section)

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Prerequisites

What you need in order to benefit from these instructions

• Basic UNIX command-line knowledge
• SSH access to the server
• MySQL access to the database
• LAMP stack ready on the new server

These instructions have been tested on Ubuntu/Debian/Linux but they should work in other environments too.

Write down database access information

Get password from config.php file on the old server:

cd /var/www/phpBB3
cat config.php

Write down database name, username and password.

Copy files

Use rsync to remotely copy forum files to a new computer. On new computer, in /var/www folder

rsync -av --compress-level=9 user@oldserver.com:/var/www/phpBB3 .

Dump and copy database

Execute the following command on the new server. It takes SSH connection to the old server and dumps phpBB3 database to the new server over the SSH connection.

ssh user@oldserver.com -C -o CompressionLevel=9 mysqldump -u databaseuser --password=databasepassword --skip-lock-tables --add-drop-table databasename > phpbb3.sql

Create a new database

Use the old access information from config.php to create a database with identical access information on the new server. You need a MySQL root access to create new databases.

mysql -uroot -p

Create database and grant access to phpBB3 user for it.

mysql> create database databasename;

mysql> GRANT ALL ON databasename.* TO 'databaseuser'@'localhost' identified by 'databasepassword';

Load the database on the new server from the dump file:

mysql> connect databasename;

mysql> source phpbb3.sql

Configure Apache virtualhost for the new server

The last step is to set-up Apache virtual host on the new server, so you can access the phpBB3 using a domain name. Note that this doesn’t need to be a real domain name, but you can spoof the domain name using /etc/hosts file on your local workstation.

Add file /etc/apache2/sites-enabled/phpbb3.conf (or pick a filename based on forum name if you host multiple forums)

<VirtualHost *>
 ServerName yourdomainname.com

 DocumentRoot /var/www/phpBB3
 <Directory />
   Options FollowSymLinks
   AllowOverride None
 </Directory>

</VirtualHost>

Note that <virtualhost *> may change depending on how Apache has been set up to listen IP addresses and ports. Also if you are using a shared hosting package or VPS you might need to use the server control panel (cPanel) to do this step.

Then check if your new config file is ok and restart Apache:

apache2ctl configtest
apache2ctl graceful

Hosts spoofing trick

If you are not having a DNS server of your own which you can use for the copy you can always use /etc/hosts file trick to spoof domain names. This way you can make Apache to serve the forum from the server even if the forum is not connected to any real domain name yet.

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scp -C -o CompressionLevel=9 user@yoursite.com:~/plonefolder/zinstance/var/filestorage/Data.fs .

This command line enables real-time compression with the highest compression level. This speeds up copying somewhat, as ZODB database compresses pretty well.

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By default XAMPP users nobody user for running Apache. If you try to load any file created by your normal system user Apache will give access denied error. This means that either you must make all PHP files readable for everyone, or change the file owner. This is painful if you need to repeat the process for every file.

Instead, it is easier to make XAMPP run under the permissions of your local user.

Edit /Applications/XAMPP/etc/httpd.conf:

<IfModule !mpm_winnt_module>
<IfModule !mpm_netware_module>
User yourusername
Group staff
</IfModule>
</IfModule>

<IfModule !mpm_winnt_module><IfModule !mpm_netware_module>

DocumentRoot "/Users/yourusername/yoursiteroot"

You also need to change the location of setting default folder execution rights htdocs location to your development location

#
# This has been changed from /Applications/XAMPP/htdocs
#
<Directory "/Users/moo/code/joomla/mobilejoomla_dev">
    Options Indexes FollowSymLinks ExecCGI Includes
   AllowOverride All

</Directory>

And now Apache will happily eat all files you create or edit.

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Below is my .zshrc configuration file I use on OSX. It is based on Phil!’s ZSH prompt. It sets up nice colored prompt, colours for ls and some aliases. For OSX, get ZSH from Macports. Any suggestions welcome – please comment.

# This is a modified version of Phil's prompt
# I removed the battery monitor, color and simplified
# the title bar to just the host
#
# Changes by calvinhp
#
# Changes by moo
#
# http://aperiodic.net/phil/prompt/

function precmd {
    local TERMWIDTH
    (( TERMWIDTH = ${COLUMNS} - 1 ))

    # Truncate the path if it's too long.
    PR_FILLBAR=""
    PR_PWDLEN=""

    local promptsize=${#${(%):---%D{%a\,%b %d}-----}}
    local pwdsize=${#${(%):-%d}}

    if [[ "$promptsize + $pwdsize" -gt $TERMWIDTH ]]; then
            ((PR_PWDLEN=$TERMWIDTH - $promptsize))
    else
        PR_FILLBAR="\${(l.(($TERMWIDTH - ($promptsize + $pwdsize)))..${PR_HBAR}.)}"
    fi

    # Only show user in the prompt if it isn't yourself
    # Make sure and set the $ME var in .zshrc
    PR_IMPOSTER=""
    [ "$ME" != "" ] && [ $(whoami) != "$ME" ] && PR_IMPOSTER="(%n%)"

    PR_PROJECT=""
    local THIRD_DIR=$(pwd | cut -f 4,5 -d /)
    if [ "$THIRD_DIR" = "sixfeetup/projects" ]; then
        PR_PROJECT="$(pwd | cut -f 6 -d /)"
        [ ! "$PR_PROJECT" = "" ] && PR_PROJECT="($PR_PROJECT)"
    fi
}

setopt extended_glob
preexec () {
    if [[ "$TERM" == "screen" ]]; then
        local CMD=${1[(wr)^(*=*|sudo|-*)]}
        echo -n "\ek$CMD\e\\"
    fi
}

setprompt () {
    # Need this so the prompt will work.
    setopt prompt_subst

 	autoload colors zsh/terminfo
    if [[ "$terminfo[colors]" -ge 8 ]]; then
		colors
    fi
    for color in RED GREEN YELLOW BLUE MAGENTA CYAN WHITE; do
        eval PR_$color='%{$terminfo[bold]$fg[${(L)color}]%}'
        eval PR_LIGHT_$color='%{$fg[${(L)color}]%}'
        (( count = $count + 1 ))
    done
    PR_NO_COLOUR="%{$terminfo[sgr0]%}"

    # See if we can use extended characters to look nicer.
    typeset -A altchar
    set -A altchar ${(s..)terminfo[acsc]}
    PR_SET_CHARSET="%{$terminfo[enacs]%}"
    PR_SHIFT_IN="%{$terminfo[smacs]%}"
    PR_SHIFT_OUT="%{$terminfo[rmacs]%}"
    PR_HBAR=${altchar[q]:--}
    PR_ULCORNER=${altchar[l]:--}
    PR_LLCORNER=${altchar[m]:--}
    PR_LRCORNER=${altchar[j]:--}
    PR_URCORNER=${altchar[k]:--}

    # Decide if we need to set titlebar text.
    case $TERM in
       xterm*)
           PR_TITLEBAR=$'%{\e]0;%m $PR_IMPOSTER $PR_PROJECT\a%}'
           ;;
       screen)
           PR_TITLEBAR=$'%{\e_screen \005 (\005t) | %m $PR_IMPOSTER\e\\%}'
           ;;
       *)
           PR_TITLEBAR=''
           ;;
    esac

    # Decide whether to set a screen title
    if [[ "$TERM" == "screen" ]]; then
        PR_STITLE=$'%{\ekzsh\e\\%}'
    else
        PR_STITLE=''
    fi

    # Finally, the prompt (removed the color - claytron)
    PROMPT='$PR_SET_CHARSET$PR_STITLE${(e)PR_TITLEBAR}\
$PR_CYAN$PR_SHIFT_IN$PR_ULCORNER$PR_BLUE$PR_HBAR$PR_SHIFT_OUT(\
$PR_MAGENTA%$PR_PWDLEN<...<%~%<<$PR_BLUE)($PR_MAGENTA%(!.%SROOT%s.%n)$PR_GREEN\
$PR_BLUE)$PR_SHIFT_IN$PR_HBAR$PR_CYAN$PR_HBAR${(e)PR_FILLBAR}$PR_BLUE$PR_HBAR$PR_SHIFT_OUT(\
$PR_MAGENTA@%m:%l\
$PR_BLUE)$PR_SHIFT_IN$PR_HBAR$PR_CYAN$PR_URCORNER$PR_SHIFT_OUT\

$PR_CYAN$PR_SHIFT_IN$PR_LLCORNER$PR_BLUE$PR_HBAR$PR_SHIFT_OUT(\
%(?..$PR_LIGHT_RED%?$PR_BLUE:)\
${(e)PR_APM}$PR_YELLOW%D{%H:%M}\
$PR_LIGHT_BLUE:%(!.$PR_RED.$PR_WHITE)%#$PR_BLUE)$PR_SHIFT_IN$PR_HBAR$PR_SHIFT_OUT\
$PR_CYAN$PR_SHIFT_IN$PR_HBAR$PR_SHIFT_OUT\
$PR_NO_COLOUR '
}

setprompt

export PATH=/opt/local/bin:/opt/local/sbin:$PATH

# For OSX users, alias nano to real editor
alias nano="open -a Smultron"

export CLICOLOR=1

# enable ls colors by default - use yellow for directories
LS_COLORS="no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:su=37;41:sg=30;43:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.svgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.rar=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:"

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Work as the site user

The site can be installed locally (under /home) or globally (under /var/www). If the site is installed globally you might need to set your effective user. You should perform the command as the same user who owns the site PHP files. You should not be using root use as the owner of the site files. If you run Joomla! site through Apache, the effective user is www-data. Use sudo command to switch to this user. Use ls -l command to figure out which user you are.

sudo -i -u www-data

Back up code files

Use tar command to pack the existing folder structure in the case the update will destroy critical files.

cd /var/www/yoursite
tar -cjf yoursite.tar.bz2 *

Back up database

mysqldump -umysql_user_name-p mysql_database_name > mysql_database_name.sql

Check Joomla! version

Download version specific Joomla! update pack

wget http://joomlacode.org/gf/download/frsrelease/12611/53380/Joomla_1.5.18_to_1.5.20-Stable-Patch_Package.tar.gz

tar -xvzf Joomla_1.5.18_to_1.5.20-Stable-Patch_Package.tar.gz

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What we do here is enabling 32-bit chroot’ed userland on 64-bit server. 32-bit userland and 32-bit Python environment reduces the memory usage of heavy website applications we are running (read: Plone/Zope), since 32-bit has only half of the pointer size and object-oriented programming is all about pointers. Zope is especially memory hungry, because it uses ZODB object database. The developer does not need to worry about when doing queries, updates or caches that much  as the persistent site state is transparent to Python (objects are automatically loaded from database or cache when they are referred). Easy persistency means that almost everything is in the database and you need to have big object cache. Plone has huge client-side, in-process, cache for persistent objects. The default setting is for the cache size 5000 objects. (sidenote: since ZODB cache is in-process and Python does not do threading too well, running big Plone sites means that you need run several processes to handle parallel requests – having multiple processes with big in-process caches means loads of memory consumption)

32-bit userland is especially useful if you need to run Plone on 64-bit VPS (virtual private server) with low amount of available memory (512 MB or 1 GB).

There are some brief measurements about 32-bit vs. 6-bit Python memory usage at the end of this article.

Unless otherwise specified, all command here should be run as the root user of the host system. Commands here are for example only and you need to know what you are doing. If you lack advanced UNIX administration skills we gladly arrange you some commercial training or hosting support.

Installing

Basic schroot installation instructions for Ubuntu can be found here https://help.ubuntu.com/community/DebootstrapChroot . We also install ZopeSkel in the chroo’ed environment for starting creating Plone sites. Note that we are using Ubuntu 8.04 which still ships with Python 2.4 – for later Ubuntus you need to compile Python 2.4 from the scratch.

apt-get install debootstrap
apt-get install schroot

# Old schroot uses global schroot.conf, new versions have
# chroot.d directory

# This is a heredoc, but use what ever editor you like
# to create the configuration
cat <<EOF > /etc/schroot/chroot.d/hardy_i386.conf
[hardy_i386]
description=Ubuntu 8.04 Hardy for i386
location=/srv/chroot/hardy_i386
personality=linux32
root-users=bob
run-setup-scripts=true
run-exec-scripts=true
type=directory
users=bob,john,alice,ploneuser
EOF

mkdir -p /srv/chroot/hardy_i386
debootstrap --variant=buildd --arch i386 hardy /srv/chroot/hardy_i386 \

http://archive.ubuntu.com/ubuntu/

# Check that the chroot is created and working
schroot -l

# Enter the chroot (logged in as bob)
schroot -c hardy_i386 -u root

# Once inside, install python2.4-dev and other needed tools
# Installing PIL with easy_install didn't work for some
# reason, so we use python-imaging package.
apt-get install python2.4-dev python-setuptools python-imaging
easy_install-2.4 ZopeSkel

And that’s about it.

Chroot’ed environment will have

• It’s own application binaries (and userland bitness)

Chroot’ed environment will share with the host system

• Ports
• Processes
• User accounts

Chroot’ed users

• Can’t list filesystem outside chroot

…giving additional safety for shared hosting in the case of chroot’ed environment is compromised.

Entering chroot’ed environment as a specific user

Try

schroot -c hardy_i386 -u root

…or…

schroot -c hardy_i386 -u plone_user # After you have set-uped normal user for chroot'ed environment

All background processes you leave running in chroot’ed environment are terminated when you exit this environment, unless you create sessions as described below.

Creating chroot sessions

Sessions enable running commands in chroot without the need to have it constantly open.

# Create a new schroot session
schroot --chroot=hardy_i386 --user=ploneuser \
--session-name=plonesession \
--begin-session

# Run commands in the created session
schroot --chroot=plonesession --user=ploneuser --run-session \
/srv/plone/yourplonesite/bin/instance start

# Ending session
schroot --chroot=plonesession --user=ploneuser --end-session

Note that --chroot parameter takes in both actual chroot installations and session ids.

Doing resets for chrooted environment

The session processes exist as long as the session exist. Unless you explicitly start a new session with –begin-session the processes are terminated as soon as you log out from the chroot’ed environent.
chroot’ed environment is temporary unless you explicitly specify it not be
Thus if you want to run daemonized services in chrooted environment you need to take care of session handling manually.
Here is an example how do you construct a session (as a real root user) and then launch a shell script which will take care of launching applications inside the chroot.

# Terminate previous session if any
schroot --chroot=hardy_i386 --user=plone_user --session-name=plone_session --end-session

#Start the session (again)
schroot --chroot=hardy_i386 --user=plone_user --session-name=plone_session --begin-session

# Run a start script inside the chroot'ed environment which will start Plone
# NGINX and other necessary 32-bit services
schroot --chroot=plone_session --user=plone_user --run-session /srv/plone/myplonesite/restart-all.sh

Running sessions at startup

You can add schroot bootstrap in real /etc/rc.local:

schroot --chroot=hardy_i386 --user=ploneuser \
--session-name=plonesession --begin-session \
&& schroot --chroot=plonesession --run-session \
/srv/plone/inst/bin/instance start

Remember that the users have to be created outside the chrooted environment. If you set the home directory to something that exists only in the chrooted environment, use something like this

adduser --no-create-home --home HOMEDIR_IN_CHROOT ploneuser

Then to create the directory inside the chroot and set its ownership to the newly created user and group.

32-bit vs 64-bit memory consumption

Reason why we even tried this is that some python applications, like Zope, use references heavily and moving from 32bit to 64bit references increases memory usage. (J Stahl 2010)

Memory figures from a development Zope/Plone 3.3.5 server

This is far from a complete study, but it would seem that the chroot does pay off even though it has to load 32bit versions of basic libraries along. If running more than one instance on same server memory savings should increase.

More information

• http://manpages.ubuntu.com/manpages/hardy/man1/schroot.1.html
• http://en.wikipedia.org/wiki/Chroot

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