Zend Framework + SVN + ZF Tools on CentOS part 2

This is the 2nd part of my attempt to write a tutorial about using svn and ZF to create a working environment for a small team of developers. It assumes you have followed the instructions provided here.

The following notations will be used in this part:
project is the name of your project, wherever you see project written with italics replace it with your actual project name. It should be one word.
developer is the name of the developer that is part of the team working on this project. For example john.
example.com is the name of your domain, replace it with the real name.
A # in front of the line means you have to execute those commands as root, while $ means you have to be a normal user.

1. Create the repository for the project

# mkdir -pv /var/svn
# svnadmin create /var/svn/project

2. Create project layout

# cd /tmp
# mkdir project
# cd project
# mkdir branches tags trunk

If you want to create a standard zf project:


# cd trunk
# zf create project
# ls

ATTENTION: zf create project is a command, so do not replace the word project.
You should have the standard structure now for a Zend Framework project.

3. Import the project files to repository

# svn import /tmp/project file:///var/svn/project -m "initial import"
# chown -R apache:apache /var/svn/project

4.1 Creating a user for the developer

# adduser -g users developer
# passwd developer

Repeat the above steps for each developer you want to add.

4.2 Creating a user for the project

# adduser project
# passwd project

5.1 Add a virtual host for each developer in apache conf file

You will have to figure out where your virtual hosts are defined in apache conf files. Most likely you can add the following lines to /etc/http/conf/httpd.conf


# developer sandbox
<VirtualHost *:80>
ServerAdmin someone@example.com
DocumentRoot /home/developer/www
ServerName developer.example.com
ErrorLog /home/developer/logs/error_log
CustomLog /home/developer/logs/access_log combined
<Directory "/home/developer/www/">
Options Indexes FollowSymLinks
AllowOverride All
Order allow,deny
Allow from all
</Directory>
</VirtualHost>

5.2 Add a virtual host for the project

# project sandbox
<VirtualHost *:80>
ServerAdmin someone@example.com
DocumentRoot /home/project/www
ServerName project.example.com
ErrorLog /home/project/logs/error_log
CustomLog /home/project/logs/access_log combined
CustomLog /home/project/logs/svn_logfile "%t %u %{SVN-ACTION}e" env=SVN-ACTION
<Directory "/home/project/www/">
Options -Indexes FollowSymLinks
AllowOverride All
Order allow,deny
Allow from all
</Directory>
<Location /svn>
Options +Indexes
DAV svn
SVNParentPath /var/svn
SVNPathAuthz off
SVNIndexXSLT "/svnindex.xsl"
Require valid-user
AuthType Basic
AuthName "Subversion repository"
AuthUserFile /var/svn/project/conf/passwd
</Location>
</VirtualHost>

* Depending on your DNS settings you may have to manually add the needed records for developer.example.com/project.example.com to properly work.

7.1 Checking out to dev boxes

# su - developer
$ mkdir svn
$ cd svn
$ svn checkout http://project.example.com/svn/project/trunk .
$ cd ..
$ rm www
$ ln -s /home/developer/svn/public www

7.2 Exporting the latest version of the project

# su - project
$ mkdir svn
$ cd svn
$ svn export http://project.example.com/svn/project/trunk . --force
$ cd ..
$ rm www
$ ln -s /home/project/svn/public www

See the project page at http://project.example.com

Next time you want to update the page remove the svn directory, and re-export it as above.

8.1 Working as a developer

To update you dev box to latest version:

$ cd svn
$ svn up

Whenever you add a NEW file/directory to the project use:

$ svn add filename

Of course you replace filename with the real name of the file. The reverse of this is svn del.

When you are satisfied with your changes don’t forget to commit:

$ svn commit -m "something meaningful for that idiot project manager"

8.2 Working as a project manager(?)

$ su - project
$ rm -rf svn

Repeat the steps from 7.2
Check logs for svn commits at /logs/svn_logfile

<< EOF

Scalr errors after install

After installing Scalr and adding a client I’ve tried to add an application to test out my setup. But at the second step I’ve got an alert saying:

Error Type: LoadXML
Description: Incorrect XML

A quick look at the apache log revealed the problem:

File does not exist: /var/scalr/app/www/farm_amis.xml

I thought that maybe I’ve missed a file so I did a svn checkout of scalr repository and tried to find the specified file:

apt-get install subversion
svn checkout http://scalr.googlecode.com/svn/trunk/ scalr-read-only
find scalr-read-only -name farm_amis.xml -type f

Nothing came up. Weird. After a bit of looking around I’ve found a file called farm_amis_xml.php. So in fact farm_amis.xml was only a mod_rewrite directive.

Time to fix it, enable mod_rewrite and .htaccess files for apache2:

Edit /etc/apache2/sites-available/000-default and change the lines containing

AllowOverride None

to

AllowOverride All

Go to /etc/apache2/mods-enabled and execute the following command:

ln -s ../mods-available/rewrite.load

Restart apache2 server and everything should be ok:

/etc/init.d/apache2 restart

How to install Scalr on Ubuntu 8.10 EC2 Instance

Presentation:

If Amazon EC2 doesn’t ring a bell to you, chances are that you are looking at the wrong page to find solutions for your problems. EC2 stands for Elastic Compute Cloud and it’s a service offered by Amazon. I will not enter in details about the advantages of using it, since this is not the scope of this post. You can read more about it here: http://aws.amazon.com/ec2/

Scalr is a fully redundant, self-curing and self-scaling hosting environment utilizing Amazon’s EC2. You basically can build farms of Amazon’s instances that can do load balancing using nginx, serve web pages using Apache 2, use MySQL master-slave servers or maybe you may want to define your own roles.

The beauty of this is that you don’t have to monitor the health of your server infrastructure, scalr will do it for you. If a node type gets overloaded scalr will launch another instance to spread the load and the cluster will be reconfigured.

Preparing:

Generate a new key for scalr instance:

ec2-add-keypair scalr-keypair > id_rsa-scalr-keypair

Edit id_rsa-scalr-keypair so it begins with

-----BEGIN RSA PRIVATE KEY-----

and is terminated with

-----END RSA PRIVATE KEY-----

Make sure you have the correct permissions for this key:

chmod 600 id_rsa-scalr-keypair

If everything went ok you should see your new key when executing

ec2-describe-keypairs

Choosing the right AMI:

For the instance we will be using ami-7806e211 which is an AMI containing a base install of Ubuntu 8.10 Intrepid Ibex Release. More details here.

Start the instance:

ec2-run-instances -z us-east-1a -k scalr-keypair ami-7806e211

You will get some output, look for the line that begins with INSTANCE and write down somewhere the id of the instance (i-XXXXXXXX) and the address of the instance(ec2-XX-XX-XX-XX.compute-1.amazonaws.com). The status of your instance should be pending.

Check in a couple of minutes the status of your instance:

ec2-describe-instances i-XXXXXXXX

When the status is running it means that your instance is ready for work. You should have at least ssh and web ports open(22 and 80). If you are not sure execute the following commands:

ec2-authorize default -p 22
ec2-authorize default -p 80

Now connect to your instance using ssh:

ssh -i id_rsa-scalr-keypair -v ec2-XX-XX-XX-XX.compute-1.amazonaws.com

First time you connect you will be asked if

Are you sure you want to continue connecting (yes/no)?

Type yes and you should be the happy owner of a fresh Ubuntu Intrepid Ibex instance.

Update your system now:

apt-get update
apt-get upgrade

After the update is completed, logout and reboot your instance:

ec2-reboot-instances i-XXXXXXXX

Installing required software:

Reconnect to your instance and install MySQL server and php extensions:

apt-get install bind9 mysql-server mysql-client apache2 php5-cli libapache2-mod-php5 php5-mysql php5-mcrypt php5-mhash

When you install MySQL server you will be prompted to setup a password for the root account. Don’t forget it, you will need it. Also you will have to restart Apache2 server after you finish installing everything, like this:

/etc/init.d/apache2 restart

You could also download their php script that checks if your system has all the prerequisites

wget http://scalr.googlecode.com/files/checkenvironment.php
mv checkenvironment.php /var/www/
chmod a+r /var/www/checkenvironment.php

Now point your browser to http://ec2-XX-XX-XX-XX.compute-1.amazonaws.com/checkenvironment.php and see if everything it’s ok.

Most likely you will get only these 2 errors:

Errors:
• Cannot find SSH2 functions. Make sure that SSH2 Functions enabled.
• Cannot find SNMP functions. Make sure that SNMP Functions enabled.

Here is how to quick fix it:
Adding SSH2 support to PHP5, better known as: why don’t we have php5-ssh2?

apt-get install php5-dev php-pear libssh2-1 libssh2-1-dev

Thought it will be easy? Not so quick. Try to install it with:

pecl install ssh2 "channel://pecl.php.net/ssh2-0.10"

I got an error saying:

ERROR: `make' failed

Great! Let’s fix that stupid error. Edit the file /tmp/pear/download/ssh2-0.10/ssh2.c and replace the line containing:

#if LIBSSH2_APINO < 200412301450

with

#if false

Go to directory /tmp/pear/download/ssh2-0.10/ and compile the stuff manually:

make && make install
echo extension=ssh2.so >> /etc/php5/apache2/php.ini

I don’t get it why they don’t fix this thing. A lot of people are having this problem and are complaining!

Luckily for you and me snmp is a breeze, it is already in repositories:

apt-get install php5-snmp

Restart apache server and check now if you have all the required extensions for scalr. You should have them.

Getting the latest version of Scalr:

At the time of writing this article latest version was 1.0 RC2
Go to Scalr download page and copy the link to the latest release. Download it using wget:

wget http://scalr.googlecode.com/files/scalr-1.0RC2.tar.gz

Extract it:

tar zxvf scalr-1.0RC2.tar.gz

Create database for scalr and import the sql:

mysqladmin -p create scalr
mysql -p scalr < scalr/sql/database.sql

Put the scalr application in /var/scalr and change permissions as suggested in the spartan documentation of scalr:

mkdir /var/scalr && cp -R scalr/* /var/scalr/
chmod 777 -R  /var/scalr/app/cache /var/scalr/app/cron/cron.pid /var/scalr/app/etc/.passwd

ATTENTION: I’m not planing on using this instance for anything else except scalr. Also this is a clean install so I don’t have anything of interest in /var/www. Read carefully the following first line:

rm -rf /var/www/
ln -sf /var/scalr/app/www /var/
chmod a+rX -R /var/www

Edit the file /var/scalr/app/etc/config.ini and update it to your values:

[db]
driver=mysql ;Actually mysql is the only option here - mysqli doesn't support nconnect(), which is essential for PCNTL (which is essential for crobjobs)
host = "localhost"
name = "scalr"
user = "root"
pass = "*YOUR PASS HERE*"

TO DO: make a mysql user for scalr.

Put your EC2 access certificate into /var/scalr/app/etc/cert-XXXXXXXXXXXX.pem
Put your EC2 private key into /var/scalr/app/etc/pk-XXXXXXXXXXXX.pem
ATTENTION: This part is a bit tricky. If you don’t put the right settings you will not be able to start instances. I warned you!
Login to Amazon AWS and go to Home->Your Account->Access Identifiers
Go to http://ec2-XX-XX-XX-XX.compute-1.amazonaws.com/ and login with admin/admin
Go to Settings->Core Settings. Modify the following fields:
Password: duh!!! change it!
Email: your email address here
Account ID: AWS Account Number, it’s called Account Number in AWS and it’s top right. Remove the ‘-‘ from the number
Key Name:Scroll down in AWS untill you see Your X.509 Certificate: Copy everything between ‘cert-‘ and ‘.pem’. Also XXXXXXXXXXXXXX is the string in the filenames of cert-XXXXXXXXXXXXX.pem and pk-XXXXXXXXXXX.pem. If they don’t match you will have problems.
Access Key:Look for Your Secret Access Key: in AWS and click on Show. Copy the string.
Access key ID: is Your Access Key ID: in AWS.

Hit save.

setting crontab:

Type crontab -e and add the following lines to cron:

* * * * * /usr/bin/php -q /var/scalr/app/cron/cron.php --Poller
1 1 * * * /usr/bin/php -q /var/scalr/app/cron/cron.php --RotateLogs
*/15 * * * * /usr/bin/php -q /var/scalr/app/cron/cron.php --MySQLMaintenance
*/6 * * * * /usr/bin/php -q /var/scalr/app/cron/cron.php --DNSMaintenance
*/3 * * * * /usr/bin/php -q /var/scalr/app/cron/cron.php --DNSZoneListUpdate
*/2 * * * * /usr/bin/php -q /var/scalr/app/cron/cron.php --DBQueueEvent
*/11 * * * * /usr/bin/php -q /var/scalr/app/cron/cron.php --Cleaner

You are done. I hope.

How to terminate the instance:

I thought to write down instructions on how to terminate an instance. You should know how, but just in case, here it is how to stop the instance forever and not pay for it anymore. ATTENTION: terminate will really delete the instance so there is no way you can reconnect to it or recover it. Double check what instance you terminate!

ec2-terminate-instances i-XXXXXXXX