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How to Cluster Magento, nginx and MySQL on Multiple Servers for High Availability

Magento is an open-source e-commerce platform built on Zend PHP and MySQL. It is widely adopted by online retailers with some 150,000 sites known to use it. Single server setups are easy to set up, but if your store is a huge success, then you probably need to think about clustering your environment with multiple servers. Clustering is done at the web, database and file-system level, as all web nodes need access to catalog images.

 

This post is similar to our previous posts on scaling Drupal and WordPress performance, and focuses on how to scale Magento on multiple servers. The software used is Magento version 1.7.0.2 , nginx, HAProxy, MySQL Galera Cluster and OCFS2 (Oracle Cluster File System) with a shared storage using Ubuntu 12.04.2 LTS (Precise) 64bit.

Our setup consists of 6 nodes or servers:

  • NODE1: web server + database server
  • NODE2: web server + database server
  • NODE3: web server + database server
  • LB1: load balancer (master) + keepalived
  • LB2: load balancer (backup) + keepalived
  • ST1: shared storage + ClusterControl

 

We will be using OCFS2, a shared disk file system to serve the web files across our web servers. Each of these web servers will have a nginx web server colocated with a MySQL Galera Cluster instance. We will be using 2 other nodes for load balancing.

Our major steps would be:

  1. Prepare 6 instances
  2. Deploy MySQL Galera Cluster onto NODE1, NODE2 and NODE3 from ST1
  3. Configure iSCSI target on ST1
  4. Configure OCFS2 and mount the shared disk onto NODE1, NODE2 and NODE3
  5. Configure nginx on NODE1, NODE2 and NODE3
  6. Configure Keepalived and HAProxy for web and database load balancing with auto failover
  7. Install Magento and connect it to the Web/DB cluster via the load balancer

 

Prepare Hosts

 

Add following hosts definition in /etc/hosts:

192.168.197.150	mymagento.com www.mymagento.com mysql.mymagento.com #virtual IP
192.168.197.151	NODE1 web1 db1
192.168.197.152	NODE2 web2 db2
192.168.197.153	NODE3 web3 db3
192.168.197.161	LB1 
192.168.197.162	LB2
192.168.197.171	ST1 clustercontrol

 

Turn off sudo with password:

$ sudo visudo

 

And append following line:

%sudo ALL=(ALL:ALL) NOPASSWD: ALL

 

Deploy MySQL Galera Cluster

 

** The deployment of the database cluster will be done from ST1

 

1. To set up MySQL Galera Cluster, go to the Galera Configurator to generate a deployment package. In the wizard, we used the following values when configuring our database cluster:

  • Vendor: Codership (based on MySQL 5.5)
  • Infrastructure: none/on-premises
  • Operating System: Ubuntu 12.04
  • Number of Galera Servers: 3+1
  • OS user: ubuntu
  • ClusterControl Server: 192.168.197.171
  • Database Servers: 192.168.197.151 192.168.197.152 192.168.197.153

At the end of the wizard, a deployment package will be generated and emailed to you.

 

2. Download the deployment package and run deploy.sh:

$ wget http://www.severalnines.com/galera-configurator/tmp/a3l3pnv560sforpeb29lruds94/s9s-galera-codership-2.4.0.tar.gz
$ tar xvfz s9s-galera-codership-2.4.0.tar.gz
$ cd s9s-galera-codership-2.4.0/mysql/scripts/install
$ bash ./deploy.sh 2>&1 | tee cc.log

 

3. The deployment takes about 15 minutes, and once it is completed, note your API key. Use it to register the cluster with the ClusterControl UI by going to http://192.168.197.171/cmonapi . You will now see your MySQL Galera Cluster in the UI.

 

Configure iSCSI

 

1. The storage server (ST1) needs to export a disk through iSCSI so it can be mounted on all three web servers (NODE1, NODE2 and NODE3). iSCSI basically tells your kernel you have a SCSI disk, and it transports that access over IP. The “server” is called the “target” and the “client” that uses that iSCSI device is the “initiator”.

Install iSCSI target in ST1:

$ sudo apt-get install -y iscsitarget iscsitarget-dkms

 

2. Enable iscsitarget:

$ sudo sed -i "s|false|true|g" /etc/default/iscsitarget

 

3. It is preferred to have separate disk for this file system clustering purpose. So we are going to use another disk mounted in ST1 (/dev/sdb) to be shared among web server nodes. Define this in iSCSI target configuration file:

$ vim /etc/iet/ietd.conf

 

And add following lines:

Target iqn.2013-06.ST1:ocfs2
        Lun 0 Path=/dev/sdb,Type=fileio
        Alias iscsi_ocfs2

 

4. Add NODE1, NODE2 and NODE3 by specifying the network into iSCSI allow list:

$ vim /etc/iet/initiators.allow

 

And append following line:

ALL 192.168.197.0/24

 

5. Start iSCSI target service:

$ sudo service iscsitarget start

 

** The following steps should be performed on NODE1, NODE2 and NODE3

 

6. Install iSCSI initiator on respective hosts:

$ sudo apt-get install -y open-iscsi

 

7. Set the iSCSI initiator to automatically start and restart the iSCSI initiator service to apply changes:

$ sudo sed -i "s|^node.startup.*|node.startup = automatic|g" /etc/iscsi/iscsid.conf
$ sudo service open-iscsi restart

 

8. Discover iSCSI targets that we have setup earlier:

$ sudo iscsiadm -m discovery -t sendtargets -p ST1
192.168.197.171:3260,1 iqn.2013-06.ST1:ocfs2

 

9. If you see some result as above, means we can see and able to connect to the iSCSI target. We just need to do another restart to access the iSCSI target:

$ sudo service open-iscsi restart

 

10. Make sure you can see the new hard disk (/dev/sdb) listed under /dev directory:

$ ls -1 /dev/sd*

 

Configure OCFS2

 

** The following steps should be performed on NODE1 unless specified.

 

1. OCFS2 allows for file system to be mounted more than one place. Install OCFS2 tools in NODE1, NODE2 and NODE3:

$ sudo apt-get install -y ocfs2-tools

 

2. Create disk partition table for hard disk drive /dev/sdb:

$ sudo cfdisk /dev/sdb

 

Create a partition by using following sequences in the wizard: New > Primary > accept Size > Write > yes

 

3. Creates an OCFS2 file system on /dev/sdb1:

$ sudo mkfs.ocfs2 -b 4K -C 128K -L "Magento_Cluster" /dev/sdb1

 

4. Create cluster configuration file and define the node and cluster directives:

# /etc/ocfs2/cluster.conf
cluster:
        node_count = 3
        name = ocfs2
node:
        ip_port = 7777
        ip_address = 192.168.197.151
        number = 1
        name = NODE1
        cluster = ocfs2
node:
        ip_port = 7777
        ip_address = 192.168.197.152
        number = 2
        name = NODE2
        cluster = ocfs2
node:
        ip_port = 7777
        ip_address = 192.168.197.153
        number = 3
        name = NODE3
        cluster = ocfs2

*Notes: The attributes under the node or cluster clause need to be after a tab.

 

** The following steps should be performed on NODE1, NODE2 and NODE3 unless specified.

 

5. Create the same configuration file (/etc/ocfs2/cluster.conf) in NODE2 and NODE3. This file should be the same on all nodes in the cluster, and changes to this file must be propagated to the other nodes in the cluster.

 

6. Enable o2cb driver to load the driver on boot on all nodes:

$ sudo sed -i "s|false|true|g" /etc/default/o2cb

 

7. Restart iSCSI initiator to update the newly created disk partition:

$ sudo service open-iscsi restart

 

8. Restart o2cb service to apply the changes in /etc/ocfs2/cluster.conf:

$ sudo service o2cb restart

 

9. Create the web files directory under /var/www:

$ sudo mkdir -p /var/www/magento

 

10. Get the block ID for the /dev/sdb1. UUID is recommended in fstab if you use iSCSI device:

$ sudo blkid /dev/sdb1 | awk {'print $3'}
UUID="82b1d98c-30e7-4ade-ab9b-590f857797fd"

 

11. Add following line into /etc/fstab:

UUID=82b1d98c-30e7-4ade-ab9b-590f857797fd		/var/www/magento     ocfs2   defaults,_netdev        0 0

 

12. Mount the filesystem:

$ sudo mount -a

 

13. In NODE1, uncompress and copy Magento web files into /var/www/magento and setup directory permission:

$ tar -xzf magento-1.7.0.2.tar.gz
$ sudo cp -Rf magento/* /var/www/magento
$ sudo chown -R www-data.www-data /var/www/magento
$ sudo chmod 777 /var/www/magento/app/etc
$ sudo chmod 777 -Rf /var/www/magento/var
$ sudo chmod 777 -Rf /var/www/magento/media

 

Configure nginx and PHP-FPM

 

** The following steps should be performed on NODE1, NODE2 and NODE3.

 

1. We will use nginx as the web server for Magento. Install nginx and all required PHP modules:

$ sudo apt-get install nginx php5-common php5-cli php5-fpm php5-mysql php5-mcrypt php5-gd php5-curl php-soap

 

2. Open nginx virtual host configuration file at /etc/nginx/sites-available/default and add following lines:

# /etc/nginx/sites-available/magento
server {
    server_name mymagento.com www.mymagento.com;
    root /var/www/magento;
 
    location / {
        index index.html index.php;
        try_files $uri $uri/ @handler;
        expires 30d;
    }
 
    location /app/                { deny all; }
    location /includes/           { deny all; }
    location /lib/                { deny all; }
    location /media/downloadable/ { deny all; }
    location /pkginfo/            { deny all; }
    location /report/config.xml   { deny all; }
    location /var/                { deny all; }
 
    location ~ /. {
        deny all;
        access_log off;
        log_not_found off;
    }
 
    location @handler {
        rewrite / /index.php;
    }
 
    location ~ .php/ {
        rewrite ^(.*.php)/ $1 last;
    }
 
    location ~ .php$ {
        if (!-e $request_filename) { rewrite / /index.php last; }
        expires        off;
        fastcgi_pass   127.0.0.1:9000;
        fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
        fastcgi_param  MAGE_RUN_CODE default;
        fastcgi_param  MAGE_RUN_TYPE store;
        include        fastcgi_params;
    }
}

 

3. Create a symbolic link from sites-available directory to enable the magento virtual host:

$ cd /etc/nginx/sites-enabled
$ sudo ln -s /etc/nginx/sites-available/magento magento

 

4. Restart nginx and PHP:

$ sudo service php5-fpm restart
$ sudo service nginx restart

 

Load Balancer and Failover

 

Instead of using HAProxy for doing SQL load balancing, we will be using some of the suggestions based on this article and just have the Magento instances connect to their local MySQL Server using localhost, with following criteria:

    • Magento in each node will connect to MySQL database using localhost and bypassing HAProxy.
    • Load balancing on database layer is only for mysql client/console. HAProxy will be used to balance HTTP.
    • Keepalived will be used to hold the virtual IP: 192.168.197.150 on load balancers LB1 and LB2

In case you plan to place the MySQL Servers on separate servers, then the Magento instances should connect to the database cluster via the HAProxy.

 

** The following steps should be performed on ST1

 

1. We have created scripts to install HAProxy and Keepalived, these can be obtained from our Git repository.

Install git and clone the repo:

$ apt-get install -y git
$ git clone https://github.com/severalnines/s9s-admin.git

 

2. Make sure LB1 and LB2 are accessible using passwordless SSH. Copy the SSH keys to LB1 and LB2:

$ ssh-copy-id -i ~/.ssh/id_rsa 192.168.197.161
$ ssh-copy-id -i ~/.ssh/id_rsa 192.168.197.162

 

3. Install HAProxy on both nodes:

$ cd s9s-admin/cluster/
$ sudo ./s9s_haproxy --install -i 1 -h 192.168.197.161
$ sudo ./s9s_haproxy --install -i 1 -h 192.168.197.162

 

4. Install Keepalived on LB1 (master) and LB2 (backup) with 192.168.197.150 as virtual IP:

$ sudo ./s9s_haproxy --install-keepalived -i 1 -x 192.168.197.161 -y 192.168.197.162 -v 192.168.197.150

 

** The following steps should be performed on LB1 and LB2

 

5. By default, the script will configure the MySQL reverse proxy service to listen on port 33306. We will need to add a few more lines to tell HAproxy to load balance our web server farm as well. Add following line in /etc/haproxy/haproxy.cfg:

frontend http-in
    bind *:80
    default_backend web_farm
 
backend web_farm
    server NODE1 192.168.197.151:80 maxconn 32
    server NODE2 192.168.197.152:80 maxconn 32
    server NODE3 192.168.197.153:80 maxconn 32

 

6. Restart HAProxy service:

$ sudo killall haproxy
$ sudo /usr/sbin/haproxy -f /etc/haproxy/haproxy.cfg -p /var/run/haproxy.pid -st `cat /var/run/haproxy.pid`

 

Install Magento

 

1. Now that we have a load-balanced setup that is ready to support Magento, we will now create our Magento database. From the ClusterControl UI, go to Manage > Schema and Users > Create Database to create the database:

 

2. Create the database user under Privileges tab:

 

3. Assign the correct privileges for magento_user on database magento_site:

At the moment, we assume you have pointed mymagento.com and www.mymagento.com to the virtual IP, 192.168.197.150.

 

4. Open web browser and go to mymagento.com. You should see an installation page similar to screenshot below:

 

* Take note that we are using localhost in the host value, session data will be saved in database. It will allow users to use the same session regardless of which web server they are connected to.

 

Notes

 

** Updated on 9th Dec 2013 **

By default Magento will setup a MyISAM table specifically for FULLTEXT indexing called catalogsearch_fulltext. MyISAM tables are supported within MySQL Galera Cluster, however, MyISAM has only basic support, primarily because the storage engine is non-transactional and so Galera cannot guarantee the data will remain consistent within the cluster.

Codership has released MySQL-wsrep 5.6 supports with Galera 3.0 which currently in beta release at the time of this update. You could either use the MySQL-wsrep 5.6 which supports InnoDB FTS or convert all non-Galera friendly tables to use InnoDB with primary keys. Alternatively, you can use external search engine (such as Solr or Sphinx) for FTS capabilities.

If you choose the latter option, you need to convert some of the tables to work well with Galera by executing following queries on one of the DB node:

mysql> ALTER TABLE magento.api2_acl_user ADD id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY FIRST;
mysql> ALTER TABLE magento.api_session ADD id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY FIRST;
mysql> ALTER TABLE magento.weee_discount ADD id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY FIRST;
mysql> ALTER TABLE magento.widget_instance_page_layout ADD id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY FIRST;
mysql> ALTER TABLE magento.xmlconnect_config_data ADD id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY FIRST;
mysql> ALTER TABLE magento.oauth_nonce ADD id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY FIRST, ENGINE='InnoDB';
mysql> ALTER TABLE magento.catalogsearch_fulltext DROP INDEX FTI_CATALOGSEARCH_FULLTEXT_DATA_INDEX;
mysql> ALTER TABLE magento.catalogsearch_fulltext ENGINE='InnoDB';

 

 

Verify The Architecture

 

1. Check the HAproxy statistics by logging into the HAProxy admin page at LB1 host port 9600. The default username/password is admin/admin. You should see some bytes in and out on the web_farm ands9s_33306_production sections:

 

2. Check and observe the traffic on your database cluster from the ClusterControl overview page athttps://192.168.197.171/clustercontrol :

 

There are many improvements that could be made to this setup. For example, you could provide redundancy to the shared storage server by installing DRBD. You can also add a Varnish Cache in the load balancing servers to provide better caching on your static contents and reduce the load on the web servers/database servers.

 

 
via How to Cluster Magento, nginx and MySQL on Multiple Servers for High Availability | Severalnines.

Because Hadoop isn’t perfect: 8 ways to replace HDFS

SUMMARY:

Hadoop is on its way to becomig the de facto platform for the next-generation of data-based applications, but it’s not without some flaws. Ironically, one of Hadoop’s biggest shortcomings right now is also one of its biggest strengths going forward — the Hadoop Distributed File System.

Hadoop is on its way to becoming the de facto platform for the next-generation of data-based applications, but it’s not without flaws. Ironically, one of Hadoop’s biggest shortcomings now is also one of its biggest strengths going forward — the Hadoop Distributed File System.

Within the Apache Software Foundation, HDFS is always improving in terms of performance and availability. Honestly, it’s probably fine for the majority of Hadoop workloads that are running in pilot projects, skunkworks projects or generally non-demanding environments. And technologies such as HBase that are built atop HDFS speak to its versatility as storage system even for non-MapReduce applications.

But if the growing number of options for replacing HDFS signifies anything, it’s that HDFS isn’t quite where it needs to be. Some Hadoop users have strict demands around performance, availability and enterprise-grade features, while others aren’t keen of its direct-attached storage (DAS) architecture. Concerns around availability might be especially valid for anyone (read “almost everyone”) who’s using an older version of Hadoop without the High Availability NameNode. Here are eight products and projects whose proprietors argue can deliver what HDFS can’t:

 

Cassandra (DataStax)

 

Not a file system at all but an open source, NoSQL key-value store, Cassandra has become a viable alternative to HDFS for web applications that rely on fast data access. DataStax, a startup commercializing the Cassandra database, has fused Hadoop atop Cassandra to provide web applications fast access to data processed by Hadoop, and Hadoop fast access to data streaming into Cassandra from web users.

 

Ceph

Ceph is an open source, multi-pronged storage system that was recently  commercialized by a startup called Inktank. Among its features is a high-performance parallel file system that some think makes it a candidate for replacing HDFS (and then some) in Hadoop environments. Indeed, some researchers started looking at this possibility as far back as 2010.

 

Dispersed Storage Network (Cleversafe)

 

Cleversafe got into the HDFS-replacement business on Monday, announcing a product that will fuse Hadoop MapReduce with the company’s Dispersed Storage Network system. By fully distributing metadata across the cluster (instead of relying on a single NameNode) and not relying on replication, Cleversafe says it’s much faster, more reliable and scalable than HDFS.

 

GPFS (IBM)

 

IBM has been selling its General Parallel File System to high-performance computing customers for years (including within some of the world’s fastest supercomputers), and in 2010 it tuned GPFS for Hadoop. IBM claims the GPFS-SNC (Shared Nothing Cluster) edition is so much faster than Hadoop in part because it runs at the kernel level as opposed to atop the OS like HDFS.

Isilon (EMC)

 

EMC has offered its own Hadoop distributions for more than a year, but in January 2012 it unveiled a new method for making HDFS enterprise-class — replace it with EMC Isilon’s OneFS file system. Technically, as EMC’s Chuck Hollis explained at the time, because Isilon can read NFS, CIFS and HDFS protocols, a single Isilon NAS system can serve to intake, process and analyze data.

Lustre

OpenSFS_Lug

Lustre is a an open source high-performance file system that some claim can make for an HDFS alternative where performance is a major concern. Truth be told, I haven’t heard of this combination running anywhere in the wild, but HPC storage provider Xyratex wrote a paper on the combination in 2011, claiming a Lustre-based cluster (even with InfiniBand) will be faster and cheaper than an HDFS-based cluster.

MapR File System

 

 

The MapR File System is probably the best-known HDFS alternative, as it’s the basis of MapR’s increasingly popular — and well-funded — Hadoop distribution. Not only does MapR claim its file system is two to five times faster than HDFS on average (although, really, up to 20 times faster), but it has features such as mirroring, snapshots and high availability that enterprise customers love.

NetApp Open Solution for Hadoop

 

 

 

OK, the NetApp Open Solution for Hadoop isn’t so much an HDFS replacement as it is an HDFS improvement, according to NetApp and early partner Cloudera. The offering still relies on HDFS, but it reenvisions the physical Hadoop architecture by putting HDFS on a RAID array. This, NetApp claims, means faster, more reliable and more secure Hadoop jobs.

This might be a good place to say rest in peace to two other HDFS alternatives that are effectively no longer with us — KosmosFS (aka CloudStore) and Appistry CloudIQ Storage. The former was created by Kosmix (since bought by @WalmartLabs) and released to the open source world in 2007, but no longer has an active community. The latter was an attempt by Appistry in 2010 to get a piece of the Hadoop pie with its computational storage technology, but the company has since switched its focus from selling the technology to providing high-performance computing services based on it.

via Because Hadoop isn’t perfect: 8 ways to replace HDFS — Tech News and Analysis.

How do I disable “Command-q” in OS X?

You can reassign menu commands in Mac’s System Preferences menu to different shortcuts, either for individual applications or for all applications. This will let you effectively reassign Cmd-Q to anything (or nothing), if you’d like.

1. Go to System Preferences, and select Keyboard.

2. Click on Keyboard Shortcuts, then select the Application Shortcuts menu bar in the lower left.

3. Click the “+” button to add a shortcut for an application. For this example, we’ll disable Cmd-Q for Google Chrome.

4. Figure out the command name for Google Chrome’s “Quit” by going to the menu bar in Google Chrome and finding the menu item. In Chrome, under the “Chrome” menu bar element, you can find the action “Quit Google Chrome” attached to Cmd-Q.

5. Put the exact name of the menu action item as a new keyboard shortcut in the Keyboard Shortcut options.

6. Select a shortcut that isn’t Cmd-Q (for example, Cmd-Option-Q). Click “Add” to finish the setting.

via How do I disable “Command-q” in OS X? – Quora.