Weez.com » please http://www.weez.com Solving everyday practical LAMP problems... one at a time Fri, 10 Feb 2012 23:07:33 +0000 en hourly 1 http://wordpress.org/?v=3.0.1 Lucky – Jason Mraz & Colbie Caillat (Cover by Anastasia) LISTEN WITH EARPHONES PLEASE!- http://www.weez.com/2010/08/lucky-jason-mraz-colbie-caillat-cover-by-anastasia-listen-with-earphones-please/ http://www.weez.com/2010/08/lucky-jason-mraz-colbie-caillat-cover-by-anastasia-listen-with-earphones-please/#comments Tue, 10 Aug 2010 16:59:42 +0000 Abidoon http://www.weez.com/2010/08/lucky-jason-mraz-colbie-caillat-cover-by-anastasia-listen-with-earphones-please/
This is dedicated to Brixton Boy. And Fedora, though I have no idea when we’ll ever jam again. xoxoxo Anastasia

]]> http://www.weez.com/2010/08/lucky-jason-mraz-colbie-caillat-cover-by-anastasia-listen-with-earphones-please/feed/ 21 Less Spam, Please Generates Temporary, Anonymous Email Addresses On-the-Fly [Downloads] http://www.weez.com/2010/08/less-spam-please-generates-temporary-anonymous-email-addresses-on-the-fly-downloads/ http://www.weez.com/2010/08/less-spam-please-generates-temporary-anonymous-email-addresses-on-the-fly-downloads/#comments Wed, 04 Aug 2010 08:55:33 +0000 Abidoon http://www.weez.com/2010/08/less-spam-please-generates-temporary-anonymous-email-addresses-on-the-fly-downloads/ Less Spam, Please Generates Temporary, Anonymous Email Addresses On-the-Fly [Downloads]
# downloads Firefox only (Windows/Mac/Linux): Firefox extension Less Spam, Please adds an item to your right-click context menu to automatically generate an anonymous, disposable email address so you can try out a new service without fear of spam. More »

Read more on Lifehacker

]]> http://www.weez.com/2010/08/less-spam-please-generates-temporary-anonymous-email-addresses-on-the-fly-downloads/feed/ 0 Please Don’t Run http://www.weez.com/2010/06/please-dont-run/ http://www.weez.com/2010/06/please-dont-run/#comments Wed, 02 Jun 2010 00:26:09 +0000 Abidoon http://www.weez.com/2010/06/please-dont-run/

]]> http://www.weez.com/2010/06/please-dont-run/feed/ 25 Pacemaker, please meet NDB Cluster or using Pacemaker/Heartbeat to start a NDB Cluster http://www.weez.com/2010/05/pacemaker-please-meet-ndb-cluster-or-using-pacemakerheartbeat-to-start-a-ndb-cluster/ http://www.weez.com/2010/05/pacemaker-please-meet-ndb-cluster-or-using-pacemakerheartbeat-to-start-a-ndb-cluster/#comments Wed, 19 May 2010 20:48:26 +0000 Abidoon http://www.weez.com/2010/05/pacemaker-please-meet-ndb-cluster-or-using-pacemakerheartbeat-to-start-a-ndb-cluster/ Customers have always asked me to make NDB Cluster starts automatically upon startup of the servers. For the ones who know NDB Cluster, it is tricky to make it starts automatically. I know at least 2 sets of scripts to manage NDB startup, ndb-initializer and from Johan configurator www.severalnines.com. If all the nodes come up at about the same time, it is not too bad but what if one the critical node takes much longer to start because of an fsck on a large ext3 partition. Then, a startup script becomes a nightmare. Finally, if the box on which the script is supposed to run didn’t start at all. That’s a lot of rules to handle.

Since all aspects of HA interest me, I was recently reading the Pacemaker documentation and I realized that Pacemaker has all the logic required to manage NDB Cluster startup. Okay it might seems weird to control a cluster by cluster but if you think about it, this is, I think, the best solution.

The Linux-HA project has split the old Heartbeat-2 project in 2 parts, the clustering and communication layer, Heartbeat and the resources manager, Pacemaker. A key new features that has been added to Pacemaker recently, a Clone resources set, that allows an optional startup if only one of 2 similar resources starts. I use this feature to start the data nodes. If after a major outage, only one of the physical host where the data nodes are located comes up, the cluster will start. The other features of Pacemaker that I need are resource location rsc_location and resource ordering rsc_order.

Let’s start by the beginning. My NDB cluster is made of the following 3 nodes:

  • testvirtbox: ndb_mgmd (10.2.2.139)
  • test1: ndbd
  • test2: ndbd

For the sake of simplicity, I am not considering the SQL nodes but given the framework, extending to SQL nodes is trivial. Installing Pacemaker and Heartbeat is very easy on Lucid Lynx, just do the following:

PLAIN TEXT
CODE:

  1. apt-get install heartbeat pacemaker

On other distributions, you might have to build from sources, look here for help.

There 2 minimal configuration files:

PLAIN TEXT
CODE:

  1. root@test2:~# cat /etc/ha.d/authkeys
  2. auth 1
  3. 1 sha1  yves
  4. root@test2:~# cat /etc/ha.d/ha.cf
  5. autojoin none
  6. bcast eth0
  7. warntime 5
  8. deadtime 15
  9. initdead 60
  10. keepalive 2
  11. node test1
  12. node test2
  13. node testvirtbox
  14. crm respawn

And then, Heartbeat can be started on all nodes with /etc/init.d/heartbeat start.

Next, since Pacemaker is used to start resources and not to manage them, we don’t need to define Stonith devices so (run on only one node):

PLAIN TEXT
CODE:

  1. crm_attribute -t crm_config -n stonith-enabled -v false

A last before defining resources, since the Heartbeat cluster is asymmetrical, meaning resources will not be able to run anywhere, we must create an “Opt-In” cluster with (run on only one node):

PLAIN TEXT
CODE:

  1. crm_attribute –attr-name symmetric-cluster –attr-value false

At this point, we have a running cluster controlling nothing. The trick with NDB Cluster is that Heartbeat is required to start the resources but not to stop them. In order to achieve this behavior, I created fake resource scripts that can be fully controlled by Heartbeat but allowing the one way behavior I wanted.

PLAIN TEXT
CODE:

  1. root@testvirtbox:~# cat /usr/local/bin/fake_ndb_mgmd
  2. #!/bin/bash
  3.  
  4. /usr/bin/nohup /usr/local/mysql/libexec/ndb_mgmd> /dev/null &
  5.  
  6. while [ 1 ]
  7. do
  8.         /bin/sleep 60
  9. done
  10.  
  11. root@testvirtbox:~# cat /usr/local/bin/fake_ndb_cluster_start
  12. #!/bin/bash
  13.  
  14. #Give some time to the nodes to connect
  15. /bin/sleep 15
  16.  
  17. /usr/local/mysql/bin/ndb_mgm -e ‘all start’> /dev/null
  18.  
  19. while [ 1 ]
  20. do
  21.         /bin/sleep 60
  22. done
  23.  
  24. root@test1:~# cat /usr/local/bin/fake_ndbd
  25. #!/bin/bash
  26.  
  27. #Give some time to ndb_mgmd to start
  28. /bin/sleep 10
  29.  
  30. nohup /usr/local/mysql/libexec/ndbd -c 10.2.2.139> /dev/null &
  31.  
  32. while [ 1 ]
  33. do
  34.         sleep 60
  35. done

With Pacemaker it is not longer required to manipulate the cib in xml format but for this post, xml offers a compact way of presenting the configuration. The first things we need to define are the resources. A very handy resource type for us is the anything resource which allow an arbitrary script or binary to be run. The resources section will look like:

PLAIN TEXT
CODE:

  1. <resources>
  2.       <primitive id=“mgmd” class=“ocf” type=“anything” provider=“heartbeat”>
  3.         <instance_attributes id=“params-mgmd”>
  4.           <nvpair id=“param-mgmd-binfile” name=“binfile” value=“/usr/local/bin/fake_ndb_mgmd”/>
  5.           <nvpair id=“param-mgmd-pidnile” name=“pidfile” value=“/var/run/heartbeat/fake_ndb_mgmd.pid”/>
  6.         </instance_attributes>
  7.       </primitive>
  8.       <clone id=“ndbdclone”>
  9.         <meta_attributes id=“ndbdclone-options”>
  10.           <nvpair id=“ndbdclone-option-1″ name=“globally-unique” value=“false”/>
  11.           <nvpair id=“ndbdclone-option-2″ name=“clone-max” value=“2″/>
  12.           <nvpair id=“ndbdclone-option-3″ name=“clone-node-max” value=“1″/>
  13.         </meta_attributes>
  14.         <primitive id=“ndbd” class=“ocf” type=“anything” provider=“heartbeat”>
  15.           <instance_attributes id=“params-ndbd”>
  16.             <nvpair id=“param-ndbd-binfile” name=“binfile” value=“/usr/local/bin/fake_ndbd”/>
  17.             <nvpair id=“param-ndbd-pidfile” name=“pidfile” value=“/var/run/heartbeat/fake_ndbd.pid”/>
  18.           </instance_attributes>
  19.         </primitive>
  20.       </clone>
  21.       <primitive id=“ndbcluster” class=“ocf” type=“anything” provider=“heartbeat”>
  22.         <instance_attributes id=“params-ndbcluster”>
  23.           <nvpair id=“param-ndbcluster-binfile” name=“binfile” value=“/usr/local/bin/fake_ndb_cluster_start”/>
  24.           <nvpair id=“param-ndbcluster-pidfile” name=“pidfile” value=“/var/run/heartbeat/fake_ndb_cluster_start.pid”/>
  25.         </instance_attributes>
  26.       </primitive>
  27.     </resources>

Please note the ndbd resource is defined through the use of a clone set. The clone set will allow the cluster to start even if only one to the ndb node group is available. If you have multiple ndb node groups, you’ll need one clone set per node group. The ndb_mgmd nodes or eventual SQL nodes could have been handled the same way although for SQL nodes, ndb_waiter is very handy. Once the resources are defined, we need to setup the constraints which cover mandatory locations and ordering.

PLAIN TEXT
CODE:

  1. <constraints>
  2.       <rsc_location id=“loc-1″ rsc=“mgmd” node=“testvirtbox” score=“INFINITY”/>
  3.       <rsc_location id=“loc-2″ rsc=“ndbcluster” node=“testvirtbox” score=“INFINITY”/>
  4.       <rsc_location id=“loc-3″ rsc=“ndbdclone” node=“test1″ score=“INFINITY”/>
  5.       <rsc_location id=“loc-4″ rsc=“ndbdclone” node=“test2″ score=“INFINITY”/>
  6.       <rsc_order id=“order-1″>
  7.         <resource_set id=“ordered-set-1″ sequential=“true”>
  8.           <resource_ref id=“mgmd”/>
  9.           <resource_ref id=“ndbdclone”/>
  10.           <resource_ref id=“ndbcluster”/>
  11.         </resource_set>
  12.       </rsc_order>
  13.     </constraints>

And… that’s it. For my part, I configured Pacemaker by dumping the cib in xml format, editing and reloading. In term of commands, it means:

PLAIN TEXT
CODE:

  1. cibadmin –query> local.xml
  2. vi  local.xml
  3. cibadmin  –replace –xml-file local.xml

Once NDB is started, you can even stop heartbeat, it is no longer required.

P.S.:

As suggested by Florian, here is the configuration in CLI format:

PLAIN TEXT
CODE:

  1. root@testvirtbox:~# crm configure show
  2. INFO: building help index
  3. INFO: object order-1 cannot be represented in the CLI notation
  4. node $id=“27687295-f72c-49bd-b82d-25f32dbfe1e2″ test2
  5. node $id=“3086852d-abb9-4bdb-93a1-9390e14c148c” test1
  6. node $id=“cad7f678-fc91-4f09-a39e-1dde6d5bcd30″ testvirtbox
  7. primitive mgmd ocf:heartbeat:anything \
  8.         params binfile=“/usr/local/bin/fake_ndb_mgmd” pidfile=“/var/run/heartbeat/fake_ndb_mgmd.pid”
  9. primitive ndbcluster ocf:heartbeat:anything \
  10.         params binfile=“/usr/local/bin/fake_ndb_cluster_start” pidfile=“/var/run/heartbeat/fake_ndb_cluster_start.pid”
  11. primitive ndbd1-IP ocf:heartbeat:anything \
  12.         params binfile=“/usr/local/bin/fake_ndbd” pidfile=“/var/run/heartbeat/fake_ndbd.pid”
  13. clone ndbdclone ndbd1-IP \
  14.         meta globally-unique=“false” clone-max=“2″ clone-node-max=“1″
  15. location loc-1 mgmd inf: testvirtbox
  16. location loc-2 ndbcluster inf: testvirtbox
  17. location loc-3 ndbdclone inf: test1
  18. location loc-4 ndbdclone inf: test2
  19. xml <rsc_order id=“order-1″> \
  20.         <resource_set id=“ordered-set-1″ sequential=“true”> \
  21.                 <resource_ref id=“mgmd”/> \
  22.                 <resource_ref id=“ndbdclone”/> \
  23.                 <resource_ref id=“ndbcluster”/> \
  24.         </resource_set> \
  25. </rsc_order>

Entry posted by Yves Trudeau |
2 comments

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]]> http://www.weez.com/2010/05/pacemaker-please-meet-ndb-cluster-or-using-pacemakerheartbeat-to-start-a-ndb-cluster/feed/ 3 I want my users to upload stories or blogs. How do i do this with php and mysql? Please give the code.? http://www.weez.com/2010/05/i-want-my-users-to-upload-stories-or-blogs-how-do-i-do-this-with-php-and-mysql-please-give-the-code/ http://www.weez.com/2010/05/i-want-my-users-to-upload-stories-or-blogs-how-do-i-do-this-with-php-and-mysql-please-give-the-code/#comments Sat, 01 May 2010 14:49:35 +0000 Abidoon http://www.weez.com/2010/05/i-want-my-users-to-upload-stories-or-blogs-how-do-i-do-this-with-php-and-mysql-please-give-the-code/ I also want people to have a minimum number of characters or letters to type in the stories or blogs. This will be greatly appreciated and I promise I will choose you as best answer!

]]> http://www.weez.com/2010/05/i-want-my-users-to-upload-stories-or-blogs-how-do-i-do-this-with-php-and-mysql-please-give-the-code/feed/ 1 For the love of god fsck, please just FINISH http://www.weez.com/2010/04/for-the-love-of-god-fsck-please-just-finish/ http://www.weez.com/2010/04/for-the-love-of-god-fsck-please-just-finish/#comments Wed, 28 Apr 2010 02:51:55 +0000 Abidoon http://www.weez.com/2010/04/for-the-love-of-god-fsck-please-just-finish/
Fsck generating tons of late night work for me. Joy.

]]> http://www.weez.com/2010/04/for-the-love-of-god-fsck-please-just-finish/feed/ 0 Help with desktop on a Fedora system please? http://www.weez.com/2010/04/help-with-desktop-on-a-fedora-system-please/ http://www.weez.com/2010/04/help-with-desktop-on-a-fedora-system-please/#comments Wed, 28 Apr 2010 01:12:02 +0000 Abidoon http://www.weez.com/2010/04/help-with-desktop-on-a-fedora-system-please/ I use a homemade computer my son built for me. I have fedora instead of windows which has really taken some getting used to, especially since I am not a computer wiz kid like him. He recently downloaded some desktops for me and said try them and take your pick. I just want to ask everyone else’s opinion as well, do you like Kde, Gnome, or Xface (may have the name wrong on the last one.) and why? Thanks!

]]> http://www.weez.com/2010/04/help-with-desktop-on-a-fedora-system-please/feed/ 1 How to Install Fedora 8 in my system(with Windows XP already in it) ?? Please help !!!!!? http://www.weez.com/2010/04/how-to-install-fedora-8-in-my-systemwith-windows-xp-already-in-it-please-help/ http://www.weez.com/2010/04/how-to-install-fedora-8-in-my-systemwith-windows-xp-already-in-it-please-help/#comments Wed, 21 Apr 2010 16:46:26 +0000 Abidoon http://www.weez.com/2010/04/how-to-install-fedora-8-in-my-systemwith-windows-xp-already-in-it-please-help/ Dear Friends,
I want 2 install Fedora 8 in my laptop IBM(R51 model). I already have Windows XP Home Edition installed in it. & i’ve already made a partition in the hard disk for installing Fedora 8.
But i am unable 2 install it. & I find difficult in following the booting instructions.
Please anyone help me & send the detailed procedure of doing it..

]]> http://www.weez.com/2010/04/how-to-install-fedora-8-in-my-systemwith-windows-xp-already-in-it-please-help/feed/ 2 How does wed hosting work? What if I have a php program do I copy and paste it please help? http://www.weez.com/2010/04/how-does-wed-hosting-work-what-if-i-have-a-php-program-do-i-copy-and-paste-it-please-help/ http://www.weez.com/2010/04/how-does-wed-hosting-work-what-if-i-have-a-php-program-do-i-copy-and-paste-it-please-help/#comments Sun, 18 Apr 2010 12:00:54 +0000 Abidoon http://www.weez.com/2010/04/how-does-wed-hosting-work-what-if-i-have-a-php-program-do-i-copy-and-paste-it-please-help/ If I want to create a site and have all the programming as php files how does it exactly work

Please helpppp

]]> http://www.weez.com/2010/04/how-does-wed-hosting-work-what-if-i-have-a-php-program-do-i-copy-and-paste-it-please-help/feed/ 5 how can i start linux kernel in fedora core 5 ( I am a first user in linux) please help me? http://www.weez.com/2010/04/how-can-i-start-linux-kernel-in-fedora-core-5-i-am-a-first-user-in-linux-please-help-me/ http://www.weez.com/2010/04/how-can-i-start-linux-kernel-in-fedora-core-5-i-am-a-first-user-in-linux-please-help-me/#comments Thu, 15 Apr 2010 13:31:32 +0000 Abidoon http://www.weez.com/2010/04/how-can-i-start-linux-kernel-in-fedora-core-5-i-am-a-first-user-in-linux-please-help-me/ http://www.weez.com/2010/04/how-can-i-start-linux-kernel-in-fedora-core-5-i-am-a-first-user-in-linux-please-help-me/feed/ 3