Practical Technology

If you want to do manual config changes/propagation (i.e. not using any GUI tools like Luci and system-config-cluster).  The reason why I don't want to use the GUI tools is this - I have NFS running as a cluster service with one client currently.  When I add two new clients and check the config file, there is a slight discrepancy - the original client setting is '1' while the new clients are set to 'on'.  The two new clients refuse to mount the NFS share stating 'access denied', except the are no /etc/exports files stating what clients can connect or not (or anything like that anywhere).  It's a long shot, but all I got!!  And I learned this, so not all is lost. Note the key difference - one requires a cluster shutdown, the other does not.  If you were not aware, having a different config version number on nodes is BAD NEWS BEARS like whoa.  Basically causes nodes to start freaking out, getting fenced, etc.  It's messy. On CentOS 5 Sh...

Yes, today is the day that I made a fine boo-boo.  A shameful one, to be honest. I was deploying config files for the monitoring software and got lazy - I overwrote files instead of moving them or renaming them...all because I wanted to get that last little bit done before I left for the day. Of course it turns out that some esoteric command was in the files.  Not mission-critical, but I'll be spending time in the backup software tomorrow (assuming the servers were ever backed up) trying to figure it out.  Or re-writing the command from scratch.  Ouch. The amount of time it will take to rename the files versus restore from backup can be described in orders of magnitude.  Honest to goodness - at least this project is almost over. Lesson:  Even if you are 100% certain you'll be okay overwriting a file - move or rename it for insurance, because restoring from backup is tedious and painful and sometimes an endeavour in panic.   Sub-les...

From a post I made here:   http://communities.vmware.com/thread/342742?tstart=0 It started out simple, then got longer, and ended a saga.  The iSCSI saga.   I would paste the whole thing here...but I'd imagine the VMware communities will be around well after this article is rendered obsolete. Bottom line :  If your switchport is accepting tagged packets on VLAN10 only, and your physical adapter is tagging packets for VLAN10, setting the virtual machine networking (bridged to said physical adapter) to ALSO tag packets for VLAN10 will break stuff.  Leave the VLAN tagging for the physical devices. After the saga came to a close, I then tried to add the iSCSI targets to my workstation, but ran into this:   http://www.jeremycole.com/blog/2007/11/09/the-iscsi-name-specified-contains-invalid-characters-or-is-too-long/ Yes, my naming scheme was foiled by a subtle Microsoft...oversight.  This is what the Initiator does:  ( http://technet.micros...

Well, misreading a forum post led me to book my VCP410 re-take for end of February - around the same time big things are happening.  So Lord-willing I'll pass it this time.  I have already begun studying in earnest, but definitely need to put effort into it. A number of people I've spoken to have said the '410 is focused on min/maxes, and after taking it  last spring, I'm inclined to agree.  Memorization has never come easily to me, so I'll really have to put all the spare time I have into this.  I had tried to go on working experience and book knowledge and got a 221 - pass is 300/400 - rather embarrassing.  Now, to be fair, I did not study at all, nor do any of the recommended lab exercises, so that probably didn't help.  Now, why did I wait so long to do a re-take?  The aforementioned 'big thing' and rebuilding our garage over the summer. I've been speaking to my employer about potentially taking the VCP5 course/exam, but would not be ...

I am sure there are other posts like this out there, but last time I checked, there wasn't much info on this, so here goes. I want to use kickstart to deploy virtual machines.  Rather, wanted.  Forgot that kickstart requires ethernet right off the bat, and the vmxnet3 NIC doesn't work until vmware tools is active.  I could use the E1000, but then I'm still having to delete/reconfigure after the fact.  This method means VM rollouts that are probably just as fast as kickstart, and possibly a little easier.  I could probably write a script to do the hostname/network cleanup as well. Anyways, here's my attempt at vCenter templates for CentOS.  This is pulled from my wiki, posted here for searchability. CentOS vCenter template creation Created a new VM and gave it 1cpu/1GB RAM/40GB thin drive. Installed CentOS 6 x86_64. I configured LVM - do so according to your wishes. (I specifically added LVs for /var/log, /var, /tmp, and /home) Set passwords,...

I've re-thought the storage layout, and now we include: Free space!  What a concept... More SCST config fun Actual iSCSI configuration steps Multiple smaller LUNs that will be used as RDMs Smaller VMFS LUNs Clearer layout and naming Bonded iSCSI! For the revised layout, now with pretty pictures: http://wiki.practicaltech.ca/index.php/Openfiler_-_Revised_architecture For the new config walkthrough: http://wiki.practicaltech.ca/index.php/Openfiler_-_iSCSI/FC_config_v2

All done!  Very excited, and I will continue to update with screenshots as they come up. http://wiki.practicaltech.ca/index.php/Openfiler_-_iSCSI/FC_config This doc will help you: Set up Openfiler FC for the first time Tear down and re-create new FC devices Use LVS commands to create your back-end storage Set up Openfiler iSCSI (though, admittedly, that is not the primary purpose) Next up...back to the cluster project!