What Does OpenStack Offer To You?

It’s free and open source!

It offers a free alternative to VMware. The license costs for VMware are quite large if you are running a big cluster. OpenStack on the other hand is free, open sourced solution. Of course there are some costs; hardware, electricity, administration, OS licence if you decide to run it on RHEL.

You don’t have to take every component that comes with OpenStack. For example you can leave Swift out of your environment if you don’t need storage. OpenStack being open source means you can modify it how you want based on how it fits to your purposes. This also means that you don’t have to wait for your vendor to fix something small in the software that would come in the next update, which can cost money when you can do it yourself.

Storage
OpenStack’s Swift is quite versatile. It can be installed on a single server, which uses only one hard drive, but it is at best when installed on multiple servers.

Adding and removing storage nodes is fast and easy. Add the node to the storage ring configuration and re-balance it. Swift starts automatically replicating the stored files to the new node. Replication is done with rsync, fast and efficient software.

Recently PayPal replaced their 80 000 VMware servers with OpenStack. Their main reason was speed, as mentioned earlier it can take months for vendor to release a fix for something small. Full article and reasons can be found here. Another PayPal’s reason was scalability. They get sudden spikes of traffic and OpenStack can help and deploy new virtual machines to balance the load

CA ARCserve and No Compute Resource Found On Specified Host

I was running CA ARCserve r16 on virtual Windows Server 2008 R2 machine. The environment it was running in had 3 physical VMware ESXi hosts and all of these were controlled by a single VMware vCenter server.

I had created a new virtual machine on one of the hosts so I could test backing up and restoring with ARCserve. When it came time to test to restore the whole virtual machine from the backup I had made earlier, I encountered this weird problem. Googling the error message didn’t help, because nobody had encountered it before. ARCserve had created an entry in the error log saying ”CreateVM Failed with error msg – ”Err_code: -133 CreateVM: Exception Raised – No Compute Resource Found On Specified Host. ”.

This problem made me stumped and I tried several things to solve it. The solution was so simple. I was trying to restore the virtual machine to VMware vCenter’s server. For some reason vCenter didn’t know how to rely the request to one of the ESXi hosts, so the solution was to change the IP-address to point directly to ESXi host. I’m not saying this is the correct way to do things, but it solved the problem for me.