Hi Digimer, there is a chance to make fencing without hardware, but only software?
Il 15/06/2014 17:28, Digimer ha scritto:
On 15/06/14 08:54 AM, Alessandro Baggi wrote:
Another question is about fencing. I've ridden that a cluster must have fencing to be considered as such. On CentOS 6.5 there is stonith that concerns node level fencing. For this type of fencing I must have ilo, ilom, drac, and other. It's possible to have fencing without Light-out devices, blade power control device and other? There are other device that can be used for fencing? Supposing a 2 node cluster with two server assembled (no hp, dell, sun, ibm..) how I can implement fencing with stonith? I can run a cluster without fencing and what implies do not use fencing?
A lot of odd problems go away once fencing is working. So this is a good time to sort this out, then go back and see if your problems remain.
A very good way to fence machines without IPMI (etc) is to use an external switched PDU, like the APC AP7900 (or your country version on).
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=ap7900
If your budget is tight, I have seen these models frequently go on sale for ~$200 (Canadian).
These work be allowing another node to log into the PDU and turn off the power going to the lost/failed node. Please do note that the brand of switched PDU you buy matters. For a device to work for fencing, it must be possible for the cluster to talk to it. This is done using a "fence handler", and there are many types that are supported (APC, Eaton, etc). So if you want to get a different make/model, please first make sure there is a fence handler.
Once you get this setup, see if your problems remain. If so, there is a good clustering mailing list at:
https://www.redhat.com/mailman/listinfo/linux-cluster
And if you're on freenode, #linux-cluster is also very good.
Cheers!