From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fabio M. Di Nitto Date: Sat, 19 Mar 2011 18:32:08 +0100 Subject: [Cluster-devel] RFC: generic improvement to fence agents api In-Reply-To: <4D84E467.7050606@alteeve.com> References: <4D844E8F.1050608@redhat.com> <4D84E467.7050606@alteeve.com> Message-ID: <4D84E898.1090704@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On 3/19/2011 6:14 PM, Digimer wrote: > On 03/19/2011 02:34 AM, Fabio M. Di Nitto wrote: >> Hi all, >> >> while discussing on linux-cluster the support of the Tripp Lite switched >> PDU, it occurred to me that we can effectively improve (almost half) the >> time it takes to perform power fencing of certain devices, when for >> example, more than one PSU needs to be powered off to complete the action. >> >> Node X has 2 PSU. >> >> In our current state, the config would look like: >> >> >> >> >> >> >> ..... >> >> it means effectively spawning, most likely the same agent, twice. >> Increasing the time it takes to fence and maybe increasing the >> possibility to fail to fence if the second connection fails. >> >> My suggestion would be to allow to specify a list of ports instead. >> >> >> >> >> >> .... >> >> Either by using a new keyword "ports" or re-using "port" itself. If >> using "port", current configuration will continue to work as-is and the >> change effectively would not introduce any backward compatibility issue. >> >> This way the agent can: >> >> 1) connect once (reducing in most cases the ssh/telnet/whatever time) >> 2) issue the OFF command as fast as possible (almost in parallel) >> 3) then wait for the results. >> >> By adopting a list, the configuration would look cleaner too IMHO. >> >> A quick glance, the change should not affect fenced (David can you >> confirm please?), and most agents could handle it via the fencing python >> lib (Marek?). >> >> Does it sound reasonable? >> >> Cheers >> Fabio > > I like this idea, but would like to suggest: > > * Keep 'port' for a single port, as it is, and add 'ports' for multiple > port definitions. > * When using ports, I'd recommend comma-separated values and > dash-separated ranges (ie: ports="1,2", ports="1-4", ports="1,3-5") and > combinations there-of. This strikes me as more "standard" and possibly > less prone to typos. > The only thing I have against "," or "-" is that they might be easily part of a port name already. Range doesn?t make sense to me and it?s complex to interpret/implement. How many machines have you seen around with so many PSU?s anyway that need a range to avoid headache? (leaving aside E10K or s390 ;)). Fabio