Hi; anyone have any thoughts about the "nodeinfo" file in modern heartbeat implementations?
Thanks! On Sun, 2012-09-16 at 17:52 -0400, Paul Smith wrote: > Hi all. > > I'm investigating an HA environment with a simple active/standby > configuration, just two nodes in a cluster with DRBD to provide a shared > partition (using standard Red Hat EL 6.2 packages, such as heartbeat > 2.1.2 and DRBD 8.4). > > These servers have multiple network interfaces: an internal private > network, over which DRBD, heartbeat, etc. are run, and also a separate > set of interfaces to provide "customer" access. The internal interfaces > have static IP addresses and unchanging hostnames. The external > interfaces do NOT: those interfaces are owned by the "customer", not by > the cluster. They might use DHCP to get IP addresses, and it's > important that the hostnames of the systems, when the customer runs > "uname" etc., be _their_ hostname and not the internal hostname of the > cluster. Users of the system must be free to change these values. > > I'm frustrated trying to get this to work robustly with heartbeat. > Explaining why the entire system must be brought down and restarted > merely to change the hostname is somewhat embarrassing as well. If I > could get heartbeat to use my internal, forever-constant names rather > than the results of "uname -n" my system would work so much more > smoothly and reliably, provide more uptime, and require a lot less > effort from me. Because this is a working environment, moving to > completely different technology like corosync is not really feasible. > > I found a thread from 2004 discussing the (then?) undocumented support > for the "/etc/ha.d/nodeinfo" file with heartbeat. This seems like the > obviously correct solution. I can't find any information on this > subject more current than that thread, though. Is this feature still > available/supported? Does it work with DRBD as well? Is it something I > can rely on going forward, insofar as heartbeat is still supported? > > > I must confess myself somewhat taken aback to read in that 2004 thread a > robust defense of the idea that "uname -n" would be the sole true > infallible identifier for a node. Hostnames may be relied upon to be > unique _at any given moment_, yes, but they are a very far ways from > being _constants_. They do change. While it's useful for status > output, logs, etc. to utilize hostnames as user-readable identifiers, a > design using an internal (constant) identifier for nodes in the cluster > seems to me to be far more reliable and straightforward to manage. I'm > no HA guru however; is there a technical reason why this is difficult or > sub-optimal? _______________________________________________________ Linux-HA-Dev: Linux-HA-Dev@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha-dev Home Page: http://linux-ha.org/
