[HBASE-1357] If one sets the hbase.master to 0.0.0.0 non local regionservers can't find the master

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.20.0, 0.20.1, 0.90.0
• Fix Version/s: 0.20.0
• Component/s: master, regionserver

Environment

All

• Hadoop Flags: Incompatible change, Reviewed

Release Note

hbase.master and hbase.master.hostname are now obsolete. hbase.cluster.distributed must be set at "true" to have a fully-distributed setup along with at least one configured ZK server which is not pointing at localhost.
Also, zoo.cfg must be in the classpath of every client.

• Assignee: Jean-Daniel Cryans
• Reporter: Alex Newman
• Created: 29/Apr/09 18:38
• Updated: 02/May/13 02:28
• Resolved: 02/Jun/09 17:54

Description

(2:11:20 PM) posix4e: so i want to run a back master on each node
(2:11:29 PM) posix4e: and i have my hbase.master set to 0.0.0.0
(2:14:59 PM) posix4e: each master only gets the local regionserver connecting
(2:15:08 PM) posix4e: as it must be using that variable to know what to connect to
(2:15:32 PM) nitay: the RS don't use hbase.master* anymore
(2:15:36 PM) nitay: ohhh i think i know th eproblem
(2:15:44 PM) nitay: so the RS use ZK to get the master address
(2:15:49 PM) nitay: but the masters are writing 0.0.0.0 to it
(2:15:58 PM) nitay: b/c they write whatever was in their conf
(2:16:20 PM) posix4e: yea
(2:16:42 PM) nitay: can u do a zookeeper dump of that node to verify my thinking?
(2:16:55 PM) posix4e: yea
(2:17:12 PM) nitay: it should be /hbase/master, unless u've changed the defaults
(2:17:59 PM) nitay: hmm s o ye this is a problem, we solved this in RS (allowing 0.0.0.0) by having master actually write RS's address to ZK when it gets contacted
(2:18:21 PM) nitay: so now we need to find a way to find out the actual address the master has bound to
(2:19:47 PM) posix4e: is their a way to do that?
(2:20:16 PM) nitay: i dont know, good question
(2:20:18 PM) posix4e: or does it require code changes i.e. regionserver checking zk
(2:20:27 PM) nitay: did u verify the master address?
(2:20:48 PM) posix4e: one sec
(2:21:03 PM) nitay: its almost like we want ZK to be able to tell us what address we're using to talk to it
(2:21:20 PM) nitay: that assumes u dont have different NICs to talk to ZK vs. HBase
(2:21:59 PM) nitay: posix4e, u can't really use the RS as far as i can tell b/c the RS knows nothing about the master until the master address appears in ZK
(2:22:25 PM) posix4e: 0:0:0:0:0:0:0:0:60000
(2:22:40 PM) nitay: yep that's the magic
(2:22:45 PM) nitay: k thx for verifying
(2:22:54 PM) nitay: u want to open up a JIRA?
(2:22:57 PM) posix4e: but if i could tell hbase.site to just use my hostname:port it would work ok
(2:22:58 PM) posix4e: yea
(2:23:09 PM) posix4e: can i quote this conversation?
(2:23:18 PM) nitay: yes please do
(2:23:45 PM) nitay: also, to fix this here and now for u, u'd essentially need to actually set hbase.master* to the ip/host u're using
(2:23:55 PM) nitay: and change it on each backup master to that guy's host/ip
(2:24:02 PM) nitay: i know, its a royal PITA
(2:24:59 PM) posix4e: yea
(2:25:03 PM) posix4e: no problem
(2:25:20 PM) nitay: but that should work till we find a better solution
(2:25:21 PM) posix4e: I am trying to think how a patch would work
(2:25:25 PM) posix4e: have a masters file?
(2:25:44 PM) nitay: yeah if u have any ideas please offer them
(2:25:46 PM) nitay: hmm interesting idea
(2:26:16 PM) nitay: and then do some local gethostbyname() type thing checking against masters file?
(2:26:26 PM) posix4e: yea
(2:28:23 PM) nitay: one thing to note is we've talked about eventually getting to a place where any RS can be master
(2:28:30 PM) nitay: but i like your idea
(2:28:37 PM) nitay: post it on the JIRA
(2:30:24 PM) nitay: i gotta run, thanks for the info posix4e - very helpful, its great to hear from people actually using this stuff
(2:32:56 PM) posix4e: yep

I also solved this by manually setting the hbase.master on each host to point to the local hostname, which sucks.

Issue Links

• is depended upon by: HBASE-1448 Add a node in ZK to tell all masters to shutdown.
• relates to: HBASE-1445 Add the ability to start a master from any machine