[wildfly-dev] WFLY-818 Slave host does not register to DC

[Brian Stansberry]

Agreed. The 3a) part needs some discussion; i.e. whether in this case 
the slave just "asks" to restart or whether it just takes the update and 
restarts servers. Currently if a slave loses contact with the master and 
then reestablishes contact, it automatically restarts servers if the 
domain config has changed. Basically we prioritize maintaining 
consistency among members of a server group over giving humans control. 
Plus, TBH, it's simpler.

If a server wasn't brought in sync automatically, I think it would have 
to be put into a state where it could no longer receive or execute any 
write ops. Reads are ok. Basically it's config is out of sync and it 
needs to be restarted.

I'm not sure if there's any reason not to immediately apply the new 
domain config to the HC itself, which is what we do now. Don't think 
there is. If we didn't, the slave couldn't fully register with the 
master, as all registered slaves need to be consistent with the master.

On 1/22/14, 5:58 AM, Emanuel Muckenhuber wrote:
>
> Hi,
>
> we don't have a solution yet. There are other open issues related to
> this, i.e. when using --cached-dc and --backup-dc at the same time. We
> do plan on allowing this case in future, which should behave similar to
> what you described. However it will probably only happen in the WidlFly
> 9 time frame.
>
> Emanuel
>
> On 01/22/2014 04:09 AM, Claudio Miranda wrote:
>> Hi, do you have any solution for this ?
>>
>> What do you think about this ?
>>
>> 1. HC starts with NO --cached-dc, it try to registers to DC, if it
>> doesn't register, HC fails to starts, as it is today.
>>
>> 2. HC starts with --cached-dc, it try to registers to DC,
>> a) if HC doesn't register to DC, HC uses the cached copy of
>> domain.xml. Try to registers to DC at interval times, if register is
>> successful see 3.a
>> b) if HC registers to DC, it works as is today copy domain.xml from DC
>> and replaces local backup.
>>
>> 3. HC starts with NO --cached-dc, HC register to DC, everything works
>> as is today. If HC disconnects from DC (unknown reason), HC keeps
>> trying to registers at interval times.
>> a) HC re-connects to DC, and detects domain.xml changed between DC and
>> HC. HC emits a warning and asks to restart the HC and their servers.
>>
>>
>> regards
>>
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-- 
Brian Stansberry
Senior Principal Software Engineer
JBoss by Red Hat