6 Replies Latest reply on Dec 5, 2016 2:14 PM by java.food

How to start a host controller without its domain controller ?

sewatech Feb 5, 2016 7:42 AM

Hi,

I would like to know if there's a way to start a host controller if it can't reach it's domain controller.

I've seen a post on f_marchioni's blog explaining the static-discovery option. It could be my solution if I can easy synchonise the domain configuration (domain.xml) on the alternate domain controller.

So, is there a solution either to start a host-controller alone, without any domain-controller, or to synchronize a domain.xml accross two (or more) domain controllers ?

1. Re: How to start a host controller without its domain controller ?

jaysensharma Feb 5, 2016 7:49 AM (in response to sewatech)

domain.sh script has an option "--cached-dc " , I guess you are looking out for the same.

--cached-dc                        If this host is not the Domain
                                        Controller and cannot contact the
                                        Domain Controller at boot, boot using a
                                        locally cached copy of the domain
                                        configuration (see --backup)

--backup                            Keep a copy of the persistent domain
                                        configuration even if this host is not
                                        the Domain Controller

Regards
Jay SenSharma
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2. Re: How to start a host controller without its domain controller ?

sewatech Feb 5, 2016 8:08 AM (in response to jaysensharma)

Thanks Jay. It looks great. I'll test it further and give you more feedback later.
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3. Re: How to start a host controller without its domain controller ?

sewatech Feb 5, 2016 10:18 AM (in response to sewatech)

Here's my feedback after some tests on WildFly 10 and JBoss EAP 6.4.

Both arguments are exclusive. Use --cached-dc or --backup.

--backup is what I was looking for. As I have a copy of the domain.xml, I can use it in several ways.
--cached-dc is interesting but not exactly the solution. When I can't reach the DC, I can start the HC with this option. But it never tries to access to the DC and when the DC comes back, the HC remains isolated.

Is there a way to reconnect the HC to his main DC without restarting it ?
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4. Re: How to start a host controller without its domain controller ?

rhn-support-shsingh Feb 6, 2016 5:23 AM (in response to sewatech)

Are you looking for a DC failover ? If yes then :-
Options --backup and --cached-dc is not meant to be a DC automatic failover.
It is mainly meant to be able to boot HC even when DC is down.

To achieve DC failover configuration, you will need to backup DC's domain.xml via some automated service (e.g.: cron/rsync). When DC is down, bring up a newly installed DC (perhaps on another machine) with those copied domain.xml on the same IP or host name as the old one. That way, the slave HC will be reconnected to this newly brought up DC (as long as it's still the same IP/Hostname).
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5. Re: How to start a host controller without its domain controller ?

sewatech Feb 8, 2016 2:03 AM (in response to sewatech)

What I'm looking for is half way between startup and failover. I want to be able to start my HC without its main DC, and I want that my HC joins his main DC when it's back, without restarting the servers.

I think that my solution will be based on --backup argument on HC, and a local, secondary, DC on HC's host. My HC will have 2 DCs : the main one and a local one. The local one will be started only if the main one cannot be reached. It will use a copy of the backup configuration file. In order to switch from one DC to the other, I'll setup my HC with the static-discovery element.
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6. Re: How to start a host controller without its domain controller ?

java.food Dec 5, 2016 2:14 PM (in response to sewatech)

We want to do the same thing. Did you make this work? If so, can you please share your solution?
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