[Spacewalk-list] Replicate spacewalk core to another data center for HA

[Paul Robert Marino]

take a look at this

http://docs.redhat.com/docs/en-US/Red_Hat_Network_Satellite/5.2/html-single/Installation_Guide/index.html#s1-redundant-satellite

keeping this in mind it should be possible to do postgresql in hot
standby mode http://www.postgresql.org/docs/9.1/interactive/hot-standby.html

the big question i have here is are all write transactions done in
explicit transactions because that would work great for hot stand by
with pgpool 2 because you could also load balance the read only
queries.
if not all of the writes are in transaction blocks then it will need
to be configured to do a full fail over in which case synchronous
replication may be a better choice.

now this still doesn't handle the replication of /var/satellite but
that could easily be handled by external script with some sort of
trigger. the trick is figuring out the trigger or adding a hook for
one into spacewalk that gets triggered every time it writes to a file
under /var/satellite
possibly in the short term a script that recursively stats the
directory structure and looks for changes might work it would also
allow for use of targeted rsyncs which would be faster than doing the
whole structure every time.



On Fri, Jun 29, 2012 at 1:23 PM, Paul Robert Marino <prmarino1 at gmail.com> wrote:
> Well in that case I still would like to avoid slony if possible
> I would prefer using the native postgresql master slave replication with
> pgpool but I would need dig into the sql queries a bit to figure out how I
> would want to configure the load ballancing also I'm not sure I need to
> double check but I think there is a way in potstgresql 9 to do more specific
> targeting of the replication
>
> On Jun 29, 2012 11:52 AM, "Musayev, Ilya" <imusayev at webmd.net> wrote:
>>
>> Paul,
>>
>> I'm going to disappoint you a bit here, satellite-sync does not sync
>> clients/systems.
>>
>> Man page only mentions:
>> Channels
>> Rpms
>> Packages
>> Errata
>> Kickstart
>>
>>
>>
>> Hence I figured I may as well setup slony with rsync or extend the satsync
>> library to include systems - I'm under assumption it was left out on
>> purpose.
>>
>> Regards
>> ilya
>>
>> -----Original Message-----
>> From: spacewalk-list-bounces at redhat.com
>> [mailto:spacewalk-list-bounces at redhat.com] On Behalf Of Paul Robert Marino
>> Sent: Thursday, June 28, 2012 2:56 PM
>> To: spacewalk-list at redhat.com
>> Subject: Re: [Spacewalk-list] Replicate spacewalk core to another data
>> center for HA
>>
>> well I have a different plan which I'm going to test in the next week or
>> so
>>
>> As far as i know satellite-sync should work between instances of spacewalk
>> so if i combine that with a squid 3 revers proxy (possibly with an ssl bump
>> configured ) or an LVS based load balancer and finally add in a few bind 9
>> tricks to do location based responses. I think I should be able to do this
>> using stock tools without too much difficulty.
>>
>> Ill let you know how it goes
>>
>>
>>
>>
>> On Thu, Jun 28, 2012 at 12:07 PM, Musayev, Ilya <imusayev at webmd.net>
>> wrote:
>> > I'm looking for a way to replicate master spacewalk server from one
>> > IDC to another - asynchronously.
>> >
>> >
>> >
>> > My setup consists of RHEL5 and Spacewalk 1.7 with CNAME pointing to
>> > spacewalk.domain.com - which in turn points to host in IDC1.
>> >
>> >
>> >
>> > I was thinking of using "slony" to replicate postgres 8.4 and rsync
>> > the content of /vat/satellite/ to another server periodically. The
>> > standby spacewalk 1.7 instance in second IDC wont have its services
>> > running until I need to fail over.
>> >
>> >
>> >
>> > When I'm ready to fail over, I break the replication in "slony",
>> > change the cname in DNS and start the spacewalk services on standby
>> > host, stop spacewalk services on active host.
>> >
>> >
>> >
>> > Are there any other - less complex methods that you know off. I looked
>> > into spacewalk replication script, but it only covers channel
>> > replications and leaves the clients out.
>> >
>> >
>> >
>> > As always, any suggestion and help is appreciated,
>> >
>> >
>> >
>> > Thanks
>> >
>> > ilya
>> >
>> >
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