[ClusterLabs] Centreon HA Cluster - VIP issue

Tue Sep 5 16:13:56 EDT 2023

Hi Ken,

thank you a big time for the feedback; much appreciated.

I suppose we go with a new *Scenario 3*: Setup 2 Clusters across different
DCs connected by booth; so could you please clarify below points to me so i
can understand better and start working on the architecture:

1- in case of separate clusters connected by booth: should each cluster
have a quorum device for the Master/slave elections?
2- separate floating IPs at each cluster: please check the attached diagram
and let me know if this is exactly what you mean?
3- To fail over, you update the DNS to point to the appropriate IP: can you
suggest any guide to work on so we can have the DNS updated automatically?

Regards
Adil Bouazzaoui

Le mar. 5 sept. 2023 à 16:48, Ken Gaillot <kgaillot at redhat.com> a écrit :

> Hi,
>
> The scenario you describe is still a challenging one for HA.
>
> A single cluster requires low latency and reliable communication. A
> cluster within a single data center or spanning data centers on the
> same campus can be reliable (and appears to be what Centreon has in
> mind), but it sounds like you're looking for geographical redundancy.
>
> A single cluster isn't appropriate for that. Instead, separate clusters
> connected by booth would be preferable. Each cluster would have its own
> nodes and fencing. Booth tickets would control which cluster could run
> resources.
>
> Whatever design you use, it is pointless to put a quorum tie-breaker at
> one of the data centers. If that data center becomes unreachable, the
> other one can't recover resources. The tie-breaker (qdevice for a
> single cluster or a booth arbitrator for multiple clusters) can be very
> lightweight, so it can run in a public cloud for example, if a third
> site is not available.
>
> The IP issue is separate. For that, you will need separate floating IPs
> at each cluster, on that cluster's network. To fail over, you update
> the DNS to point to the appropriate IP. That is a tricky problem
> without a universal automated solution. Some people update the DNS
> manually after being alerted of a failover. You could write a custom
> resource agent to update the DNS automatically. Either way you'll need
> low TTLs on the relevant records.
>
> On Sun, 2023-09-03 at 11:59 +0000, Adil BOUAZZAOUI wrote:
> > Hello,
> >
> > My name is Adil, I’m working for Tman company, we are testing the
> > Centreon HA cluster to monitor our infrastructure for 13 companies,
> > for now we are using the 100 IT license to test the platform, once
> > everything is working fine then we can purchase a license suitable
> > for our case.
> >
> > We're stuck at scenario 2: setting up Centreon HA Cluster with Master
> > & Slave on a different datacenters.
> > For scenario 1: setting up the Cluster with Master & Slave and VIP
> > address on the same network (VLAN) it is working fine.
> >
> > Scenario 1: Cluster on Same network (same DC) ==> works fine
> > Master in DC 1 VLAN 1: 172.30.9.230 /24
> > Slave in DC 1 VLAN 1: 172.30.9.231 /24
> > VIP in DC 1 VLAN 1: 172.30.9.240/24
> > Quorum in DC 1 LAN: 192.168.253.230/24
> > Poller in DC 1 LAN: 192.168.253.231/24
> >
> > Scenario 2: Cluster on different networks (2 separate DCs connected
> > with VPN) ==> still not working
> > Master in DC 1 VLAN 1: 172.30.9.230 /24
> > Slave in DC 2 VLAN 2: 172.30.10.230 /24
> > VIP: example 102.84.30.XXX. We used a public static IP from our
> > internet service provider, we thought that using a IP from a site
> > network won't work, if the site goes down then the VIP won't be
> > reachable!
> > Quorum: 192.168.253.230/24
> > Poller: 192.168.253.231/24
> >
> >
> > Our goal is to have Master & Slave nodes on different sites, so when
> > Site A goes down, we keep monitoring with the slave.
> > The problem is that we don't know how to set up the VIP address? Nor
> > what kind of VIP address will work? or how can the VIP address work
> > in this scenario? or is there anything else that can replace the VIP
> > address to make things work.
> > Also, can we use a backup poller? so if the poller 1 on Site A goes
> > down, then the poller 2 on Site B can take the lead?
> >
> > we looked everywhere (The watch, youtube, Reddit, Github...), and we
> > still couldn't get a workaround!
> >
> > the guide we used to deploy the 2 Nodes Cluster:
> >
> https://docs.centreon.com/docs/installation/installation-of-centreon-ha/overview/
> >
> > attached the 2 DCs architecture example, and also most of the
> > required screenshots/config.
> >
> >
> > We appreciate your support.
> > Thank you in advance.
> >
> >
> >
> > Regards
> > Adil Bouazzaoui
> >
> >        Adil BOUAZZAOUI Ingénieur Infrastructures & Technologies
> >  GSM         : +212 703 165 758 E-mail  : adil.bouazzaoui at tmandis.ma
> >
> >
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> --
> Ken Gaillot <kgaillot at redhat.com>
>
>

-- 

*Adil Bouazzaoui*
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