<div dir="ltr"><div>Hi Ken,</div><div><br></div><div>thank you a big time for the feedback; much appreciated.</div><div><br></div><div>I suppose we go with a new <b>Scenario 3</b>: 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:
</div><div><br>1- in case of separate clusters connected by booth: should each cluster have a quorum device for the Master/slave elections?<br>2- separate floating IPs at each cluster: please check the attached diagram and let me know if this is exactly what you mean?<br>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?<br></div><div><br></div><div>Regards</div><div>Adil Bouazzaoui<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Le mar. 5 sept. 2023 à 16:48, Ken Gaillot <<a href="mailto:kgaillot@redhat.com">kgaillot@redhat.com</a>> a écrit :<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi,<br>
<br>
The scenario you describe is still a challenging one for HA.<br>
<br>
A single cluster requires low latency and reliable communication. A<br>
cluster within a single data center or spanning data centers on the<br>
same campus can be reliable (and appears to be what Centreon has in<br>
mind), but it sounds like you're looking for geographical redundancy.<br>
<br>
A single cluster isn't appropriate for that. Instead, separate clusters<br>
connected by booth would be preferable. Each cluster would have its own<br>
nodes and fencing. Booth tickets would control which cluster could run<br>
resources.<br>
<br>
Whatever design you use, it is pointless to put a quorum tie-breaker at<br>
one of the data centers. If that data center becomes unreachable, the<br>
other one can't recover resources. The tie-breaker (qdevice for a<br>
single cluster or a booth arbitrator for multiple clusters) can be very<br>
lightweight, so it can run in a public cloud for example, if a third<br>
site is not available.<br>
<br>
The IP issue is separate. For that, you will need separate floating IPs<br>
at each cluster, on that cluster's network. To fail over, you update<br>
the DNS to point to the appropriate IP. That is a tricky problem<br>
without a universal automated solution. Some people update the DNS<br>
manually after being alerted of a failover. You could write a custom<br>
resource agent to update the DNS automatically. Either way you'll need<br>
low TTLs on the relevant records.<br>
<br>
On Sun, 2023-09-03 at 11:59 +0000, Adil BOUAZZAOUI wrote:<br>
> Hello,<br>
> <br>
> My name is Adil, I’m working for Tman company, we are testing the<br>
> Centreon HA cluster to monitor our infrastructure for 13 companies,<br>
> for now we are using the 100 IT license to test the platform, once<br>
> everything is working fine then we can purchase a license suitable<br>
> for our case.<br>
> <br>
> We're stuck at scenario 2: setting up Centreon HA Cluster with Master<br>
> & Slave on a different datacenters.<br>
> For scenario 1: setting up the Cluster with Master & Slave and VIP<br>
> address on the same network (VLAN) it is working fine.<br>
> <br>
> Scenario 1: Cluster on Same network (same DC) ==> works fine<br>
> Master in DC 1 VLAN 1: 172.30.9.230 /24<br>
> Slave in DC 1 VLAN 1: 172.30.9.231 /24<br>
> VIP in DC 1 VLAN 1: <a href="http://172.30.9.240/24" rel="noreferrer" target="_blank">172.30.9.240/24</a><br>
> Quorum in DC 1 LAN: <a href="http://192.168.253.230/24" rel="noreferrer" target="_blank">192.168.253.230/24</a><br>
> Poller in DC 1 LAN: <a href="http://192.168.253.231/24" rel="noreferrer" target="_blank">192.168.253.231/24</a><br>
> <br>
> Scenario 2: Cluster on different networks (2 separate DCs connected<br>
> with VPN) ==> still not working<br>
> Master in DC 1 VLAN 1: 172.30.9.230 /24<br>
> Slave in DC 2 VLAN 2: 172.30.10.230 /24<br>
> VIP: example 102.84.30.XXX. We used a public static IP from our<br>
> internet service provider, we thought that using a IP from a site<br>
> network won't work, if the site goes down then the VIP won't be<br>
> reachable!<br>
> Quorum: <a href="http://192.168.253.230/24" rel="noreferrer" target="_blank">192.168.253.230/24</a><br>
> Poller: <a href="http://192.168.253.231/24" rel="noreferrer" target="_blank">192.168.253.231/24</a><br>
> <br>
> <br>
> Our goal is to have Master & Slave nodes on different sites, so when<br>
> Site A goes down, we keep monitoring with the slave.<br>
> The problem is that we don't know how to set up the VIP address? Nor<br>
> what kind of VIP address will work? or how can the VIP address work<br>
> in this scenario? or is there anything else that can replace the VIP<br>
> address to make things work.<br>
> Also, can we use a backup poller? so if the poller 1 on Site A goes<br>
> down, then the poller 2 on Site B can take the lead?<br>
> <br>
> we looked everywhere (The watch, youtube, Reddit, Github...), and we<br>
> still couldn't get a workaround!<br>
> <br>
> the guide we used to deploy the 2 Nodes Cluster: <br>
> <a href="https://docs.centreon.com/docs/installation/installation-of-centreon-ha/overview/" rel="noreferrer" target="_blank">https://docs.centreon.com/docs/installation/installation-of-centreon-ha/overview/</a><br>
> <br>
> attached the 2 DCs architecture example, and also most of the<br>
> required screenshots/config.<br>
> <br>
> <br>
> We appreciate your support.<br>
> Thank you in advance.<br>
> <br>
> <br>
> <br>
> Regards<br>
> Adil Bouazzaoui<br>
> <br>
> Adil BOUAZZAOUI Ingénieur Infrastructures & Technologies <br>
> GSM : +212 703 165 758 E-mail : <a href="mailto:adil.bouazzaoui@tmandis.ma" target="_blank">adil.bouazzaoui@tmandis.ma</a> <br>
> <br>
> <br>
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-- <br>
Ken Gaillot <<a href="mailto:kgaillot@redhat.com" target="_blank">kgaillot@redhat.com</a>><br>
<br>
</blockquote></div><br clear="all"><br><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><p style="font-size:12.8px"><b><span style="font-size:11pt;font-family:Calibri,sans-serif;color:black"><br></span></b></p><p style="font-size:12.8px"><b><span style="font-size:11pt;font-family:Calibri,sans-serif;color:black">Adil Bouazzaoui</span></b><span style="font-size:11pt;font-family:Calibri,sans-serif;color:black"><u></u><u></u></span></p></div></div>