Re: [MooseFS-Users] [v4] Suggestions about HA

[Alexander A. <ba...@ya...>]

Hi Gandalf!

Could you describe your question more exactly?

I cant's see who prevents you to set up as many DNS servers as needed to 
achieve HA of DNS-service?

They can be isolated from all the rest of network (i.e. by firewall) to 
be accessible only from MFS cluster parts.

I.e. they also can colocate with Master servers on the same hardware and 
host some fake DNS zone which is used only by MFS cluster.


Also by the way I have to share my humble experience in making Moose 
Master high available.

I'v achieved HA using CARP+DEVD on FreeBSD using MooseFS community edition.

In short when CARP controlled IP moves from one host to another (CARP 
interface changes role from BACKUP to MASTER)

this event is catched by DEVD. DEVD executes my script which stops the 
Metalogger and starts Master.

They both use the same DATA_PATH. So Metalogger who has an actual 
metadata becomes a new Master.

An vice versa in a case of CARP event MASTER -> BACKUP script stops 
Master and starts Metalogger.

All chunk server and clients are configured to use CARP IP as Master's 
address.

So no DNS at all ;--)


Yes. I know this is not an ideal solution but it works ! :--)

wbr

Alexander


On 27.06.2018 11:20, Gandalf Corvotempesta wrote:
> In v4, HA depends on DNS. We have to add one A record for every master server.
> This is good only in some environments, where you have public access
> to a DNS server.
> As some users could deploy MooseFS as a SAN, with limited (if not at
> all) internet access, using a DNS server is not a simple task.
>
> Could I suggest something similiar like Consul? It provide a DNS
> interface to query and also expose a very simple API that could be
> used by master server to register itself (and automatically update the
> DNS record)
>
> Doing this doesn't require any internet access in SAN nor expose
> MooseFS to DNS attacks.
> Using a locally configured DNS server is still not trivial, you have
> to manually update all locale dns server instances (obviously, you
> wan't run with just 1 server) and so on.
>
> Any workaround ?
>
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