[Pacemaker] Online add a new node to cluster communicating by UDPU

[Dan Frincu]

On Tue, Feb 12, 2013 at 1:28 PM, Vladislav Bogdanov
<bubble at hoster-ok.com> wrote:
> 12.02.2013 14:11, Viacheslav Biriukov wrote:
>> Why don't you use it? Do you know any issues with this method?
>
> I just did not need it yet.
>
> And, one also needs to check that it is possible to cleanly delete nodes

Since the hostnames don't change, there shouldn't be a requirement to
delete the node. If the IP's are dynamically allocated, but stay the
same, and you don't hit bugs such as the dnsmasq one mentioned
earlier, then the DHCP IP renewal process won't take the interface
down (IIRC the client sends the server a request for a lease when half
of the time allocated for the current lease expires, and retries
several times prior to the lease expiring).

Dynamically adding nodes to the cluster shouldn't be a problem,
removing them should be done manually (that's how I see it) as you
can't differentiate between a node which has been down for a prolonged
period of time due to maintenance and one which is no longer part of
the cluster and should be removed automatically.

My 2 cents.

> from a CIB (both configuration and status sections) and they do not
> reappear there anymore (I recall related issues in the past when node
> reappears in CIB after membership change). Hopefully that was fixed, but
> I'm not sure. Also, as I do not play with cluster size changes right
> now, I don't know exactly how does pacemaker currently deals with
> dynamic change of number of clone instances.
>
> May be Andrew or David can comment on this?
>
> I must admit that it would be very nice to have dynamic membership
> support polished in 2.0 :)
>
> Vladislav
>
>
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-- 
Dan Frincu
CCNA, RHCE