[pve-devel] [RFC cluster 5/6] node join: use new corosync link parameters

[Fabian Grünbichler]

On Tue, Jun 11, 2019 at 02:17:49PM +0200, Thomas Lamprecht wrote:
> On 5/29/19 10:50 AM, Fabian Grünbichler wrote:
> > I wonder whether we should support clusters without link0 as well? might
> > happen easily:
> > 
> > cluster only has link0 configured
> > network topology change, add new link1
> > deconfigure link0
> > 
> > cluster joining no longer possible without specifying a bogus link0
> > address and manually cleaning up corosync.conf afterwards?
> 
> man corosync says:
> 
> > linknumber
> >  This  specifies  the link number for the interface.  When using the knet
> >  protocol,  each  interface  should  specify  separate  link  numbers  to
> >  uniquely  identify to the membership protocol which interface to use for
> >  which link.  The linknumber must start at 0. For UDP the only  supported
> >  linknumber is 0.
> 
> While a live addition seems not to problematic, a full stop start of
> corosync shows:
> > Jun 11 14:10:44 dev6 corosync[564072]:   [TOTEM ] knet_link_set_ping_timers for nodeid 1, link 0 failed: Invalid argument (22)
> > Jun 11 14:10:44 dev6 corosync[564072]:   [TOTEM ] knet_link_set_pong_count for nodeid 1, link 0 failed: Invalid argument (22)
> 
> So, as the man page specifies it and corosync behaviour is a bit questionable,
> and at least not error free, I'm not really sure the "no special treatment for
> link 0" holds, could get worse in the future - as they specifically ..

that might be fixed by [1], but I am not sure whether link 0 is not
special cased in other ways - e.g., I noticed the following in
corosync-cfgtool's man page:

"The local link (which will only ever be enabled on link 0) shows as
enabled but not connected for internal reasons."

1: https://github.com/corosync/corosync/commit/01ce5a96ef9dea2d517d84abec7aecc6af99e7aa

> I do not get above errors when having a link 0 configured..
> 
> > 
> > in general, we probably want to remove any special handling of link0/1,
> > and just set fallback defaults on link0 if no other link is specified..
> >
> 
> 
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