[ClusterLabs] Samba failover and Windows access

[Klaus Wenninger]

On Sat, Dec 10, 2022 at 6:39 PM Dave Withheld <davewithheld at hotmail.com>
wrote:

> On Thu, Dec 8, 2022 at 8:03 AM Dave Withheld <davewithheld at hotmail.com>
> wrote:
>
> In our production factory, we run a 2-node cluster on CentOS 8 with
> pacemaker, a virtual IP, and drbd for shared storage with samba (among
> other services) running as a resource on the active node.  Everything works
> great except when we fail over.  All resources are moved to the other node
> and start just fine, but Windows hosts that have connections to the samba
> shares all have to be rebooted before they can reconnect.  Clients that
> were not connected can connect.  We have samba configured for only SMB1
> protocol and all Windows clients are configured to allow it.
>
> >>Did you test if it is samba/smb-client related or windows IP-stack
> related - like ping the samba-host from the windows machines?
> >>Is the virtual IP using the physical MAC address of the interface - like
> windows missing the gratuitous ARP?
>
> Not just ping, but several other services (custom daemons, http, Mariadb,
> etc) all connect seamlessly.  It's only the samba connections that don't
> (obviously ping works, too).
>
> As for the MAC address, it is the same:  ip a shows two IPs for the
> interface but only one link/ether.
>
> This server (2-node cluster) is replacing an old system I built in 2008,
> which used heartbeat (no pacemaker or corosync) and had a much older
> version of samba.  It had no problem failing over:  mapped drives on the
> Windows clients worked just as well after a failover as they did before and
> UNCs worked seamlessly, as well.  In fact, the few times it failed over, no
> one even knew it until we saw a message in our emails sent by the servers
> when the resources moved.
>
> On the old system, ifconfig showed an eth0 interface, as well as an eth0:0
> interface on the active node which the virtual IP.  The docs called the
> virtual IP an "alias".  On the new server, ifconfig does not show the
> virtual IP at all and I have to use "ip a" to see the two addresses on one
> interface.  I tried using the command "ifconfig eno1:0 XXX.XXX.XXX.XXX up"
> to manually add an IP in a similar manner to the old server and the address
> I added did show up in ifconfig.  The point is, the virtual address is
> being added differently and I suspect the Windows clients treat it
> differently.
>
> I will be looking closely at the resource agents and see how they
> compare.  If any of this rings a bell, I would love to hear more from
> anyong with experience.  Thanks!
>

Sry didn't say I had a clue for you. Just thought this info was missing ;-)
My personal experience with samba is both minimal and dated.
What you could do - if nobody has a clue - would be capturing the traffic -
both cases if the old setup is still available.

Klaus

>
> >>Klaus
>
> Maybe this is a question for the samba folks, but thought I'd try here
> first since it's only a problem when the other node takes over the samba
> resource.  Anyone seen this problem and solved it?
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