Hello,
Am 8. Januar 2025 11:12:02 MEZ schrieb Iztok Gregori <iztok.greg...@elettra.eu>:
>Hi!
>
>On 07/01/25 15:15, DERUMIER, Alexandre wrote:
>> Personnaly, I'll recommand to disable HA temporary during the network
>> change (mv /etc/pve/ha/resources.cfg to a tmp directory, stop all
>> pve-ha-lrm , tehn stop all pve-ha-crm to stop the watchdog)
>>
>> Then, after the migration, check the corosync logs during 1 or 2 days , and
>> after that , if no retransmit occur, reenable HA.
>>
>
>Good advice. But with the pve-ha-* services down the "HA-VMs" cannot migrate
>from a node to the other, because the migration is handled by the HA (or at
>least that is how I remember to happen some time ago). So I've (temporary)
>removed all the resources (VMs) from HA, which has the effect to tell
>"pve-ha-lrm" to disable the watchdog( "watchdog closed (disabled)" ) and no
>reboot should occur.
>
>> It's really possible that it's a corosync bug (I remember to have had this
>> kind of error with pve 7.X)
>
>I'm leaning to a similar conclusion, but I'm still lacking in understanding of
>how corosync/watchdog is handled in Proxmox.
>
>For example I still don't know who is updating the watchdog-mux service? Is
>corosync (but no "watchdog_device" is set in corosync.conf and by manual "if
>unset, empty or "off", no watchdog is used.") or is pve-ha-lrm?
As far as i can say it's the pve-ha... service.
If you dont use HA in your cluster, the watchdog isnt used.
Thats how i understand this.
Hth
>
>I think that, after the migration, my best shot is to upgrade the cluster, but
>I have to understand if newer libcephfs client libraries support old Ceph
>clusters.
>
>> Also, for "big" clusters (20-30 nodes), I'm using sctp protocol now, instead
>> udp. for me , it's a lot more reliable when you have a network saturation on
>> 1 now.
>>
>> (I had the case of interne udp flood attack coming from outside on 1 on my
>> node, lagging the whole corosync cluster).²
>>
>>
>> corosync.conf
>>
>> totem {
>> cluster_name: ....
>> ....
>> interface {
>> knet_transport: sctp
>> linknumber: 0
>> }
>> ....
>>
>>
>> (This need a full restart of corosync everywhere, and HA need to be disable
>> before, because udp can't communite with sctp, so you'll have a loss of
>> quorum during the change)
>
>I've read about it, I think I'll follow your suggestion. In those bigger
>cluster have you tinker with corosync values as "token" or
>"token_retransmits_before_loss_const"?
>
>Thank you!
>
>Iztok
>
>
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