[libvirt-users] concurrent migration of several domains rarely fails

[Lentes, Bernd]

Hi,

i have a two-node cluster with several domains as resources. During testing i tried several times to migrate some domains concurrently.
Usually it suceeded, but rarely it failed. I found one clue in the log:

Dec 03 16:03:02 ha-idg-1 libvirtd[3252]: 2018-12-03 15:03:02.758+0000: 3252: error : virKeepAliveTimerInternal:143 : internal error: connection closed due to keepalive timeout

The domains are configured similar:
primitive vm_geneious VirtualDomain \
        params config="/mnt/san/share/config.xml" \
        params hypervisor="qemu:///system" \
        params migration_transport=ssh \
        op start interval=0 timeout=120 trace_ra=1 \
        op stop interval=0 timeout=130 trace_ra=1 \
        op monitor interval=30 timeout=25 trace_ra=1 \
        op migrate_from interval=0 timeout=300 trace_ra=1 \
        op migrate_to interval=0 timeout=300 trace_ra=1 \
        meta allow-migrate=true target-role=Started is-managed=true \
        utilization cpu=2 hv_memory=8000

What is the algorithm to discover the port used for live migration ?
I have the impression that "params migration_transport=ssh" is worthless, port 22 isn't involved for live migration.
My experience is that for the migration tcp ports > 49151 are used. But the exact procedure isn't clear for me.
Does live migration uses first tcp port 49152 and for each following domain one port higher ?
E.g. for the concurrent live migration of three domains 49152, 49153 and 49154.

Why does live migration for three domains usually succeed, although on both hosts just 49152 and 49153 is open ?
Is the migration not really concurrent, but sometimes sequential ?

Bernd






-- 

Bernd Lentes 
Systemadministration 
Institut für Entwicklungsgenetik 
Gebäude 35.34 - Raum 208 
HelmholtzZentrum münchen 
[ mailto:bernd.lentes at helmholtz-muenchen.de | bernd.lentes at helmholtz-muenchen.de ] 
phone: +49 89 3187 1241 
fax: +49 89 3187 2294 
[ http://www.helmholtz-muenchen.de/idg | http://www.helmholtz-muenchen.de/idg ] 

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