Errors on docker-machine ls with high count of machines (~450)

[feldsam]

Hello, I am getting following errors when issuing ls command, when high count of machines is provisioned (about 450).

Wrapper Docker Machine process exiting due to closed plugin server (unexpected EOF)
Error attempting call to get driver name: connection is shut down
Wrapper Docker Machine process exiting due to closed plugin server (unexpected EOF)
Error attempting call to get driver name: connection is shut down
Wrapper Docker Machine process exiting due to closed plugin server (unexpected EOF)
Error attempting call to get driver name: connection is shut down
Wrapper Docker Machine process exiting due to closed plugin server (unexpected EOF)
Error attempting call to get driver name: connection is shut down
NAME                                                                    ACTIVE   DRIVER       STATE     URL                       SWARM   DOCKER     ERRORS
add-supplier-code-ecomail                                                        opennebula   Timeout                                                
after-christmas                                                                  opennebula   Timeout                                                
aktuality                                                                        opennebula   Timeout                                                
ans-forgotten-groups                                                             opennebula   Timeout                                                
ans-sync-fix                                                                     opennebula   Timeout                                                
ao-nb-91-detail-bibloo                                                           opennebula   Timeout                                                
ao-nb-94-detail-name-price-colors-bibloo                                         opennebula   Timeout                                                
ao-nb-96-info-tiles-bibloo                                                       opennebula   Timeout                                                
ao-nb-98-video-bibloo                                                            opennebula   Timeout                                                
ao-nb-99-inspiration-bibloo                                                      opennebula   Timeout                                                
ao-nb-107-pagination-bibloo                                                      opennebula   Timeout                                                
ao-nb-289-wishlist-items-bibloo                                                  opennebula   Timeout                                                
ao-nb-402-shop-terms-bibloo                                                      opennebula   Timeout                                                
ao-nb-424-brand-product-list-bibloo                                              opennebula   Timeout                                                
ao-nb-459-product-list-bibloo                                                    opennebula   Timeout                                                
at-nb-90-bibloo                                                                  opennebula   Timeout                                                
at-nb-100-similar-products-bibloo                                                opennebula   Timeout                                                
at-nb-161-fix-params-bibloo                                             -        opennebula   Running   tcp://172.22.0.39:2376            v19.03.5   
at-nb-1023-bibloo                                                                opennebula   Timeout                                                
back-to-cart-revert                                                     -        opennebula   Running   tcp://172.22.0.24:2376            v19.03.5   
banners-shoes                                                                    opennebula   Timeout                                                
breadcrumb-update                                                                opennebula   Timeout                                                
brno-nestiha                                                                     opennebula   Timeout                                                
call-centrum-opening                                                             opennebula   Timeout                                                
cart-voucher-link                                                                opennebula   Timeout                                                
category-banners                                                                 opennebula   Timeout       

...

xmass-links                                                                      opennebula   Timeout                                                
xmass-winner                                                                     opennebula   Timeout                                                
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: unexpected EOF
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down
Error attempting call to get driver name: connection is shut down

Full log with --debug option here https://pastebin.pl/view/c222bb71

I don't know, if this is driver problem, or docker-machine problem.