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private vswitch - centos vms communication issues RRS feed

  • Question

  • I have 2 centos 8 VMS in hyper-v 10

    Both of them are using Private network switch.

    VM1 network details:

    eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 10.0.0.8  netmask 255.0.0.0  broadcast 10.255.255.255
            inet6 fe80::2210:d8c1:157b:f6f0  prefixlen 64  scopeid 0x20<link>
            ether 00:15:5d:6f:54:1b  txqueuelen 1000  (Ethernet)
            RX packets 133497108  bytes 27999225355 (26.0 GiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 127787552  bytes 100474013733 (93.5 GiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

    VM2 network details:

    eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 10.0.0.6  netmask 255.0.0.0  broadcast 10.255.255.255
            inet6 fe80::b51f:b87b:d7c7:3b8  prefixlen 64  scopeid 0x20<link>
            ether 00:15:5d:6f:54:1c  txqueuelen 1000  (Ethernet)
            RX packets 150934101  bytes 102001685767 (94.9 GiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 133496885  bytes 27999209773 (26.0 GiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

    From time to time, they can't communicate with each other.

    Executing from VM2 telneting to mysql on VM1 "telnet 10.0.0.8 3306" to test the connection, sometimes succedes and other time fails.

    Not sure how to debug this kind of problem.

    Any advice please?

    Tuesday, June 9, 2020 3:46 PM

All replies

  • have you confirmed/checked that you are loosing connectivity between the VMs entirely, or only for mysql?

    Here are a few suggestions:

    1. install the latest LIS drivers from RPM - I think it's 4.3.5 now.

    2. check the messages/dmesg logs for any messages from hv_netvsc. that is the network driver that will show you if there have been any events on the NICs that might reveal any issues.

    Wednesday, June 10, 2020 9:26 PM