Bug: After hard power off == virtual network link in bad state == virtual network dead

cynar — Wed, 12 Apr 2023 07:08:46 GMT

I suspect (now) that there is a bug in VMware Workstation 17.0.1 which corrupts the product's _internal_ state tracking associated with a virtual NIC's connected / disconnected state.

The net effect of this is that
* in the product's status bar, the virtual network is flagged as _connected_
* inside the virtual machine (guest) the virtual network link is flagged as DOWN

It would seem as if this erratic state can somehow be triggered by a hard power off of the virtual machine (VM -> Power -> Power Off), possibly also by a hard shutdown of the host (resulting in a rather unclean shutdown of VMware Workstation).

Adding or removing a virtual network adapter does not change any of that, which is totally surprising.

Obviously, the net effect of all this is that the guest system has no networking at all, and no amount of rebooting fixes that. That is ... not good.

The reason that I suspect that this is a bug in the VMware Workstation product is that
* it has happened to me twice now, both in hard shutdown scenarios (see above)
* the first time, I was unable to recover the network
* this (just now) second time, with a different guest, I played enough with command-line tools to get the network working - and it has been working ever since, after a reboot

... and the only one magic trick that I think that I applied is literally click "Disconnect" and then "Connect" on the virtual NIC status bar icon, to make the product "see" that I took down the link and brought it up again.

I did not make _any_ persistent changes whatsoever to the guest operating system - the only persistence therefore is coming from VMware Workstation.

This only affected the one _running_ virtual machine which got hard-killed. The other VM running at the time continued to work fine, totally unaffected.

The command-line commands I used to "play" were

* `ip link set ens160 up` <-- I _had_ to do that in the broken state although the status bar suggested that the NIC was in fact connected
* `systemctl restart NetworkManager`
* `nmcli networking off`
* `nmcli networking on`
* `ip addr show`

Honestly, I do not believe that any of these commands did anything to contribute to getting the network situation sorted out. For lack of (and motivation to create) a full reproducer I do only strongly believe that simply toggling via the VMware Workstation UI the virtual NICs "Disconnect" / "Connect" state fixed that.

This post, in a way, is also a reminder for myself for troubleshooting, in case the VMware Workstation 17.0.1 virtual network for a guest dies (again).

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Bug: After hard power off == virtual network link in bad state == virtual network dead