My Ubuntu VM (16.04 Desktop) has become inaccessible and I have no idea why. The VM provides web services for me (and is actually the development side of the site) and is hosted in an Ubuntu 16.04 Server host. At the time of failure the website started giving all sorts of errors that normally point to the file system going read only, but when I tried to ssh into the VM the connection timed out. I checked that the VM was still running using vboxmanage. It was.
I restarted the VM, but still couldn't ssh into it. No web activity either.
I restarted the host machine and then restarted the VM. Still no ssh or http activity. In all the above tries, I checked the VirtualBox guest log files to see if anything looked off. There were a couple of errors that I'll come to shortly.
Next I copied the VM files onto a Windows 10 host and started it. I made no changes to the config files. Suddenly I can ssh into the VM. HTTP is also working. This suggests that the VM files are OK and the issue is with the host.
So I went back to the Ubuntu host to try and see what was going on. With the VM started I tried querying the guest for information. First I tried
vboxmanage debugvm aow_main osinfo
This returned an error (which was also seen is some of the log files:
VBoxManage: error: DBGFR3OSQueryNameAndVersion failed with VERR_DBGF_OS_NOT_DETCTED
VBoxManage: error: Details: code VBOX_E_VM_ERROR (0x80bb0003), component MachineDebuggerWrap, interface IMachineDebugger, callee nsISupports
VBoxManage: error: Context: "GetOSName(bstrName.asOutParam())" at line 366 of file VBoxManageDebugVM.cpp
I also tried:
VBoxManage guestproperty enumerate aow_main
Which returned:
Name: /VirtualBox/GuestInfo/OS/Product, value: Linux, timestamp: 1482248718375707200, flags:
Name: /VirtualBox/HostInfo/GUI/LanguageID, value: en_US, timestamp: 1482249727470339600, flags: RDONLYGUEST
Name: /VirtualBox/HostInfo/VBoxVerExt, value: 6.0.6, timestamp: 1557737810049398001, flags: TRANSIENT, RDONLYGUEST
Name: /VirtualBox/GuestAdd/Vbgl/Video/SavedMode, value: 1920x1080x32, timestamp: 1445589583275156701, flags:
Name: /VirtualBox/VMInfo/ResumeCounter, value: 0, timestamp: 1557737809981173000, flags: TRANSIENT, RDONLYGUEST
Name: /VirtualBox/GuestInfo/OS/Version, value: #26~14.04.1-Ubuntu SMP Fri Jul 24 21:18:00 UTC 2015, timestamp: 1482248718379707701, flags:
Name: /VirtualBox/GuestAdd/VersionExt, value: 4.3.36_Ubuntu, timestamp: 1482248718380207801, flags:
Name: /VirtualBox/GuestAdd/Revision, value: 105129, timestamp: 1482248718380207802, flags:
Name: /VirtualBox/HostGuest/SysprepExec, value: , timestamp: 1557737809981173000, flags: TRANSIENT, RDONLYGUEST
Name: /VirtualBox/GuestAdd/Vbgl/Video/0, value: 1920x1080x32,0x0,1, timestamp: 1445589583275156700, flags:
Name: /VirtualBox/HostGuest/SysprepArgs, value: , timestamp: 1557737809981173000, flags: TRANSIENT, RDONLYGUEST
Name: /VirtualBox/GuestAdd/Version, value: 4.3.36, timestamp: 1482248718380207800, flags:
Name: /VirtualBox/VMInfo/ResetCounter, value: 0, timestamp: 1557737809981173000, flags: TRANSIENT, RDONLYGUEST
Name: /VirtualBox/HostInfo/VBoxRev, value: 130049, timestamp: 1557737810049398002, flags: TRANSIENT, RDONLYGUEST
Name: /VirtualBox/HostInfo/VBoxVer, value: 6.0.6, timestamp: 1557737810049398000, flags: TRANSIENT, RDONLYGUEST
Name: /VirtualBox/GuestInfo/OS/Release, value: 3.19.0-25-generic, timestamp: 1482248718379707700, flags:
Name: /VirtualBox/GuestAdd/HostVerLastChecked, value: 5.0.6, timestamp: 1445591681341077300, flags:
I compared these states to that from the Windows 10 host. I noted the states here didn't include anything mention of the network adapter.
I've run out of ideas on how to debug this so any ideas are gratefully received. In case anyone is aware of any software conflicts the host machine is running Docker 18.06 and Virtual Box 6.0.6. Besides the OS, nothing else is running on the host.
I've not posted the log files because they're huge, but I can add them is needed.
Thanks.
