昨天我的系统崩溃了，迫使我在运行 2 个虚拟机时对主机进行硬重置。第一台机器幸免于难，第二台机器已进入只读模式。登录虚拟机后，我看到以下消息。
Unable to setup logging. [Errno 30] Read-only file system: '/var/log/landscape/sysinfo.log' run-parts: /etc/update-mot.d/50-landscape-sysinfo exited with return code 1 /usr/lib/ubuntu-release-upgrader/release-upgrade-motd: 31: cannot create /var/lib/ubuntu-release-upgrader/release-upgrade-available: Read-only file system mktemp: failedd to create file via template '/var/lib/update-notifier/tmp.XXXXXXXXXX': Read-only file system run-parts: /etc/update-motd.d/95-hwe-eol exited with return code 1 /usr/lib/update-notifier/update-motd-fsck-at-reboot: 38: cannot create /var/lib/update-notifier/fsck-at-reboot: Read-only file system
我已经检查了来自主机的磁盘映像文件，在本例中是一个与 KVM 一起使用的 qcow2 文件。
sudo qemu-img check ubuntu204.qcow2
其结果是：
No errors were found on the image. 245760/245760 = 100.00% allocated, 0.00% fragmented, 0.00% compressed clusters Image end offset: 16108814336
我读到过这是一种保护文件系统的强制状态，如果我扫描磁盘并且一切正常，我就可以退出只读模式，我该如何在只读模式下使用 tty 上的以下分区表来执行此操作？
loop0 0
loop1 0
loop2 0
loop3 0
loop4 0
loop5 0
|-sda 0 15G 0 disk
|-sda1 0 1M 0 part
|-sda2 0 1G 0 part /boot
|-sda3 0 14G 0 part
|-ubuntu--vg-ubuntu--lv 0 14G 0 lvm /
|-sr0 1 1024M 0 rom
根据这些警告，我怀疑可能存在问题，unattended-upgrades我还对您建议的进一步检查的任何进一步意见感兴趣，以确保两台机器的完整性。
答案1
如何使用主机的 fsck 恢复 qcow2 磁盘映像文件
加载网络块设备模块：
sudo modprobe nbd max_part=8
关机：
sudo virsh destroy virtual-machine
连接磁盘映像：
sudo qemu-nbd --connect=/dev/nbd0 /var/lib/libvirt/images/virtual-machine.qcow2
检查磁盘：（磁盘现在已安装在主机上，您可以在 nautilus/explorer 中看到它）
sudo fsck /dev/nbd0p2
对于我来说，我安装了两个额外的驱动器，我刚刚扫描了 nbd-dm3 和 nbd0p2，这是一个预期输出的示例，我对所有输出都回答了“是”。
fsck from util-linux 2.25.2
e2fsck 1.42.12 (29-Aug-2014)
/dev/nbd0p1: recovering journal
/dev/nbd0p1 contains a file system with errors, check forced.
Pass 1: Checking inodes, blocks, and sizes
Inodes that were part of a corrupted orphan linked list found. Fix<y>? yes
Inode 274 was part of the orphaned inode list. FIXED.
Inode 132276 was part of the orphaned inode list. FIXED.
Deleted inode 142248 has zero dtime. Fix<y>? yes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
Block bitmap differences: -603674 -623174 +(689342--689343)
Fix<y>? yes
Free blocks count wrong for group #18 (15076, counted=15077).
Fix<y>? yes
Free blocks count wrong for group #19 (11674, counted=11675).
Fix<y>? yes
Free blocks count wrong (632938, counted=670871).
Fix<y>? yes
Inode bitmap differences: -274 -132276 -142248
Fix<y>? yes
Free inodes count wrong for group #0 (52, counted=53).
Fix<y>? yes
Free inodes count wrong for group #16 (99, counted=100).
Fix<y>? yes
Free inodes count wrong for group #17 (519, counted=520).
Fix<y>? yes
Free inodes count wrong (204392, counted=204599).
Fix<y>? yes
/dev/nbd0p1: ***** FILE SYSTEM WAS MODIFIED *****
/dev/nbd0p1: 101833/306432 files (0.2% non-contiguous), 553321/1224192 blocks
断开设备：
sudo qemu-nbd --disconnect /dev/nbd0
/dev/nbd0 已断开连接
启动机器并检查其是否正常工作：
virsh start virtual-machine
来源：https://gist.github.com/islander/8517685e3a9f7e0e1d458033710f0893