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我的 docker 容器基础镜像是 ubuntu，我使用完全权限选项运行它，这意味着在运行命令中我使用这些开关：

--cap-add=SYS_ADMIN --security-opt apparmor:unconfined

我想使用以下命令使用 blktrce：

sudo blktrace -d / -a issue -o - | blkparse -f "%p %T.%9t %D %S ^C %d\n" -i - >stream.out

但是，第一次使用此命令时出现此错误：

Debugfs is not mounted at /sys/kernel/debug

我搜索并找到了导致使用此命令的解决方案：

mount -t debugfs none /sys/kernel/debug

之后，当我blktrace再次使用该命令时，出现此错误：

BLKTRACESETUP(2) / failed: 25/Inappropriate ioctl for device
Thread 1 failed open /sys/kernel/debug/block/(null)/trace1: 2/No such file or directory
Thread 0 failed open /sys/kernel/debug/block/(null)/trace0: 2/No such file or directory
Thread 2 failed open /sys/kernel/debug/block/(null)/trace2: 2/No such file or directory
Thread 4 failed open /sys/kernel/debug/block/(null)/trace4: 2/No such file or directory
Thread 3 failed open /sys/kernel/debug/block/(null)/trace3: 2/No such file or directory
Thread 5 failed open /sys/kernel/debug/block/(null)/trace5: 2/No such file or directory
Thread 7 failed open /sys/kernel/debug/block/(null)/trace7: 2/No such file or directory
Thread 8 failed open /sys/kernel/debug/block/(null)/trace8: 2/No such file or directory
Thread 6 failed open /sys/kernel/debug/block/(null)/trace6: 2/No such file or directory
Thread 12 failed open /sys/kernel/debug/block/(null)/trace12: 2/No such file or directory
Thread 10 failed open /sys/kernel/debug/block/(null)/trace10: 2/No such file or directory
Thread 13 failed open /sys/kernel/debug/block/(null)/trace13: 2/No such file or directory
Thread 15 failed open /sys/kernel/debug/block/(null)/trace15: 2/No such file or directory
Thread 14 failed open /sys/kernel/debug/block/(null)/trace14: 2/No such file or directory
Thread 17 failed open /sys/kernel/debug/block/(null)/trace17: 2/No such file or directory
Thread 16 failed open /sys/kernel/debug/block/(null)/trace16: 2/No such file or directory
Thread 18 failed open /sys/kernel/debug/block/(null)/trace18: 2/No such file or directory
Thread 11 failed open /sys/kernel/debug/block/(null)/trace11: 2/No such file or directory
Thread 19 failed open /sys/kernel/debug/block/(null)/trace19: 2/No such file or directory
Thread 20 failed open /sys/kernel/debug/block/(null)/trace20: 2/No such file or directory
Thread 9 failed open /sys/kernel/debug/block/(null)/trace9: 2/No such file or directory
Thread 21 failed open /sys/kernel/debug/block/(null)/trace21: 2/No such file or directory
Thread 22 failed open /sys/kernel/debug/block/(null)/trace22: 2/No such file or directory
Thread 23 failed open /sys/kernel/debug/block/(null)/trace23: 2/No such file or directory
FAILED to start thread on CPU 0: 1/Operation not permitted
FAILED to start thread on CPU 1: 1/Operation not permitted
FAILED to start thread on CPU 2: 1/Operation not permitted
FAILED to start thread on CPU 3: 1/Operation not permitted
FAILED to start thread on CPU 4: 1/Operation not permitted
FAILED to start thread on CPU 5: 1/Operation not permitted
FAILED to start thread on CPU 6: 1/Operation not permitted
FAILED to start thread on CPU 7: 1/Operation not permitted
FAILED to start thread on CPU 8: 1/Operation not permitted
FAILED to start thread on CPU 9: 1/Operation not permitted
FAILED to start thread on CPU 10: 1/Operation not permitted
FAILED to start thread on CPU 11: 1/Operation not permitted
FAILED to start thread on CPU 12: 1/Operation not permitted
FAILED to start thread on CPU 13: 1/Operation not permitted
FAILED to start thread on CPU 14: 1/Operation not permitted
FAILED to start thread on CPU 15: 1/Operation not permitted
FAILED to start thread on CPU 16: 1/Operation not permitted
FAILED to start thread on CPU 17: 1/Operation not permitted
FAILED to start thread on CPU 18: 1/Operation not permitted
FAILED to start thread on CPU 19: 1/Operation not permitted
FAILED to start thread on CPU 20: 1/Operation not permitted
FAILED to start thread on CPU 21: 1/Operation not permitted
FAILED to start thread on CPU 22: 1/Operation not permitted
FAILED to start thread on CPU 23: 1/Operation not permitted

我该如何解决？

更新1：

在这个文件夹中有sda文件夹，在/sys/kernel/debug/block/这个文件夹中有这些文件：

trace0 trace1 trace2 etc.

更新2：

@abligh 感谢您的回答，但没有帮助。关于的strace输出ioctl是：

ioctl(3, BLKTRACESETUP, {act_mask=64, buf_size=524288, buf_nr=4, start_lba=0, end_lba=0, pid=0}, 0x7ffe8a4ceac0) = -1 ENOTTY (Inappropriate ioctl for device)
write(2, "BLKTRACESETUP(2) / failed: 25/Inappropriate ioctl for device\n", 61) = 61
ioctl(3, BLKTRACESTOP, 0x7f6fd19789d0) = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(3, BLKTRACESTOP, 0x7ffe8a4ce540) = -1 ENOTTY (Inappropriate ioctl for device)
ioctl(3, BLKTRACESTOP, 0x7f6fd19789e0) = -1 ENOTTY (Inappropriate ioctl for device)`
ioctl(3, BLKTRACETEARDOWN, 0x7f6fd19789e0) = -1 ENOTTY (Inappropriate ioctl for device)

要回答你关于我为什么blktrace在容器中运行的问题，我会说我使用容器作为集群，所以我需要每个节点的跟踪。

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1 回答 1

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我没有足够的信息来调试它，但您要求发布答案。

问题的根源似乎在这里：

BLKTRACESETUP(2) / failed: 25/Inappropriate ioctl for device

这表明ioctl设置块跟踪的调用失败。它在容器内失败，但根据评论在容器外工作。这表明问题出在容器设置或内核中的限制，它根本无法ioctl在容器中使用。

错误inappropriate ioctl for device是 errno 25，即ENOTTY. 我无法立即看到会返回什么，除非它根本找不到设备节点（鉴于您已经证明它在编译块跟踪代码的容器之外工作）。我不记得这是否在模块中，但值得先尝试在容器外进行块跟踪（然后在容器内检查它），只是为了检查这不是模块加载问题。

调试的第一步是使用strace工具（如上所述），这样您就可以确切地知道使用什么参数进行了哪个系统调用。EG运行：

sudo strace -f -s2048 -o/tmp/trace blktrace -d / -a issue -o - | blkparse -f "%p %T.%9t %D %S ^C %d\n" -i - >stream.out

然后再看/tmp/trace。strace将列出所有的系统调用。看看你是否可以从ioctl失败中确定。

其次，我会确保您尝试跟踪的块设备实际上出现在 和 中的正确/proc/位置/sys/。这里发生了一些错误：

Thread 0 failed open /sys/kernel/debug/block/(null)/trace0: 2/No such file or directory

请注意(null)调试行中的 ，它显然不应该存在 - 那应该是块设备的名称。这可能是失败的结果ioctl，或者可能表明/sys/层次结构中存在问题。

BLKTRACESETUP在这里在内核中处理。这最终调用doblktracesetup 这里。我无法立即看到为什么这在适当许可的容器中不起作用的任何原因，这让我怀疑您的/sys层次结构可能设置不正确。但输出strace会有所帮助。

此外，不可避免的评论：你为什么要在容器中这样做？为什么不在容器外运行呢？

编辑：看起来它可能是内核的东西。请参阅https://github.com/scaleway/kernel-tools/issues/107 - 这表明您 (a) 需要先对特定模块进行 modprobe，并且 (b) 可能需要特定内核。

于 2016-05-16T13:03:16.793 回答