[linux-lvm] lvm commands hanging when run from inside a kubernetes pod
Abhishek Agarwal
mragarwal.developer at gmail.com
Tue May 31 18:50:32 UTC 2022
Hi Roger. Thanks for your reply. I have rerun the command with `strace -f`
as you suggested. Here is the pastebin link containing the detailed output
of the command: https://pastebin.com/raw/VRuBbHBc
Thanks & Regards
On Tue, 31 May 2022 at 11:22, Roger Heflin <rogerheflin at gmail.com> wrote:
> You need to rerun with an "strace -f". That way it will also strace the
> fork's one of which it appears to be waiting on.
>
> On Mon, May 30, 2022 at 1:52 AM Abhishek Agarwal <
> mragarwal.developer at gmail.com> wrote:
>
>> When a kubernetes pod is scheduled on the node having lvm2 libraries
>> already installed and trying to run lvm commands using those node binaries
>> from inside the pod container, the commands hang and are waiting on
>> something to complete. Although when ctrl+c is pressed the terminal session
>> resumes and checking the final code for the execution returns a "0" error
>> code and the commands operation is also carried out successfully.
>>
>>
>> Below is the command output and strace for the command:-
>>
>> strace of lvcreate on the pod container scheduled on the node where lvm2
>> binaries are present:
>> # strace /sbin/lvm-eg/lvcreate -n test-lv -L 1G shared-vg
>> execve("/sbin/lvm-eg/lvcreate", ["/sbin/lvm-eg/lvcreate", "-n",
>> "test-lv", "-L", "1G", "shared-vg"], 0x7ffe7d7a6c98 /* 37 vars */) = 0
>> brk(NULL) = 0x55d196f41000
>> arch_prctl(0x3001 /* ARCH_??? */, 0x7ffdd8247a80) = -1 EINVAL (Invalid
>> argument)
>> access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or
>> directory)
>> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
>> fstat(3, {st_mode=S_IFREG|0644, st_size=8679, ...}) = 0
>> mmap(NULL, 8679, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f0d37895000
>> close(3) = 0
>> openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) =
>> 3
>> read(3,
>> "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360A\2\0\0\0\0\0"..., 832)
>> = 832
>> pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"...,
>> 784, 64) = 784
>> pread64(3,
>> "\4\0\0\0\20\0\0\0\5\0\0\0GNU\0\2\0\0\300\4\0\0\0\3\0\0\0\0\0\0\0", 32,
>> 848) = 32
>> pread64(3,
>> "\4\0\0\0\24\0\0\0\3\0\0\0GNU\0\237\333t\347\262\27\320l\223\27*\202C\370T\177"...,
>> 68, 880) = 68
>> fstat(3, {st_mode=S_IFREG|0755, st_size=2029560, ...}) = 0
>> mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
>> = 0x7f0d37893000
>> pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"...,
>> 784, 64) = 784
>> pread64(3,
>> "\4\0\0\0\20\0\0\0\5\0\0\0GNU\0\2\0\0\300\4\0\0\0\3\0\0\0\0\0\0\0", 32,
>> 848) = 32
>> pread64(3,
>> "\4\0\0\0\24\0\0\0\3\0\0\0GNU\0\237\333t\347\262\27\320l\223\27*\202C\370T\177"...,
>> 68, 880) = 68
>> mmap(NULL, 2037344, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) =
>> 0x7f0d376a1000
>> mmap(0x7f0d376c3000, 1540096, PROT_READ|PROT_EXEC,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x22000) = 0x7f0d376c3000
>> mmap(0x7f0d3783b000, 319488, PROT_READ,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x19a000) = 0x7f0d3783b000
>> mmap(0x7f0d37889000, 24576, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f0d37889000
>> mmap(0x7f0d3788f000, 13920, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f0d3788f000
>> close(3) = 0
>> arch_prctl(ARCH_SET_FS, 0x7f0d37894580) = 0
>> mprotect(0x7f0d37889000, 16384, PROT_READ) = 0
>> mprotect(0x55d196662000, 8192, PROT_READ) = 0
>> mprotect(0x7f0d378c5000, 4096, PROT_READ) = 0
>> munmap(0x7f0d37895000, 8679) = 0
>> getuid() = 0
>> getgid() = 0
>> getpid() = 19163
>> rt_sigaction(SIGCHLD, {sa_handler=0x55d196657c30, sa_mask=~[RTMIN RT_1],
>> sa_flags=SA_RESTORER, sa_restorer=0x7f0d376e40c0}, NULL, 8) = 0
>> geteuid() = 0
>> brk(NULL) = 0x55d196f41000
>> brk(0x55d196f62000) = 0x55d196f62000
>> getppid() = 19160
>> stat("/", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
>> stat(".", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
>> openat(AT_FDCWD, "/sbin/lvm-eg/lvcreate", O_RDONLY) = 3
>> fcntl(3, F_DUPFD, 10) = 10
>> close(3) = 0
>> fcntl(10, F_SETFD, FD_CLOEXEC) = 0
>> geteuid() = 0
>> getegid() = 0
>> rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0},
>> 8) = 0
>> rt_sigaction(SIGINT, {sa_handler=0x55d196657c30, sa_mask=~[RTMIN RT_1],
>> sa_flags=SA_RESTORER, sa_restorer=0x7f0d376e40c0}, NULL, 8) = 0
>> rt_sigaction(SIGQUIT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0},
>> 8) = 0
>> rt_sigaction(SIGQUIT, {sa_handler=SIG_DFL, sa_mask=~[RTMIN RT_1],
>> sa_flags=SA_RESTORER, sa_restorer=0x7f0d376e40c0}, NULL, 8) = 0
>> rt_sigaction(SIGTERM, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0},
>> 8) = 0
>> rt_sigaction(SIGTERM, {sa_handler=SIG_DFL, sa_mask=~[RTMIN RT_1],
>> sa_flags=SA_RESTORER, sa_restorer=0x7f0d376e40c0}, NULL, 8) = 0
>> read(10, "#!/bin/sh\npath=$(/sbin/lvm-eg/ge"..., 8192) = 79
>> pipe([3, 4]) = 0
>> clone(child_stack=NULL,
>> flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
>> child_tidptr=0x7f0d37894850) = 19164
>> close(4) = 0
>> read(3, "/usr/sbin/lvcreate\n", 128) = 19
>> --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=19164,
>> si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
>> rt_sigreturn({mask=[]}) = 19
>> read(3, "", 128) = 0
>> close(3) = 0
>> wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 19164
>> stat("/usr/local/sbin/chroot", 0x7ffdd8247710) = -1 ENOENT (No such file
>> or directory)
>> stat("/usr/local/bin/chroot", 0x7ffdd8247710) = -1 ENOENT (No such file
>> or directory)
>> stat("/usr/sbin/chroot", {st_mode=S_IFREG|0755, st_size=43352, ...}) = 0
>> clone(child_stack=NULL,
>> flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
>> child_tidptr=0x7f0d37894850) = 19168
>> wait4(-1, ^Cstrace: Process 19163 detached
>> <detached ...>
>>
>> # ^C
>>
>> `lvs` output on the node after pressing ctrl+c on the pod
>> container's terminal:
>> ubuntu at ip-172-31-85-197:~$ sudo lvs
>> LV VG Attr LSize Pool Origin Data%
>> Meta% Move Log Cpy%Sync Convert
>> test-lv shared-vg -wi-a----- 1.00g
>>
>> If ctrl+c is not pressed and trying to see the above output on the node
>> also hangs until the pod operation is interrupted.
>> _______________________________________________
>> linux-lvm mailing list
>> linux-lvm at redhat.com
>> https://listman.redhat.com/mailman/listinfo/linux-lvm
>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm at redhat.com
> https://listman.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>
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