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=$(/sbin/lvm-eg/ge"..., 8192) = 79
pipe([3, 4]) = 0
clone(child_stack=NULL,
flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
child_tidptr=0x7f0d37894850) = 19164
close(4) = 0
read(3, "/usr/sbin/lvcreate\n", 128) = 19
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=19164, si_uid=0,
si_status=0, si_utime=0, si_stime=0} ---
rt_sigreturn({mask=[]}) = 19
read(3, "", 128) = 0
close(3) = 0
wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 19164
stat("/usr/local/sbin/chroot", 0x7ffdd8247710) = -1 ENOENT (No such file or
directory)
stat("/usr/local/bin/chroot", 0x7ffdd8247710) = -1 ENOENT (No such file or
directory)
stat("/usr/sbin/chroot", {st_mode=S_IFREG|0755, st_size=43352, ...}) = 0
clone(child_stack=NULL,
flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
child_tidptr=0x7f0d37894850) = 19168
wait4(-1, ^Cstrace: Process 19163 detached
<detached ...>
# ^C
`lvs` output on the node after pressing ctrl+c on the pod
container's terminal:
ubuntu@ip-172-31-85-197:~$ 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.
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