Coredump
業務進程宕機以後開發需要查看dump查找定位問題,所有服務器初始化環境時候統一定製coredump路徑;
1.Core文件簡介
Core文件其實就是內存的映像,當程序崩潰時,存儲內存的相應信息,主用用於對程序進行調試。當程序崩潰時便會產生core文件,其實準確的應該說是core dump 文件,默認生成位置與可執行程序位於同一目錄下,文件名爲core.***,其中***是某一數字。
2.開啓或關閉Core文件的生成
關閉或阻止core文件生成:
$ulimit -c 0
打開core文件生成:
$ulimit -c unlimited
檢查core文件的選項是否打開:
$ulimit -a
ulimit參數含義如下:
-a All current limits are reported
-c The maximum size of core files created
-d The maximum size of a process data segment
-e The maximum scheduling priority ("nice")
-f The maximum size of files written by the shell and its children
-i The maximum number of pending signals
-l The maximum size that may be locked into memory
-m The maximum resident set size (has no effect on Linux)
-n The maximum number of open file descriptors (most systems do not allow this value to be set)
-p The pipe size in 512-byte blocks (this may not be set)
-q The maximum number of bytes in POSIX message queues
-r The maximum real-time scheduling priority
-s The maximum stack size
-t The maximum amount of cpu time in seconds
-u The maximum number of processes available to a single user
-v The maximum amount of virtual memory available to the shell
-x The maximum number of file locks
#ulimit -a
core file size (blocks, -c) unlimited
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 127974
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 100000
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 655360
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited而我們需要修改的是open files (-n) 1024的值
於是命令就是limit -n 2048(隨各自需要設置)
以上配置只對當前會話起作用,下次重新登陸後,還是得重新配置。要想配置永久生效,得在/etc/profile或者/etc/security/limits.conf文件中進行配置。
首先以root權限登陸,然後打開/etc/security/limits.conf文件,進行配置:
#vim /etc/security/limits.conf
<domain> <type> <item> <value>
* soft core unlimited
或者在/etc/profile中作如下配置:
#vim /etc/profile
ulimit -S -c unlimited >/dev/null 2>&1
或者想配置只針對某一用戶有效,則修改此用戶的~/.bashrc或者~/.bash_profile文件:
limit -c unlimited
ulimit -c 0 是禁止產生core文件,而ulimit -c 1024則限制產生的core文件的大小不能超過1024kb
3.設置Core Dump的核心轉儲文件目錄和命名規則
/proc/sys/kernel/core_uses_pid可以控制產生的core文件的文件名中是否添加pid作爲擴展,如果添加則文件內容爲1,否則爲0
/proc/sys/kernel/core_pattern可以設置格式化的core文件保存位置或文件名,比如原來文件內容是core-%e
可以這樣修改:
echo "/data/common/coredump/core-%e-%p-%t" >/proc/sys/kernel/core_pattern
將會控制所產生的core文件會存放到/data/common/coredump目錄下,產生的文件名爲core-進程名-pid-時間戳
以下是參數列表:
%p - insert pid into filename 添加pid
%u - insert current uid into filename 添加當前uid
%g - insert current gid into filename 添加當前gid
%s - insert signal that caused the coredump into the filename 添加導致產生core的信號
%t - insert UNIX time that the coredump occurred into filename 添加core文件生成時的unix時間
%h - insert hostname where the coredump happened into filename 添加主機名
%e - insert coredumping executable name into filename 添加命令名
4.core文件的使用
在core文件所在目錄下鍵入:
gdb -c core (-c指定core文件)
它會啓動GNU的調試器,來調試core文件,並且會顯示生成此core文件的程序名,中止此程序的信號等等
如果你已經知道是由什麼程序生成此core文件的,比如MyServer崩潰了生成core.12345,那麼用此指令調試:
gdb -c core MyServer
源:https://www.cnblogs.com/xiaodoujiaohome/p/6222895.html
5.永久生效:
當前不重啓生效:
你可以用下列方式來完成
sysctl -w kernel.core_pattern=/data/common/coredump/core-%e-%p-%t
或
echo "/data/common/coredump/core-%e-%p-%t" >/proc/sys/kernel/core_pattern
這些操作一旦計算機重啓,則會丟失,如果你想持久化這些操作,可以在 /etc/sysctl.conf文件中增加:
kernel.core_pattern=/data/common/coredump/core-%e-%p-%t
加好後,如果你想不重啓看看效果的話,則用下面的命令:
sysctl -p /etc/sysctl.conf
# sysctl -p /etc/sysctl.conf
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
net.ipv6.conf.lo.disable_ipv6 = 1
net.ipv4.conf.all.promote_secondaries = 1
net.ipv4.conf.default.promote_secondaries = 1
net.ipv6.neigh.default.gc_thresh3 = 4096
net.ipv4.neigh.default.gc_thresh3 = 4096
kernel.softlockup_panic = 1
kernel.sysrq = 1
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
vm.overcommit_memory = 1
kernel.numa_balancing = 0
kernel.shmmax = 68719476736
kernel.printk = 5
kernel.core_pattern = /data/common/coredump/core-%e-%p-%t