升级Zabbix proxy到3.0.2后无法启动报错
一 问题描述
将一台zabbix proxy由2.4.5升级到3.0.2后启动了就直接崩溃了。
错误信息如下：
2367:20160508:153246.830 One child process died (PID:42385,exitcode/signal:11). Exiting ...
42367:20160508:153248.904 Zabbix Proxy stopped. Zabbix 3.0.2 (revision 59540).
将日志级别调高点，设置DebugLevel=4，查看报错
42629:20160508:153529.004 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42628:20160508:153529.004 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42634:20160508:153529.004 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42651:20160508:153529.004 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42659:20160508:153529.004 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42661:20160508:153529.005 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42655:20160508:153529.005 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42663:20160508:153529.005 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42664:20160508:153529.005 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42666:20160508:153529.005 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42665:20160508:153529.006 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42667:20160508:153529.006 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42630:20160508:153529.006 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42668:20160508:153529.006 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42671:20160508:153529.006 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42670:20160508:153529.007 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42647:20160508:153529.007 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42674:20160508:153529.007 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42680:20160508:153529.007 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ... 42679:20160508:153529.008 Got signal [signal:15(SIGTERM),sender_pid:42623,sender_uid:498,reason:0]. Exiting ...
9102:20160508:170455.283 End of zbx_strpool_destroy() 9102:20160508:170455.283 End of free_configuration_cache() 9102:20160508:170455.283 In free_ipmi_handler() 9102:20160508:170455.283 End of free_ipmi_handler() 9102:20160508:170455.284 In free_selfmon_collector() collector:0x7fa793e23000 9102:20160508:170455.284 End of free_selfmon_collector() 9102:20160508:170455.284 In unload_modules() 9102:20160508:170455.284 End of unload_modules() 9102:20160508:170455.284 Zabbix Proxy stopped. Zabbix 3.0.2 (revision 59540). zabbix_proxy [9152]: [file:'selfmon.c',line:375] lock failed: [22] Invalid argument
总共有4台proxy，每台proxy的操作系统版本都是CentOS6。就单独这一台zabbix proxy启动有问题，刚启动就有进程死掉。
二 问题解决
查看这台proxy服务器的内核版本是3.9.8-1.el6.elrepo.x86_64，而其他几台proxy的内核版本是2.6.32-358.el6.x86_64 刚开始也没有朝着内核版本的问题方向思考。以为还是proxy的版本或者系统参数设置有问题。
1.排查Linux下的信号量
查看Zabbix的官方BUG追踪平台Invalid argument可能是信号量达到了限制
可以尝试增大信号量的值
echo 256 40000 32 32000 > /proc/sys/kernel/sem
这个四个参数分别是
SEMMSL 每个信号量集的含有的信号量的最大值
SEMMNS 系统层面的信号量数量最大限制
SEMOPM semop(2)调用可以指定的最大操作数量
SEMMNI 系统层面的信号数量最小限制
通过echo方式更改重启后会失效，可以更改/etc/sysctl.conf
kernel.sem = 250 32000 100 10000
然后执行sysctl -p
更改参数后proxy启动仍然会崩溃
2.排查内核版本原因
Updating to latest kernel (3.10.0-327.10.1.el7.x86_64) + reboot solved it for me 
The error reported originally may be something else than what affected me.
查看帖子怀疑是内核版本造成的，这台proxy以前有人升级过内核，更改linux启动项设置默认启动内核为2.6.32.重启后问题得到解决，proxy不再崩溃。但是之前proxy 2.4.5在3.9.8的内核上可以正常运行。
遇到这个BUG的人挺多的，有好几个帖子都是反馈这个问题。
三 补充知识
这个BUG涉及到Linux下的信号量相关的知识。信号量是为了解决在多进程编程下资源共享的问题。著名的用信号量来解决的就是哲学家就餐问题。
Linux下使用ipcs命令来查看共享内存，信号量和消息队列
ipcs 默认是-a参数，显示所有信息
# ipcs ------ Shared Memory Segments -------- key shmid owner perms bytes nattch status 0x6c6c6536 0 root 600 4096 0 0x68031618 1835009 zabbix 600 8388583 0 0x6c030ad7 11632648 zabbixagen 600 365056 13 0x68031672 2392073 zabbix 600 8388583 0 0x78031672 2424842 zabbix 600 16777216 0 0x74031672 2457611 zabbix 600 4194304 0 0x67031672 2490380 zabbix 600 1336934400 0 0x73031672 2523149 zabbix 600 235929600 0 ------ Semaphore Arrays -------- key semid owner perms nsems 0x00000000 0 root 600 1 0x00000000 32769 root 600 1 0x00000000 4325378 apache 600 1 0x7a031618 622595 zabbix 600 12 0x00000000 4358148 apache 600 1 0x7a030ad7 4292613 zabbixagen 600 13 0x7a031672 851974 zabbix 600 12 0x7a031638 1015815 zabbix 600 12 0x7a031620 1441800 zabbix 600 12 ------ Message Queues -------- key msqid owner perms used-bytes messages
ipcs -m 单独显示共享内存片段信息
ipcs -s 单独显示信号量
ipcs -q 单独显示消息队列
# ipcs -u ------ Shared Memory Status -------- segments allocated 71 pages allocated 1795473 pages resident 68130 pages swapped 57636 Swap performance: 0 attempts 0 successes ------ Semaphore Status -------- used arrays = 16 allocated semaphores = 152 ------ Messages: Status -------- allocated queues = 0 used headers = 0 used space = 0 bytes
参考资料：
https://support.zabbix.com/browse/ZBX-10657
http://www.cnblogs.com/forilen/p/4316358.html
https://support.zabbix.com/browse/ZBX-3974
http://blog.zabbix.com/mysterious-zabbix-problems-how-we-debug-them/1023/
https://en.wikipedia.org/wiki/Semaphore_(programming)
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