Linux服务器OOM分析

 1 服务器告警短信

【监控告警】告警名称:商业业务数字科技中心机器发生oom,

状态:CRITICAL,

环境:xxx-阿里云-生产集群(生产)-生产,

告警内容: log.sys.oom(max,120s) > 0,当前值：1.00,

资源类型:服务器(n9e),

告警对象:10.231.82.xxx,

触发时间:2021-11-02 18:26:30,

查看详情:http://monitor.longhu.net/Linux/xxxxxxx

2 HDP集群组件钉钉告警

3 查看系统日志

/var/log/messages

Nov 2 18:26:37 c2-kl-snamenode kernel: titanagent invoked oom-killer: gfp_mask=0x201da, order=0, oom_score_adj=0
Nov 2 18:26:38 c2-kl-snamenode kernel: titanagent cpuset=/ mems_allowed=0
Nov 2 18:26:38 c2-kl-snamenode kernel: CPU: 5 PID: 13361 Comm: titanagent Kdump: loaded Tainted: G OE ------------ 3.10.0-957.12.2.el7.x86_64 #1
Nov 2 18:26:38 c2-kl-snamenode kernel: Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 8a46cfe 04/01/2014
Nov 2 18:26:38 c2-kl-snamenode kernel: Call Trace:
Nov 2 18:26:38 c2-kl-snamenode kernel: [] dump_stack+0x19/0x1b
Nov 2 18:26:38 c2-kl-snamenode kernel: [] dump_header+0x90/0x229
Nov 2 18:26:38 c2-kl-snamenode kernel: [] ? ktime_get_ts64+0x52/0xf0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] ? delayacct_end+0x8f/0xb0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] oom_kill_process+0x254/0x3d0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] ? oom_unkillable_task+0xcd/0x120
Nov 2 18:26:38 c2-kl-snamenode kernel: [] ? find_lock_task_mm+0x56/0xc0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] out_of_memory+0x4b6/0x4f0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] __alloc_pages_slowpath+0x5d6/0x724
Nov 2 18:26:38 c2-kl-snamenode kernel: [] __alloc_pages_nodemask+0x404/0x420
Nov 2 18:26:38 c2-kl-snamenode kernel: [] alloc_pages_current+0x98/0x110
Nov 2 18:26:38 c2-kl-snamenode kernel: [] __page_cache_alloc+0x97/0xb0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] filemap_fault+0x298/0x490
Nov 2 18:26:38 c2-kl-snamenode kernel: [] ext4_filemap_fault+0x36/0x50 [ext4]
Nov 2 18:26:38 c2-kl-snamenode kernel: [] __do_fault.isra.59+0x8a/0x100
Nov 2 18:26:38 c2-kl-snamenode kernel: [] ? __switch_to+0x151/0x580
Nov 2 18:26:38 c2-kl-snamenode kernel: [] ? update_curr+0x86/0x1e0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] do_read_fault.isra.61+0x4c/0x1b0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] ? update_cfs_shares+0xa9/0xf0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] handle_pte_fault+0x2f4/0xd10
Nov 2 18:26:38 c2-kl-snamenode kernel: [] ? finish_task_switch+0x57/0x1c0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] handle_mm_fault+0x39d/0x9b0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] __do_page_fault+0x203/0x4f0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] trace_do_page_fault+0x56/0x150
Nov 2 18:26:38 c2-kl-snamenode kernel: [] do_async_page_fault+0x22/0xf0
Nov 2 18:26:38 c2-kl-snamenode kernel: [] async_page_fault+0x28/0x30
Nov 2 18:26:38 c2-kl-snamenode kernel: Mem-Info:
Nov 2 18:26:38 c2-kl-snamenode kernel: active_anon:3870217 inactive_anon:96 isolated_anon:0#012 active_file:1922 inactive_file:4988 isolated_file:162#012 unevictable:0 dirty:32 writeback:3 unstable:0#012 slab_reclaimable:31911 slab_unreclaimable:16332#012 mapped:830 shmem:205 pagetables:13667 bounce:0#012 free:33838 free_pcp:0 free_cma:0
Nov 2 18:26:38 c2-kl-snamenode kernel: Node 0 DMA free:15908kB min:64kB low:80kB high:96kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15992kB managed:15908kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
Nov 2 18:26:38 c2-kl-snamenode kernel: lowmem_reserve[]: 0 2812 15866 15866
Nov 2 18:26:38 c2-kl-snamenode kernel: Node 0 DMA32 free:63996kB min:11968kB low:14960kB high:17952kB active_anon:2672360kB inactive_anon:64kB active_file:1412kB inactive_file:6028kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:3129192kB managed:2882968kB mlocked:0kB dirty:32kB writeback:0kB mapped:1120kB shmem:172kB slab_reclaimable:38752kB slab_unreclaimable:14104kB kernel_stack:8912kB pagetables:8508kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:73256 all_unreclaimable? yes
Nov 2 18:26:38 c2-kl-snamenode kernel: lowmem_reserve[]: 0 0 13053 13053
Nov 2 18:26:38 c2-kl-snamenode kernel: Node 0 Normal free:55448kB min:55548kB low:69432kB high:83320kB active_anon:12808508kB inactive_anon:320kB active_file:6276kB inactive_file:13924kB unevictable:0kB isolated(anon):0kB isolated(file):648kB present:13631488kB managed:13366892kB mlocked:0kB dirty:96kB writeback:12kB mapped:2200kB shmem:648kB slab_reclaimable:88892kB slab_unreclaimable:51224kB kernel_stack:28688kB pagetables:46160kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:37125 all_unreclaimable? yes
Nov 2 18:26:38 c2-kl-snamenode kernel: lowmem_reserve[]: 0 0 0 0
Nov 2 18:26:38 c2-kl-snamenode kernel: Node 0 DMA: 1*4kB (U) 0*8kB 0*16kB 1*32kB (U) 2*64kB (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15908kB
Nov 2 18:26:38 c2-kl-snamenode kernel: Node 0 DMA32: 1151*4kB (UEM) 1297*8kB (UEM) 1229*16kB (UEM) 416*32kB (UEM) 106*64kB (UEM) 11*128kB (UE) 31*256kB (UE) 3*512kB (U) 0*1024kB 0*2048kB 0*4096kB = 65620kB
Nov 2 18:26:38 c2-kl-snamenode kernel: Node 0 Normal: 3680*4kB (UEM) 2890*8kB (UE) 1103*16kB (UEM) 13*32kB (EM) 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 55904kB
Nov 2 18:26:38 c2-kl-snamenode kernel: Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB
Nov 2 18:26:38 c2-kl-snamenode kernel: Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
Nov 2 18:26:38 c2-kl-snamenode kernel: 7729 total pagecache pages
Nov 2 18:26:38 c2-kl-snamenode kernel: 0 pages in swap cache
Nov 2 18:26:38 c2-kl-snamenode kernel: Swap cache stats: add 0, delete 0, find 0/0
Nov 2 18:26:38 c2-kl-snamenode kernel: Free swap = 0kB
Nov 2 18:26:38 c2-kl-snamenode kernel: Total swap = 0kB
Nov 2 18:26:38 c2-kl-snamenode kernel: 4194168 pages RAM
Nov 2 18:26:38 c2-kl-snamenode kernel: 0 pages HighMem/MovableOnly
Nov 2 18:26:38 c2-kl-snamenode kernel: 127726 pages reserved
Nov 2 18:26:38 c2-kl-snamenode kernel: [ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 1790] 0 1790 64980 103 132 0 0 systemd-journal
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 1811] 0 1811 47590 100 28 0 0 lvmetad
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 1829] 0 1829 11129 154 24 0 -1000 systemd-udevd
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3413] 0 3413 13880 118 27 0 -1000 auditd
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3445] 999 3445 153085 1682 62 0 0 polkitd
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3446] 32 3446 17316 135 37 0 0 rpcbind
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3452] 0 3452 5415 101 15 0 0 irqbalance
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3464] 0 3464 6657 173 17 0 0 systemd-logind
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3467] 81 3467 14554 156 35 0 -900 dbus-daemon
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3503] 0 3503 48775 119 34 0 0 gssproxy
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3544] 0 3544 31579 180 19 0 0 crond
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3559] 0 3559 6476 53 17 0 0 atd
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3582] 0 3582 27523 32 10 0 0 agetty
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3583] 0 3583 27523 33 10 0 0 agetty
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3785] 0 3785 25710 524 49 0 0 dhclient
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3846] 0 3846 143483 2796 97 0 0 tuned
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3854] 0 3854 232412 56050 382 0 0 rsyslogd
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 3904] 0 3904 340102 19651 119 0 0 n9e-collector
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4177] 0 4177 5731 89 14 0 0 argusagent
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4179] 0 4179 308752 3450 60 0 0 /usr/local/clou
Nov 2 18:26:38 c2-kl-snamenode kernel: [12470] 0 12470 28216 256 58 0 -1000 sshd
Nov 2 18:26:38 c2-kl-snamenode kernel: [23550] 998 23550 29448 130 30 0 0 chronyd
Nov 2 18:26:38 c2-kl-snamenode kernel: [25161] 0 25161 56017 505 113 0 0 httpd
Nov 2 18:26:38 c2-kl-snamenode kernel: [17170] 0 17170 37325 897 29 0 0 python
Nov 2 18:26:38 c2-kl-snamenode kernel: [17174] 0 17174 717657 40285 223 0 0 python
Nov 2 18:26:38 c2-kl-snamenode kernel: [12170] 1016 12170 731784 66076 344 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [12326] 1009 12326 147520 2550 72 0 0 python2.7
Nov 2 18:26:38 c2-kl-snamenode kernel: [14099] 1007 14099 1354046 56626 295 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [14496] 1016 14496 714714 33040 173 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 310] 1020 310 47777 1440 44 0 0 python
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 311] 1020 311 1904045 34660 179 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [21603] 0 21603 109262 189 28 0 0 AliSecGuard
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 5807] 1018 5807 2897189 254199 1008 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [11866] 0 11866 2687 55 11 0 0 jsvc
Nov 2 18:26:38 c2-kl-snamenode kernel: [11880] 1018 11880 697340 38125 159 0 0 jsvc
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 2797] 1018 2797 769655 102332 361 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [22546] 1009 22546 28845 86 13 0 0 bash
Nov 2 18:26:38 c2-kl-snamenode kernel: [22560] 1009 22560 1020455 500837 1235 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [22616] 1009 22616 1652841 221421 684 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [20278] 1010 20278 1039497 287501 657 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 6637] 1010 6637 1055965 118005 318 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [14342] 0 14342 201779 1185 13 0 0 aliyun-service
Nov 2 18:26:38 c2-kl-snamenode kernel: [14445] 0 14445 4451 123 13 0 0 assist_daemon
Nov 2 18:26:38 c2-kl-snamenode kernel: [17671] 0 17671 10482 394 20 0 0 AliYunDunUpdate
Nov 2 18:26:38 c2-kl-snamenode kernel: [23521] 1004 23521 28845 85 14 0 0 bash
Nov 2 18:26:38 c2-kl-snamenode kernel: [23535] 1004 23535 1431755 103152 391 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 1182] 1020 1182 28845 85 13 0 0 bash
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 1196] 1020 1196 854319 146975 527 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [26591] 0 26591 127511 342 33 0 0 AliNet
Nov 2 18:26:38 c2-kl-snamenode kernel: [26746] 0 26746 578461 2993 79 0 0 AliHips
Nov 2 18:26:38 c2-kl-snamenode kernel: [27031] 1018 27031 754075 83566 375 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 744] 0 744 44485 12650 88 0 0 AliYunDun
Nov 2 18:26:38 c2-kl-snamenode kernel: [26067] 1016 26067 1593210 610784 1391 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [32663] 0 32663 144907 557 42 0 0 AliDetect
Nov 2 18:26:38 c2-kl-snamenode kernel: [24142] 1004 24142 28845 87 13 0 0 bash
Nov 2 18:26:38 c2-kl-snamenode kernel: [24156] 1004 24156 1926525 1023090 2199 0 0 java
Nov 2 18:26:38 c2-kl-snamenode kernel: [25057] 48 25057 56017 466 111 0 0 httpd
Nov 2 18:26:38 c2-kl-snamenode kernel: [25058] 48 25058 56017 466 111 0 0 httpd
Nov 2 18:26:38 c2-kl-snamenode kernel: [25059] 48 25059 56017 466 111 0 0 httpd
Nov 2 18:26:38 c2-kl-snamenode kernel: [25060] 48 25060 56017 466 111 0 0 httpd
Nov 2 18:26:38 c2-kl-snamenode kernel: [25061] 48 25061 56017 466 111 0 0 httpd
Nov 2 18:26:38 c2-kl-snamenode kernel: [13131] 0 13131 118125 13948 130 0 0 titanagent
Nov 2 18:26:38 c2-kl-snamenode kernel: [13133] 0 13133 21926 122 13 0 0 titan_monitor
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4393] 0 4393 57508 4449 67 0 0 python
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4564] 0 4564 3437 54 12 0 0 ambari-sudo.sh
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4565] 0 4565 28844 71 14 0 0 bash
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4569] 0 4569 22553 145 49 0 0 su
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4573] 0 4573 28811 53 14 0 0 bash
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4575] 0 4575 28844 88 13 0 0 bash
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4598] 0 4598 52172 2653 56 0 0 python
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4607] 1014 4607 29343 67 12 0 0 bash
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4657] 0 4657 45598 250 46 0 0 crond
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4658] 0 4658 45598 250 46 0 0 crond
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4674] 1014 4674 18754 186 40 0 0 curl
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4705] 0 4705 3437 54 12 0 0 ambari-sudo.sh
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4706] 0 4706 3437 54 12 0 0 ambari-sudo.sh
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4713] 0 4713 22048 135 49 0 0 su
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4714] 0 4714 22048 136 47 0 0 su
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4734] 0 4734 2365 23 8 0 0 sh
Nov 2 18:26:38 c2-kl-snamenode kernel: [ 4735] 0 4735 2365 22 9 0 0 sh
Nov 2 18:26:38 c2-kl-snamenode kernel: Out of memory: Kill process 24156 (java) score 252 or sacrifice child
Nov 2 18:26:38 c2-kl-snamenode kernel: Killed process 24156 (java) total-vm:7706100kB, anon-rss:4092360kB, file-rss:0kB, shmem-rss:0kB
Nov 2 18:26:39 c2-kl-snamenode systemd: Started Session 125873 of user root.
Nov 2 18:26:39 c2-kl-snamenode systemd: Started Session 125872 of user root.

 查看HDP组件TIMELINE_READER进程的启动时间

       从上面的日志和告警中就可以看出HDP集群TIMELINE_READER组件被系统 kill 了，只不过Ambari 上面配置自动重启，挂掉后会重新启动。

4 OOM基本概念

Linux有一个特性：OOM Killer，一个保护机制，用于避免在内存不足的时候不至于出现严重问题，把一些无关的进程优先杀掉，即在内存严重不足时，系统为了继续运转，内核会挑选一个进程，将其杀掉，以释放内存，缓解内存不足情况，不过这种保护是有限的，不能完全的保护进程的运行。

    在很多情况下，经常会看到还有剩余内存时，oom-killer依旧把进程杀死了，现象是在/var/log/messages日志文件中有如下信息：

    Out of Memory: Killed process [PID] [process name].

    该问题是low memory耗尽，因为内核使用low memory来跟踪所有的内存分配。

    当low memory耗尽，不管high memory剩多少，oom-killer都会杀死进程，以保持系统的正常运行。

    在32位CPU下寻址范围是有限的，Linux内核定义了下面三个区域：

### 从上面日志中可以看到
# DMA: 0x00000000 - 0x00999999 (0 - 16 MB) # LowMem: 0x01000000 - 0x037999999 (16 - 896 MB) - size: 880MB# HighMem: 0x038000000 - <硬件特定>

属于进程的数据，如 Stacks、Heaps 等。可以被进一步分解为

• 活动内存（active_anon）
• 非活动内存（inactive_anon）

[root@hdp101 ~]# ps -ef | grep 10412
root 10412 1 0 06:41 ? 00:02:58 /usr/java/jdk1.8.0_162/bin/java -server -XX:NewRatio=3 -XX:+UseConcMarkSweepGC -XX:-UseGCOverheadLimit -XX:CMSInitiatingOccupancyFraction=60 -Djava.io.tmpdir=/var/lib/smartsense/hst-server/tmp -Dlog.file.name=hst-server.log -Xms1024m -Xmx2048m -cp /etc/hst/conf:/usr/hdp/share/hst/hst-common/lib/* com.hortonworks.support.tools.server.SupportToolServer
root 12725 12592 0 20:25 pts/0 00:00:00 grep --color=auto 10412
[root@hdp101 ~]#
[root@hdp101 ~]#
[root@hdp101 ~]#
### 开启 OOM ， 每个进程都有OOM参数可以设置
[root@hdp101 ~]# ll /proc/10412/oom*
-rw-r--r-- 1 root root 0 Nov 6 20:26 /proc/10412/oom_adj
-r--r--r-- 1 root root 0 Nov 6 20:26 /proc/10412/oom_score
-rw-r--r-- 1 root root 0 Nov 6 20:26 /proc/10412/oom_score_adj
[root@hdp101 ~]#

鉴于服务器资源紧张，所以就不得不扩内存。