java根据负载自动抓取jstack dump详情
java应用CPU有波动,事后怎么分析?
目前我采用的方案是根据CPU负载自动执行jstack,并将文件上传到OSS。
环境:阿里云 + k8s + SpringCloud + prometheus + oss
容器镜像安装python 2.7
涉及以下几个文件:
oss相关的文件包括:oss客户端和配置文件;
逻辑主要在脚本:mon_cpu_jstack.py
- 两个参数:CPU阈值,profile环境(prod \ test等)
- 每10s 执行一次脚本(跳过起初的3分钟,因为应用启动时CPU负载高是正常的);
- 通过top获取CPU,超过阈值则执行jstack;
- 如果CPU消耗最大进程是GC,拉取jmap信息;
- 每小时最大执行3次jstack(太多无意义);
- 生成文件后通过oss客户端上传OSS;
# more mon_cpu_jstack.py
# -*- coding: utf-8 -*-
import time
import commands as cm
import os,sys
from signal import signal, SIGPIPE, SIG_DFL
signal(SIGPIPE,SIG_DFL)
if len(sys.argv) != 3:
print 'Usage: ' + sys.argv[0] + ' [cpu_threshold] [profiles]'
sys.exit(1)
cpu_th = float(sys.argv[1])
profiles = sys.argv[2]
base_dir = '/opt/perf'
time_list = []
def oss_upload(app_name,logfile):
comm_upload = base_dir + '/ossutil64 -c ' + base_dir + '/ossutilconfig cp ' + logfile + ' oss://k8s-jstack-log/' + profiles + '/' + app_name + '/'
comm_delete = 'rm -f ' + logfile
os.system(comm_upload)
time.sleep(1)
os.system(comm_delete)
def mon_and_catch():
global time_list
# up to 3 times hourly
if len(time_list) == 3:
if time.time() - time_list[-1] <= 3600:
return
host_name = cm.getoutput('hostname')
java_pid = cm.getoutput('top -b -n1 | grep java|awk \'{printf $1}\'')
if (java_pid == ''):
print 'no java_pid'
return
cpu_pct_str = cm.getoutput('top -b -p ' + java_pid + ' -n1 | tail -1 |awk \'{printf $9}\'')
cpu_pct = float(cpu_pct_str)
time_str = time.strftime("%Y-%m-%d_%H-%M-%S", time.localtime())
log_name = base_dir + '/' + host_name + '_' + time_str + '_cpu_' + cpu_pct_str.split('.')[0] + '.log'
if(cpu_pct > cpu_th):
time_list.insert(0, time.time())
time_list = time_list[:3]
os.system('top -Hbp' + java_pid + ' -n1 >> ' + log_name)
os.system('echo >> ' + log_name)
os.system('jstack -l ' + java_pid + ' >> '+log_name)
# if cpu is used by gc, exec jmap
top_thread_id = cm.getoutput('cat ' + log_name + ' | grep java | head -1 | awk \'{print $1}\'')
top_thread_id_hex = "0x" + cm.getoutput('printf \'%x\n\' ' + top_thread_id) + " "
top_thread_gc = cm.getoutput('cat ' + log_name + ' | grep "' + top_thread_id_hex + '" | grep "GC" | wc -l')
if top_thread_gc == '1':
os.system('echo >> ' + log_name)
os.system('jmap -histo:live ' + java_pid + ' | head -100 >> ' + log_name)
# get app_name from hostname
hostname_list = host_name.split('-')
app_name_list = hostname_list[:len(hostname_list)-2]
app_name='-'.join(app_name_list)
if app_name[-1] in ['1','2']:
app_name = app_name[:len(app_name)-1]
oss_upload(app_name, log_name)
if __name__ == '__main__':
i = 0
while (True):
# skip at startup
if i > 18:
mon_and_catch()
time.sleep(10)
i = i + 1
poststart.sh调用上述Python脚本(profile直接从环境变量中获取)
# more poststart.sh
cpu_th=$1
nohup python -u /opt/perf/mon_cpu_jstack.py ${cpu_th} ${spring_profiles_active} > /opt/perf/poststart.log 2>&1 &
exit 0
通过postStart调用脚本自动执行:
最终生成的oss文件:
第一层目录:profiles
第二层目录:应用名称
第三层目录:具体jstack文件
文件名最后的数字是当时的CPU使用量,如166指1.66C
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