Kubernetes下的应用监控解决方案

所谓应用监控，更多的是基于java jvm的监控，因为公司运行的中间件大部分都是基于tomcat,Springboot,SpringCloud,当然也必须支持WebLogic.在Kubernetes现有方案中，监控那块主要是通过cAdvisor,Heapster的组件获取Pod消耗的memory,CPU和网络的信息，但如果需要更深入的了解Pod中运行的应用的信息就基本没有提供缺省的方案。

那么到底应用监控涉及什么的指标，我整理一下大致包括：

• JVM Heap
• JVM Non Heap Memory
• GC
• Thread montoring
• DataSource
• Transactions Per Seconds
• Throughput 等等等等。。。

我这篇是基于JMX+InfluxDB+Grafana的尝试。

• 1.整体架构

主要技术点在于：

• 在tomcat下打开jmx监控选项，暴露另一个端口35135
• 通过jmxtrans基于JSON文件获取需要的jmx数据，然后将数据传入InfluxDB
• 基于Grafana选择InfluxDB数据进行展现。

• 2.实施步骤
• 2.1 镜像准备

InfuxDB和Grafana都基于Pod方式部署，首先拉取镜像

docker pull docker.io/influxdb:1.4.
docker pull docker.io/grafana/grafana:4.6.

[root@k8s-master tomcatjmx]# cat grafana.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: grafana
spec:
  replicas:
  template:
    metadata:
      labels:
        app: "grafana"
    spec:
      containers:
      - name: grafana
        image: docker.io/grafana/grafana:4.6.
        ports:
        - containerPort:
---
apiVersion: v1
kind: Service
metadata:
  name: grafanasvc
  labels:
    app: grafana
spec:
  ports:
  - port:
    protocol: TCP
    targetPort:
    name: http
  type: NodePort
  selector:
    app: grafana

[root@k8s-master tomcatjmx]# cat influxdb.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: influxdb
spec:
  replicas:
  template:
    metadata:
      labels:
        app: "influxdb"
    spec:
      containers:
      - name: influxdb
        image: docker.io/influxdb:1.4.
        ports:
        - containerPort:
          name: influxdbport
        - containerPort:
          name: influxadmin
---
apiVersion: v1
kind: Service
metadata:
  name: influxdbsvc
  labels:
    app: influxdb
spec:
  ports:
  - port:
    protocol: TCP
    targetPort:
    name: http
  - port:
    protocol: TCP
    targetPort:
    name: admin
  type: NodePort
  selector:
    app: influxdb

• 2.2 应用镜像构建

整个结构如下：

 jmx的打开问题

首先需要修改catalina.sh,打开jmx选项

JAVA_OPTS="$JAVA_OPTS $JSSE_OPTS -Xms512m -Xmx1024m -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.port=35135"

jmx的获取问题

下载jmxtrans-all.jar包

jmxtrans运行命令如下：

java -Djmxtrans.log.dir='/usr/local/log' -jar /usr/local/jmxtrans--all.jar -j /usr/local/

其中-j指到需要获取指标的配置文件，比如tomcat.json文件。

[root@node1 caas]# cat tomcat.json
{
  "servers" : [ {
    "port" : "",
    "host" : "HOSTNAME",
    "queries" : [
      {
        "obj" : "java.lang:type=Memory",
        "attr" : [ "HeapMemoryUsage", "NonHeapMemoryUsage" ],
        "resultAlias":"jvmMemory",
        "outputWriters" : [ {
          "@class" : "com.googlecode.jmxtrans.model.output.InfluxDbWriterFactory",
          "url" : "http://influxdbsvc:8086/",
          "username" : "root",
          "password" : "root",
          "database" : "caasdb"
        }]
      },
      {
        "obj" : "java.lang:type=Threading",
        "attr" : [ "ThreadCount", "PeakThreadCount", "TotalStartedThreadCount", "DaemonThreadCount"],
        "resultAlias":"jvmThreading",
        "outputWriters" : [ {
          "@class" : "com.googlecode.jmxtrans.model.output.InfluxDbWriterFactory",
          "url" : "http://influxdbsvc:8086/",
          "username" : "root",
          "password" : "root",
          "database" : "caasdb"
        }]
      },
      {
        "obj" : "java.lang:type=Memory",
        "attr" : [ "HeapMemoryUsage"],
        "resultAlias":"HeapMemoryUsage",
        "outputWriters" : [ {
          "@class" : "com.googlecode.jmxtrans.model.output.InfluxDbWriterFactory",
          "url" : "http://influxdbsvc:8086/",
          "username" : "root",
          "password" : "root",
          "database" : "caasdb"
        }]
      },
      {
        "obj" : "Catalina:type=GlobalRequestProcessor,name=\"http-apr-8080\"",
        "attr" : [ "bytesSent" ],
        "resultAlias":"tomcatByteSent",
        "outputWriters" : [ {
          "@class" : "com.googlecode.jmxtrans.model.output.InfluxDbWriterFactory",
          "url" : "http://influxdbsvc:8086/",
          "username" : "root",
          "password" : "root",
          "database" : "caasdb"
        }]
      },
      {
        "obj" : "java.lang:name=CMS Old Gen,type=MemoryPool",
        "resultAlias": "cmsoldgen",
        "attr" : [ "Usage" ],
        "outputWriters" : [ {
          "@class" : "com.googlecode.jmxtrans.model.output.InfluxDbWriterFactory",
          "url" : "http://influxdbsvc:8086/",
          "username" : "root",
          "password" : "root",
          "database" : "caasdb"
        }]
      },
      {
        "obj" : "java.lang:type=GarbageCollector,name=*",
        "resultAlias": "gc",
        "attr" : [ "CollectionCount", "CollectionTime" ],
        "outputWriters" : [ {
          "@class" : "com.googlecode.jmxtrans.model.output.InfluxDbWriterFactory",
          "url" : "http://influxdbsvc:8086/",
          "username" : "root",
          "password" : "root",
          "database" : "caasdb"
        }]
      },
      {
        "obj" : "Catalina:type=Engine",
        "attr" : [ "backgroundProcessorDelay"],
        "resultAlias":"EngineDelay",
        "outputWriters" : [ {
          "@class" : "com.googlecode.jmxtrans.model.output.InfluxDbWriterFactory",
          "url" : "http://influxdbsvc:8086/",
          "username" : "root",
          "password" : "root",
          "database" : "caasdb"
        }]
      }
    ]
  }]
}

详解

"outputWriters" : [ {
          "@class" : "com.googlecode.jmxtrans.model.output.InfluxDbWriterFactory",
          "url" : "http://influxdbsvc:8086/",
          "username" : "root",
          "password" : "root",
          "database" : "caasdb"

这一段主要是访问influxdb的服务，同时创建caasdb数据库，用户名密码都是root

"servers" : [ {
    "port" : "",
    "host" : "HOSTNAME",

port主要是tomcat暴露出来的jmx端口

host是指tomcat位于的主机位置或者主机名称

在容器中运行多个进程问题

这样jmxtrans会启动另一个进程，也就是说在这个Pod中会同时启动俩个进程。所以我们要通过supervisor来启动。

supervisor配置

[root@node1 caas]# cat supervisord.conf
[supervisord]
nodaemon=true

[program:tomcat]
command=/usr/local/apache-tomcat-8.5./bin/catalina.sh run

[program:jmxtrans]
command=/usr/local/updatejson.sh

为什么不是直接java -jar而是一个叫updatejson.sh的脚本呢？

因为我们需要在这个脚本中将配置json文件的host字段替换成为Pod的主机名或者ip

[root@node1 caas]# cat updatejson.sh
#!/bin/bash

sed -i "s/HOSTNAME/${HOSTNAME}/" /usr/local/tomcat.json

java -Djmxtrans.log.dir='/usr/local/log' -jar /usr/local/jmxtrans--all.jar -j /usr/local/

Supervisord不显示tomcat日志问题

需要在supervisord.conf下加入loglevel和redirect_stderr选项

[root@node1 caas]# cat supervisord.conf
[supervisord]
nodaemon=true
loglevel=debug

[program:tomcat]
command=/usr/local/apache-tomcat-8.5./bin/catalina.sh run
stdout_logfile=/usr/local/apache-tomcat-8.5./logs/catalina.log
redirect_stderr=true

[program:jmxtrans]
command=/usr/local/updatejson.sh

基本OK了，整个Dockerfile如下

FROM linux7-jre:8u151

RUN mkdir -p "/usr/local"

COPY caas/*.*  /usr/local/

WORKDIR /usr/local

RUN yum install -y python-setuptools && \
    easy_install supervisor && \
    yum clean all && \
    tar -xvf apache-tomcat-8.5.6.tar.gz && \
    cp /usr/local/catalina.sh /usr/local/apache-tomcat-8.5.6/bin/catalina.sh && \
    mv /usr/local/supervisord.conf /etc/  && \
    chmod +x /usr/local/updatejson.sh 

ENV CATALINA_HOME /usr/local/apache-tomcat-8.5.6
ENV PATH $CATALINA_HOME/bin:$PATH
ENV JAVA_HOME /usr/java/default

WORKDIR $CATALINA_HOME

EXPOSE 8080 35135

CMD ["supervisord"]

启动以后看到pod运行

服务如下：

比较核心的需要kubectl logs influxdb-4115439627-rm9zb查看一下，确认有数据写入。

• 2.3 Grafana配置

datasource配置

新建一个Dashboard

点击Panel Title,然后选择编辑Edit

选择相应的指标，形成报告。

grafana配置详情参考下图

• 3.其他问题
• 为什么jmxtrans不放在host中进行对多个tomcat的收集

每个jmxtrans需要指定一个配置文件，在这个配置文件中指定监控的主机名，如果都共用一个的话，那所有的指标都会汇集到一起，如果要区分的话，就必须放到Pod中。

• grafana每次当pod发生变化时，图标无法自动更新，必须手工配置，这个比较难搞。

• Q. How do I use the second y axis, secondYAxis function does not work

  A. You can switch any series to the second y axis by clicking on the colored line to left of the series name in the legend below the graph. Alternately, use the "Display Styles" > "Series Specific overrides" to define an alias or regex + "Y-axis: 2" to move metrics to the right Axis

• 4.例子程序

消耗CPU的小程序

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@page import="java.util.*"%>

<%@ page contentType="text/html;charset=windows-1252"%>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=windows-1252"/>
    <title>Random</title>
  </head>
  <html>
    <body>
<h3>

      <%
               java.util.Random generator = new java.util.Random();
                generator.ints(, , ).sorted();
      %>
      random sort finished .........
      </h3>

    </body>
</html>

消耗内存的小程序

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@page import="java.util.*"%>

<%@ page contentType="text/html;charset=windows-1252"%>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=windows-1252"/>
    <title>Outofmemory</title>
  </head>
  <html>
    <body>
<h3>

      <%

            List<String> heapList = new ArrayList<String>();

         for (int i=;i<;i++) {
                heapList.add(new String("Shobhna"));
        }

      %>
      put  heapList success.........
      </h3>

    </body>
</html>