Java 容器化的历史坑（史坑） - 资源限制篇
· ☕ 5 分钟
由来
时间回到 2017 年，老东家要上 Kubernetes 了，有幸参与和学习（主要是学习）。当时遇到的一了所有 Java 容器化者都遇到的坑：JDK8 不为容器化设计综合症。最简单的例子是Runtime.getRuntime().availableProcessors()返回了主机的 CPU 数，而非期望的容器自身的cpu share/quota，或说 k8s 的 cpu request/limit。
记一次 Istio 冲刺调优
· ☕ 5 分钟
为何要调优
如果说，引入一个技术需要兴趣和冲劲，那么，让这个技术上线需要的是坚持和执着。 Cloud Native 如是， Istio 如是。
在上线前的性能测试中，Istio 的使用提供了可观察性、运维上的便利，同时也引入了痛苦：增加了服务响应延时。如何让痛苦减到最低，成了当下之急。
你的 Istio Mesh 性能及格吗？
· ☕ 4 分钟
前言
话说，一年前项目响应时代的号召，引入了 Istio，从此如刘备得卧龙、凤雏，走上了 Service Mesh 的光辉大道。现到准备益州之战(上线)之时。上线前，还得评估一下性能变化。
Benchmark Tools
· ☕ 1 分钟
CPU Benchmark
The SysBench system benchmark suite has a simple CPU benchmark tool that calculates prime numbers. For example:
# sysbench --num-threads=8 --test=cpu --cpu-max-prime=100000 run
sysbench 0.4.12: multi-threaded system evaluation benchmark
Running the test with following options:
Number of threads: 8
Doing CPU performance benchmark
Threads started!
Done.
Maximum prime number checked in CPU test: 100000
Test execution summary:
total time: 30.4125s
total number of events: 10000
total time taken by event execution: 243.2310
per-request statistics:
min: 24.31ms
avg: 24.32ms
max: 32.44ms
approx. 95 percentile: 24.32ms
Threads fairness:
events (avg/stddev): 1250.0000/1.22
execution time (avg/stddev): 30.4039/0.01
This executed eight threads, with a maximum prime number of 100,000. The runtime was 30.4 s, which can be used for comparison with the results from other systems or configurations (assuming many things, such as that identical compiler options were used to build the software; see Chapter 12, Benchmarking).
tty
· ☕ 3 分钟
Jobs
-
SIGHUP- 默认动作：Terminate
- 可能动作：Terminate, Ignore, Function call
当检测到 hangup 时，UART 驱动会向整个 session 发送 SIGHUP 信号。 正常情况下，这会 kill 掉所有进程。某些程序，例如
nohup(1)和screen(1)，会从他们的 session（和 TTY）中 detach 出来， 因此这些程序的子进程无法关注到 hangup 事件。
Java 内置 Class Loader
· ☕ 3 分钟
内置 Classloader
Class loaders load classes and resources present on their respective classpath:
- System or application class loaders load classes from the application classpath
- Extension class loaders search on the Extension classpath (JRE/lib/ext)
- Bootstrap class loader looks on the Bootstrap classpath (JRE/lib/rt.jar)
We can customize the default class loading behavior as well. We can explicitly specify the class loader while loading a class dynamically.
However, we should note that if we load the same class from different types of class loaders, these will be seen as different resources by the JVM.
Opentelemetry Java Agent 浅度解构
· ☕ 2 分钟
Conf
Creating spans around methods with otel.instrumentation.methods.include
Format is "java -Dotel.instrumentation.methods.include=my.package.MyClass1[method1,method2];my.package.MyClass2[method3]"
Classloader
[arthas@16908]$ classloader -t
+-BootstrapClassLoader
+-io.opentelemetry.javaagent.bootstrap.AgentClassLoader@379619aa
+-sun.misc.Launcher$ExtClassLoader@41fa769c
+-com.taobao.arthas.agent.ArthasClassloader@3697b340
+-sun.misc.Launcher$AppClassLoader@18b4aac2
+-java.net.URLClassLoader@71b2d611
+-java.net.URLClassLoader@69cd1085
| +-WebAppClassLoader=266661735@fe4ef67
| | +-com.mycom.sig.foundation.servicediscovery.ExtendedClassLoader@573f7aae
| +-WebAppClassLoader=Server Initiated@1ccb04b3
| | +-com.mycom.sig.foundation.servicediscovery.ExtendedClassLoader@4b3b9a06
| | +-jnr.ffi.provider.jffi.AsmClassLoader@73cb9ccb
| | +-jnr.ffi.provider.jffi.AsmClassLoader@7c380e94
| | +-jnr.ffi.provider.jffi.AsmClassLoader@69ec5d1f
| +-WebAppClassLoader=OAuth Server@10d98940
| | +-com.mycom.ece.common.svcfinder.ExtendedClassLoader@3528968e
| | +-com.mycom.sig.foundation.servicediscovery.ExtendedClassLoader@2919aff3
| | +-jnr.ffi.provider.jffi.AsmClassLoader@1b0e6bac
| | +-jnr.ffi.provider.jffi.AsmClassLoader@2f12d8d1
| | +-jnr.ffi.provider.jffi.AsmClassLoader@73123f21
| +-WebAppClassLoader=1133988396@43974a2c
| +-com.mycom.sig.foundation.servicediscovery.ExtendedClassLoader@39d87c5f
+-java.net.URLClassLoader@1b4c457c
+-java.net.URLClassLoader@3a477cf5
Affect(row-cnt:24) cost in 31 ms.
[arthas@16908]$ classloader
name numberOfInstances loadedCountTotal
org.eclipse.jetty.webapp.WebAppClassLoader 4 24687
BootstrapClassLoader 1 4341
io.opentelemetry.javaagent.bootstrap.AgentClassLoader 1 3502
com.taobao.arthas.agent.ArthasClassloader 1 1430
java.net.URLClassLoader 4 1252
sun.misc.Launcher$AppClassLoader 1 570
sun.reflect.DelegatingClassLoader 378 378
sun.misc.Launcher$ExtClassLoader 1 56
jnr.ffi.provider.jffi.AsmClassLoader 6 8
com.mycom.sig.foundation.servicediscovery.ExtendedClassLoader 4 6
com.mycom.ece.common.svcfinder.ExtendedClassLoader 1 1
|
|
[arthas@16908]$ sc io.opentelemetry.javaagent.instrumentation.methods.MethodInstrumentationModule
io.opentelemetry.javaagent.instrumentation.methods.MethodInstrumentationModule
Affect(row-cnt:1) cost in 54 ms.
[arthas@16908]$ sc -d io.opentelemetry.javaagent.instrumentation.methods.MethodInstrumentationModule
class-info io.opentelemetry.javaagent.instrumentation.methods.MethodInstrumentationModule
code-source /
name io.opentelemetry.javaagent.instrumentation.methods.MethodInstrumentationModule
isInterface false
isAnnotation false
isEnum false
isAnonymousClass false
isArray false
isLocalClass false
isMemberClass false
isPrimitive false
isSynthetic false
simple-name MethodInstrumentationModule
modifier public
annotation
interfaces
super-class +-io.opentelemetry.javaagent.tooling.InstrumentationModule
+-java.lang.Object
class-loader +-io.opentelemetry.javaagent.bootstrap.AgentClassLoader@379619aa
classLoaderHash 379619aa
[arthas@16908]$ sc -d io.opentelemetry.javaagent.instrumentation.methods.MethodTracer
class-info io.opentelemetry.javaagent.instrumentation.methods.MethodTracer
code-source
name io.opentelemetry.javaagent.instrumentation.methods.MethodTracer
isInterface false
isAnnotation false
isEnum false
isAnonymousClass false
isArray false
isLocalClass false
isMemberClass false
isPrimitive false
isSynthetic false
simple-name MethodTracer
modifier public
annotation
interfaces
super-class +-io.opentelemetry.javaagent.shaded.instrumentation.api.tracer.BaseTracer
+-java.lang.Object
class-loader +-WebAppClassLoader=Server Initiated@1ccb04b3
+-java.net.URLClassLoader@69cd1085
+-sun.misc.Launcher$AppClassLoader@18b4aac2
+-sun.misc.Launcher$ExtClassLoader@41fa769c
classLoaderHash 1ccb04b3
class-info io.opentelemetry.javaagent.instrumentation.methods.MethodTracer
code-source
name io.opentelemetry.javaagent.instrumentation.methods.MethodTracer
isInterface false
isAnnotation false
isEnum false
isAnonymousClass false
isArray false
isLocalClass false
isMemberClass false
isPrimitive false
isSynthetic false
simple-name MethodTracer
modifier public
annotation
interfaces
super-class +-io.opentelemetry.javaagent.shaded.instrumentation.api.tracer.BaseTracer
+-java.lang.Object
class-loader +-WebAppClassLoader=OAuth Server@10d98940
+-java.net.URLClassLoader@69cd1085
+-sun.misc.Launcher$AppClassLoader@18b4aac2
+-sun.misc.Launcher$ExtClassLoader@41fa769c
classLoaderHash 10d98940
shaded
io.opentelemetry.instrumentation.api.config.Config
->
sc -d io.opentelemetry.javaagent.shaded.instrumentation.api.config.Config
[arthas@16908]$ sc -d io.opentelemetry.javaagent.shaded.instrumentation.api.config.Config
class-info io.opentelemetry.javaagent.shaded.instrumentation.api.config.Config
code-source
name io.opentelemetry.javaagent.shaded.instrumentation.api.config.Config
isInterface false
isAnnotation false
isEnum false
isAnonymousClass false
isArray false
isLocalClass false
isMemberClass false
isPrimitive false
isSynthetic false
simple-name Config
modifier abstract,public
annotation
interfaces
super-class +-java.lang.Object
class-loader
classLoaderHash null
K8s Custom Resources(CR)
· ☕ 2 分钟
Custom Resource 的入口
请求是这样分发到 api 扩展点的：
例如我们有 （Custom Resource）CR
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相应的 CustomResourceDefinition (CRD) 会是这样：
K8s API 核心对象 —— client-go
· ☕ 3 分钟
API 入口
Client Sets
接收变更通知和缓存（Informers and Caching）
Client Sets可以 watch 变更，但一般我们用更高级的 Informers，因为它有缓存、索引等功能。
- Lister ：被应用调用，返回缓存中的数据列表
- Informer：监听器
Informer 有两个功能
Helm base
· ☕ 1 分钟
Concept
umbrella chart
you can also create a chart with dependencies to other charts (a.k.a. umbrella chart) which are completely external using the requirements.yaml file.
versioning
Simple 1-1 versioning
Chart versus application versioning
参考
https://codefresh.io/docs/docs/new-helm/helm-best-practices/
Kubernetes extends concept
· ☕ 3 分钟
前言
最近由于工作需要，重新系统回顾 Kubernetes 的编程。发现《Programming Kubernetes》这书写得比较系统。于是边学，边记录一些重点。
Controller
Controller Loop
Kubernetes 自动扩缩容
· ☕ 1 分钟
本文状态：草稿
配置例子
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算法
desiredReplicas = ceil[currentReplicas * ( currentMetricValue / desiredMetricValue )]
currentMetricValue 为相关 pod 的 metric 平均数。