ARP协议

2021-03-29

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ARP

Address Resolution Protocol，地址解析协议，实现IP地址到MAC地址的映射。

在局域网中，网络中实际传输的是“帧”，帧里面是有目标主机的MAC地址的。在以太网中，一个主机和另一个主机进行直接通信，必须要知道目标主机的MAC地址。但这个目标MAC地址是如何获得的呢？它就是通过地址解析协议获得的。所谓“地址解析”就是主机在发送帧前将目标IP地址转换成目标MAC地址的过程。ARP协议的基本功能就是通过目标设备的IP地址，查询目标设备的MAC地址，以保证通信的顺利进行。

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操作系统进程如何通信

2021-03-29

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进程如何互相通信

共享内存

操作系统通过页表让不同的进程共享一个物理地址空间，他们对应的逻辑地址空间可能不同，但是物理地址空间是相同的。共享内存不提供同步机制，我们需要额外的手段来保证同步。

管道

管道的参数如下

1	int pipe(int pipefd[2]);

成功则返回0，否则返回-1，pipefd中会得到两个文件描述符，一个可读，一个可写，就实现了管道，一般用于父子进程通信，父进程可fork，然后写pipefd[1], 子进程即可读pipefd[0], 或者父进程fork两次

命名管道

# docker run --rm -it centos:centos8 bash
mkfifo mypipe
for i in {1..100}; do echo $i>mypipe; sleep 1s;  done &
for i in {1..100}; do echo $i>mypipe; sleep 1s;  done &
for i in {1..100}; do echo $i>mypipe; sleep 1s;  done &
tail -300f mypipe

信号量

详见link

消息队列

消息队列是由消息的链表存放在内核并有消息队列标识符标识。消息队列克服了信号传递信息量少，管道只能承载无格式字节流以及缓冲区太小受限。

信号

信号又被称为软件中断，一个有权限的进程可以向另一个进程发送信号，但发往进程的信号诸多都源于内核。

有时需要确保一段代码不被传递来的信号中断，为了做到这点，可将信号添加到进程的信号掩码中——目前会阻塞该组信号的到达。如果所产生的信号属于阻塞之列，那么信号将保持等待状态，直至稍后对其解除阻塞

套接字

socket，不赘述了。

参考

在操作系统中进程是如何通信的

计算机操作系统基础(十六)—进程同步之共享内存

【操作系统原理】使用管道完成进程间通信（匿名管道pipe、命名管道fifo）

操作系统基本概念——信号（一）

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腾讯实习

2021-03-27

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腾讯的实习暂时结束了，新的位置在哪我也不知道。这图还是去年的，哈哈哈哈。

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k8s学习

2021-03-25

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k8s 学习总结

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mermaid基本操作

2020-05-01

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Mermaid

这是一个画图的东西，他可以画有向图、无向图、流程图、时序图、类图、状态图等等，官网在这
有一个坑，就是md文件第一非空行不可以是#mermaid, 否则渲染失败，所以我这用了Mermaid作为开头，

why this blog

简单介绍一下用法，避免每次都去官网找半天

基础用法

参数	备注
TB	top bottom
BT	bottom top
RL	right left
LR	left right
TD	same as TB

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logstash

2021-03-16

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# install logstash
yum install -y java-1.8.0-openjdk.x86_64 wget vim
wget https://artifacts.elastic.co/downloads/logstash/logstash-7.0.0.tar.gz
tar -xzvf logstash-7.0.0.tar.gz
mv logstash-7.0.0 /usr/local/logstash
echo "LOGSTASH_HOME=/usr/local/logstash" >> ~/.bashrc
echo "PATH=\$LOGSTASH_HOME/bin:\$PATH" >> ~/.bashrc
source ~/.bashrc

grok语法

https://github.com/logstash-plugins/logstash-patterns-core/tree/master/patterns

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filebeat

2021-03-15

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curl -L -O https://artifacts.elastic.co/downloads/beats/filebeat/filebeat-7.5.1-x86_64.rpm
rpm -vi filebeat-7.5.1-x86_64.rpm
filebeat modules enable logstash
filebeat setup
cat<<EOF>/etc/filebeat/filebeat.yml
filebeat.inputs:
- type: log
  enabled: true
  paths:
    - /data/*.log
filebeat.config.modules:
  path: \${path.config}/modules.d/*.yml
  reload.enabled: false
setup.template.settings:
  index.number_of_shards: 1
setup.kibana:
output.elasticsearch:
  hosts: ["localhost:9200"]
processors:
  - add_host_metadata: ~
  - add_cloud_metadata: ~
  - add_docker_metadata: ~
  - add_kubernetes_metadata: ~
EOF
mkdir /data
for i in $(seq 1 10000); do echo "{\"x\"="$i"}" >> /data/10000.log; sleep 1s;done &
/usr/share/filebeat/bin/filebeat -c /etc/filebeat/filebeat.yml -path.home /usr/share/filebeat -path.config /etc/filebeat -path.data /var/lib/filebeat -path.logs /var/log/filebeat -e &

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docker-mysql

2021-03-15

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mysql安装

可以酌情修改内存大小和交换内存大小。

# filename: $HOME/data/mysql/conf/docker.cnf
[mysqld]
performance_schema_max_table_instances=400
table_definition_cache=400
table_open_cache=256
performance_schema = off
skip-host-cache
skip-name-resolve

docker run \
  --cpus 0.2 \
  -d -e MYSQL_ROOT_PASSWORD=123456 \
  --name mysql \
  -v $HOME/data/mysql/data:/var/lib/mysql \
  -v $HOME/data/mysql/conf:/etc/mysql/conf.d \
  -p 3306:3306 \
  mysql

允许远程登录

1
2
3

docker exec -it mysql bash
mysql -u root -p123456
ALTER USER 'root'@'%' IDENTIFIED WITH MYSQL_NATIVE_PASSWORD BY '123456';

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k8s故障

2021-03-15

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很多POD处于evicted状态

#!/bin/bash
for pod in $(kubectl get pods|grep Evicted|awk '{print $1}');
do
  kubectl delete pods $pod
done

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hexo博客搭建浅谈

2020-04-05

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博客崩溃了

我很难受，重新开始配置一下，然后我记录一下过程

初始化博客

script

hexo init

然后我碰到了第一个问题

script

INFO  Cloning hexo-starter https://github.com/hexojs/hexo-starter.git
Cloning into '/Users/s/Documents/debug'...
remote: Enumerating objects: 30, done.
remote: Counting objects: 100% (30/30), done.
remote: Compressing objects: 100% (24/24), done.
remote: Total 161 (delta 12), reused 12 (delta 4), pack-reused 131
Receiving objects: 100% (161/161), 31.79 KiB | 262.00 KiB/s, done.
Resolving deltas: 100% (74/74), done.
Submodule 'themes/landscape' (https://github.com/hexojs/hexo-theme-landscape.git) registered for path 'themes/landscape'
Cloning into '/Users/s/Documents/debug/themes/landscape'...
remote: Enumerating objects: 1063, done.        
remote: Total 1063 (delta 0), reused 0 (delta 0), pack-reused 1063        
Receiving objects: 100% (1063/1063), 3.21 MiB | 2.87 MiB/s, done.
Resolving deltas: 100% (585/585), done.
Submodule path 'themes/landscape': checked out '73a23c51f8487cfcd7c6deec96ccc7543960d350'
INFO  Install dependencies

> ejs@2.7.4 postinstall /Users/s/Documents/debug/node_modules/ejs
> node ./postinstall.js

Thank you for installing EJS: built with the Jake JavaScript build tool (https://jakejs.com/)

npm notice created a lockfile as package-lock.json. You should commit this file.
added 254 packages from 454 contributors and audited 470 packages in 12.565s

5 packages are looking for funding
  run `npm fund` for details

found 1 low severity vulnerability
  run `npm audit fix` to fix them, or `npm audit` for details
INFO  Start blogging with Hexo!

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