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張 旭

How to write excellent Dockerfiles - 0 views

  • minimize image size, build time and number of layers.
  • maximize build cache usage
  • Container should do one thing
    • 張 旭
       
      這個有待商榷,在 baseimage 的 blog 介紹中有詳細的討論。
  • ...25 more annotations...
  • Use COPY and RUN commands in proper order
  • Merge multiple RUN commands into one
  • alpine versions should be enough
  • Use exec inside entrypoint script
  • Prefer COPY over ADD
  • Specify default environment variables, ports and volumes inside Dockerfile
  • problems with zombie processes
  • prepare separate Docker image for each component, and use Docker Compose to easily start multiple containers at the same time
  • Layers are cached and reused
  • Layers are immutable
  • They both makes you cry
  • rely on our base image updates
  • make a cleanup
  • alpine is a very tiny linux distribution, just about 4 MB in size.
  • Your disk will love you :)
  • WORKDIR command changes default directory, where we run our RUN / CMD / ENTRYPOINT commands.
  • CMD is a default command run after creating container without other command specified.
  • put your command inside array
  • entrypoint adds complexity
  • Entrypoint is a script, that will be run instead of command, and receive command as arguments
  • Without it, we would not be able to stop our application grecefully (SIGTERM is swallowed by bash script).
  • Use "exec" inside entrypoint script
  • ADD has some logic for downloading remote files and extracting archives.
  • stick with COPY.
  • ADD
    • 張 旭
       
      不是說要用 COPY 嗎?
crazylion lee

Tinyproxy - A light-weight HTTP/HTTPS proxy - 0 views

  •  
    輕量的 http https proxy
張 旭

Getting Started with Docker - Servers for Hackers - 0 views

  • Docker is an isolated portion of the host computer, sharing the host kernel (OS) and even its bin/libraries if appropriate.
  • the Docker Container contains the parts that make Ubuntu different from CoreOS.
  • A Docker container only stays alive as long as there is an active process being run in it.
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  • Allocate a (pseudo) tty
  • Keep stdin open (so we can interact with it)
  • Docker allows us make changes to an image, commit those changes, and then push those changes out somehwere.
  • Docker tracks any changes we make to a container
  • The Dockerfile provides a set of instructions for Docker to run on a container.
  • what image (and tag in this case) to base this off of
  • run the given command (as user "root")
  • copy a file from the host machine into the container
  • expose a port to the host machine. You can expose multiple ports
  • run a command
張 旭

The Rubyist's Guide to Environment Variables - Honeybadger.io Blog - 0 views

  • If you want to be able to effectively manage web apps in development and in production, you have to understand environment variables.
  • Every program you run on your server has at least one process. That process gets its own set of environment variables.
  • Once it has them, nothing outside of that process can change them.
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  • Every program you run on your server gets its own set of environment variables at the moment you launch it.
  • Environment variables die with their process
  • Every process has a parent. That’s because every program has to be started by some other program.
  • Child processes inherit env vars from their parent
  • By default a child will get copies of every environment variable that its parent has. But the parent has control over this.
  • Changes to the environment don’t sync between running processes
  • shells do provide their own “local” shell variable systems
  • Environment variables are NOT the same as shell variables
  • use the export command to convert the local variable into an environment variable.
張 旭

Authentication, Permissions and Roles in Rails with Devise, CanCan and Role Model | Phase2 - 0 views

  • Devise is a modular user authentication system
  • just gradually investigating the components you need for your app and configuring them as you need
  • define permissions
張 旭

Run Reference - Docker Documentation - 0 views

  • In detached mode (-d=true or just -d), all I/O should be done through network connections or shared volumes because the container is no longer listening to the command line where you executed docker run.
  • start the process in the container and attach the console to the process's standard input, output, and standard error. It can even pretend to be a TTY (this is what most command line executables expect) and pass along signals.
  • For interactive processes (like a shell) you will typically want a tty as well as persistent standard input (STDIN), so you'll use -i -t together in most interactive cases.
張 旭

How to Use Docker on OS X: The Missing Guide | Viget - 0 views

  • Docker is a client-server application.
  • The Docker server is a daemon that does all the heavy lifting: building and downloading images, starting and stopping containers, and the like. It exposes a REST API for remote management.
  • The Docker client is a command line program that communicates with the Docker server using the REST API.
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  • interact with Docker by using the client to send commands to the server.
  • The machine running the Docker server is called the Docker host
  • Docker uses features only available to Linux, that machine must be running Linux (more specifically, the Linux kernel).
  • boot2docker is a “lightweight Linux distribution made specifically to run Docker containers.”
  • Docker server will run inside our boot2docker VM
  • boot2docker, not OS X, is the Docker host, not OS X.
  • Docker mounts volumes from the boot2docker VM, not from OS X
  • initialize boot2docker (we only have to do this once):
  • The Docker client assumes the Docker host is the current machine. We need to tell it to use our boot2docker VM by setting the DOCKER_HOST environment variable
張 旭

单表60亿记录等大数据场景的MySQL优化和运维之道 - 快课网 - 0 views

  • 存储引擎使用InnoDB
  • 变长字符串尽量使用varchar varbinary
  • 不在数据库中存储图片、文件等
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  • 库名、表名、字段名、索引名使用小写字母,以下划线分割 ,需要见名知意
  • 所有字段均定义为NOT NULL ,除非你真的想存Null
  • 使用TIMESTAMP存储时间
  • 使用DECIMAL存储精确浮点数,用float有的时候会有问题
  • 单个索引字段数不超过5,单表索引数量不超过5,索引设计遵循B+ Tree索引最左前缀匹配原则
  • 建立的索引能覆盖80%主要的查询,不求全,解决问题的主要矛盾
  • 避免冗余索引
  • 索引这个东西是一把双刃剑,在加速读的同时也引入了很多额外的写入和锁,降低写入能力
  • 字段定义为varchar,但传入的值是个int,就会导致全表扫描,要求程序端要做好类型检查
  • 避免使用大表的JOIN,MySQL优化器对join优化策略过于简单
  • UPDATE、DELETE语句不使用LIMIT ,容易造成主从不一致
  • 高危操作检查,Drop前做好数据备份
  • 日志分析,主要是指的MySQL慢日志和错误日志
  • Percona公司根据Facebook OSC思路,用perl重写了一版,就是我们现在用得很多的pt-online-schema-change,软件本身非常成熟,支持目前主流版本
  • 原生主从同步肯定存在着性能和安全性问题
  • Sharding is very complex, so itʼs best not to shard until itʼs obvious that you will actually need to!
  • 有中间层控制拆分逻辑最好,否则拆分过细管理成本会很高
  • 全量binlog备份
  • xtrabackup热备
  • 采用分布式文件系统存储备份
  • 基于库级别的复制,所以如果你只有一个库,使用这个意义不大
  • 半同步复制,从5.5开始支持
  • 半同步通过从库返回ACK这种方式确认从库收到数据
  • Secondsbehindmaster来判断延时不可靠,在网络抖动或者一些特殊参数配置情况下,会造成这个值是0但其实延时很大了。通过heartbeat表插入时间戳这种机制判断延时是更靠谱的
  • Binlog格式,建议都采用row格式,数据一致性更好
  • 成熟开源事务存储引擎,支持ACID,支持事务四个隔离级别,更好的数据安全性,高性能高并发,MVCC,细粒度锁,支持O_DIRECT
  • 数据安全性至关重要,InnoDB完胜
  • 主流使用TokuDB主要是看中了它的高压缩比
  • TokuDB在测试过程中写入稳定性是非常好的
  • 单表容量在InnoDB下1TB+,使用Tokudb的lzma压缩到80GB
  • 独立写程序好一些,与程序解耦方便后期维护
  • 追踪字段值变化可以通过分析row格式binlog好一些
  • 解决了单表过大恢复时间问题,也支持online DDL
  • 物理备份采用xtrabackup热备方案比较好
張 旭

Why we should stop using Grunt & Gulp - 0 views

  • All of these task runners (or build systems if you want to call them that) try to abstract some kind of task paradigm away into their own siloed incantations.
  • Gulp isn't the only culprit either; Jake, Broccoli, Brunch and Mimosa all require plugins to install as well, which means when using any of these task runners, you're essentially just installing 1 more dependency (the task runner) than if you had no task runner, and just used each of the projects own binaries
張 旭

一位开发者的 Linux 容器之旅 - 51CTO.COM - 0 views

  • 容器是一个 Linux 进程,Linux 认为它只是一个运行中的进程。该进程只知道它被告知的东西。
  • 容器进程也分配了它自己的 IP 地址
  • 和典型虚拟机的静态方式不同。所有这些资源的共享都由容器管理器来管理。
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  • 可以在容器管理器上运行命令,使容器 IP 映射到主机中能访问公网的 IP 地址。建立了该映射,无论出于什么意图和目的,容器就是网络上一个可访问的独立机器,从概念上类似于虚拟机。
  • 容器是拥有不同 IP 地址从而使其成为网络上可识别的独立 Linux 进程
  • 容器/进程以动态、合作的方式共享主机上的资源。
  • 容器能非常快速地启动
  • 操作系统被所有容器所共享,减少了容器足迹的重复和冗余。每个容器只包括该容器特有的部分
  • 获得了虚拟机独立和封装的好处,而抛弃了静态资源专有的缺陷
  • 托管容器的计算机运行着被剥离的只剩下主要部分的某个 Linux 版本
  • Ubuntu Snappy
  • Red Hat Atomic Host
  • CoreOS
  • 在容器化方面,容器进程有它自己的 IP 地址。一旦给予了一个 IP 地址,该进程就是宿主网络中可识别的资源
  • 一个容器组件被称为层(layer)
  • 层是一个容器镜像
  • 容器管理器只提供你所要的操作系统在宿主操作系统中不存在的部分
  • 在容器配置文件中重新定义层
  • 容器的各种功能都由一个称为容器管理器(container manager)的软件控制
  • Docker
  • Rocket
  • 镜像存储在注册库(registry)中,注册库通过网络访问
  • 注册库类似于一个使用 Java 的人眼中的 Maven 仓库、使用 .NET 的人眼中的 NuGet 服务器。
  • 容器管理器会封装你应用程序的所有东西为一个独立容器,该容器将会在容器管理器的管理下运行在宿主计算机上。
  • 每个容器有一个独立的 IP 地址
  • 在一个负载均衡容器后运行容器集群以获得更高的性能和高可用计算
  • Deis 的容器配置技术
  • 每次添加实例到环境中时,你不需要手动配置负载均衡器以便接受你的容器镜像。
  • 使用服务发现技术让容器告知均衡器它可用
張 旭

一位开发者的 Linux 容器之旅-技术 ◆ 学习|Linux.中国-开源社区 - 1 views

  • 容器是一个 Linux 进程,Linux 认为它只是一个运行中的进程。该进程只知道它被告知的东西。
  • 容器进程也分配了它自己的 IP 地址。
  • 在容器化方面,容器进程有它自己的 IP 地址。一旦给予了一个 IP 地址,该进程就是宿主网络中可识别的资源
  • ...20 more annotations...
  • 使容器 IP 映射到主机中能访问公网的 IP 地址。建立了该映射,无论出于什么意图和目的,容器就是网络上一个可访问的独立机器,从概念上类似于虚拟机。
  • 容器是拥有不同 IP 地址从而使其成为网络上可识别的独立 Linux 进程
  • CPU、内存和存储空间的分配是动态的,和典型虚拟机的静态方式不同。所有这些资源的共享都由容器管理器来管理。
  • 容器能非常快速地启动
  • 托管容器的计算机运行着被剥离的只剩下主要部分的某个 Linux 版本。
  • 操作系统被所有容器所共享,减少了容器足迹的重复和冗余。每个容器只包括该容器特有的部分
  • 层是一个容器镜像
  • 一个容器组件被称为层(layer)
  • 容器的各种功能都由一个称为容器管理器(container manager)的软件控制
  • 流行的容器管理器是 Docker 和 Rocket
  • 镜像存储在注册库(registry)中,注册库通过网络访问
  • 镜像代表了你的容器需要完成其工作的容器模板
  • 应用程序所需镜像的容器配置文件
  • 每个容器有一个独立的 IP 地址。因此,能把它放到负载均衡器后面。将容器放到负载均衡器后面,这就上升了一个层面。
  • Deis 的容器配置技术
  • 可以部署一个或多个容器镜像到主机上的负载均衡器下
  • 每次添加实例到环境中时,你不需要手动配置负载均衡器以便接受你的容器镜像。你可以使用服务发现技术让容器告知均衡器它可用。
  • 类似 CoreOS、RHEL Atomic、和 Ubuntu 的 Snappy 宿主操作系统
  • 类似 Docker 和 Rocket 的容器管理技术结合起来
  • 类似 Deis 这样的配置技术使容器创建和部署变得更加简单
張 旭

Flynn: first preview release | Hacker News - 0 views

  • Etcd and Zookeeper provide essentially the same functionality. They are both a strongly consistent key/value stores that support notifications to clients of changes. These two projects are limited to service discovery
  • So lets say you had a client application that would talk to a node application that could be on any number of servers. What you could do is hard code that list into your application and randomly select one, in order to "fake" load balancing. However every time a machine went up or down you would have to update that list.
  • What Consul provides is you just tell your app to connect to "mynodeapp.consul" and then consul will give you the proper address of one of your node apps.
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  • Consul and Skydock are both applications that build on top of a tool like Zookeeper and Etcd.
  • What a developer ideally wants to do is just push code and not have to worry about what servers are running what, and worry about failover and the like
  • What Flynn provides (if I get it), is a diy Heroku like platform
  • Another project that I believe may be similar to Flynn is Apache Mesos.
  • a self hosted Heroku
  • Google Omega is Google's answer to Apache Mesos
  • Omega would need a service like Raft to understand what services are currently available
  • Raft is a consensus algorithm for keeping a set of distributed state machines in a consistent state.
  • I want to use Docker, but it has no easy way to say "take this file that contains instructions and make everything". You can write Dockerfiles, but you can only use one part of the stack in them, otherwise you run into trouble.
  •  
    " So lets say you had a client application that would talk to a node application that could be on any number of servers. What you could do is hard code that list into your application and randomly select one, in order to "fake" load balancing. However every time a machine went up or down you would have to update that list. What Consul provides is you just tell your app to connect to "mynodeapp.consul" and then consul will give you the proper address of one of your node apps."
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