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crazylion lee

jkbrzt/httpie - 0 views

shared by crazylion lee on 08 Aug 15 - No Cached
  •  
    "CLI HTTP client; user-friendly cURL replacement featuring intuitive UI, JSON support, syntax highlighting, wget-like downloads, extensions, etc. http://httpie.org"
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
crazylion lee

GitHub - sindresorhus/ky: Tiny and elegant HTTP client based on the browser Fetch API - 0 views

  •  
    "Tiny and elegant HTTP client based on the browser Fetch API"
張 旭

Let's Encrypt & Docker - Træfik - 0 views

  • automatically discover any services on the Docker host and let Træfik reconfigure itself automatically when containers get created (or shut down) so HTTP traffic can be routed accordingly.
  • use Træfik as a layer-7 load balancer with SSL termination for a set of micro-services used to run a web application.
  • Docker containers can only communicate with each other over TCP when they share at least one network.
  • ...15 more annotations...
  • Docker under the hood creates IPTable rules so containers can't reach other containers unless you'd want to
  • Træfik can listen to Docker events and reconfigure its own internal configuration when containers are created (or shut down).
  • Enable the Docker provider and listen for container events on the Docker unix socket we've mounted earlier.
  • Enable automatic request and configuration of SSL certificates using Let's Encrypt. These certificates will be stored in the acme.json file, which you can back-up yourself and store off-premises.
  • there isn't a single container that has any published ports to the host -- everything is routed through Docker networks.
  • Thanks to Docker labels, we can tell Træfik how to create its internal routing configuration.
  • container labels and service labels
  • With the traefik.enable label, we tell Træfik to include this container in its internal configuration.
  • tell Træfik to use the web network to route HTTP traffic to this container.
  • Service labels allow managing many routes for the same container.
  • When both container labels and service labels are defined, container labels are just used as default values for missing service labels but no frontend/backend are going to be defined only with these labels.
  • In the example, two service names are defined : basic and admin. They allow creating two frontends and two backends.
  • Always specify the correct port where the container expects HTTP traffic using traefik.port label.
  • all containers that are placed in the same network as Træfik will automatically be reachable from the outside world
  • With the traefik.frontend.auth.basic label, it's possible for Træfik to provide a HTTP basic-auth challenge for the endpoints you provide the label for.
張 旭

Secrets Management with Terraform - 0 views

  • Terraform is an Infrastructure as Code (IaC) tool that allows you to write declarative code to manage your infrastructure.
  • Keeping Secrets Out of .tf Files
  • .tf files contain the declarative code used to create, manage, and destroy infrastructure.
  • ...17 more annotations...
  • .tf files can accept values from input variables.
  • variable definitions can have default values assigned to them.
  • values are stored in separate files with the .tfvars extension.
  • looks through the working directory for a file named terraform.tfvars, or for files with the .auto.tfvars extension.
  • add the terraform.tfvars file to your .gitignore file and keep it out of version control.
  • include an example terraform.tfvars.example in your Git repository with all of the variable names recorded (but none of the values entered).
  • terraform apply -var-file=myvars.tfvars
  • Terraform allows you to keep input variable values in environment variables.
  • the prefix TF_VAR_
  • If Terraform does not find a default value for a defined variable; or a value from a .tfvars file, environment variable, or CLI flag; it will prompt you for a value before running an action
  • state file contains a JSON object that holds your managed infrastructure’s current state
  • state is a snapshot of the various attributes of your infrastructure at the time it was last modified
  • sensitive information used to generate your Terraform state can be stored as plain text in the terraform.tfstate file.
  • Avoid checking your terraform.tfstate file into your version control repository.
  • Some backends, like Consul, also allow for state locking. If one user is applying a state, another user will be unable to make any changes.
  • Terraform backends allow the user to securely store their state in a remote location, such as a key/value store like Consul, or an S3 compatible bucket storage like Minio.
  • at minimum the repository should be private.
張 旭

How To Benchmark HTTP Latency with wrk on Ubuntu 14.04 | DigitalOcean - 0 views

  • wrk, which measures the latency of your HTTP services at high loads.
  • Latency refers to the time interval between the moment the request was made (by wrk) and the moment the response was received (from the service).
  • Tests can't be compared to real users, but they should give you a good estimate of expected latency
張 旭

Scalable architecture without magic (and how to build it if you're not Google) - DEV Co... - 0 views

  • Don’t mess up write-first and read-first databases.
  • keep them stateless.
  • you should know how to make a scalable setup on bare metal.
  • ...29 more annotations...
  • Different programming languages are for different tasks.
  • Go or C which are compiled to run on bare metal.
  • To run NodeJS on multiple cores, you have to use something like PM2, but since this you have to keep your code stateless.
  • Python have very rich and sugary syntax that’s great for working with data while keeping your code small and expressive.
  • SQL is almost always slower than NoSQL
  • databases are often read-first or write-first
  • write-first, just like Cassandra.
  • store all of your data to your databases and leave nothing at backend
  • Functional code is stateless by default
  • It’s better to go for stateless right from the very beginning.
  • deliver exactly the same responses for same requests.
  • Sessions? Store them at Redis and allow all of your servers to access it.
  • Only the first user will trigger a data query, and all others will be receiving exactly the same data straight from the RAM
  • never, never cache user input
  • Only the server output should be cached
  • Varnish is a great cache option that works with HTTP responses, so it may work with any backend.
  • a rate limiter – if there’s not enough time have passed since last request, the ongoing request will be denied.
  • different requests blasting every 10ms can bring your server down
  • Just set up entry relations and allow your database to calculate external keys for you
  • the query planner will always be faster than your backend.
  • Backend should have different responsibilities: hashing, building web pages from data and templates, managing sessions and so on.
  • For anything related to data management or data models, move it to your database as procedures or queries.
  • a distributed database.
  • your code has to be stateless
  • Move anything related to the data to the database.
  • For load-balancing a database, go for cluster.
  • DB is balancing requests, as well as your backend.
  • Users from different continents are separated with DNS.
  • Keep is scalable, keep is stateless.
  •  
    "Don't mess up write-first and read-first databases."
張 旭

Helm | - 0 views

  • Helm will figure out where to install Tiller by reading your Kubernetes configuration file (usually $HOME/.kube/config). This is the same file that kubectl uses.
  • kubectl cluster-info
  • Role-Based Access Control (RBAC) enabled
  • ...133 more annotations...
  • initialize the local CLI
  • install Tiller into your Kubernetes cluster
  • helm install
  • helm init --upgrade
  • By default, when Tiller is installed, it does not have authentication enabled.
  • helm repo update
  • Without a max history set the history is kept indefinitely, leaving a large number of records for helm and tiller to maintain.
  • helm init --upgrade
  • Whenever you install a chart, a new release is created.
  • one chart can be installed multiple times into the same cluster. And each can be independently managed and upgraded.
  • helm list function will show you a list of all deployed releases.
  • helm delete
  • helm status
  • you can audit a cluster’s history, and even undelete a release (with helm rollback).
  • the Helm server (Tiller).
  • The Helm client (helm)
  • brew install kubernetes-helm
  • Tiller, the server portion of Helm, typically runs inside of your Kubernetes cluster.
  • it can also be run locally, and configured to talk to a remote Kubernetes cluster.
  • Role-Based Access Control - RBAC for short
  • create a service account for Tiller with the right roles and permissions to access resources.
  • run Tiller in an RBAC-enabled Kubernetes cluster.
  • run kubectl get pods --namespace kube-system and see Tiller running.
  • helm inspect
  • Helm will look for Tiller in the kube-system namespace unless --tiller-namespace or TILLER_NAMESPACE is set.
  • For development, it is sometimes easier to work on Tiller locally, and configure it to connect to a remote Kubernetes cluster.
  • even when running locally, Tiller will store release configuration in ConfigMaps inside of Kubernetes.
  • helm version should show you both the client and server version.
  • Tiller stores its data in Kubernetes ConfigMaps, you can safely delete and re-install Tiller without worrying about losing any data.
  • helm reset
  • The --node-selectors flag allows us to specify the node labels required for scheduling the Tiller pod.
  • --override allows you to specify properties of Tiller’s deployment manifest.
  • helm init --override manipulates the specified properties of the final manifest (there is no “values” file).
  • The --output flag allows us skip the installation of Tiller’s deployment manifest and simply output the deployment manifest to stdout in either JSON or YAML format.
  • By default, tiller stores release information in ConfigMaps in the namespace where it is running.
  • switch from the default backend to the secrets backend, you’ll have to do the migration for this on your own.
  • a beta SQL storage backend that stores release information in an SQL database (only postgres has been tested so far).
  • Once you have the Helm Client and Tiller successfully installed, you can move on to using Helm to manage charts.
  • Helm requires that kubelet have access to a copy of the socat program to proxy connections to the Tiller API.
  • A Release is an instance of a chart running in a Kubernetes cluster. One chart can often be installed many times into the same cluster.
  • helm init --client-only
  • helm init --dry-run --debug
  • A panic in Tiller is almost always the result of a failure to negotiate with the Kubernetes API server
  • Tiller and Helm have to negotiate a common version to make sure that they can safely communicate without breaking API assumptions
  • helm delete --purge
  • Helm stores some files in $HELM_HOME, which is located by default in ~/.helm
  • A Chart is a Helm package. It contains all of the resource definitions necessary to run an application, tool, or service inside of a Kubernetes cluster.
  • it like the Kubernetes equivalent of a Homebrew formula, an Apt dpkg, or a Yum RPM file.
  • A Repository is the place where charts can be collected and shared.
  • Set the $HELM_HOME environment variable
  • each time it is installed, a new release is created.
  • Helm installs charts into Kubernetes, creating a new release for each installation. And to find new charts, you can search Helm chart repositories.
  • chart repository is named stable by default
  • helm search shows you all of the available charts
  • helm inspect
  • To install a new package, use the helm install command. At its simplest, it takes only one argument: The name of the chart.
  • If you want to use your own release name, simply use the --name flag on helm install
  • additional configuration steps you can or should take.
  • Helm does not wait until all of the resources are running before it exits. Many charts require Docker images that are over 600M in size, and may take a long time to install into the cluster.
  • helm status
  • helm inspect values
  • helm inspect values stable/mariadb
  • override any of these settings in a YAML formatted file, and then pass that file during installation.
  • helm install -f config.yaml stable/mariadb
  • --values (or -f): Specify a YAML file with overrides.
  • --set (and its variants --set-string and --set-file): Specify overrides on the command line.
  • Values that have been --set can be cleared by running helm upgrade with --reset-values specified.
  • Chart designers are encouraged to consider the --set usage when designing the format of a values.yaml file.
  • --set-file key=filepath is another variant of --set. It reads the file and use its content as a value.
  • inject a multi-line text into values without dealing with indentation in YAML.
  • An unpacked chart directory
  • When a new version of a chart is released, or when you want to change the configuration of your release, you can use the helm upgrade command.
  • Kubernetes charts can be large and complex, Helm tries to perform the least invasive upgrade.
  • It will only update things that have changed since the last release
  • $ helm upgrade -f panda.yaml happy-panda stable/mariadb
  • deployment
  • If both are used, --set values are merged into --values with higher precedence.
  • The helm get command is a useful tool for looking at a release in the cluster.
  • helm rollback
  • A release version is an incremental revision. Every time an install, upgrade, or rollback happens, the revision number is incremented by 1.
  • helm history
  • a release name cannot be re-used.
  • you can rollback a deleted resource, and have it re-activate.
  • helm repo list
  • helm repo add
  • helm repo update
  • The Chart Development Guide explains how to develop your own charts.
  • helm create
  • helm lint
  • helm package
  • Charts that are archived can be loaded into chart repositories.
  • chart repository server
  • Tiller can be installed into any namespace.
  • Limiting Tiller to only be able to install into specific namespaces and/or resource types is controlled by Kubernetes RBAC roles and rolebindings
  • Release names are unique PER TILLER INSTANCE
  • Charts should only contain resources that exist in a single namespace.
  • not recommended to have multiple Tillers configured to manage resources in the same namespace.
  • a client-side Helm plugin. A plugin is a tool that can be accessed through the helm CLI, but which is not part of the built-in Helm codebase.
  • Helm plugins are add-on tools that integrate seamlessly with Helm. They provide a way to extend the core feature set of Helm, but without requiring every new feature to be written in Go and added to the core tool.
  • Helm plugins live in $(helm home)/plugins
  • The Helm plugin model is partially modeled on Git’s plugin model
  • helm referred to as the porcelain layer, with plugins being the plumbing.
  • helm plugin install https://github.com/technosophos/helm-template
  • command is the command that this plugin will execute when it is called.
  • Environment variables are interpolated before the plugin is executed.
  • The command itself is not executed in a shell. So you can’t oneline a shell script.
  • Helm is able to fetch Charts using HTTP/S
  • Variables like KUBECONFIG are set for the plugin if they are set in the outer environment.
  • In Kubernetes, granting a role to an application-specific service account is a best practice to ensure that your application is operating in the scope that you have specified.
  • restrict Tiller’s capabilities to install resources to certain namespaces, or to grant a Helm client running access to a Tiller instance.
  • Service account with cluster-admin role
  • The cluster-admin role is created by default in a Kubernetes cluster
  • Deploy Tiller in a namespace, restricted to deploying resources only in that namespace
  • Deploy Tiller in a namespace, restricted to deploying resources in another namespace
  • When running a Helm client in a pod, in order for the Helm client to talk to a Tiller instance, it will need certain privileges to be granted.
  • SSL Between Helm and Tiller
  • The Tiller authentication model uses client-side SSL certificates.
  • creating an internal CA, and using both the cryptographic and identity functions of SSL.
  • Helm is a powerful and flexible package-management and operations tool for Kubernetes.
  • default installation applies no security configurations
  • with a cluster that is well-secured in a private network with no data-sharing or no other users or teams.
  • With great power comes great responsibility.
  • Choose the Best Practices you should apply to your helm installation
  • Role-based access control, or RBAC
  • Tiller’s gRPC endpoint and its usage by Helm
  • Kubernetes employ a role-based access control (or RBAC) system (as do modern operating systems) to help mitigate the damage that can be done if credentials are misused or bugs exist.
  • In the default installation the gRPC endpoint that Tiller offers is available inside the cluster (not external to the cluster) without authentication configuration applied.
  • Tiller stores its release information in ConfigMaps. We suggest changing the default to Secrets.
  • release information
  • charts
  • charts are a kind of package that not only installs containers you may or may not have validated yourself, but it may also install into more than one namespace.
  • As with all shared software, in a controlled or shared environment you must validate all software you install yourself before you install it.
  • Helm’s provenance tools to ensure the provenance and integrity of charts
  •  
    "Helm will figure out where to install Tiller by reading your Kubernetes configuration file (usually $HOME/.kube/config). This is the same file that kubectl uses."
crazylion lee

Swoole®: PHP的异步、并行、高性能网络通信引擎 - 0 views

  •  
    " PHP的异步、并行、高性能网络通信引擎,使用纯C语言编写,提供了PHP语言的异步多线程服务器,异步TCP/UDP网络客户端,异步MySQL,异步Redis,数据库连接池,AsyncTask,消息队列,毫秒定时器,异步文件读写,异步DNS查询。 Swoole内置了Http/WebSocket服务器端/客户端、Http2.0服务器端。"
張 旭

ruby-grape/grape: An opinionated framework for creating REST-like APIs in Ruby. - 0 views

shared by 張 旭 on 17 Dec 16 - No Cached
  • Grape is a REST-like API framework for Ruby.
  • designed to run on Rack or complement existing web application frameworks such as Rails and Sinatra by providing a simple DSL to easily develop RESTful APIs
  • Grape APIs are Rack applications that are created by subclassing Grape::API
  • ...54 more annotations...
  • Rails expects a subdirectory that matches the name of the Ruby module and a file name that matches the name of the class
  • mount multiple API implementations inside another one
  • mount on a path, which is similar to using prefix inside the mounted API itself.
  • four strategies in which clients can reach your API's endpoints: :path, :header, :accept_version_header and :param
  • clients should pass the desired version as a request parameter, either in the URL query string or in the request body.
  • clients should pass the desired version in the HTTP Accept head
  • clients should pass the desired version in the UR
  • clients should pass the desired version in the HTTP Accept-Version header.
  • add a description to API methods and namespaces
  • Request parameters are available through the params hash object
  • Parameters are automatically populated from the request body on POST and PUT
  • route string parameters will have precedence.
  • Grape allows you to access only the parameters that have been declared by your params block
  • By default declared(params) includes parameters that have nil values
  • all valid types
  • type: File
  • JSON objects and arrays of objects are accepted equally
  • any class can be used as a type so long as an explicit coercion method is supplied
  • As a special case, variant-member-type collections may also be declared, by passing a Set or Array with more than one member to type
  • Parameters can be nested using group or by calling requires or optional with a block
  • relevant if another parameter is given
  • Parameters options can be grouped
  • allow_blank can be combined with both requires and optional
  • Parameters can be restricted to a specific set of values
  • Parameters can be restricted to match a specific regular expression
  • Never define mutually exclusive sets with any required params
  • Namespaces allow parameter definitions and apply to every method within the namespace
  • define a route parameter as a namespace using route_param
  • create custom validation that use request to validate the attribute
  • rescue a Grape::Exceptions::ValidationErrors and respond with a custom response or turn the response into well-formatted JSON for a JSON API that separates individual parameters and the corresponding error messages
  • custom validation messages
  • Request headers are available through the headers helper or from env in their original form
  • define requirements for your named route parameters using regular expressions on namespace or endpoint
  • route will match only if all requirements are met
  • mix in a module
  • define reusable params
  • using cookies method
  • a 201 for POST-Requests
  • 204 for DELETE-Requests
  • 200 status code for all other Requests
  • use status to query and set the actual HTTP Status Code
  • raising errors with error!
  • It is very crucial to define this endpoint at the very end of your API, as it literally accepts every request.
  • rescue_from will rescue the exceptions listed and all their subclasses.
  • Grape::API provides a logger method which by default will return an instance of the Logger class from Ruby's standard library.
  • Grape supports a range of ways to present your data
  • Grape has built-in Basic and Digest authentication (the given block is executed in the context of the current Endpoint).
  • Authentication applies to the current namespace and any children, but not parents.
  • Blocks can be executed before or after every API call, using before, after, before_validation and after_validation
  • Before and after callbacks execute in the following order
  • Grape by default anchors all request paths, which means that the request URL should match from start to end to match
  • The namespace method has a number of aliases, including: group, resource, resources, and segment. Use whichever reads the best for your API.
  • test a Grape API with RSpec by making HTTP requests and examining the response
  • POST JSON data and specify the correct content-type.
張 旭

[Elasticsearch] 分散式特性 & 分散式搜尋的機制 | 小信豬的原始部落 - 0 views

  • 水平擴展儲存空間
  • Data HA:若有 node 掛掉,資料不會遺失
  • 若是要查詢 cluster 中的 node 狀態,可以使用 GET /_cat/nodes API
  • ...39 more annotations...
  • 決定每個 shard 要被分配到哪個 data node 上
  • 為 cluster 設置多個 master node
  • 一旦發現被選中的 master node 出現問題,就會選出新的 master node
  • 每個 node 啟動時就預設是一個 master eligible node,可以透過設定 node.master: false 取消此預設設定
  • 處理 request 的 node 稱為 Coordinating Node,其功能是將 request 轉發到合適的 node 上
  • 所有的 node 都預設是 Coordinating Node
  • coordinating node 可以直接接收 search request 並處理,不需要透過 master node 轉過來
  • 可以保存資料的 node,每個 node 啟動後都會預設是 data node,可以透過設定 node.data: false 停用 data node 功能
  • 由 master node 決定如何把分片分發到不同的 data node 上
  • 每個 node 上都保存了 cluster state
  • 只有 master 才可以修改 cluster state 並負責同步給其他 node
  • 每個 node 都會詳細紀錄本身的狀態資訊
  • shard 是 Elasticsearch 分散式儲存的基礎,包含 primary shard & replica shard
  • 每一個 shard 就是一個 Lucene instance
  • primary shard 功能是將一份被索引後的資料,分散到多個 data node 上存放,實現儲存方面的水平擴展
  • primary shard 的數量在建立 index 時就會指定,後續是無法修改的,若要修改就必須要進行 reindex
  • 當 primary shard 遺失時,replica shard 就可以被 promote 成 primary shard 來保持資料完整性
  • replica shard 數量可以動態調整,讓每個 data node 上都有完整的資料
  • ES 7.0 開始,primary shard 預設為 1,replica shard 預設為 0
  • replica shard 若設定過多,會降低 cluster 整體的寫入效能
  • replica shard 必須和 primary shard 被分配在不同的 data node 上
  • 所有的 primary shard 可以在同一個 data node 上
  • 透過 GET _cluster/health/<target> 可以取得目前 cluster 的健康狀態
  • Yellow:表示 primary shard 可以正常分配,但 replica shard 分配有問題
  • 透過 GET /_cat/shards/<target> 可以取得目前的 shard 狀態
  • replica shard 無法被分配,因此 cluster 健康狀態為黃色
  • 若是擔心 reboot 機器造成 failover 動作開始執行,可以設定將 replication 延遲一段時間後再執行(透過調整 settings 中的 index.unassigned.node_left.delayed_timeout 參數),避免無謂的 data copy 動作 (此功能稱為 delay allocation)
  • 集群變紅,代表有 primary shard 丟失,這個時候會影響讀寫。
  • 如果 node 重新回來,會從 translog 中恢復沒有寫入的資料
  • 設定 index settings 之後,primary shard 數量無法隨意變更
  • 不建議直接發送請求到master節點,雖然也會工作,但是大量請求發送到 master,會有潛在的性能問題
  • shard 是 ES 中最小的工作單元
  • shard 是一個 Lucene 的 index
  • 將 Index Buffer 中的內容寫入 Segment,而這寫入的過程就稱為 Refresh
  • 當 document 被 refresh 進入到 segment 之後,就可以被搜尋到了
  • 在進行 refresh 時先將 segment 寫入 cache 以開放查詢
  • 將 document 進行索引時,同時也會寫入 transaction log,且預設都會寫入磁碟中
  • 每個 shard 都會有對應的 transaction log
  • 由於 transaction log 都會寫入磁碟中,因此當 node 從故障中恢復時,就會優先讀取 transaction log 來恢復資料
張 旭

Kubernetes Components | Kubernetes - 0 views

  • A Kubernetes cluster consists of a set of worker machines, called nodes, that run containerized applications
  • Every cluster has at least one worker node.
  • The control plane manages the worker nodes and the Pods in the cluster.
  • ...29 more annotations...
  • The control plane's components make global decisions about the cluster
  • Control plane components can be run on any machine in the cluster.
  • for simplicity, set up scripts typically start all control plane components on the same machine, and do not run user containers on this machine
  • The API server is the front end for the Kubernetes control plane.
  • kube-apiserver is designed to scale horizontally—that is, it scales by deploying more instances. You can run several instances of kube-apiserver and balance traffic between those instances.
  • Kubernetes cluster uses etcd as its backing store, make sure you have a back up plan for those data.
  • watches for newly created Pods with no assigned node, and selects a node for them to run on.
  • Factors taken into account for scheduling decisions include: individual and collective resource requirements, hardware/software/policy constraints, affinity and anti-affinity specifications, data locality, inter-workload interference, and deadlines.
  • each controller is a separate process, but to reduce complexity, they are all compiled into a single binary and run in a single process.
  • Node controller
  • Job controller
  • Endpoints controller
  • Service Account & Token controllers
  • The cloud controller manager lets you link your cluster into your cloud provider's API, and separates out the components that interact with that cloud platform from components that only interact with your cluster.
  • If you are running Kubernetes on your own premises, or in a learning environment inside your own PC, the cluster does not have a cloud controller manager.
  • An agent that runs on each node in the cluster. It makes sure that containers are running in a Pod.
  • The kubelet takes a set of PodSpecs that are provided through various mechanisms and ensures that the containers described in those PodSpecs are running and healthy.
  • The kubelet doesn't manage containers which were not created by Kubernetes.
  • kube-proxy is a network proxy that runs on each node in your cluster, implementing part of the Kubernetes Service concept.
  • kube-proxy maintains network rules on nodes. These network rules allow network communication to your Pods from network sessions inside or outside of your cluster.
  • kube-proxy uses the operating system packet filtering layer if there is one and it's available.
  • Kubernetes supports several container runtimes: Docker, containerd, CRI-O, and any implementation of the Kubernetes CRI (Container Runtime Interface).
  • Addons use Kubernetes resources (DaemonSet, Deployment, etc) to implement cluster features
  • namespaced resources for addons belong within the kube-system namespace.
  • all Kubernetes clusters should have cluster DNS,
  • Cluster DNS is a DNS server, in addition to the other DNS server(s) in your environment, which serves DNS records for Kubernetes services.
  • Containers started by Kubernetes automatically include this DNS server in their DNS searches.
  • Container Resource Monitoring records generic time-series metrics about containers in a central database, and provides a UI for browsing that data.
  • A cluster-level logging mechanism is responsible for saving container logs to a central log store with search/browsing interface.
張 旭

The differences between Docker, containerd, CRI-O and runc - Tutorial Works - 0 views

  • Docker isn’t the only container contender on the block.
  • Container Runtime Interface (CRI), which defines an API between Kubernetes and the container runtime
  • Open Container Initiative (OCI) which publishes specifications for images and containers.
  • ...20 more annotations...
  • for a lot of people, the name “Docker” itself is synonymous with the word “container”.
  • Docker created a very ergonomic (nice-to-use) tool for working with containers – also called docker.
  • docker is designed to be installed on a workstation or server and comes with a bunch of tools to make it easy to build and run containers as a developer, or DevOps person.
  • containerd: This is a daemon process that manages and runs containers.
  • runc: This is the low-level container runtime (the thing that actually creates and runs containers).
  • libcontainer, a native Go-based implementation for creating containers.
  • Kubernetes includes a component called dockershim, which allows it to support Docker.
  • Kubernetes prefers to run containers through any container runtime which supports its Container Runtime Interface (CRI).
  • Kubernetes will remove support for Docker directly, and prefer to use only container runtimes that implement its Container Runtime Interface.
  • Both containerd and CRI-O can run Docker-formatted (actually OCI-formatted) images, they just do it without having to use the docker command or the Docker daemon.
  • Docker images, are actually images packaged in the Open Container Initiative (OCI) format.
  • CRI is the API that Kubernetes uses to control the different runtimes that create and manage containers.
  • CRI makes it easier for Kubernetes to use different container runtimes
  • containerd is a high-level container runtime that came from Docker, and implements the CRI spec
  • containerd was separated out of the Docker project, to make Docker more modular.
  • CRI-O is another high-level container runtime which implements the Container Runtime Interface (CRI).
  • The idea behind the OCI is that you can choose between different runtimes which conform to the spec.
  • runc is an OCI-compatible container runtime.
  • A reference implementation is a piece of software that has implemented all the requirements of a specification or standard.
  • runc provides all of the low-level functionality for containers, interacting with existing low-level Linux features, like namespaces and control groups.
crazylion lee

GitHub - dstotijn/hetty: Hetty is an HTTP toolkit for security research. It aims to bec... - 0 views

  •  
    "Hetty is an HTTP toolkit for security research. It aims to become an open source alternative to commercial software like Burp Suite Pro, with powerful features tailored to the needs of the infosec and bug bounty community."
張 旭

Choosing an HTTP Status Code - Stop Making It Hard - Racksburg - 0 views

  •  
    絕佳的解說
crazylion lee

dularion/streama: It's like Netflix, but self-hosted! http://dularion.github.io/streama/ - 0 views

  •  
    "It's like Netflix, but self-hosted! http://dularion.github.io/streama/"
張 旭

React 入门实例教程 - 阮一峰的网络日志 - 0 views

  • React 起源于 Facebook 的内部项目,因为该公司对市场上所有 JavaScript MVC 框架,都不满意,就决定自己写一套,用来架设 Instagram 的网站。
  • 项目本身也越滚越大,从最早的UI引擎变成了一整套前后端通吃的 Web App 解决方案
  • React Native 项目,目标更是宏伟,希望用写 Web App 的方式去写 Native App。
  • ...9 more annotations...
  • 凡是使用 JSX 的地方,都要加上 type="text/babel"
  • Browser.js 的作用是将 JSX 语法转为 JavaScript 语法,这一步很消耗时间,实际上线的时候,应该将它放到服务器完成。
  • HTML 语言直接写在 JavaScript 语言之中,不加任何引号,这就是 JSX 的语法,它允许 HTML 与 JavaScript 的混写
  • JSX 的基本语法规则:遇到 HTML 标签(以 < 开头),就用 HTML 规则解析;遇到代码块(以 { 开头),就用 JavaScript 规则解析。
  • JSX 允许直接在模板插入 JavaScript 变量。如果这个变量是一个数组,则会展开这个数组的所有成员
  • 所有组件类都必须有自己的 render 方法,用于输出组件
  • 组件类的第一个字母必须大写,否则会报错
  • 组件类只能包含一个顶层标签
  • 添加组件属性,有一个地方需要注意,就是 class 属性需要写成 className ,for 属性需要写成 htmlFor ,这是因为 class 和 for 是 JavaScript 的保留字。
crazylion lee

torch/torch7: http://torch.ch - 0 views

張 旭

Specification - Swagger - 0 views

shared by 張 旭 on 29 Jul 16 - No Cached
  • A list of parameters that are applicable for all the operations described under this path.
  • MUST NOT include duplicated parameters
  • this field SHOULD be less than 120 characters.
  • ...33 more annotations...
  • Unique string used to identify the operation.
  • The id MUST be unique among all operations described in the API.
  • A list of MIME types the operation can consume.
  • A list of MIME types the operation can produce
  • A unique parameter is defined by a combination of a name and location.
  • There can be one "body" parameter at most.
  • Required. The list of possible responses as they are returned from executing this operation.
  • The transfer protocol for the operation. Values MUST be from the list: "http", "https", "ws", "wss".
  • Declares this operation to be deprecated. Usage of the declared operation should be refrained. Default value is
  • A declaration of which security schemes are applied for this operation.
  • A unique parameter is defined by a combination of a name and location.
  • Path
  • Query
  • Header
  • Body
  • Form
  • Required. The location of the parameter. Possible values are "query", "header", "path", "formData" or "body".
  • the parameter value is actually part of the operation's URL
  • Parameters that are appended to the URL
  • The payload that's appended to the HTTP request.
  • Since there can only be one payload, there can only be one body parameter.
  • The name of the body parameter has no effect on the parameter itself and is used for documentation purposes only
  • body and form parameters cannot exist together for the same operation
  • This is the only parameter type that can be used to send files, thus supporting the file type.
  • If the parameter is in "path", this property is required and its value MUST be true.
  • default value is false.
  • The schema defining the type used for the body parameter.
  • The value MUST be one of "string", "number", "integer", "boolean", "array" or "file"
  • Default value is false
  • Required if type is "array". Describes the type of items in the array.
  • Determines the format of the array if type array is used
  • enum
  • pattern
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