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張 旭

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

viget.com/...cker-on-os-x-the-missing-guide

docker mac system deploy

shared by 張 旭 on 25 Oct 14 - No Cached
  • 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.
  • ...9 more annotations...
  • 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
crazylion lee

Supervisor: A Process Control System - supervisor 3.1a1-dev documentation - 1 views

supervisord.org

monitoring sysadmin python linux unix supervisor

shared by crazylion lee on 13 Feb 14 - Cached
  • crazylion lee on 13 Feb 14
     
    Supervisor is a client/server system that allows its users to monitor and control a number of processes on UNIX-like operating systems. It shares some of the same goals of programs like launchd, daemontools, and runit. Unlike some of these programs, it is not meant to be run as a substitute for init as "process id 1". Instead it is meant to be used to control processes related to a project or a customer, and is meant to start like any other program at boot time.
crazylion lee

Writing a Bootloader | Blog of Osanda - 1 views

osandamalith.wordpress.com/...writing-a-bootloader

bootloader linux c

shared by crazylion lee on 06 Nov 15 - No Cached
  • crazylion lee on 06 Nov 15
     
    "A bootloader is a special program that is executed each time a bootable device is initialized by the computer during its power on or reset that will load the kernel image into the memory. This application is very close to hardware and to the architecture of the CPU. All x86 PCs boot in Real Mode. In this mode you have only 16-bit instructions. Our bootloader runs in Real Mode and our bootloader is a 16-bit program."
crazylion lee

DiskMaker X - 1 views

diskmakerx.com

mac boot usb

shared by crazylion lee on 24 Sep 16 - No Cached
crazylion lee

netboot.xyz - 0 views

netboot.xyz

netboot ipxe network boot linux

shared by crazylion lee on 27 Feb 16 - No Cached
  • crazylion lee on 27 Feb 16
     
    "The DHCP bootloaders will automatically get a network address if you have DHCP on your network while the static bootloaders will prompt you for network information. SHA256 checksums are generated during each build of iPXE and are located here. You can also view the scripts that are embedded into the images here. "
張 旭

phusion/baseimage-docker - 1 views

github.com/...baseimage-docker

docker ubuntu base system

shared by 張 旭 on 24 Jun 15 - No Cached
    • 張 旭
      張 旭 on 24 Jun 15
       
      原始的 docker 在執行命令時，預設就是將傳入的 COMMAND 當成 PID 1 的程序，執行完畢就結束這個  docker，其他的 daemons 並不會執行，而 baseimage 解決了這個問題。
    • crazylion lee
      crazylion lee on 17 Dec 15
       
      好棒棒
  • docker exec
  • Through SSH
  • ...57 more annotations...
  • docker exec -t -i YOUR-CONTAINER-ID bash -l
  • Login to the container
  • Baseimage-docker only advocates running multiple OS processes inside a single container.
  • Password and challenge-response authentication are disabled by default. Only key authentication is allowed.
  • A tool for running a command as another user
  • The Docker developers advocate the philosophy of running a single logical service per container. A logical service can consist of multiple OS processes.
  • All syslog messages are forwarded to "docker logs".
  • Splitting your logical service into multiple OS processes also makes sense from a security standpoint.
  • Baseimage-docker provides tools to encourage running processes as different users
  • sometimes it makes sense to run multiple services in a single container, and sometimes it doesn't.
  • Baseimage-docker advocates running multiple OS processes inside a single container, and a single logical service can consist of multiple OS processes.
  • using environment variables to pass parameters to containers is very much the "Docker way"
  • add additional daemons (e.g. your own app) to the image by creating runit entries.
  • the shell script must run the daemon without letting it daemonize/fork it.
  • All executable scripts in /etc/my_init.d, if this directory exists. The scripts are run in lexicographic order.
  • variables will also be passed to all child processes
  • Environment variables on Unix are inherited on a per-process basis
  • there is no good central place for defining environment variables for all applications and services
  • centrally defining environment variables
  • One of the ideas behind Docker is that containers should be stateless, easily restartable, and behave like a black box.
  • a one-shot command in a new container
  • immediately exit after the command exits,
  • However the downside of this approach is that the init system is not started. That is, while invoking COMMAND, important daemons such as cron and syslog are not running. Also, orphaned child processes are not properly reaped, because COMMAND is PID 1.
  • Baseimage-docker provides a facility to run a single one-shot command, while solving all of the aforementioned problems
  • Nginx is one such example: it removes all environment variables unless you explicitly instruct it to retain them through the env configuration option.
  • Mechanisms for easily running multiple processes, without violating the Docker philosophy
  • Ubuntu is not designed to be run inside Docker
  • According to the Unix process model, the init process -- PID 1 -- inherits all orphaned child processes and must reap them
  • Syslog-ng seems to be much more stable
  • cron daemon
  • Rotates and compresses logs
  • /sbin/setuser
  • A tool for installing apt packages that automatically cleans up after itself.
  • a single logical service inside a single container
  • A daemon is a program which runs in the background of its system, such as a web server.
  • The shell script must be called run, must be executable, and is to be placed in the directory /etc/service/<NAME>. runsv will switch to the directory and invoke ./run after your container starts.
  • If any script exits with a non-zero exit code, the booting will fail.
  • If your process is started with a shell script, make sure you exec the actual process, otherwise the shell will receive the signal and not your process.
  • any environment variables set with docker run --env or with the ENV command in the Dockerfile, will be picked up by my_init
  • not possible for a child process to change the environment variables of other processes
  • they will not see the environment variables that were originally passed by Docker.
  • We ignore HOME, SHELL, USER and a bunch of other environment variables on purpose, because not ignoring them will break multi-user containers.
  • my_init imports environment variables from the directory /etc/container_environment
  • /etc/container_environment.sh - a dump of the environment variables in Bash format.
  • modify the environment variables in my_init (and therefore the environment variables in all child processes that are spawned after that point in time), by altering the files in /etc/container_environment
  • my_init only activates changes in /etc/container_environment when running startup scripts
  • environment variables don't contain sensitive data, then you can also relax the permissions
  • Syslog messages are forwarded to the console
  • syslog-ng is started separately before the runit supervisor process, and shutdown after runit exits.
  • RUN apt-get update && apt-get upgrade -y -o Dpkg::Options::="--force-confold"
  • /sbin/my_init --skip-startup-files --quiet --
  • By default, no keys are installed, so nobody can login
  • provide a pregenerated, insecure key (PuTTY format)
  • RUN /usr/sbin/enable_insecure_key
  • docker run YOUR_IMAGE /sbin/my_init --enable-insecure-key
  • RUN cat /tmp/your_key.pub >> /root/.ssh/authorized_keys && rm -f /tmp/your_key.pub
  • The default baseimage-docker installs syslog-ng, cron and sshd services during the build process
張 旭

Queue Workers: How they work - Diving Laravel - 0 views

divinglaravel.com/queue-workers-how-they-work

php programming laravel queue worker

shared by 張 旭 on 02 Mar 19 - No Cached
  • define workers as a simple PHP process that runs in the background with the purpose of extracting jobs from a storage space and run them with respect to several configuration options.
  • have to manually restart the worker to reflect any code change you made in your application.
  • avoiding booting up the whole app on every job
  • ...7 more annotations...
  • instruct Laravel to create an instance of your application and start executing jobs, this instance will stay alive indefinitely which means the action of starting your Laravel application happens only once when the command was run & the same instance will be used to execute your jobs
  • This will start an instance of the application, process a single job,
  • and then kill the script.
  • Using queue:listen ensures that a new instance of the app is created for every job, that means you don't have to manually restart the worker in case you made changes to your code, but also means more server resources will be consumed.
  • the queue:listen command runs the WorkCommand inside a loop
  • The connection this worker will be pulling jobs from
  • The queue the worker will use to find jobs
  • 張 旭 on 02 Mar 19
     
    "define workers as a simple PHP process that runs in the background with the purpose of extracting jobs from a storage space and run them with respect to several configuration options."
張 旭

Queues - Laravel - The PHP Framework For Web Artisans - 0 views

laravel.com/queues

php programming laravel queue worker framework

shared by 張 旭 on 02 Mar 19 - No Cached
  • Laravel queues provide a unified API across a variety of different queue backends, such as Beanstalk, Amazon SQS, Redis, or even a relational database.
  • The queue configuration file is stored in config/queue.php
  • a synchronous driver that will execute jobs immediately (for local use)
  • ...56 more annotations...
  • A null queue driver is also included which discards queued jobs.
  • In your config/queue.php configuration file, there is a connections configuration option.
  • any given queue connection may have multiple "queues" which may be thought of as different stacks or piles of queued jobs.
  • each connection configuration example in the queue configuration file contains a queue attribute.
  • if you dispatch a job without explicitly defining which queue it should be dispatched to, the job will be placed on the queue that is defined in the queue attribute of the connection configuration
  • pushing jobs to multiple queues can be especially useful for applications that wish to prioritize or segment how jobs are processed
  • specify which queues it should process by priority.
  • If your Redis queue connection uses a Redis Cluster, your queue names must contain a key hash tag.
  • ensure all of the Redis keys for a given queue are placed into the same hash slot
  • all of the queueable jobs for your application are stored in the app/Jobs directory.
  • Job classes are very simple, normally containing only a handle method which is called when the job is processed by the queue.
  • we were able to pass an Eloquent model directly into the queued job's constructor. Because of the SerializesModels trait that the job is using, Eloquent models will be gracefully serialized and unserialized when the job is processing.
  • When the job is actually handled, the queue system will automatically re-retrieve the full model instance from the database.
  • The handle method is called when the job is processed by the queue
  • The arguments passed to the dispatch method will be given to the job's constructor
  • delay the execution of a queued job, you may use the delay method when dispatching a job.
  • dispatch a job immediately (synchronously), you may use the dispatchNow method.
  • When using this method, the job will not be queued and will be run immediately within the current process
  • specify a list of queued jobs that should be run in sequence.
  • Deleting jobs using the $this->delete() method will not prevent chained jobs from being processed. The chain will only stop executing if a job in the chain fails.
  • this does not push jobs to different queue "connections" as defined by your queue configuration file, but only to specific queues within a single connection.
  • To specify the queue, use the onQueue method when dispatching the job
  • To specify the connection, use the onConnection method when dispatching the job
  • defining the maximum number of attempts on the job class itself.
  • to defining how many times a job may be attempted before it fails, you may define a time at which the job should timeout.
  • using the funnel method, you may limit jobs of a given type to only be processed by one worker at a time
  • using the throttle method, you may throttle a given type of job to only run 10 times every 60 seconds.
  • If an exception is thrown while the job is being processed, the job will automatically be released back onto the queue so it may be attempted again.
  • dispatch a Closure. This is great for quick, simple tasks that need to be executed outside of the current request cycle
  • When dispatching Closures to the queue, the Closure's code contents is cryptographically signed so it can not be modified in transit.
  • Laravel includes a queue worker that will process new jobs as they are pushed onto the queue.
  • once the queue:work command has started, it will continue to run until it is manually stopped or you close your terminal
  • queue workers are long-lived processes and store the booted application state in memory.
  • they will not notice changes in your code base after they have been started.
  • during your deployment process, be sure to restart your queue workers.
  • customize your queue worker even further by only processing particular queues for a given connection
  • The --once option may be used to instruct the worker to only process a single job from the queue
  • The --stop-when-empty option may be used to instruct the worker to process all jobs and then exit gracefully.
  • Daemon queue workers do not "reboot" the framework before processing each job.
  • you should free any heavy resources after each job completes.
  • Since queue workers are long-lived processes, they will not pick up changes to your code without being restarted.
  • restart the workers during your deployment process.
  • php artisan queue:restart
  • The queue uses the cache to store restart signals
  • the queue workers will die when the queue:restart command is executed, you should be running a process manager such as Supervisor to automatically restart the queue workers.
  • each queue connection defines a retry_after option. This option specifies how many seconds the queue connection should wait before retrying a job that is being processed.
  • The --timeout option specifies how long the Laravel queue master process will wait before killing off a child queue worker that is processing a job.
  • When jobs are available on the queue, the worker will keep processing jobs with no delay in between them.
  • While sleeping, the worker will not process any new jobs - the jobs will be processed after the worker wakes up again
  • the numprocs directive will instruct Supervisor to run 8 queue:work processes and monitor all of them, automatically restarting them if they fail.
  • Laravel includes a convenient way to specify the maximum number of times a job should be attempted.
  • define a failed method directly on your job class, allowing you to perform job specific clean-up when a failure occurs.
  • a great opportunity to notify your team via email or Slack.
  • php artisan queue:retry all
  • php artisan queue:flush
  • When injecting an Eloquent model into a job, it is automatically serialized before being placed on the queue and restored when the job is processed
張 旭

鳥哥的 Linux 私房菜 -- 第二章、主機規劃與磁碟分割 - 0 views

linux.vbird.org/...0130designlinux.php

linux system

shared by 張 旭 on 23 Jun 21 - Cached
  • BIOS會依據使用者的設定去取得能夠開機的硬碟， 並且到該硬碟裡面去讀取第一個磁區的MBR位置。 MBR這個僅有446 bytes的硬碟容量裡面會放置最基本的開機管理程式， 此時BIOS就功成圓滿，而接下來就是MBR內的開機管理程式的工作了。
  • 開機管理程式的目的是在載入(load)核心檔案， 由於開機管理程式是作業系統在安裝的時候所提供的，所以他會認識硬碟內的檔案系統格式，因此就能夠讀取核心檔案， 然後接下來就是核心檔案的工作，開機管理程式與 BIOS 也功成圓滿
  • 開機管理程式除了可以安裝在MBR之外， 還可以安裝在每個分割槽的開機磁區(boot sector)
  • 張 旭 on 23 Jun 21
     
    "BIOS會依據使用者的設定去取得能夠開機的硬碟， 並且到該硬碟裡面去讀取第一個磁區的MBR位置。 MBR這個僅有446 bytes的硬碟容量裡面會放置最基本的開機管理程式， 此時BIOS就功成圓滿，而接下來就是MBR內的開機管理程式的工作了。"
張 旭

LXC vs Docker: Why Docker is Better | UpGuard - 0 views

www.upguard.com/...docker-vs-lxc

docker container devops

shared by 張 旭 on 28 Jun 21 - No Cached
  • LXC (LinuX Containers) is a OS-level virtualization technology that allows creation and running of multiple isolated Linux virtual environments (VE) on a single control host.
  • Docker, previously called dotCloud, was started as a side project and only open-sourced in 2013. It is really an extension of LXC’s capabilities.
  • run processes in isolation.
  • ...35 more annotations...
  • Docker is developed in the Go language and utilizes LXC, cgroups, and the Linux kernel itself. Since it’s based on LXC, a Docker container does not include a separate operating system; instead it relies on the operating system’s own functionality as provided by the underlying infrastructure.
  • Docker acts as a portable container engine, packaging the application and all its dependencies in a virtual container that can run on any Linux server.
  • a VE there is no preloaded emulation manager software as in a VM.
  • In a VE, the application (or OS) is spawned in a container and runs with no added overhead, except for a usually minuscule VE initialization process.
  • LXC will boast bare metal performance characteristics because it only packages the needed applications.
  • the OS is also just another application that can be packaged too.
  • a VM, which packages the entire OS and machine setup, including hard drive, virtual processors and network interfaces. The resulting bloated mass usually takes a long time to boot and consumes a lot of CPU and RAM.
  • don’t offer some other neat features of VM’s such as IaaS setups and live migration.
  • LXC as supercharged chroot on Linux. It allows you to not only isolate applications, but even the entire OS.
  • Libvirt, which allows the use of containers through the LXC driver by connecting to 'lxc:///'.
  • 'LXC', is not compatible with libvirt, but is more flexible with more userspace tools.
  • Portable deployment across machines
  • Versioning: Docker includes git-like capabilities for tracking successive versions of a container
  • Component reuse: Docker allows building or stacking of already created packages.
  • Shared libraries: There is already a public registry (http://index.docker.io/ ) where thousands have already uploaded the useful containers they have created.
  • Docker taking the devops world by storm since its launch back in 2013.
  • LXC, while older, has not been as popular with developers as Docker has proven to be
  • LXC having a focus on sys admins that’s similar to what solutions like the Solaris operating system, with its Solaris Zones, Linux OpenVZ, and FreeBSD, with its BSD Jails virtualization system
  • it started out being built on top of LXC, Docker later moved beyond LXC containers to its own execution environment called libcontainer.
  • Unlike LXC, which launches an operating system init for each container, Docker provides one OS environment, supplied by the Docker Engine
  • LXC tooling sticks close to what system administrators running bare metal servers are used to
  • The LXC command line provides essential commands that cover routine management tasks, including the creation, launch, and deletion of LXC containers.
  • Docker containers aim to be even lighter weight in order to support the fast, highly scalable, deployment of applications with microservice architecture.
  • With backing from Canonical, LXC and LXD have an ecosystem tightly bound to the rest of the open source Linux community.
  • Docker Swarm
  • Docker Trusted Registry
  • Docker Compose
  • Docker Machine
  • Kubernetes facilitates the deployment of containers in your data center by representing a cluster of servers as a single system.
  • Swarm is Docker’s clustering, scheduling and orchestration tool for managing a cluster of Docker hosts. 
  • rkt is a security minded container engine that uses KVM for VM-based isolation and packs other enhanced security features. 
  • Apache Mesos can run different kinds of distributed jobs, including containers. 
  • Elastic Container Service is Amazon’s service for running and orchestrating containerized applications on AWS
  • LXC offers the advantages of a VE on Linux, mainly the ability to isolate your own private workloads from one another. It is a cheaper and faster solution to implement than a VM, but doing so requires a bit of extra learning and expertise.
  • Docker is a significant improvement of LXC’s capabilities.
張 旭

phusion/passenger-docker: Docker base images for Ruby, Python, Node.js and Meteor web apps - 0 views

github.com/...passenger-docker

docker ruby rails

shared by 張 旭 on 14 Jan 22 - No Cached
  • Ubuntu 20.04 LTS as base system
  • 2.7.5 is configured as the default.
  • Python 3.8
  • ...23 more annotations...
  • A build system, git, and development headers for many popular libraries, so that the most popular Ruby, Python and Node.js native extensions can be compiled without problems.
  • Nginx 1.18. Disabled by default
  • production-grade features, such as process monitoring, administration and status inspection.
  • Redis 5.0. Not installed by default.
  • The image has an app user with UID 9999 and home directory /home/app. Your application is supposed to run as this user.
  • running applications without root privileges is good security practice.
  • Your application should be placed inside /home/app.
  • COPY --chown=app:app
  • Passenger works like a mod_ruby, mod_nodejs, etc. It changes Nginx into an application server and runs your app from Nginx.
  • placing a .conf file in the directory /etc/nginx/sites-enabled
  • The best way to configure Nginx is by adding .conf files to /etc/nginx/main.d and /etc/nginx/conf.d
  • files in conf.d are included in the Nginx configuration's http context.
  • any environment variables you set with docker run -e, Docker linking and /etc/container_environment, won't reach Nginx.
  • To preserve these variables, place an Nginx config file ending with *.conf in the directory /etc/nginx/main.d, in which you tell Nginx to preserve these variables.
  • By default, Phusion Passenger sets all of the following environment variables to the value production
  • Setting these environment variables yourself (e.g. using docker run -e RAILS_ENV=...) will not have any effect, because Phusion Passenger overrides all of these environment variables.
  • PASSENGER_APP_ENV environment variable
  • passenger-docker autogenerates an Nginx configuration file (/etc/nginx/conf.d/00_app_env.conf) during container boot.
  • The configuration file is in /etc/redis/redis.conf. Modify it as you see fit, but make sure daemonize no is set.
  • You can add additional daemons to the image by creating runit entries.
  • The shell script must be called run, must be executable
  • the shell script must run the daemon without letting it daemonize/fork it.
  • We use RVM to install and to manage Ruby interpreters.
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