Turner  Crona

Turner Crona

1595825880

How to access files outside a Docker container

If containers are isolated, how can they communicate to the host machine, perhaps to store data? Because when we create a container from an image, any data generated is lost when the container is removed.

So we need a way to have permanent storage.

We can do so using Bind Mounts and Volumes.

There’s not a lot of difference between the two, except Bind Mounts can point to any folder on the host computer, and are not managed by Docker directly.

Let’s start with them. One classic example is logs. Suppose your app creates a log file, inside the container, in /usr/src/app/logs. You can map that to a folder on the host machine, using the -v (same as --volume) flag when you run the container with docker run, like this: -v ~/logs:/usr/src/app/logs

This will map that folder to the logs subfolder in the user’s home directory.

Node: the _-m_ or _--mount_ flag works in a very similar way

This is the flag used with the examplenode image we created previously:

docker run -d -p 80:3000 -v ~/logs:/usr/src/app/logs --name node-app examplenode

So now we can run our Node app, and any log will be stored in the host computer, rather than inside the Docker container.

Note that the _examplenode_ app does not generate any log in _/usr/src/app/logs_, it’s just an example and you would need to set that logging up first.

The details about the volume will be listed when you run docker inspect on the container name, under “Mounts”:

"Mounts": [
    {
        "Type": "bind",
        "Source": "/Users/flavio/logs",
        "Destination": "/usr/src/app/logs",
        "Mode": "",
        "RW": true,
        "Propagation": "rprivate"
    }
],

#docker #container #volumes #bind mounts

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How to access files outside a Docker container
Mikel  Okuneva

Mikel Okuneva

1602317778

Ever Wondered Why We Use Containers In DevOps?

At some point we’ve all said the words, “But it works on my machine.” It usually happens during testing or when you’re trying to get a new project set up. Sometimes it happens when you pull down changes from an updated branch.

Every machine has different underlying states depending on the operating system, other installed programs, and permissions. Getting a project to run locally could take hours or even days because of weird system issues.

The worst part is that this can also happen in production. If the server is configured differently than what you’re running locally, your changes might not work as you expect and cause problems for users. There’s a way around all of these common issues using containers.

What is a container

A container is a piece of software that packages code and its dependencies so that the application can run in any computing environment. They basically create a little unit that you can put on any operating system and reliably and consistently run the application. You don’t have to worry about any of those underlying system issues creeping in later.

Although containers were already used in Linux for years, they became more popular in recent years. Most of the time when people are talking about containers, they’re referring to Docker containers. These containers are built from images that include all of the dependencies needed to run an application.

When you think of containers, virtual machines might also come to mind. They are very similar, but the big difference is that containers virtualize the operating system instead of the hardware. That’s what makes them so easy to run on all of the operating systems consistently.

What containers have to do with DevOps

Since we know how odd happenings occur when you move code from one computing environment to another, this is also a common issue with moving code to the different environments in our DevOps process. You don’t want to have to deal with system differences between staging and production. That would require more work than it should.

Once you have an artifact built, you should be able to use it in any environment from local to production. That’s the reason we use containers in DevOps. It’s also invaluable when you’re working with microservices. Docker containers used with something like Kubernetes will make it easier for you to handle larger systems with more moving pieces.

#devops #containers #containers-devops #devops-containers #devops-tools #devops-docker #docker #docker-image

Iliana  Welch

Iliana Welch

1597368540

Docker Tutorial for Beginners 8 - Build and Run C++ Applications in a Docker Container

Docker is an open platform that allows use package, develop, run, and ship software applications in different environments using containers.
In this course We will learn How to Write Dockerfiles, Working with the Docker Toolbox, How to Work with the Docker Machine, How to Use Docker Compose to fire up multiple containers, How to Work with Docker Kinematic, Push images to Docker Hub, Pull images from a Docker Registery, Push stacks of servers to Docker Hub.
How to install Docker on Mac.

#docker tutorial #c++ #docker container #docker #docker hub #devopstools

Iliana  Welch

Iliana Welch

1595249460

Docker Explained: Docker Architecture | Docker Registries

Following the second video about Docker basics, in this video, I explain Docker architecture and explain the different building blocks of the docker engine; docker client, API, Docker Daemon. I also explain what a docker registry is and I finish the video with a demo explaining and illustrating how to use Docker hub

In this video lesson you will learn:

  • What is Docker Host
  • What is Docker Engine
  • Learn about Docker Architecture
  • Learn about Docker client and Docker Daemon
  • Docker Hub and Registries
  • Simple demo to understand using images from registries

#docker #docker hub #docker host #docker engine #docker architecture #api

August  Murray

August Murray

1615124700

Docker Swarm: Container Orchestration Using Docker Swarm

Introduction

A swarm consists of multiple Docker hosts that run in swarm mode and act as managers (to manage membership and delegation) and workers (which run swarm services). A given Docker host can be a manager, a worker, or perform both roles.

When Docker is running in swarm mode, you can still run standalone containers on any of the Docker hosts participating in the swarm, as well as swarm services. A key difference between standalone containers and swarm services is that only swarm managers can manage a swarm, while standalone containers can be started on any daemon.

In this demonstration, we will see how to configure the docker swarm and how to perform basic tasks.

Pre-requisites

  1. For our demonstration, we will be using centos-07.
  2. We will be using 3 machines for our lab, 1 machine as a swarm Manager node and 2 swarm worker nodes. These servers have below IP details:

192.168.33.76 managernode.unixlab.com

192.168.33.77 workernode1.unixlab.com

192.168.33.78 workernode2.unixlab.com

3. The memory should be at least 2 GB and there should be at least 2 core CPUs for each node.

#docker #containers #container-orchestration #docker-swarm

Haylie  Conn

Haylie Conn

1623747973

Implementing Non-Trivial Containerized Systems: Picking Components

We’ll use Icecast, Liquidsoap, youtube-dl, and FFmpeg as the base components for creating our radio station.

So, you want to start a radio station, eh?

This is the first part of a multi-part series on designing and building non-trivial containerized solutions. We’re making a radio station using off-the-shelf components and some home-spun software, all on top of Docker, Docker Compose, and eventually, Kubernetes.
In this part, we’re going to explore how the different parts of the system interface with one another, to set the stage for our next post, where we Dockerize everything!

I first met Icecast (https://icecast.org/) when I worked at a web-hosting startup around the turn of the millennium. One night, one of my co-workers and I had the crazy idea to load a bunch of audio files on the networked file server and stream them to our workstations. We could listen to music while we worked 90+ hours a week. Strange times. After realizing it wasn’t as simple as exporting .ogg files over HTTP, we found Icecast (and its pal, Ices2) and built a rudimentary, local-network broadcast radio station.

#open source #cloud #tutorial #docker #containers #docker containers #docker container