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Questions tagged [containers]

Use for generic questions on containers that do not fall under a specific container technology, like Docker, LXC, FreeBSD Jails, OpenBSD sysjails, Solaris Containers, WPARs, etc. Also use where the specific technology is not relevant to the question.

Containers are Operating System level Virtualization technology. Where kernel of OS allows for the existence of multiple isolated user-space instances. Containers may appear as fully virtualize operating system, nevertheless they share kernel with the host OS and any issue affecting the kernel may equally affect all running containers.

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Why it is recommended to run only one process in a container?

In many blog posts, and general opinion, there is a saying that goes "one process per container". Why does this rule exist? Why not run ntp, nginx, uwsgi and more processes in a single container that needs to have all processes to work? blog posts…
Evgeny Zislis
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What are the reasons Docker should not be used for databases?

I'm having a discussion with a friend about use cases for Docker. One guy in the team wants to use Docker for everything - like a kind of universal unix process wrapper. The other thinks that Docker should only be used for stateless applications…
hawkeye
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What is a container?

There are some questions about containers, such as: What role do Configuration Managment tools play in immutable infrastructure? Which problems does a container orchestration solve? Simple CI/CD Containers in AWS My questions: What is actually a…
Pierre.Vriens
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Difference between chroot and Docker

I don't understand the difference between docker and chroot. Yes its nice in terms of the packaging the registry. But somehow I get the feeling its just chroot with extra bells and whistles. I know I'm missing something. It'd would be great to know…
Vipin Menon
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Where should I put my application configuration?

I've been reading lately a debate about "Where should properties that depend on the environment be stored?". The classical way is to have multiple property files, one by environment, and based on an environment variable (DEV, PROD...), you choose…
carcaret
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On Azure, how do I run a short-lived Docker container on a schedule?

I have a fairly simple Unix shell script packaged up in an Alpine Linux Docker container hosted on an Azure container registry. A VM runs this script with cron: docker login docker pull example.com/bar:latest docker run …
Sijmen Mulder
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Simple CI/CD Containers in AWS

I am using AWS Code Pipeline, Code Build to create a new Docker container and push it to ECR. My application is a simple straight-forward single-container based. What would be less friction approach to pull down current running Container and…
Naveen Vijay
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Does Docker allow containers to be OS agnostic?

We currently use a Windows based server to host 2 VMs. One VM uses Windows with a Windows app and the other VM uses Linux with a Linux app. Is the below scenario possible? Bare server with Windows 2016 (no VMs). Install Docker engine. Install…
nanonerd
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Combine Docker Swarm and Kubernetes

My company is trying to play a little catch-up in the DevOps space. I have been doing a lot of research on containerization of applications and the orchestration systems that go with it. I came across an article (one that I wish I had saved) where…
EvanM
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Which problems does a container orchestration solve?

Every company who has anything to do with containers these days, including public cloud providers, is creating their own solution for container orchestration. These include: Kubernetes Docker Swarm Amazon EC2 Container Service Apache…
Evgeny Zislis
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How to investigate a main process that has died in a docker container?

Sometimes you have to investigate a container, which is stopped, or a container which after starting up dies very quickly and stops. docker exec -ti bash only works on running containers, once it finishes, the bash prompt terminates as…
SztupY
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What role do Configuration Managment tools play in immutable infrastructure?

If I'm using immutable servers/containers, do I need tools like Chef, Puppet, Ansible, or Salt? Those config management tools are designed to establish a configuration and then maintain it. If I'm deploying immutable servers, should I use…
Dave Swersky
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Docker Container capacity planning

I'm running my application on 4 Virtual Machines with 8 3.2 GHz Virtual CPUs and 32 GB, however, I will be splitting up the processes into separate containers. I am not sure how many containers to run per host. What are the typical numbers? For…
shrao
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Should worker processes of web applications be placed in separate containers?

My setup is based on a Flask app that has a PostgreSQL and Redis database. In addition, a worker process is started to handle asynchronous tasks such as sending emails. I use Gunicorn to create multiple app processes. Passing of jobs from the app…
Moritz
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Does "docker run" actually SSH into the container?

If I run docker run -it ubuntu bash Does it actually SSH into the container, or does it use another protocol?
Buvanesh Kumar
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