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.

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Is database persistence scaled outside of a container in general and Kubernetes in particular?

Kubernetes launches thousands of containers on demand. I thought this was to accommodate load and scale as needed, load balancing between all the containers. What happens to the database? Do they ...
1 vote
0 answers
13 views

PreStop container hook on Pod termination

I have two containers in my Pod (one main app container and another one is just a simple nginx reverse proxy) containers: - name: my-app - name: my-nginx lifecycle: ...
0 votes
1 answer
23 views

Check TZ in Container Image without creating instance?

I have a requirement to assure that the container image we build runs in UTC only. I'd like to avoid starting it up just to check the link on /etc/localtime. I thought maybe a tool like dive that ...
0 votes
2 answers
55 views

Creating container image without docker

Is it possible to build a container image as a simple user account on a system which does not have docker or podman installed? In other words, is there a user-space tool/application which can build an ...
0 votes
0 answers
12 views

How are containers secured with MACVLAN networks?

Containers cannot be connected both to an internal bridge and to the host network at the same time, according to this question. However, this is what I need; I want a set of containers to be connected ...
22 votes
3 answers
18k views

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'...
4 votes
2 answers
73 views

Docker vs Virtualisation

I am trying to understand the underlining architecture of Docker. The diagram that's been shown everywhere claims that in contrast with Virtualisation technologies such as "VirtualBox", ...
2 votes
1 answer
29 views

Container deployment sync problem with Ansible

Imagine the following situation after you have switched from docker-compose to Ansible: You start a DB container which needs time to boot up You want to load data dump into it (could be also you ...
0 votes
0 answers
33 views

install helm chart package without public container registry (offline,locally)

When I want to install a package in kubernetes cluster with helm chart, for example install gitlab with helm, during installation there is need to download docker image from a public registry and I ...
5 votes
4 answers
2k views

ERROR: Unable to read database state: No such file or directory

I was trying to install Photon by pulling the docker image. But when I run docker build -t photon . I am getting the below error. ---> Running in 3076fb42ef8b ERROR: Unable to read database state:...
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0 answers
23 views

Duplicate docker layers should not count twice in quota

On my machine, I have a 1 Gb docker image with several layers. I tag it many times with different tags. On my machine it still takes 1 Gb, as shown by "docker system df". But when I push ...
1 vote
0 answers
23 views

Access AWS Secret inside docker file

I have a docker file running on AWS that looks like the following: FROM ubuntu:latest RUN apt-get update RUN apt-get install -y python3 RUN apt-get install -y git RUN git init RUN git clone https://&...
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0 answers
19 views

Azure Devops build and deployment process for .NET Core app - excessive disk space use on servers by Docker

My Azure Virtual Machine Scaleset instances, used for hosting of an application, are filling up due to excessive disk space usage by Docker. The deployment of the application is based on an Azure ...
1 vote
0 answers
12 views

Private certificate authority and container images

We have a internal domain name, let's say "mycompany.net" with a private CA which delivers all our internal application HTTPS certificates for this domain like "myapp.mycompany.net"...
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0 answers
17 views

Best Practice for Managing Ephemeral Storage on Bare Metal Kubernetes Instance?

Host OS: Ubuntu 20.04 Kubernetes: 1.23 RAM: 64g HDD: 3.7Tb Containers are failing and rescheduling due to low ephemeral storage. Ex. The node was low on resource: ephemeral-storage. Container <...
0 votes
2 answers
33 views

How to create a container from an image

I have this following image: REPOSITORY TAG IMAGE ID CREATED SIZE nvcr.io/nvidia/pytorch 18.04-py3 c3555fec4fe6 3 years ago 5.9GB The goal is to use Ubuntu ...
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0 answers
16 views

How to containerise developement of GUI apps (C++, C#)

I'm looking for a solution to virtualise the environment for the development of C++/C# Windows apps that have a UI that display live video. The apps needs to run native on the local machine during ...
1 vote
4 answers
2k views

How to get exposed ports from inside of container?

I want to know which port(s) are exposed when user run the image. docker run -p 1000:1234 myimagename I want to get 1234 value in container since I will use it for some configurations(IIS bindings ...
0 votes
0 answers
8 views

Commit and Push Container Running in Azure Container Group?

My question has to do with the posture of Azure container groups. I'm comfortable working with Docker images and and deploying those in a Kubernetes environment. I'm new to Azure. I have a ...
0 votes
0 answers
45 views

Access API on a container from another container

I have 2 containers A and B which both contains webapps A is listening on 443 (apache2) B is listening on 4000 (node.js) Since I need to access to both services with https from my machine (win10), I ...
0 votes
0 answers
27 views

What is the difference between `gitlab-runner start` and `gitlab-runner run`? What is the purpose of `run`?

What is the difference between gitlab-runner start and gitlab-runner run? The documentation is not very clear on this: gitlab-runner run This is main command that is executed when GitLab Runner is ...
0 votes
0 answers
26 views

Where can I set the restart policy for a Azure Linux (container) App Service from the portal?

Is it possible to set the restart policy for a Azure Linux container from the portal? I build, push and deploy my application from the Azure Pipeline portal, but I need to change the restart policy ...
3 votes
1 answer
50 views

How to dockerize a jupyer notebooks project?

I have a project composed of 6 different Jupyter Notebooks and 4 CSV files. I would like also my colleagues can try to use this project, even if they don't have python installed and maybe with another ...
0 votes
0 answers
11 views

Tools for "scanning" container (hardening) vulnerabilities vs tools for "performing" the hardening

Container hardening is the process of fixing the vulnerabilities. CIS has published a list of container vulnerabilities which should be addressed to complete the hardening process. Q1. Are there ...
1 vote
0 answers
26 views

Launching VM instances only when needed

I am looking for the right tool to launch VM instances on a cloud platform only when I need them. Once launched, they should run a containerized script (let's call it a job) that runs for about 5 to ...
3 votes
2 answers
7k views

VPN container providing access to host's LAN?

I'm kinda new to this Docker thing and I'm interested in getting a biffed up VPS for some containers (websites/data, mysql, nginx, rocket.chat, etc) but I wouldn't like to access them in the wild (...
2 votes
2 answers
115 views

Restart container if its application hangs

I have a critical container application which task consist of polling sensors and taking consequent action on some external hardware. If the application of the container crashes it's fine. restart: ...
1 vote
1 answer
95 views

Docker Swarm stop working with redeploy service, require system reboot

I got a Docker Swarm with 3 nodes, and contain around 40-50 stack on it, now its random stop working to redeploy my new changes its just say in new mode, and really don't know what going one here. ID ...
2 votes
1 answer
2k views

How to communicate between AWS ECS containers

Problem How do ECS containers communicate between each others? Situation I use docker compose ecs integration. In AWS docker context, docker compose up did a deploy correctly. But reverse proxy doesn'...
1 vote
2 answers
171 views

Best Practice for Container Image Versioning

I'm looking for some guidance on best practices for container image versioning and despite reading a number of the best practice guides they leave some ambiguity. I understand that most container ...
46 votes
3 answers
13k views

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 ...
5 votes
1 answer
604 views

Docker Images via Container vs Dockerfile

Pardon the dumb questions, but I've been learning about Docker and container technologies and I was learning about using Dockerfiles to specify build instructions for an image, and how each ...
0 votes
1 answer
102 views

How can I deal with container "patching" in a strict release process?

I am building a new Container and Kubernetes system for my company. Overall it is going well, but container patching has me a bit confused. We follow a fairly strict release process. New versions ...
0 votes
1 answer
262 views

Difference between Docker container with Debian vs VM with Debian?

What is the difference between running a Docker container with Debian (eg. https://hub.docker.com/_/debian/) and then running a virtual machine with Debian? And why is it still an advantage if any? I'...
3 votes
1 answer
2k views

Accessing TPM from inside a Docker Container

I want to implement Vault as part of the DevOps build pipeline to store all the secrets like passwords and certificates. I understand that Vault keeps the data encrypted but I have been asked to look ...
0 votes
1 answer
43 views

When do I run applications on a server in a pod and when to run them directly on the base operating system?

I am trying to get started in the DevOps Field by setting up a small server currently with Virtualbox, later on for a small team. For my basic setup I plan to use gitea as self-hosted git and Jenkins ...
2 votes
2 answers
857 views

Container Image Promotion across environments in ECR/ECS

We have started doing some initial work on deploying containers on ECS Fargate service. However we are not yet completely figured out how to manage our image promotion across different environments. ...
1 vote
2 answers
433 views

How to get into an App Container Manually with Garden-RunC Backend?

So I have been trying this-tutorial to access the runC container from the diego-cell VM. However, when I try to run /var/vcap/packages/runc/bin/runc exec -t <instance_id> /bin/bash I get the ...
1 vote
1 answer
103 views

How to create a local network mapping in linux

I'm deploying nextcloud via docker, however the way the configuration is set up, it creates a subnetwork at 10.10.10.0/24 on the system it's running on instead of running it on 127.0.0.1. Then the ...
0 votes
1 answer
1k views

How to build, package and deploy a react-native-web app in a Docker container?

Given there is a react-native-web solution, what needs to be done to build it and run inside a Docker container? What is the build environment/toolchain? Which environment is required to run? From ...
1 vote
1 answer
32 views

Testing docker image builds when low level libraries change

Background In our organization we have many small repos for shared libraries used among our applications. Particularly, we have many Python libraries and Python applications. We have a structures like:...
0 votes
1 answer
178 views

How can I use a buildah script for image generation using GitHub Actions?

Buildah scripts typically use shell. You can see an example of a script here, #!/bin/sh ctr=$(buildah from alpine:3) buildah commit "$ctr" myAlpineImage Let's say I have such a shell script ...
0 votes
2 answers
60 views

Service to service communication - through proxy or direct?

A common scenario is two or more services behind a reverse proxy, typically each deployed in a container: | service 1 | | service 2 | \ / \ / ...
0 votes
1 answer
36 views

Does RAM Come Into The Container vs VM Decision?

I am currently running a Java trading system on a VM that needs ~32 GB RAM and runs (almost) 24/7. There are a couple of engines linked to it that require 4GB + 8BG respectively. I am considering ...
0 votes
1 answer
48 views

Increase concurrent users by limiting container resources with docker-swarm

Consider the scenario where I have: 4 replicas of an app 4 cores On load, the app consumes 100% for a single core Can I tell each replica to only use 50% of the core and if so, would this allow at ...
1 vote
1 answer
5k views

Docker Build Ending Up `returned a non-zero code: 1`

Running mktexlsr /var/lib/texmf ... done. Building format(s) --all. This may take some time... done. build.sh: line 81: -: No such file or directory The command '/bin/sh -c bash build.sh' ...
0 votes
1 answer
356 views

kubernetes quota vs limit. What are they? How are they different? When should I use one or the other?

I have been reading through the docs but it still is not clear as to why I should use one or the other. They have great examples of how to configure them but don't answer the why for quotes or limits ...
4 votes
1 answer
337 views

Change docker container’s log PATH

Team: All my container logs are under /var/log/containers.. Where in kubelet or docker config can I specify this path such that logs are instead created under new path? Ex : /shared ? Instead of /var/...
139 votes
5 answers
59k views

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 ...
1 vote
1 answer
395 views

kubelet connecting to docker.sock instead of containerd.sock

Kubernetes version: latest Installation method: kubeadm Host OS: debian9 container runtime: containerd Kubelet fails when starting and after inspecting the logs using journalctl -xeu kubelet i see ...