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Questions tagged [docker]

Docker is an open source project that automates the deployment of applications inside software containers.

Docker is an open source project that automates the deployment of applications inside software containers. Docker extends a common container format called Linux Containers (LXC), with a high-level API providing a lightweight virtualization solution that runs processes in isolation. Docker utilizes LXC, cgroups, and the Linux kernel itself. Unlike traditional virtual machines, a Docker container does not include a separate operating system, instead it relies on the operating system’s functionality provided by the underlying infrastructure.

4302 questions
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How to remove an image tag in Docker without removing the image itself?

Let's say I want to tag a Docker image, and make a typo. How do I remove the tag without removing the image itself? Neither the manpages nor the Docker documentation mention removing tags. docker tag 0e5574283393 my-imaj docker tag 0e5574283393…
Mihai
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How can I override CMD when running a docker image?

I want to inspect a docker image created by someone else with both an entrypoint and cmd specified, for example: ENTRYPOINT ["/usr/sbin/apache2ctl"] CMD ["-D", "FOREGROUND"] I currently do: docker run --interactive --tty --entrypoint=/bin/bash…
warp
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8 answers

Multiple commands in Docker CMD directive

Not understanding what is happening when I try to execute two commands at runtime via CMD directive in `Dockerfile. I assumed that this should work: CMD ["/etc/init.d/nullmailer", "start", ";", "/usr/sbin/php5-fpm"] But it's not working. Container…
Vladan
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Why isn't ifconfig available in Ubuntu Docker container?

With the base ubuntu:12.04, ifconfig is not available in the container, though the ip command is available, why is this? and, how to get ifconfig in the container?
Pellaeon
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5 answers

The right way to keep docker container started when it used for periodic tasks

I have docker container with installed and configured software. There is no any programm supposed to be started/runned all the time. What I want - its ability to start some command depending on external events. like: docker exec mysupercont…
Korjavin Ivan
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2 answers

When building from Dockerfile, Debian/Ubuntu package install debconf Noninteractive install not allowed

I've set the following environment so that no question/dialog is asked during apt-get install: ENV DEBIAN_FRONTEND noninteractive # export DEBIAN_FRONTEND="noninteractive" Which is equivalent to: export DEBIAN_FRONTEND="noninteractive" Yet,…
Phil L.
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Why can't I cd to a directory with docker run?

I need to run an application from a specific directory. $ sudo docker run -P ubuntu/decomposer 'cd /local/deploy/decomposer; ./decomposer-4-15-2014' 2014/10/09 21:30:03 exec: "cd /local/deploy/decomposer; ./decomposer-4-15-2014": stat cd…
schmmd
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Removing Docker data volumes?

The official Docker documentation mentions that I need to run docker rm -v containername to specifically remove a data volume. But what do you do if you already removed all the containers referencing the specific data volume ?
p4guru
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55
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6 answers

"No command specified" from re-imported docker image/container

I am trying to take a docker container from one machine and run it on another and encountering this error: "Error response from daemon: No command specified". Below is a simplified example showing the problem: docker --version Docker version 1.10.1,…
Greendrake
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4 answers

docker-compose no such service: myapp

I've run an image with: 'docker-compose up' With 'docker ps' i get: CREATED STATUS PORTS NAMES 55e1fd18acf1 simpleappnodedocker_web "node app.js" 6 seconds ago Up 6 seconds …
stackdave
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4 answers

How can I run a full OS in a Docker container, without specifying a command?

I'm following the CoreOS Docker Documentation and it mentions starting containers with commands like: docker run someImageName /bin/somebinary Where someImageName is an image. When /bin/somebinary exits, the image will no longer be running. I would…
mikemaccana
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1 answer

docker - volumes vs mount binds. what are the use cases?

After reading and playing around with docker for a short while, I am considering using it in my production environment. However I am still trying to understand the difference between mount binds and volumes. According to Dockers documentation on…
GKman
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6 answers

How do I expose the docker API over TCP?

I am using portainer and am unable to manage remote endpoints. I tried using the command line to connect to remote docker nodes, but got a message Cannot connect to the Docker daemon at tcp://:. Is the docker daemon running?. Yes,…
Lord Loh.
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2 answers

How to debug Docker cache invalidation?

Docker has a cache, which is great, but all I see in the "docker build" output is either: ---> Using cache or the output of the command (which implies it's not using the cache). After one step in my Dockerfile (a COPY), it clearly doesn't use the…
Timmay
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4 answers

Is it a good practice to put update/upgrade statements inside the Dockerfile?

new to Docker here and I am trying to make it right. I want to create a docker container to 'deep freeze' an application created with bash scripts and a lot of dependencies, so that I don't have to maintain it as much anymore. I think docker is…
MortyAndFam
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