Questions tagged [docker]
Docker is an open source project that automates the deployment of applications inside software containers.
4,108
questions
352
votes
27
answers
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views
How can I use environment variables in Nginx.conf
I have a docker container running Nginx, that links to another docker container. The host name and IP address of the second container is loaded into the Nginx container as environment variables on ...
- 3,669
264
votes
4
answers
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views
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 ...
- 2,996
254
votes
11
answers
550k
views
Docker Container time & timezone (will not reflect changes)
Where do Docker containers get their time information? I've created some containers from the basic ubuntu:trusty image, and when I run it and request 'date', I get UTC time.
For awhile I got around ...
- 2,683
221
votes
3
answers
333k
views
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 ...
- 2,429
196
votes
10
answers
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views
How to install tzdata on a ubuntu docker image?
I have the following line in the Dockerfile.
RUN apt-get install -y tzdata
When I run it, it asks for my input. After I provided my input, it hung there. Does anybody know how to solve this problem?
...
- 2,119
155
votes
6
answers
279k
views
How can I debug a docker container initialization?
I had an issue with a container, even though it builds perfectly it does not properly start. The cause is a workaround I've added to the Dockerfile (for having a self-configured /etc/hosts routing)
...
- 2,131
140
votes
4
answers
45k
views
How to handle security updates within Docker containers?
When deploying applications onto servers, there is typically a separation between what the application bundles with itself and what it expects from the platform (operating system and installed ...
- 1,964
129
votes
4
answers
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views
Why do we use a OS Base Image with Docker if containers have no Guest OS?
I've just started to study Docker and there's something that's being quite confusing for me. As I've read on Docker's website a container is different from a virtual machine. As I understood a ...
- 1,403
127
votes
10
answers
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views
Can you run Docker natively on the new Windows 10 (Ubuntu) bash userspace?
My understanding was that the primary limitation of running docker on other OSs was the Linux Network containers that made it possible. (Certainly for Macs).
Recently Microsoft announced a beta of a ...
- 2,689
122
votes
4
answers
170k
views
How do I auto-start docker containers at system boot?
What is a good way to automatically start docker containers when the system boots up?
Is there a preferred way to do this on Ubuntu 14.04?
I've used supervisord in the past to auto start web apps. ...
- 1,330
111
votes
8
answers
122k
views
Is it possible to rerun kubernetes job?
I have the following Kubernetes Job configuration:
---
apiVersion: batch/v1
kind: Job
metadata:
name: dbload
creationTimestamp:
spec:
template:
metadata:
name: dbload
spec:
...
- 1,243
108
votes
3
answers
119k
views
Can Mac OS X be run inside Docker? [closed]
Can Mac OS X be run inside Docker? If so, any suggestion as to how?
And would it be running headless, or there would be a possibility to connect to the GUI remotely?
- 1,281
97
votes
7
answers
318k
views
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/...
- 1,093
80
votes
6
answers
140k
views
Make a Docker application write to stdout
I'm deploying a 3rd-party application in compliance with the 12 factor advisory, and one of the points tell that application logs should be printed to stdout/stderr: then clustering software can ...
- 11k
80
votes
5
answers
128k
views
Configuring Docker to not use the 172.17.0.0 range
Due to problems with captive portals and the default Docker IP range I am trying to make Docker use the 198.18.0.0 range, instead of 172.17.0.0, which clashes with the captive portals used on the ...
- 1,136
77
votes
2
answers
129k
views
Downloading docker image for transfer to non-internet-connected machine
I'm working in an office where my laptop is internet-connected, but tightly controlled. I am not allowed to install unauthorized software onto it.
My development workstation is mine to do with as I ...
- 3,343
75
votes
4
answers
155k
views
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?
- 953
73
votes
5
answers
201k
views
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 ...
- 2,250
73
votes
7
answers
182k
views
How to specify hostname for the running container?
I'm having trouble setting the hostname on a running docker container. I'm also having trouble understanding how to specify hostname after the image is started.
I started a container from an image I ...
- 855
72
votes
13
answers
212k
views
Docker containers can't resolve DNS on Ubuntu 14.04 Desktop Host
I'm running into a problem with my Docker containers on Ubuntu 14.04 LTS.
Docker worked fine for two days, and then suddenly I lost all network connectivity inside my containers. The error output ...
- 2,031
72
votes
5
answers
136k
views
Which OS is running in my Docker container?
Most of the time, using one of these two, I can tell which OS is running in my Docker container (alpine, centOS, etc)
But this time, I can't tell:
bash-4.2$ uname -a
Linux 6fe5c6d1451c 2.6.32-...
- 831
71
votes
1
answer
190k
views
How does "restart: always" policy work in docker-compose?
I have docker compose file with PostgreSQL and my application, like this:
version: '3'
services:
postgresql:
image: postgres:9.6.6
ports:
- 9932:5432
expose:
- "5432"
...
- 813
70
votes
4
answers
222k
views
failed to get D-Bus connection: Operation not permitted
I'm trying to list services on my CentOS image running in Docker using
systemctl list-units
but I get this error message:
Failed to get D-Bus connection: Operation not permitted
Any suggestions ...
- 1,107
67
votes
3
answers
63k
views
How to use docker secrets without a swarm cluster?
Currently we im a running application on a single docker container, the application needs all sorts of sensitive data to be passed as environments variables,
Im putting those on the run command so ...
- 1,233
66
votes
5
answers
145k
views
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/...
- 763
64
votes
2
answers
66k
views
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 ...
- 1,085
59
votes
5
answers
54k
views
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 ...
- 963
57
votes
4
answers
20k
views
Relationship between Vagrant, Docker, Chef and OpenStack (or similar products)?
I am a web developer, but I am also interested in a few administrative tasks. Hence, the new move from pure administration to dev-ops comes handy for me.
Anyway, I have some problems to put a few ...
- 781
56
votes
1
answer
27k
views
Pros and cons of using Windows containers instead of Linux containers for Docker?
I'm installing Docker for Windows (CE) on Windows 10 and the first screen asks me:
[ ] Use Windows containers instead of Linux containers (this can be changed after installation)
This ...
- 700
54
votes
3
answers
49k
views
Docker: failed to add the pair interfaces (operation not supported)
After installing Docker, I am getting an error when I try to run the Hello World example:
Error response from daemon: Cannot start container ...
- 543
54
votes
12
answers
183k
views
Docker COPY issue - "no such file or directory"
In my Dockerfile I have the following 'COPY" statement:
# Copy app code
COPY /srv/visitor /srv/visitor
It should go without saying that in my host system, under the "/srv/visitor" directory, there ...
- 1,674
53
votes
6
answers
115k
views
"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 ...
- 1,371
51
votes
4
answers
121k
views
How to install Docker on AWS EC2 instance with AMI (CE/EE Update)
What is the current way of installing Docker on an AWS EC2 instance running the AMI?
There has been an announcement of Docker Enterprise Edition and now I want to know if anything has changed.
Until ...
- 682
49
votes
2
answers
66k
views
docker-compose: option to automaticaly remove container after run in docker-compose.yml
The docker-compose run reference states that it has the --rm option to
Remove container after run.
I want to make this a default run behavior for some of services I specify in docker-compose.yml.
...
- 1,214
48
votes
11
answers
187k
views
Docker pull: TLS handshake timeout
I get this consistenly (Ubuntu 16.04 LTS):
$ docker pull nginx
Using default tag: latest
Error response from daemon: Get https://registry-1.docker.io/v2/: net/http: TLS handshake timeout
However ...
- 2,852
48
votes
5
answers
69k
views
Steps for limiting outside connections to docker container with iptables?
My goal is to limit access to docker containers to just a few public IP addresses. Is there a simple, repeatable process to accomplish my goal? Understanding only the basics of iptables while using ...
- 719
46
votes
4
answers
90k
views
How is Docker Compose version 2 "volumes" syntax supposed to look?
With Docker Compose v1.6.0+, there now is a new/version 2 file syntax for the docker-compose.yml file. The changes include a separate top level key named volumes. This allows to "centralize" volume ...
- 1,251
44
votes
11
answers
71k
views
Check is container/service running with docker-compose
I am using the docker-compose.
Some commands like up -d service_name or start service_name are returning right away and this is pretty useful if you don't want the containers running to depend on ...
- 1,214
44
votes
3
answers
71k
views
How to set system time dynamically in a Docker container
Is there any way to set a Docker containers system time dynamically (at run time) without effecting the host machine?
Using
hwclock --set --date "Sat Aug 17 08:31:24 PDT 2016"
gives the following ...
- 1,537
41
votes
3
answers
52k
views
Writing Apache2 Logs to stdout/stderr?
I'm running Apache2 in a docker container, and want to write nothing to the disk, writing logs to stdout and stderr. I've seen a few different ways to do this (Supervisord and stdout/stderr, Apache ...
- 695
40
votes
11
answers
74k
views
How do you restart all Tasks of a Service?
We have a task that loads some configuration files from an external data source. After the settings are uploaded we would like to be able to restart all the tasks in a service so that the settings ...
- 501
40
votes
7
answers
27k
views
Update the container of a service in Amazon ECS
What kind of approach is recommended for updating the container of a service which is running in Amazon ECS?
The AWS documentation says: "If you have updated the Docker image of your application, you ...
- 502
36
votes
3
answers
81k
views
What does "the input device is not a TTY" exactly mean in "docker run" output?
This is a command that works:
$ echo 'hi there' | docker run -i ubuntu cat
hi there
This is a command that responds with an error message:
$ echo 'hi there' | docker run -it ubuntu cat
the input ...
- 599
36
votes
6
answers
35k
views
Mount Docker container contents in host file system
I want to be able to inspect the contents of a Docker container (read-only). An elegant way of doing this would be to mount the container's contents in a directory. I'm talking about mounting the ...
- 563
36
votes
1
answer
18k
views
What is the point of the docker-proxy process? Why is a userspace tcp proxy needed?
I have noticed that there is docker-proxy process running for each published port. What is the purpose of this process? Why is a user space tcp proxy needed for this?
$ ps -Af | grep proxy
root ...
- 1,038
34
votes
9
answers
96k
views
Clearing/Deleting Docker Logs
On our docker implementation on GCE, we are running out of space on the root file system.
Since images themselves are stored on a separate 1TB volume, the images themselves shouldn't be the problem.
...
- 463
33
votes
7
answers
122k
views
Creating a docker mysql container with a prepared database scheme
I want to create a docker image on top of the mysql one that already contains the necessary scheme for my app.
I tried adding lines to the Dockerfile that will import my scheme as a sql file. I did ...
- 621
33
votes
4
answers
18k
views
Docker daemon doesn't start on boot on CoreOS
I have a vanilla install of CoreOS (835.9.0) and it doesn't start the docker daemon on startup. It only starts when I SSH in and do eg docker ps.
How can i make the docker daemon automatically start ...
- 1,261
33
votes
5
answers
43k
views
Send mail from Docker container with host's Postfix
I am running an Ubuntu 14.04 (Linux) server. I have installed and configured Postfix and OpenDKIM very nicely on the server; I can send emails to myself with commands such as echo hi | sendmail root, ...
- 491
32
votes
3
answers
88k
views
How to get php-fpm to log to stdout / stderr when running in a docker container
I have php-fpm in a docker container and in the Dockerfile I edit the fpm config file (/etc/php5/fpm/pool.d/www.conf) to set up access logs to go to /var/log/fpm-access.log and error logs to go to /...
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