I have a failure to understand how does the docker container stay up and running. From what I know, if the container doesn't have any active processes it will shut down automatically independent of commands given.
That's the reason I have instructed my docker-compose.yml to do this command which keeps it alive:
gateway:
build: .
image: me/gateway
container_name: gateway
command: tail -F /dev/null <------
# restart: always
ports:
- "10091:10091"
volumes:
- ./logs:/root/logs
- vendor:/root/vendor
- .:/root
env_file:
- .env
While my Dockerfile does the following:
FROM php:7-fpm-alpine
EXPOSE 10091
WORKDIR /root
COPY . .
COPY src/scripts/generateConfig.sh /usr/local/bin/generateConfig
RUN ["chmod", "+x", "/usr/local/bin/generateConfig"]
In this scenario the container stays up, and it's all fine. However I would like to run a script once the container starts, so I have added the additional line to the end of my Dockerfile:
ENTRYPOINT ["generateConfig"]
After the command is ran, the container automatically stops. There are no errors when I inspect the log, as the script does the job as it is supposed to. Script is responsible for running a Ratchet web socket process indefinitely.
How can I make the script run and simultaneously keep my container running?
When you start a container it runs the command you defined in ENTRYPOINT or in CMD.
This command usually starts a process and as long as this process runs in the foreground the container will still run.
If your process is run in the background the container will stop.
Thus, if you are running a script you need to make sure it never ends.
You can simply achieve that by adding such line to the end of your script:
tail -f <some log file> # keep listening on your application log file.
Alternatively, you can add some while true:
while true; sleep 2; done
Hope it'll help
I have found the issue. Script which was in command to start the web socket process had this line starting it:
nohup php ${serviceProcess} >> /dev/null 2>&1 &
The solution was not to suppress output by using only:
nohup php ${serviceProcess}
It works well now
Related
I'm using docker compose for running my application in dev. environment.
version: '3.4'
services:
web:
build:
context: .
target: base
ports:
- "5000:5000"
stdin_open: true
tty: true
volumes:
- ./src:/src
command: node src/main/server/index.js
Composer is starting container and I can see logs output from node application. When I press CTR-C - container is stopped and my application is stopped as well.
I would like to have my application to be stopped when I press CTRL-C instead of whole container.
The same behavior when running an app within Windows CMD or Linux shell. For example, to restart an app - press CTRL-C, repeat startup command (node src/main/server/index.js by pressing top arrow key), and press enter.
I was thinking I could use something like this, but it does not work.
command: bash -c "node src/main/server/index.js
I know I can use command below to achieve expected behavior:
docker-compose up -d (to start in detached mode)
docker-compose exec web bash (run interactive shell)
node src/main/server/index.js (start node manually)
But maybe there is a way to start bash interactive bash and run an application in bash using singe command docker-compose up ?
Docker runs a main process in its containers, as such, stopping the main process will also stop the container.
I will attempt to answer your question, but I don't think that you should work like that in a Dev environment.
Answering your question, you can "trap" the container in a main process, then just bash into the container and perform the app start.
In order to trap the container, just change the docker-compose command to:
command: while true; do sleep 1; done;
To get into an interactive bash in the container:
docker exec -it <CONTAINER-ID> bash
And then you can start or stop the node app.
It seems that the problem you are facing is a container taking a lot to start, you should probably reorder your Dockerfile to prevent it from redownloading all dependencies (or other long process) every time a file changes.
You should place your COPY command after all commands that should persist from across builds, and take advantage of docker's image layering.
If you need a "hot reload" feature, you can research Webpack hot reloading.
You would need to bind your host volume to the container's work directory in order to let webpack properly watch the files and reload the app.
I'm trying to launch container using docker-compose services.But unfortunetly, container exited whith code 0.
Containers is build thanks to a repository which is from a .tar.gz archive. This archive is a Centos VM.
I want to create 6 container from the same archive.
Instead of typing 6 times docker command, I would like to create a docker-compose.yml file where i can summarize their command and tag.
I have started to write docker-compose.yml file just for create one container.
Here is my docker-compose.yml :
version: '2'
services:
dvpt:
image: compose:test.1
container_name: cubop1
command: mkdir /root/essai/
tty: true
Do not pay attention to the command as I have just to specify one.
So my question is, why the container is exiting ? Is there a another solution to build these container at the same time ?
Thanks for your responses.
The answer is actually the first comment. I'll explain Miguel's comment a bit.
First, we need to understand that a Docker container runs a single command. The container will be running as long as that process the command started is running. Once the process is completed and exits then the container will stop.
With that understanding, we can make an assumption of what is happening in your case. When you start your dvpt service it runs the command mkdir /root/essai/. That command creates the folder and then exits. At this point, the Docker container is stopped because the process exited (with status 0, indicating that mkdir completed with no error).
run your docker in background with -d
$ docker-compose up -d
and on docker-compose.yml add:
mydocker:
tty: true
You can end with command like tail -f /dev/null
It often works in my docker-compose.yml with
command: tail -f /dev/null
And it is easy to see how I keep the container running.
docker ps
We had a problem where two of the client services(vitejs) exited with code 0. I added the tty: true and it started to work.
dashboard:
tty: true
container_name: dashboard
expose:
- 8001
image: tilt.dev/dashboard
labels:
- "traefik.enable=true"
- "traefik.http.routers.dashboard.tls=true"
- "traefik.http.routers.dashboard.entrypoints=web"
- "traefik.http.routers.dashboard-wss.tls=true"
- "traefik.http.routers.dashboard-wss.entrypoints=wss"
One solution is to create a process that doesn't end, an infinite loop or something that can run continuously in the background. This will keep the container opened because the the process won't exit.
This is very much a hack though. I'm still looking for a better solution.
The Zend Server image does something like this. In their .sh script they have a final command:
exec /usr/local/bin/nothing
Which executes a file that continuously runs in the background. I've tried to copy the file contents here but it must be in binary.
EDIT:
You can also end your file with /bin/bash which begins a new terminal process in the container and keeps it from closing.
It can be case that program (from ENTRYPOINT/CMD) run successfully and exited (without demonizing itself). So check your ENTRYPOINT/CMD in Dockerfile.
Create a Dockerfile and add the below line to execute any shell scripts or commands without exit code 0 error. In your case, it should be
RUN mkdir /root/essai/
However, use the below line to execute shell script
RUN /<absolute_path_of_container>/demo.sh
I know i am too late for the answer but few days ago i also ran into the same problem and everything mentioned above not working. The real problem is as mentioned in the above answer that the docker stops after the command exits.
So i did a hack for this
Note i have used Dockerfile for creating image you can do it in your way below is just an example.
I used Supervisor for monitoring the process. As long as supervisor is monitoring the docker container will also not exit.
For those who also ran into the same problem will do the following thin to solve the issue:
#1 Install supervisor in Dockerfile
RUN apt-get install -y supervisor
#2 Create a config file (named supervisord.conf )for supervisor like this
[include]
files = /etc/supervisor/conf.d/*.conf
[program:app]
command=bash
#directory will be any folder where you wnat supervisor to cd before executing.
directory=/project
autostart=true
autorestart=true
startretries=3
#user will be anyone you want but make sure that user will have the enough privilage.
user=root
[supervisord]
nodaemon=true
[supervisorctl]
#3 Copy the supervisor conf file to docker
COPY supervisord.conf /etc/supervisord.conf
#4 Define an entrypoint
ENTRYPOINT ["supervisord","-c","/etc/supervisord.conf"]
Tht`s it now just build the file and run the container. it will keep container running.
Hope it helps you to solve the problem.
And Happy coding :-)
According to Controlling startup order in Compose, one can control the order in which Docker Compose starts containers by using a "wait-for-it" script. Script wait-for-it.sh expects both a host:port argument as well as the command that the script should execute when the port is available. The documentation recommends that Docker Compose invoke this script using the entrypoint: option. However, if one uses this option, the container will no longer run its default ENTRYPOINT or CMD because entrypoint: overrides the default.
How might one provide this default command to wait-for-it.sh so that the script can invoke the default ENTRYPOINT or CMD when the condition for which it waits is satisfied?
In my case, I've implemented a script wait-for-file.sh that polls waiting for a file to exist:
#!/bin/bash
set -e
waitFile="$1"
shift
cmd="$#"
until test -e $waitFile
do
>&2 echo "Waiting for file [$waitFile]."
sleep 1
done
>&2 echo "Found file [$waitFile]."
exec $cmd
Docker Compose invokes wait-for-file.sh as the entry-point to a slightly custom container derived from tomcat:8-jre8:
platinum-oms:
image: opes/platinum-oms
ports:
- "8080:8080"
volumes_from:
- liquibase
links:
- postgres:postgres
- activemq:activemq
depends_on:
- liquibase
- activemq
entrypoint: /wait-for-file.sh /var/run/liquibase/done
Before it exits successfully, another custom container liquibase creates /var/run/liquibase/done and so platinum-oms effectively waits for container liquibase to complete.
Once container liquibase creates file /var/run/liquibase/done, wait-for-file.sh prints Found file [/var/run/liquibase/done]., but fails to invoke default command catalina.sh run in base container tomcat:8-jre8. Why?
Test Scenario
I created a simplified test scenario docker-compose-wait-for-file to demonstrate my problem. Container ubuntu-wait-for-file waits for container ubuntu-create-file to create file /wait/done and then I expect container ubuntu-wait-for-file to invoke the default ubuntu container command /bin/bash, but instead, it exits. Why doesn't it work as I expect?
However, if one uses this option, the container will no longer run its default ENTRYPOINT or CMD command because entrypoint: overrides the default.
That is expected, which is why the wait-for-it is presented as a wrapper script.
It does allow to execute a "subcommand" though:
wait-for-it.sh host:port [-s] [-t timeout] [-- command args]
^^^^^^^^^^^^
The subcommand will be executed regardless if the service is up or not.
If you wish to execute the subcommand only if the service is up, add the --strict argument.
That means the CMD part of your image can be used for your actual container command, as its parameters will passed in parameters to the ENTRYPOINT command:
entrypoint: wait-for-it.sh host:port --
cmd: mycmd myargs
This should work... except for docker-compose issue 3140 (mentioned by the OP Derek Mahar in the comments)
entrypoint defined in docker-compose.yml wipes out CMD defined in Dockerfile
That issue suggests (Jan. 2021)
If you have a custom image you can add a startscript to the build and call it inside the dockerfile and in the docker-compose you can call it again.
Thats a way to avoid duplicate for more complicated entrypoints.
I want to install linode/lamp container to work on some wordpress project locally without messing up my machine with all the lamp dependencies.
I followed this tutorial which worked great (it's actually super simple).
Now I'd like to use docker-compose because I find it more convenient to simply having to type docker-compose up and being good to go.
Here what I have done:
Dockerfile:
FROM linode/lamp
RUN service apache2 start
RUN service mysql start
docker-compose.yml:
web:
build: .
ports:
- "80:80"
volumes:
- .:/var/www/example.com/public_html/
When I do docker-compose up, I get:
▶ docker-compose up
Recreating gitewordpress_web_1...
Attaching to gitewordpress_web_1
gitewordpress_web_1 exited with code 0
Gracefully stopping... (press Ctrl+C again to force)
I'm guessing I need a command argument in my docker-compose.yml but I have no idea what I should set.
Any idea what I am doing wrong?
You cannot start those two processes in the Dockerfile.
The Dockerfile determines what commands are to be run when building the image.
In fact many base images like the Debian ones are specifically designed to not allow starting any services during build.
What you can do is create a file called run.sh in the same folder that contains your Dockerfile.
Put this inside:
#!/usr/bin/env bash
service apache2 start
service mysql start
tail -f /dev/null
This script just starts both services and forces the console to stay open.
You need to put it inside of your container though, this you do via two lines in the Dockerfile. Overall I'd use this Dockerfile then:
FROM linode/lamp
COPY run.sh /run.sh
RUN chmod +x /run.sh
CMD ["/bin/bash", "-lc", "/run.sh"]
This ensures that the file is properly ran when firing up the container so that it stays running and also that those services actually get started.
What you should also look out for is that your port 80 is actually available on your host machine. If you have anything bound to it already this composer file will not work.
Should this be the case for you ( or you're not sure ) try changing the port line to like 81:80 or so and try again.
I would like to point you to another resource where LAMP server is already configured for you and you might find it handy for your local development environment.
You can find it mentioned below:
https://github.com/sprintcube/docker-compose-lamp
I am trying to get my head around the COMMAND option in docker compose. In my current docker-compose.yml i start the prosody docker image (https://github.com/prosody/prosody-docker) and i want to create a list of users when the container is actually started.
The documentation of the container states that a user can be made using environment options LOCAL, DOMAIN, and PASSWORD, but this is a single user. I need a list of users.
When reading some stuff around the internet it seemed that using the command option i should be able to execute commands in a starting or running container.
xmpp:
image: prosody/prosody
command: prosodyctl register testuser localhost testpassword
ports:
- "5222:5222"
- "127.0.0.1:5347:5347"
But this seems not to work, i checked to running container using docker exec -it <imageid> bash but the user is not created.
Is it possible to execute a command on a started container using docker-compose or are there other options?
The COMMAND instruction is exactly the same as what is passed at the end of a docker run command, for example echo "hello world" in:
docker run debian echo "hello world"
The command is interpreted as arguments to the ENTRYPOINT of the image, which in debian's case is /bin/bash. In the case of your image, it gets passed to this script. Looking at that script, your command will just get passed to the shell. I would have expected any command you pass to run successfully, but the container will exit once your command completes. Note that the default command is set in the Dockerfile to CMD ["prosodyctl", "start"] which is presumably a long-running process which starts the server.
I'm not sure how Prosody works (or even what it is), but I think you probably want to either map in a config file which holds your users, or set up a data container to persist your configuration. The first solution would mean adding something like:
volumes:
- my_prosodoy_config:/etc/prosody
To the docker-compose file, where my_prosody_config is a directory holding the config files.
The second solution could involve first creating a data container like:
docker run -v /etc/prosody -v /var/log/prosody --name prosody-data prosody-docker echo "Prosody Data Container"
(The echo should complete, leaving you with a stopped container which has volumes set up for the config and logs. Just make sure you don't docker rm this container by accident!)
Then in the docker-compose file add:
volumes_from:
- prosody-data
Hopefully you can then add users by running docker exec as you did before, then running prosodyctl register at the command line. But this is dependent on how prosody and the image behave.
CMD is directly related to ENTRYPOINT in Docker (see this question for an explanation). So when changing one of them, you also have to check how this affects the other. If you look at the Dockerfile, you will see that the default command is to start prosody through CMD ["prosodyctl", "start"]. entrypoint.sh just passes this command through as Adrian mentioned. However, your command overrides the default command, so your prosody demon is never started. Maybe you want to try something like
xmpp:
image: prosody/prosody
command: sh -c prosodyctl register testuser localhost testpassword && prosodyctl start
ports:
- "5222:5222"
- "127.0.0.1:5347:5347"
instead. More elegant and somehow what the creator seems to have intended (judging from the entrypoint.sh script) would be something like
xmpp:
image: prosody/prosody
environment:
- LOCAL=testuser
- DOMAIN=localhost
- PASSWORD=testpassword
ports:
- "5222:5222"
- "127.0.0.1:5347:5347"
To answer your final question: no, it is not possible (as of now) to execute commands on a running container via docker-compose. However, you can easily do this with docker:
docker exec -i prosody_container_name prosodyctl register testuser localhost testpassword
where prosody_container_name is the name of your running container (use docker ps to list running containers).