How to stat a docker container. I had created it using
docker run -d -P -v /Users/bsr:/usr/local/users --name test ubuntu
I do have virtual box guest addition installed, and mounting works. But, I am not sure why I can't I keep the shell running.
bsr[~/tmp/web] $ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
cf620ff6c36a ubuntu:latest "/bin/bash" 2 hours ago Exited (0) 2 minutes ago test
8213c8d49842 nginx:latest "nginx" 3 hours ago Up About an hour 0.0.0.0:49154->80/tcp web
bsr[~/tmp/web] $ docker start test
test
bsr[~/tmp/web] $ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
cf620ff6c36a ubuntu:latest "/bin/bash" 2 hours ago Exited (0) 2 seconds ago test
8213c8d49842 nginx:latest "nginx" 3 hours ago Up About an hour 0.0.0.0:49154->80/tcp web
bsr[~/tmp/web] $
Edit:
it may be because the command (/bin/bash ??) finishes immediately. When I tried,
docker run -d -P -v /Users/bsr:/usr/local/users --name test5 ubuntu /bin/bash -c "while true; do echo Hello world; sleep 1; done"
I could get the terminal. But isn't there any way to just start a container and get to the terminal ??
If you want to run an interactive process, you should use the -i (keep stdin open in case you detach) and -t (allocate a pseudo-tty) flags:
docker run -it ubuntu
You can look at the docs for more information on those flags and their usage.
You can start by using simple command.
docker run "CONTAINER_ID"
Related
I'm using docker-compose for a project that has multiple services.
To run it, I simply type docker-compose up and docker ps would show a list of running services as follows:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
94cc0fca9ff5 backend_app "sh entrypoint.sh /b…" 4 hours ago Up 4 hours 0.0.0.0:3000->3000/tcp backend_app_1
e770466bc28b backend_worker "sh entrypoint.sh /b…" 4 hours ago Up 4 hours 3000/tcp backend_worker_1
Till this point, I have no problem, all as expected. Now, I'm trying to run bash for the image backend_app. I tried:
docker-compose exec app bash
docker exec -it backend_app /bin/bash
docker exec -it 94cc0fca9ff5 /bin/bash
among a hundred other things, but none seem to work. What should I do to run bash when starting the image using docker-compose?
Depending on the image you're using, bash might not be installed, should work 100% using sh instead.
Step 1:
docker ps -a
container Id: dd5cf6b519b4
I need to inspect inside the stopped docker container which is cannot start.
I tried with docker exec -it container-id bin/bash But this is for running container.
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS NAMES
0dfd54557799 ubuntu "/bin/bash" 25 seconds ago Exited (1) 4 seconds ago peaceful_feynman
Commit the stopped image
$ docker commit 0dfd54557799 debug/ubuntu
now we have a new image
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
debug/ubuntu <none> cc9db32dcc2d 2 seconds ago 64.3MB
create a new container from the "broken" image
$ docker run -it --rm --entrypoint sh debug/ubuntu
inside of the container we can inspect - for example, the file system
$ ls /app
App.dll
App.pdb
App.deps.json
You can start container with specific entrypoint
docker run --entrypoint sleep YOUR_IMAGE 3600
It will block current terminal for 3600 seconds. You can open new terminal tab(do not close current one) and you can verify if your container is working with the
docker ps
If you do not want to block current terminal, you can add -d flag to docker run:
docker run -d --entrypoint sleep YOUR_IMAGE 3600
Above command will start docker which will be doing nothing, then you can ssh into the container when it is working with
docker exec -ti CONTAINER HASH sh
I ran this command:
docker run -d -ti foo
it works, but I realized that I probably forgot to remote the -ti part.
I assume that docker ignores those flags if -d is used, does anyone know?
It seems like -ti and -d would contradict each other?
It still sets up the input filehandle, and allocates a pseudo tty for the container. If the app inside the container attempts to read from stdin, it will hang waiting on input rather than exit immediately or fail. Later on, you can attach to that process. E.g.
$ docker run -dit --name test-dit busybox sh
f0e057ce47e03eb227aacb42e3a358b14fa5d8b26ad490fcec7cbfe0cd3cce73
$ docker run -d --name test-d busybox sh
4f2583d3380953f328b702c88884fbe55f16c44bce13dbccc00c4bb81f3270f2
$ docker container ls -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4f2583d33809 busybox "sh" 5 seconds ago Exited (0) 4 seconds ago test-d
f0e057ce47e0 busybox "sh" 14 seconds ago Up 13 seconds test-dit
$ docker container attach test-dit
/ #
/ # ls
bin dev etc home proc root sys tmp usr var
/ # exit
$ docker container ls -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4f2583d33809 busybox "sh" 22 seconds ago Exited (0) 21 seconds ago test-d
f0e057ce47e0 busybox "sh" 31 seconds ago Exited (0) 2 seconds ago test-dit
In the first container ls command, you can see the shell without the -it option immediately exited, while the one with -it was available to connect and run commands.
It does not ignore -ti.
The -ti part means it enables direct user interaction, and the -d part means it detaches the container the moment it gets started. So, in order to actually interact with it, you'll have to do
?> docker attach foo
So, yes, it might not be very useful, but it neither causes an impossible situation, nor one you cannot get out of.
docker ps or docker container ls returns an overview of all running containers. The meaning of all columns is clear to me, except one. What does the column 'COMMAND' mean?
This is the command which is passed to the container.
$ docker run -d busybox top
$docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
3eca7c034b21 busybox "top" 6 seconds ago Up 5 seconds recursing_dirac
If you check above, top is the command which has been passed to the busybox container and that's what it's showing in the docker ps -a.
It's the command passed to docker run <image> [command].
$ docker run -d ubuntu sleep 60
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS
f0c9cd92a938 ubuntu "sleep 60" 3 seconds ago Up 1 second
If no command was specified there then it's the CMD from the Dockerfile. In ubuntu's case that would be CMD ["/bin/bash"]:
$ docker run -di ubuntu
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS
9cd752ee86f4 ubuntu "/bin/bash" 4 seconds ago Up 2 seconds
I have installed Docker and have running some Ubuntu image with command:
sudo docker run ubuntu
I would like to create some text file on it and find it next time the same image will run. How to achieve that?
UPD.
Got problems with attaching to docker.
I have running docker
docker ps -a
aef01293fdc9 ubuntu "/bin/bash" 6 hours ago Up 6 hours priceless_ramanujan
Since it is Up mode, I suppose I don't need to execute command:
docker start priceless_ramanujan
So, I run command attach
docker attach priceless_ramanujan
And got nothing in output while command not returns.
Why I can't get to container's bash?
Simple example:
$ docker run -it ubuntu
root#4d5643e8c1a8:/# echo "test" > test.txt
root#4d5643e8c1a8:/# cat test.txt
test
root#4d5643e8c1a8:/# exit
exit
$ docker run -it ubuntu
root#cdb44750bffc:/# cat test.txt
cat: test.txt: No such file or directory
root#cdb44750bffc:/#
docker run image_name
This command creates and starts a new container based on the provided image_name. If a name is not set for the container, a random one is generated and assigned by docker. In the above example 2 containers were created based on ubuntu.
with docker ps -a we can see that modest_jennings and optimistic_leakey are the random names created:
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
cdb44750bffc ubuntu "/bin/bash" About a minute ago Exited (1) 4 seconds ago optimistic_leakey
4d5643e8c1a8 ubuntu "/bin/bash" 2 minutes ago Exited (0) 2 minutes ago modest_jennings
cat test.txt failed the 2nd time because the file didn't exist. The container started from a "clean" ubuntu image.
Actually, we created test.txt inside modest_jennings only.
docker start container_name
This command starts a stopped container. So, in our case, the file is still there:
$ docker start modest_jennings
modest_jennings
$ docker attach modest_jennings
root#4d5643e8c1a8:/# cat test.txt
test
root#4d5643e8c1a8:/#
docker commit container_name image_name
This command is to create a new image, so that you can use it later and run containers based on that image. Continuing our example...
$ docker commit modest_jennings my_ubuntu
sha256:a4357f37153ac0b94e37315595f1a3b540538283adc3721df4d4e3b39bf8334f
$ docker run -it my_ubuntu
root#2e38616d532a:/# cat test.txt
test
root#2e38616d532a:/#
If you want a custom image, you can create a Dockerfile
`FROM ubuntu:16.04
ADD ./test.txt /tmp/`
after you can build it docker build -t ubuntu:custom .
and finally run your custom image docker run --name myubuntu ubuntu:custom sleep 3000
You can check your file with docker exec -it myubuntu /bin/bash and more /tmp/test.txt