Related
I understand that docker start starts a container and docker run creates and starts a container given an image. But naively at first I just ran the command docker start image_name and it just outputs image_name to the console and no container is created and started.
Does docker start image_name do anything besides echo the name to the console? The doc is not very illustrative. If so, what a bad way to fail, better would have been to tell me, that that is not a container but an image and I should first create a container, but maybe I'm missing some useful action which docker start image_name does?
What happens when I run docker start image_name?
$ docker start --help
Usage: docker start [OPTIONS] CONTAINER [CONTAINER...]
Start one or more stopped containers
it just outputs image_name to the console and no container is created and started
a, --attach Attach STDOUT/STDERR and forward signals
The default is not to attach.
Does docker start image_name do anything besides echo the name to the console?
Yes it Start(-s) one or more stopped containers.
I'm missing some useful action which docker docker start image_name does?
It restarts the stopped container.
$ docker run --name work alpine sh -c 'echo important_work ; sleep 10 ; echo success'
important_work
success
$ docker start -a work
important_work
success
Most probably your container that you tested does nothing or expects interactive session to work, and without input it just exits.
Running the docker registry with below command always throws an error:
dev:tmp me$ docker run \
-d --name registry-v1 \
-e SETTINGS_FLAVOR=local \
-e STORAGE_PATH=/registry \
-e SEARCH_BACKEND=sqlalchemy \
-e LOGLEVEL=DEBUG \
-p 5000:5000 \
registry:0.9.1
Error response from daemon: Conflict. The name "registry-v1" is already in use by container f9e5798a82e0. You have to delete (or rename) that container to be able to reuse that name.
How can I prevent this error ?
I got confused by this also. There are two commands relevant here:
docker run # Run a command in a **new** container
docker start # Start one or more stopped containers
That means you have already started a container in the past with the parameter
docker run --name registry-v1 ...
You need to delete that first before you can re-create a container with the same name with
docker rm registry-v1
When that container is sill running you need to stop it first before you can delete it with
docker stop registry-v1
Or simply choose a different name for the new container.
To get a list of existing containers and their names simply invoke
docker ps -a
Here what i did, it works fine.
step 1:(it lists docker container with its name)
docker ps -a
step 2:
docker rm name_of_the_docker_container
When you are building a new image you often want to run a new container each time and with the same name. I found the easiest way was to start the container with the --rm option:
--rm Automatically remove the container when it exits
e.g.
docker run --name my-micro-service --rm <image>
Sadly it's used almost randomly in the examples from the docs
Edit: Read Lepe's comment below.
Just to explain what others are saying (it took me some time to understand) is that, simply put, when you see this error, it means you already have a container and what you have to do is run it. While intuitively docker run is supposed to run it, it doesn't. The command docker run is used to only START a container for the very first time. To run an existing container what you need is docker start $container-name. So much for asking developers to create meaningful/intuitive commands.
You have 2 options to fix this...
Remove previous container using that name, with the command docker rm $(docker ps -aq --filter name=myContainerName)
OR
Rename current container to a different name i.e change this portion --name registry-v1 to something like --name myAnotherContainerName
You are getting this error because that container name ( i.e registry-v1) was used by another container in the past...even though that container may have exited i.e (currently not in use).
Cause
A container with the same name is still existing.
Solution
To reuse the same container name, delete the existing container by:
docker rm <container name>
Explanation
Containers can exist in following states, during which the container name can't be used for another container:
created
restarting
running
paused
exited
dead
You can see containers in running state by using :
docker ps
To show containers in all states and find out if a container name is taken, use:
docker ps -a
Here is how I solved this on ubuntu 18:
$ sudo docker ps -a
copy the container ID
For each container do:
$ sudo docker stop container_ID
$ sudo docker rm container_ID
removing all the exited containers
docker rm $(docker ps -a -f status=exited -q)
The Problem: you trying to create new container while in background container with same name is running and this situation causes conflicts.
The error would be like:
Cannot create continer for service X :Conflict. The name X is already in use by container abc123xyz. You have to remove ot delete (or rename) that container to be able to reuse that name.
Solution rename the service name in docker-compose.yml or delete the running container and rebuild it again (this solution related to Unix/Linux/macOS systems):
get all running containers sudo docker ps -a
get the specific container id
stop and remove the duplicated container / force remove it
sudo docker stop <container_id>
sudo docker rm <container_id>
or
sudo docker rm --force <container_id>
You can remove it with command sudo docker rm YOUR_CONTAINER_ID, then run a new container with sudo docker run ...;
or restart an existing container with sudo docker start YOUR_CONTAINER_ID
I was running into this issue that when I run docker rm (which usually works) I would get:
Error: No such image
The easiest solution to this is removing all stopped containers by running:
docker container prune
I have solved the issue by doing following steps and I hope it helps.
Type docker ps -a to list all the containers in your system.
Check the NAMES part where you have initialized your docker container.
Then type docker rm --force name_of_container
Install the docker container as you wish.
I had problem using NIFI and I have removed and reinstalled using docker. Good luck.
TL:DR;
List all containers:
docker ps -a
Remove the concerned container by id:
docker container rm <container_id>
I'm just learning docker and this got me as well. I stopped the container with that name already and therefore I thought I could run a new container with that name.
Not the case. Just because the container is stopped, doesn't mean it can't be started again, and it keeps all the same parameters that it was created with (including the name).
when I ran docker ps -a that's when I saw all the dummy test containers I created while I was playing around.
No problem, since I don't want those any more I just did docker rm containername at which point my new container was allowed to run with the old name.
Ah, and now that I finish writing this answer, I see Slawosz's comment on Walt Howard's answer above suggesting the use of docker ps -a
The OP's problem is the error. Deleting state isn't the only solution - or even a good one. The problem is docker run isn't re-entrant, and docker start is impotent w/o run. So we have to combine them.
For example to run Postgres w/o destroying previous state, try this:
docker start postgres || docker run -d -p 5432:5432 --name postgres -e POSTGRES_PASSWORD=password postgres:13-alpine
Ok, so I didn't understand either, then I left my pc, went to do other things, and upon my return, it clicked :D
You download a docker image file. docker pull *image-name* will just pull the image from docker hub without running it.
Now, you use docker run, and give it a name (e.g. newWebServer).
docker run -d -p 8080:8080 -v volume --name newWebServer image-name/version
You perhaps only need docker run --name *name* *image*, but the other stuff will become useful quickly.
-d (detached) - means the container will exit when the root process used to run the container exits.
-p (port) - specify the container port and the host port. Kind of the internal and external port. The internal one being the port the container uses, and the external one is the port you use outside of it and probably the one you need to put in your web browser if that's how you access your app.
--name (what you want to call this instance of the container) - you could have several instances of the same container all with different names, which is useful when you're trying to test something.
image-name/version is the actual image you want to create the container from. You can see a list of all the images on your system with docker images -a. You may have more than one version, so make sure you choose the correct one/tag.
-v (volume) - perhaps not needed initially, but soon you'll want to persist data after your container exits.
OK. So now, docker run just created a container from your image. If it isn't running, you can now start it with it's name:
docker start newWebServer
You can check all your containers (they may or may not be running) with
docker ps -a
You can stop and start them (or pause them) with their name or the container id (or just the first few characters of it) from the CONTAINER ID column e.g:
docker stop newWebServer
docker start c3028a89462c
And list all your images, with
docker images -a
In a nutshell, download an image; docker run creates a container from it; start it with docker start (name or container id); stop it with docker stop (name or container id).
I had this issue because I had two or more containers with the same container_name in the docker-compose.yml file.
Simple Solution: Goto your docker folder in the system and delete .raw file or docker archive with large size.
For me, the issue was that I used an image name more than once in the dockerfile.
This happened to me on the docker tutorial! The port I tried to use was taken, but docker still created.. an image? A process to run docker? I'll find out soon. Anyways, to choose a different port, I had to remove the older image, and then docker run again.
Sometimes a tutorial can be too terse. What you want is concise, not terse, or even succinct.
When writing a bash script that starts a docker container, it is useful to refer to the started docker container. How do you get the specific container id of a docker container when you start it?
P.S. I know that I can use --name to name the container, which I can use to filter the list of containers using docker ps -aqf "name=containername", but this will fail if I ever start the script twice. And then there's the possibility of name conflicts. Besides, what's the point of container IDs if you can't use them?
When you start a detached container, it returns the container ID. e.g.:
$ docker run -d ubuntu:18.04
71329cf6a02d89cf5f211072dd37716fe212787315ce4503eaee722da6ddf18f
In bash, you can define a new variable from the output like this:
CID=$(docker run -d ubuntu:18.04)
Then, later you can use this variable to refer to your container like this:
docker stop $CID
docker rm $CID
In the documentation for docker run under "capture container id", they advise using the --cidfile flag for this purpose.
--cidfile takes a file name as an argument and will write the long ID of the container to that location. E.g.,
docker run --cidfile /tmp/hello-world.cid hello-world && cat /tmp/hello-world.cid
This is useful when you don't want to run the image in a detached state, but still want access to the ID.
docker ps is giving me a different output compared to docker-compose ps.
For example
docker ps
is not showing the same containers as
docker-compose ps
and vice-versa.
What is the reason for this?
I was thinking docker-compose is working on top of docker.
docker ps lists all running containers in docker engine. docker-compose ps lists containers related to images declared in docker-compose file.
The result of docker-compose ps is a subset of the result of docker ps.
docker ps - lists all running containers in Docker engine.
docker-compose ps - lists containers for the given docker compose configuration. The result will depend on configuration and parameters passed to docker-compose command.
Example
Start the containers with the following command:
docker-compose -p prod up -d
(-p in the command above defines the project name)
Running docker-compose ps won't list containers since the project name parameters is not passed:
docker-compose ps
Name Command State Ports
------------------------------
Running docker-compose -p prod ps will list all containers:
Name Command State Ports
--------------------------------------------------------------------------------------------------------
dev_app_1 sh -c exec java ${JAVA_OPT ... Up 0.0.0.0:5005->5005/tcp, 0.0.0.0:9001->9000/tcp
dev_database_1 docker-entrypoint.sh postgres Up 0.0.0.0:5432->5432/tcp
dev_nginx_1 /docker-entrypoint.sh ngin ... Up 0.0.0.0:8443->443/tcp, 0.0.0.0:8080->80/tcp
dev_pgadmin_1 /entrypoint.sh Up 443/tcp, 0.0.0.0:9100->80/tcp
The same goes if you define for example docker compose files with -f parameter.
Running the docker registry with below command always throws an error:
dev:tmp me$ docker run \
-d --name registry-v1 \
-e SETTINGS_FLAVOR=local \
-e STORAGE_PATH=/registry \
-e SEARCH_BACKEND=sqlalchemy \
-e LOGLEVEL=DEBUG \
-p 5000:5000 \
registry:0.9.1
Error response from daemon: Conflict. The name "registry-v1" is already in use by container f9e5798a82e0. You have to delete (or rename) that container to be able to reuse that name.
How can I prevent this error ?
I got confused by this also. There are two commands relevant here:
docker run # Run a command in a **new** container
docker start # Start one or more stopped containers
That means you have already started a container in the past with the parameter
docker run --name registry-v1 ...
You need to delete that first before you can re-create a container with the same name with
docker rm registry-v1
When that container is sill running you need to stop it first before you can delete it with
docker stop registry-v1
Or simply choose a different name for the new container.
To get a list of existing containers and their names simply invoke
docker ps -a
Here what i did, it works fine.
step 1:(it lists docker container with its name)
docker ps -a
step 2:
docker rm name_of_the_docker_container
When you are building a new image you often want to run a new container each time and with the same name. I found the easiest way was to start the container with the --rm option:
--rm Automatically remove the container when it exits
e.g.
docker run --name my-micro-service --rm <image>
Sadly it's used almost randomly in the examples from the docs
Edit: Read Lepe's comment below.
Just to explain what others are saying (it took me some time to understand) is that, simply put, when you see this error, it means you already have a container and what you have to do is run it. While intuitively docker run is supposed to run it, it doesn't. The command docker run is used to only START a container for the very first time. To run an existing container what you need is docker start $container-name. So much for asking developers to create meaningful/intuitive commands.
You have 2 options to fix this...
Remove previous container using that name, with the command docker rm $(docker ps -aq --filter name=myContainerName)
OR
Rename current container to a different name i.e change this portion --name registry-v1 to something like --name myAnotherContainerName
You are getting this error because that container name ( i.e registry-v1) was used by another container in the past...even though that container may have exited i.e (currently not in use).
Cause
A container with the same name is still existing.
Solution
To reuse the same container name, delete the existing container by:
docker rm <container name>
Explanation
Containers can exist in following states, during which the container name can't be used for another container:
created
restarting
running
paused
exited
dead
You can see containers in running state by using :
docker ps
To show containers in all states and find out if a container name is taken, use:
docker ps -a
Here is how I solved this on ubuntu 18:
$ sudo docker ps -a
copy the container ID
For each container do:
$ sudo docker stop container_ID
$ sudo docker rm container_ID
removing all the exited containers
docker rm $(docker ps -a -f status=exited -q)
The Problem: you trying to create new container while in background container with same name is running and this situation causes conflicts.
The error would be like:
Cannot create continer for service X :Conflict. The name X is already in use by container abc123xyz. You have to remove ot delete (or rename) that container to be able to reuse that name.
Solution rename the service name in docker-compose.yml or delete the running container and rebuild it again (this solution related to Unix/Linux/macOS systems):
get all running containers sudo docker ps -a
get the specific container id
stop and remove the duplicated container / force remove it
sudo docker stop <container_id>
sudo docker rm <container_id>
or
sudo docker rm --force <container_id>
You can remove it with command sudo docker rm YOUR_CONTAINER_ID, then run a new container with sudo docker run ...;
or restart an existing container with sudo docker start YOUR_CONTAINER_ID
I was running into this issue that when I run docker rm (which usually works) I would get:
Error: No such image
The easiest solution to this is removing all stopped containers by running:
docker container prune
I have solved the issue by doing following steps and I hope it helps.
Type docker ps -a to list all the containers in your system.
Check the NAMES part where you have initialized your docker container.
Then type docker rm --force name_of_container
Install the docker container as you wish.
I had problem using NIFI and I have removed and reinstalled using docker. Good luck.
TL:DR;
List all containers:
docker ps -a
Remove the concerned container by id:
docker container rm <container_id>
The OP's problem is the error. Deleting state isn't the only solution - or even a good one. The problem is docker run isn't re-entrant, and docker start is impotent w/o run. So we have to combine them.
For example to run Postgres w/o destroying previous state, try this:
docker start postgres || docker run -d -p 5432:5432 --name postgres -e POSTGRES_PASSWORD=password postgres:13-alpine
I'm just learning docker and this got me as well. I stopped the container with that name already and therefore I thought I could run a new container with that name.
Not the case. Just because the container is stopped, doesn't mean it can't be started again, and it keeps all the same parameters that it was created with (including the name).
when I ran docker ps -a that's when I saw all the dummy test containers I created while I was playing around.
No problem, since I don't want those any more I just did docker rm containername at which point my new container was allowed to run with the old name.
Ah, and now that I finish writing this answer, I see Slawosz's comment on Walt Howard's answer above suggesting the use of docker ps -a
Ok, so I didn't understand either, then I left my pc, went to do other things, and upon my return, it clicked :D
You download a docker image file. docker pull *image-name* will just pull the image from docker hub without running it.
Now, you use docker run, and give it a name (e.g. newWebServer).
docker run -d -p 8080:8080 -v volume --name newWebServer image-name/version
You perhaps only need docker run --name *name* *image*, but the other stuff will become useful quickly.
-d (detached) - means the container will exit when the root process used to run the container exits.
-p (port) - specify the container port and the host port. Kind of the internal and external port. The internal one being the port the container uses, and the external one is the port you use outside of it and probably the one you need to put in your web browser if that's how you access your app.
--name (what you want to call this instance of the container) - you could have several instances of the same container all with different names, which is useful when you're trying to test something.
image-name/version is the actual image you want to create the container from. You can see a list of all the images on your system with docker images -a. You may have more than one version, so make sure you choose the correct one/tag.
-v (volume) - perhaps not needed initially, but soon you'll want to persist data after your container exits.
OK. So now, docker run just created a container from your image. If it isn't running, you can now start it with it's name:
docker start newWebServer
You can check all your containers (they may or may not be running) with
docker ps -a
You can stop and start them (or pause them) with their name or the container id (or just the first few characters of it) from the CONTAINER ID column e.g:
docker stop newWebServer
docker start c3028a89462c
And list all your images, with
docker images -a
In a nutshell, download an image; docker run creates a container from it; start it with docker start (name or container id); stop it with docker stop (name or container id).
I had this issue because I had two or more containers with the same container_name in the docker-compose.yml file.
Simple Solution: Goto your docker folder in the system and delete .raw file or docker archive with large size.
For me, the issue was that I used an image name more than once in the dockerfile.
This happened to me on the docker tutorial! The port I tried to use was taken, but docker still created.. an image? A process to run docker? I'll find out soon. Anyways, to choose a different port, I had to remove the older image, and then docker run again.
Sometimes a tutorial can be too terse. What you want is concise, not terse, or even succinct.