Is there a docker command which works like the vagrant up command?
I'd like to use the arangodb docker image and provide a Dockerfile for my team without forcing my teammates to get educated on the details of its operation, it should 'just work'. Within the the project root, I would expect the database to start and stop with a standard docker command. Does this not exist? If so, why not?
Docker Compose could do it.
docker-compose up builds image, creates container and starts it.
docker-compose stop stops the container.
docker-compose start restarts the container.
docker-compose down stops the container and removes image and the container.
With Docker compose file you can configure the ArangoDB (expose ports, volume mapping for db initialisation, etc.). Place the compose file to the project root, and run the up command.
Related
TLDR: When using docker compose, I can simply recreate a container by changing its configuration and/or image in the docker-compose.yml file along with running docker-compose up. Is there any generic equivalent for recreating a container (to apply changes) which was created by a bare docker create/run command?
Elaborating a bit:
The associated docker compose documentation states:
If there are existing containers for a service, and the service’s configuration or image was changed after the container’s creation, docker-compose up picks up the changes by stopping and recreating the containers (preserving mounted volumes).
I'm having troubles to understand which underlaying steps are actually performed during this recreation, as e.g. the docker (without compose) documentation doesn't really seem to use the recreate term at all.
Is it safe to simply run docker container rm xy and then docker container create/run (along with passing the full and modified configuration)? Or is docker compose actually doing more under the hood?
I already found answers about applying specific configuration changes like e.g. this one about port mappings, but I'm still wondering whether there is a more general answer to this.
I'm having troubles to understand which underlaying steps are actually performed during this recreation, as e.g. the docker (without compose) documentation doesn't really seem to use the recreate term at all.
docker-compose is a high level tool; it performs in a single operation what would require multiple commands using the docker cli. When docker-compose says, "docker-compose up picks up the changes by stopping and recreating the containers", it means it is doing the equivalent of:
docker stop <somecontainer>
docker rm <somecontainer>
docker run ...
(Where ... represents whatever configuration is implied by the service definition in your docker-compose.yaml).
Let's say it recognizes a change in container1 it does (not really, working via API):
docker compose rm -fs container1
docker compose create (--build) container1
docker compose start container1
What is partially close to (depending on your compose-config):
docker rm -f projectname_container1
(docker build --flags)
docker create --allDozensOfAttributes projectname_container1
docker start projectname_container1
docker network connect (--flags) projectname_networkname projectname_container1
and maybe more..
so i would advise to use the docker compose commands for single services instead of docker cli if suitable..
The issue is that the variables and settings are not exposed through any docker apis. It may be possible by way of connecting directly to the docker socket, parsing the variables, and then stopping/removing the container and recreating it.
This would be prone to all kinds of errors and would require lots of debugging to get these values.
What I do is to simply store my docker commands in a shell script. You can just save the command you need to run into a text file, name it .sh, set the -x on the file, then run it. Then when you stop/delete the container, you can just rerun the shell script.
Another thing you can do would be to replace the docker command with a function (in something like your ~/.bashrc) that stores the arguments to a text file and rechecks that text file with a passed argument (like "recreate" followed by a name). However, I'm more a fan of doing docker containers in their own shell scripts as its more portable.
I have already created containers running in my server.
They were created through the command line with docker run.
I believe using docker-compose will result in a more portable containers (I don't need to docker run all containers in a different server, only put the same file).
Is there a way to translate the already created containers to a docker-compose file?
In their website (https://docs.docker.com/compose/gettingstarted/), it is mentioned to use docker-compose migrate_to_labels, but it seems the command is not working in the latest version of docker-compose
As everyone knows, we can use docker start [dockerID] to start a closed container.
But, If this container exits immediately after startup. What should I do?
For example, I have a MySQL container, it runs without any problems. But the system is down. At next time I start this container. It tell me a file is worry so that this container immediately exit.
Now I want to delete this file, but this container can not be activated, so I can't enter this container to delete this file. What should I do?
And if I want to open bash in this state container, What should I do?
Delete the container and launch a new one.
docker rm dockerID
docker run --name dockerID ... mysql:5.7
Containers are generally treated as disposable; there are times you're required to delete and recreate a container (to change some networking or environment options; to upgrade to a newer version of the underlying image). The flip side of this is that containers' state is generally stored outside the container filesystem itself (you probably have a docker run -v or Docker Compose volumes: option) so it will survive deleting and recreating the container. I almost never use docker start.
Creating a new container gets you around the limitations of docker start:
If the container exits immediately but you don't know why, docker run or docker-compose up it without the -d option, so it prints its logs to the console
If you want to run a different command (like an interactive shell) as the main container command, you can do it the same as any other container,
docker run --rm -it -v ...:/var/lib/mysql/data mysql:5.6 sh
docker-compose run db sh
If the actual problem can be fixed with an environment variable or other setting, you can add that to the startup-time configuration, since you're already recreating the container
So I am using gitlab-ci to deploy my websites in docker containers, because the gitlab-ci docker runner doesn't seem to do what I want to do I am using the shell executor and let it run docker-compose up -d. Here comes the problem.
I have 2 volumes in my docker-container. ./:/var/www/html/ (which is the content of my git repo, so files I want to replace on build) and a mount that is "inside" of this mount /srv/data:/var/www/html/software/permdata (which is a persistent mount on my server).
When the gitlab-ci runner starts it tries to remove all files while the container is running, but because of this mount in mount it gets a device busy and aborts. So I have to manually stop and remove the container before I can run my build (which kind of defeats the point of build automation).
Options I thought about to fix this problem:
stop and remove the container before gitlab-ci-multi-runner starts (seems not possible)
add the git data to my docker container and only mount my permdata (seems like you can't add data to a container without the volume option with docker compose like you can in a Dockerfile)
Option 2 would be ideal because then it would also sort out my issues with permissions on the files.
Maybe someone has gone through the same problem and could give me an advice
seems like you can't add data to a container without the volume option with docker compose like you can in a Dockerfile
That's correct. The Compose file is not meant to replace the Dockerfile, it's meant to run multiple images for an application or project.
You can modify the Dockerfile to copy in the git files.
I am running a Docker container in CoreOS (host) and mounted a host folder with a container's folder.
docker run -v /home/core/folder_name:/folder_name <container_name>
Now, each time I am changing (insert/delete) some file in that host folder (folder_name), I have to restart the container (container_name) to see the effects.
docker restart <container_name>
Is there any way from the host side or docker side to restart it automatically when there is a change (insert/delete) in the folder?
Restarting the docker container on a folder change is rather antithetical to the whole notion of the -v command in the first place. If you really really really need to restart the container in the manner you are suggesting then the only way to do it is from the docker host. There are a couple tools (I can name off the top of my head, there are definitely more) you could use to monitor the host folder and when a file is inserted or deleted you could trigger the docker restart <container_name> command. Those tools are incron and inotify-tools. Here is another question someone asked similar to yours and the answer recommended using one of the tools I suggested.
Now, there is no way that the files in the host folder are not being changed in the docker container as well. It must be that the program you are using in the docker container isn't updating it's view of the /folder_name folder after it starts up. Is it possible for you to force the program you are running in the docker container to refresh or update? The -v command works via bind mounting and has been a stable feature in docker for quite a while. With bind mounting, the home/core/folder_name folder IS (for all practical purposes) the same folder as /folder_name in the container.
run the command
docker run -t -i -v /home/core/folder_name:/folder_name <container_name> /bin/sh
This command gives you an interactive shell within the container. In this shell issue the command:
cd /folder_name; touch a_file
Now go to /home/core/folder_name on the docker host in a shell or some file browser. The file a_file will be there. You can delete that file on the host and go back to the shell running in the docker container and run ls /folder_name. The file a_file will not be there.
So, you either need to use inotify or incron to go about restarting your container anytime a file changes on the host, or figure out how to work with the program you are running in the docker container to have it update its view of the /folder_name folder.