I have a service definition that starts a docker container using systemd on CentOS 7:
[Unit]
Description=MappingService
After=portal.service
Requires=docker.service
[Service]
TimeoutStartSec=3000
Type=forking
WorkingDirectory=/home/user/Downloads/MS_0.3.4_artifact
ExecStartPre=-/bin/docker rm -f eb-mapping-service-container
ExecStartPre=/home/user/Downloads/MS_0.3.4_artifact/deploy.sh /home/user/Downloads/MS_0.3.4_artifact/eb-mapping-service.tgz
ExecStartPre=/bin/docker run -v /dev/log:/dev/log -d -ti --log-driver=journald --network=bridge -p 9090:9090 --name eb-mapping-service-container eb-mapping-service /bin/bash -c "cd /build/MappingService; ./start_multiple_clients_mapping_service.sh"
ExecStart=/bin/docker start -a eb-mapping-service-container
ExecStop=/bin/docker stop eb-mapping-service-container
[Install]
WantedBy=multi-user.target
This service works. The Docker container it launches is up.
Whenever I boot the computer it is running. My problem with this service is that it's never reaching the Active(Running) status. Instead, it is stuck in 'Activating(start)' status.
The 'start_multiple_clients_mapping_service.sh' script starts a node.js server and it starts listening, so it isn't exiting directly.
I've searched everywhere and scoured Docker's documentation about this and couldn't find an answer.
Also, if I remove the '-a' from the docker start command, then the status will be Inactive(dead) even though the container will be up and running.
Update:
After a while, I don't have an exact number, the service fails with the timeout reason. This isn't after 3000 seconds but way earlier. Although the service failed, the docker is still on the air and can be used.
I've verified with docker container ls
Question:
How do I change my service definition to reflect the Active(Running) status for the docker?
I understood the problem. There were a couple of things wrong:
the docker run command should not be used with the flags -d and -ti.
the Type should be set to exec instead of forking.
After doing these two changes, I got the much sought after Active(Running) status with the Docker successfully launched.
Related
I have been running a nvidia docker image since 13 days and it used to restart without any problems using docker start -i <containerid> command. But, today while I was downloading pytorch inside the container, download got stuck at 5% and gave no response for a while.
I couldn't exit the container either by ctrl+d or ctrl+c. So, I exited the terminal and in new terminal I ran this docker start -i <containerid> again. But ever since this particular container is not responding to any command. Be it start/restart/exec/commit ...nothing! any command with this container ID or name is just non-responsive and had to exit out of it only after ctrl+c
I cannot restart the docker service since it will kill all running docker containers.
Cannot even stop the container using this docker container stop <containerid>
Please help.
You can make use of docker RestartPolicy:
docker update --restart=always <container>
while mindful of caveats on the docker version you running.
or explore an answer by #Yale Huang from a similar question: How to add a restart policy to a container that was already created
I had to restart docker process to revive my container. There was nothing else I could do to solve it. used sudo service docker restart and then revived my container using docker run. I will try to build the dockerfile out of it in order to avoid future mishaps.
I use following command to build web server
docker run --name webapp -p 8080:4000 mypyweb
When it stopped and I want to restart, I always use:
sudo docker start webapp && sudo docker exec -it webapp bash
But I can't see the server state as the first time:
Digest: sha256:e61b45be29f72fb119ec9f10ca660c3c54c6748cb0e02a412119fae3c8364ecd
Status: Downloaded newer image for ericgoebelbecker/stackify-tutorial:1.00
* Running on http://0.0.0.0:4000/ (Press CTRL+C to quit)
How can I see the state instead of interacting with the shell?
When you use docker run, the default behavior is to run the container detached. This runs in the background and is detached from your shell's stdin/out.
To run the container in the foreground and connected to stdin/out:
docker run --interactive --tty --publish=8080:4000 mypyweb
To docker start a container, similarly:
docker start --interactive --attach [CONTAINER]
NB --attach rather than -tty
You may list (all add --all) running containers:
docker container ls
E.g. I ran Nginx:
CONTAINER ID IMAGE PORTS NAMES
7cc4b4e1cfd6 nginx 0.0.0.0:8888->80/tcp nostalgic_thompson
NB You may use the NAME or any uniquely identifiable subset of the ID to reference the container
Then:
docker stop nostalgic_thompson
docker start --interative --attach 7cc4
You may check the container's logs (when running detached or from another shell) by grabbing the container's ID or NAMES
docker logs nostalgic_thompson
docker logs 7cc4
HTH!
Using docker exec is causing the shell to attach to the container. If you are comparing the behavior of docker run versus docker start, they behave differently, and it is confusing. Try this:
$ sudo docker start -a webapp
the -a flag tells docker to attach stdout/stderr and forward signals.
There are some other switches you can use with the start command (and a huge number for the run command). You can run docker [command] --help to get a summary of the options.
One other command that you might want to use is logs which will show the console output logs for a running container:
$ docker ps
[find the container ID]
$ docker logs [container ID]
If you think your container's misbehaving, it's often not wrong to just delete it and create a new one.
docker rm webapp
docker run --name webapp -p 8080:4000 mypyweb
Containers occasionally have more involved startup sequences and these can assume they're generally starting from a clean slate. It should also be extremely routine to delete and recreate a container; it's required for some basic tasks like upgrading the image underneath a container to a newer version or changing published ports or environment variables.
docker exec probably shouldn't be part of your core workflow, any more than you'd open a shell to interact with your Web browser. I generally don't tend to docker stop containers, except to immediately docker rm them.
I am using docker logs -f mycontainer to check the logs. If I restart mycontainer by docker rm -f mycontainer then docker run -d --name mycontainer, I need to use Ctrl-C then rerun the docker logs command to get the logs. I wonder if there is a better way for me to keep receiving the logs even after the container restarts.
As other commenters have mentioned, the "rm" command is destroying your container, not restarting it.
But to answer your question you could use something like this:
watch -n 0 "docker logs mycontainer"
The docker logs command doesn't keep running for a stopped container, but you can achieve a similar effect using the "watch" command. And since it's not a Docker command, it doesn't care if the container is running or not.
If you're on a Mac you might not have watch. It can be installed using pip. The same thing can be achieved with a one-liner bash script but I find watch to be much neater.
2 things
with docker rm -f mycontainer you are not stopping your container, you are killing it, then you start another brand new after
you can use docker stop mycontainer and start or simply docker restart mycontainer to keep logs.
Because container are stateless, you will lost logs if you delete your container. In that case, you have to use a volume where to write your application logs. They will be on the host instead of into your container.
I created the container with the following command:
docker run -d -p 52022:22 basickarl/docker-git-test
Here are the commands:
root#basickarl:~# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
root#basickarl:~# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e4ac54468455 basickarl/docker-git-test:latest "/bin/bash" 7 minutes ago Exited (0) 26 seconds ago adoring_lumiere
22d7c5d83871 basickarl/docker-git-test:latest "/bin/bash" 2 hours ago Exited (127) About an hour ago thirsty_wright
root#basickarl:~# docker attach --sig-proxy=false e4
FATA[0000] You cannot attach to a stopped container, start it first
root#basickarl:~# docker start e4
e4
root#basickarl:~# docker attach --sig-proxy=false e4
FATA[0000] You cannot attach to a stopped container, start it first
root#basickarl:~#
Not much to say really, I'm expecting the container to start and stay upp. Here are logs:
root#basickarl:~# docker logs e4
root#basickarl:~#
You are trying to run bash, an interactive shell that requires a tty in order to operate. It doesn't really make sense to run this in "detached" mode with -d, but you can do this by adding -it to the command line, which ensures that the container has a valid tty associated with it and that stdin remains connected:
docker run -it -d -p 52022:22 basickarl/docker-git-test
You would more commonly run some sort of long-lived non-interactive process (like sshd, or a web server, or a database server, or a process manager like systemd or supervisor) when starting detached containers.
If you are trying to run a service like sshd, you cannot simply run service ssh start. This will -- depending on the distribution you're running inside your container -- do one of two things:
It will try to contact a process manager like systemd or upstart to start the service. Because there is no service manager running, this will fail.
It will actually start sshd, but it will be started in the background. This means that (a) the service sshd start command exits, which means that (b) Docker considers your container to have failed, so it cleans everything up.
If you want to run just ssh in a container, consider an example like this.
If you want to run sshd and other processes inside the container, you will need to investigate some sort of process supervisor.
What I need is to use Docker with MariaDb on different port /3301/ on my Ubuntu machine because I already had MySql installed and running on 3306.
To do this after half day searching did it using:
docker run -it -d -p 3301:3306 -v ~/mdbdata/mariaDb:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=root --name mariaDb mariadb
This pulls the image with latest MariaDb, creates container called mariaDb, and run mysql on port 3301. All data of which is located in home directory in /mdbdata/mariaDb.
To login in mysql after that can use:
mysql -u root -proot -h 127.0.0.1 -P3301
Used sources are:
The answer of Iarks in this article /using -it -d was the key :) /
how-to-install-and-use-docker-on-ubuntu-16-04
installing-and-using-mariadb-via-docker
mariadb-and-docker-use-cases-part-1
Good luck all!
I have a docker image with all the necessary tools and environment properly set up. However, I am having a hard time running it in the background.
Seems like there are two approaches:
(1) can run the box as daemon and I can attach to it whenever I want to use the box. However, the container exit with code zero right after I run it as daemon.
$:~/docker/docker_scrapy$ sudo docker run -ti -v ~/docker/docker_scrapy/myvolume:/var/myvolume 3fb9894af1d9 /bin/bash
root#3fc39116a586:/# python -c 'from bs4 import BeautifulSoup'
root#3fc39116a586:/# cd /var/myvolume/
root#3fc39116a586:/var/myvolume#
$:~/docker/docker_scrapy$ sudo docker run -d -v ~/docker/docker_scrapy/myvolume:/var/myvolume 3fb9894af1d9
c5fab6e6ac02a579e3371aa641b18ca67feb93a9f4f4934b6d083157182fe4e1
$:~/docker/docker_scrapy$ sudo docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
Clearly, I can start the box in the interactive mode, but when I try to run it as a daemon, it will exit with code 0 right after I started. And I can not attach to it because I need to start it. Does that mean you can not run a image in the daemon mode if it is idle?
(2 )Or setting it up as a SSH server, and I can ssh in and do the work whenever I want. Like Vagrant up/ssh..
In summary:
(1) What did I do wrong with the detach/attach?
(2) Which is the proper way to have a run docker in the background? daemon/ssh
If you give it another command to run after starting the service that waits for input then the container will keep running until you attach and exit that command. I usually leave a shell running after the service starts so I can debug things. here's a simple example:
First let's create a service that runs in the background
arthur#a:~$ docker run -ti ubuntu bash
root#5dc7f330b947:/# cat <<'EOF' >start-service.sh
> while true
> do
> echo service is running >> service.log
> sleep 10
> done
> EOF
root#5dc7f330b947:/# chmod +x start-service.sh
root#5dc7f330b947:/# exit
arthur#a:~$ docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
5dc7f330b947 ubuntu:12.04 bash 50 seconds ago Exited (0) 3 seconds ago jolly_nobel
arthur#a:~$ docker commit 5dc7f330b947 service/example
4c37b69b129287d79a6fe3916e4293f935194966b1de49d125f1cf8d6ab14f6f
then we can start it (i background it with a & here. in your example the & would not be required). Note it's fine to use both the interactive and detach options.
arthur#a:~$ docker run -ti -d service/example bash -c "./start-service.sh & bash"
b35a5397ea2d29b4085d93ef32270379b09e49118380b0376309bca74fd719d0
arthur#a:~$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
b35a5397ea2d service/example:latest bash -c './start-ser 7 seconds ago Up 7 seconds cranky_wright
later we can attach and check on the service by looking in it's log file:
arthur#a:~$ docker attach b35a5397ea2d
root#b35a5397ea2d:/# cat service.log
service is running
service is running
service is running
root#b35a5397ea2d:/#
I don't recommend running sshd inside the container because it leaves an option for attackers that isn't strictly useful for me.
A lots of questions in there. I would firstly suggest you go through the docker tutorial to grasp some of the underlying concepts. That said...
That Dockerfile will never run in the background, that's not how docker works. There is no cmd, no entrypoint, nothing to run.
Docker by default runs one task, when that returns the container stops. So if all you wanted was a sshd you would run that as your CMD in non daemon mode. (sshd -D)
There are ways to run daemonized apps though:
Using supervisord, as documented on the docker site.
Another alternative is phusion/baseimage.
Phusion/baseimage provides ssh access, but honestly to do what I need in containers I find nsenter easier to use. Especially when paired with the phusion docker-bash tool.
Notice: this answer promotes a tool I've written.
First of all, conceptually running multiple processes in one container is not the right approach (https://docs.docker.com/articles/dockerfile_best-practices/). A more favorable solution is one that involves multiple containers each running their own process/service. Linking them together would result in a coherent application.
I've created a containerized SSH server that you can 'stick' to any running container. This way you can create compositions with every container, without that container even knowing about ssh. The only requirement is that the container has bash.
The following example would start an SSH server attached to a container with name 'sshd-web-server1'.
docker run -ti --name sshd-web-server1 -e CONTAINER=web-server1 -p 2222:22 \
-v /var/run/docker.sock:/var/run/docker.sock -v $(which docker):/usr/bin/docker \
jeroenpeeters/docker-ssh
You connect to the SSH server with your ssh client of choice, just as you normally would.
Be adviced: Docker-SSH is currently still under development, but it does work! Please let me know what you think
For more pointers and documentation see: https://github.com/jeroenpeeters/docker-ssh