After restarting my machine with "dapr", docker ps is empty - docker

I installed "dapr cli" on my ubuntu and was able to initialize and run it successfully.
I'm able to view the output of "docker ps" command that shows the container details of placement, zipkin and redis.
But when i restarted my ubuntu, "docker ps" output is empty.
I am not able to find a way to restart them and make it automatic every time we restart the ubuntu system.

Related

What to do if the docker container hangs and does not respond to any command other than ctrl+c?

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.

Running docker -ps returns an empty list although containers are running

I installed docker CE version on an ubuntu 18.04 server. Then, I installed a new jenkins container and everything worked well for two weeks.
After two weeks, for some reason, when I run docker ps I receive an empty list although the jenkins container is running and functioning (it worked in the past). I also tried to run docker ps -a, docker images and again, everything is empty. Also tried restarting the server and still every time the list is empty.
I then uninstalled and reinstalled docker and right after the installation, when running docker ps I see the containers....I thought that the problem was fixed, but today it happened to me again and I still see an empty list when running docker ps. Any ideas ? it will be much appreciated.
Run the command sudo service docker stop
After that find the process dockerd
ps aux | grep "dockerd"
and kill the one by
sudo kill {paste_dockerd_pid_here} -9
Start docker service
sudo service docker start

Cannot run docker 'hello world' example

I just installed docker on a Mac (docker toolbox from here; at least I hope to have it installed correctly), but when following the tutorial and type the following command
docker run hello-world
I get the following error:
docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.
Did I do something wrong? Do I miss some installation steps? Do I miss something that is 'obvious' to the experts, but not to docker beginners like me?
I don't see anything in the instructions that says anything about a 'docker daemon'...
On the shell it says:
docker is configured to use the default machine with IP aa.bb.cc.d
The version command seems to work:
Docker version 17.07.0-ce, build 8784753
Update:
I tried to start the daemon by using the command
sudo dockerd
but all I got was
sudo: dockerd: command not found
Correction: The command works, but only in the sell that opened magically during the installation. The command does not work in any other shell. But when I have to close the shell/restart the computer - what to do then? How to 'start docker???
Maybe there is a tutorial that is complete and working and explains why I need a docker-deacon, how to start it, how to start a docker image or whatever, including the complete terminology for beginners?
Docker Toolbox runs a virtual linux machine on which the docker-daemon runs. To control the virtual machine, you use the docker-machine command. For example docker-machine start to start the machine after you reboot your computer, or docker-machine stop to shut it down.
There is also the docker-machine env command which will set the environment variables needed for docker to work. Check the bottom line of it's output, it shows you how to run the command correctly to set the environment variables. Should be exec $(docker-machine env) on Mac if I'm correct. You need to set the environment variables in each shell in which you want to use docker commands.
Docker for mac starts a linux virtual machine in the background which contains the actual docker stuff. When you start a normal terminal, the terminal is not connected to the vm to execute the docker commands.
The docker quick start terminal is the one that you need to use. This terminal will execute the commands on the VM that is running in the background.
With docker toolbox, if you don't launch your terminal from the docker menu, you'll need to configure your environment separately:
eval "$(docker-machine env default)"

Build docker ubuntu image by Dockerfile

If command "docker run ubuntu bash" the container won't last.
but if I command "docker run -it ubuntu bash"
the container will make a pseudo-tty and keep this container alive.
my question is
is there any way I can make a Dockerfile for building an image based on ubuntu/centos then I just need to command "docker run my-image" and
the container will last.
apologize for my poor english, I don't know if my question is clear enough.
thanks for any response
There are three ways to run containers:
task containers - do one thing and then exit, like docker run ubuntu ls /
interactive containers - open a connection to the container with -it, like docker run -it ubuntu bash
background containers - keep a container running detached in the background with -d, like docker run -d ubuntu:14.04 ping localhost
Docker keeps the container running as long as there is an active process in the container. The first container exits when the ls command completes. The second container will exit when you exit the bash session. The third container will stay running as long as the ping process keeps running (note that ping has been removed from the recent Ubuntu images, which is why the example specifies 14.04).

How to "start over" with Docker?

I am trying to run Tomcat in a Docker container with limited success. After I tried various things, I wanted to "reset" without completely deleting everything. I did stop and remove the virtual machine from the Virtualbox console. I then tried docker-machine create and docker-machine restart. My question is, if things reach a state in which the application appears to be hanging, what is the best procedure for starting from scratch that does not involve, for example, actually rebuilding the Docker container?
EDIT: All I am now asking is, given that "docker version" returns Client information but when it reaches the Server information I get the "An error occurred trying to connect" message, is what now needs to be done? What is it not connecting to? I tried with apparent success "docker-machine restart" but got no further with "docker version" after that.
First, don't delete the boot2docker VM itself (created by docker-machine)
If you want to reset, you might have to delete the container and image (quickly rebuilt with a docker build). But you can stay in the same docker-based boot2docker VM. No need for deletion.
Retrying a docker container session simply involve killing/removing the current container, and doing a new docker run.
Then, don't forget check what is not working: does a docker ps -a shows your container running? Can you access Tomcat from the boot2docker Linux host? From your actual OS host?
Based on that diagnostic and the exact content of your Dockerfile, you will be able to debug the issue.
The main issue might come from the fact docker command are executed from outside the VM.
That works only if the commands from docker-machine env <machine-name> are set.
See docker-machine env:
For cmd.exe:
$ docker-machine.exe env --shell cmd dev
set DOCKER_TLS_VERIFY=1
set DOCKER_HOST=tcp://192.168.99.101:2376
set DOCKER_CERT_PATH=C:\Users\captain\.docker\machine\machines\dev
set DOCKER_MACHINE_NAME=dev
# Run this command to configure your shell: copy and paste the above values into your command prompt.
(replace "dev" by the name of your docker machine here, probably "default")
But it is also perfectly fine to make all docker command from within the VM. No "env" to set.
Everything is on the VM (images, Dockerfile which can be on the Windows host as well, as long as it is under C:\Users\<yourLogin>, since that folder is automatically mounted as /c/Users/<yourLogin>)

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