i try to start two detached containers.
first a MySql
docker run -td --name mysql -p 3306:3306 -e MYSQL_PASS="admin" tutum/mysql
the i try to start a self built container for apache, typo3
docker run -td --name typo -p 80:80 --link mysql:mysql thomasm/typo3-45
i would now expect that the two containers show up in docker ps
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
96607b9ee0f9 tutum/mysql:latest "/run.sh" 19 minutes ago Up 19 minutes 0.0.0.0:3306->3306/tcp mysql,typo/mysql
but both seem to be in this one container id (watch the NAMES column).
docker ps -a now shows that the "typo" container has exited
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4d5ab7351d49 thomasm/typo3-45:latest "/start.sh" 8 minutes ago Exited (0) 8 minutes ago typo
I'm a bit confused. Why does the typo name show up in the names column of the mysql container. And why does the typo container exit? I don't see any error messages. Non detached, with bash the typo container works...
output from docker logs
$ docker logs typo
* Starting web server apache2
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.17.0.16.
Set the 'ServerName' directive globally to suppress this message
*
Why does the typo name show up in the names column of the mysql container
because they are linked together
why does the typo container exit?
You might find clues by running docker logs typo. A common mistake is to have the container run the process in the background instead of in the foreground.
Related
The following command works and results in the container continuing to run
$ docker run --name mysql -d -p 3306:3306 -e MYSQL_ROOT_PASSWORD=P#ssword1 mysql:5.7.31
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
fd096c5aa2f6 mysql:5.7.31 "docker-entrypoint.s…" 4 seconds ago **Up 3 seconds** 0.0.0.0:3306->3306/tcp, 33060/tcp mysql
If I change the placement of the port definition (put it at the end) the container exits immediately
$ docker run --name mysql -d -e MYSQL_ROOT_PASSWORD=P#ssword1 mysql:5.7.31 -p 3306:3306
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c723a5e63da0 mysql:5.7.31 "docker-entrypoint.s…" 2 seconds ago **Exited (1) 2 seconds ago** mysql
Can someone explain why this is? It seems at odd with just about every other application where the order of the command line options arguments is largely irrelevant. It is also very difficult for a new user to work out what is wrong and a poor experience.
Oddly too, if the -p 3306:3306 is omitted the container works.
The order of options is completely irrelevant. That said, the documentation clearly states that for docker run command options be must be specified before the name of the image, like in your first and third example.
In your second example -p 3306:3306 is after the image name and is therefore considered to be a command to be run inside the container. Since it's not a valid command, the container exits immediately.
Finally, you last example works, because exposing ports is not mandatory.
I've created a Dockerfile which looks like this:
FROM openjdk:8-jdk
COPY . .
ENTRYPOINT ["/bin/graphdb"]
EXPOSE 7200
On doing docker run 34a1650b461d -p 127.0.0.1:7200:7200 I see my service running as shown in the terminal output - however when I go to localhost:7200 I keep seeing This site can’t be reached 127.0.0.1 refused to connect.
Could anyone explain what I'm missing?
Also fyi - when I do docker ps, under PORTS I see 7200/tcp.
I read this page and followed what was described but to no luck.
Any help appreciated.
Thanks.
For docker run the order of the parameters matter, so this:
docker run 34a1650b461d -p 7200:7200
Is not the same as:
docker run -p 7200:7200 34a1650b461d
In the first case you are passing the parameters -p 7200:7200 to your ENTRYPOINT command /bin/graphdb; whereas in the second case, you are passing -p 7200:7200 to docker run, which is what you wanted.
How to validate when ports are correctly forwarded?
You can validate this by running docker ps and checking the PORTS column:
$ docker run -d 34a1650b461d -p 7200:7200
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
03abc0b390ef mytest "/bin/graphdb -p 720…" 6 seconds ago Up 5 seconds 7200/tcp elegant_wescoff
Do you see how the COMMAND includes your -p? That's not what you wanted. So docker run was not interpreting that parameter at all. Also, you can see the PORTS column, which shows the port is exposed but not forwarded.
Whereas doing it like this:
$ docker run -d -p 7200:7200 34a1650b461d
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
03abc0b390ef mytest "/bin/graphdb" 6 seconds ago Up 5 seconds 0.0.0.0:7200->7200/tcp elegant_wescoff
You can see now that -p is not being passed to COMMAND and that the port is forwarded: 0.0.0.0:7200->7200/tcp.
Is there a way to start a Docker container automatically when the host starts? Before, I use the ‘—restart always’ parameter with docker run but it only works if Docker Engine is not killed.
As your comment, I think you have misunderstood about --restart always.
Once docker run --restart always container is run, the container is restarted every time the host is restarted even though you stop the container explicitly .
For example.
$ docker run --restart always --detach --name auto-start-redis redis
d04dfbd73eb9d2ba5beac41363aa5c45c0e034e08173daa6146c3c704e0cd1da
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d04dfbd73eb9 redis "docker-entrypoint..." 4 seconds ago Up 4 seconds 6379/tcp auto-start-redis
$ reboot
# After reboot-------------------------------
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d04dfbd73eb9 redis "docker-entrypoint..." About a minute ago Up 21 seconds 6379/tcp auto-start-redis
$ docker stop auto-start-redis
auto-start-redis
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d04dfbd73eb9 redis "docker-entrypoint..." 2 minutes ago Exited (0) 30 seconds ago auto-start-redis
$ reboot
# After reboot-------------------------------
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d04dfbd73eb9 redis "docker-entrypoint..." 3 minutes ago Up 12 seconds 6379/tcp auto-start-redis
However, of course, it is based upon a premise that docker-host is auto-started. docker-host in here means docker daemon process itself. Usually docker-host will auto-start by default but if it is not, you need to set it yourself.
I am not sure which OS you are using but when it comes to Ubuntu16, you can make it with systemctl command.
$ sudo systemctl enable docker
# To tell systemd to start services automatically at boot, you must enable.
If you use docker swarm, you can make global service with --mode global flag that ensures run on every node in docker swarm.
docker service create --mode global ...
If you don't use docker swarm, the best solution I think is to use init system of your system like systemd as #I.R.R said. You can make your own service file for systemd and specify the condition when the service starts like below.
[Unit]
Description=Your App
After=docker
Refer to this article by digital ocean.
I am learning "Docker for Mac"
$ docker run -d -p 80:80 --name webserver nginx
docker: Error response from daemon: Conflict. The name "/webserver" is already in use by container 728da4a0a2852869c2fbfec3e3df3e575e8b4cd06cc751498d751fbaa75e8f1b. You have to remove (or rename) that container to be able to reuse that name..
But when I run
$ docker ps
It shows no containers listed.
But due to the previous error message tells me that there is this container 728da....
I removed that container
$ dockder rm 728da4a0a2852869c2fbfec3e3df3e575e8b4cd06cc751498d751fbaa75e8f1b
Now I run this statement again
$ docker run -d -p 80:80 --name webserver nginx
It is working fine this time.
And then I run $ docker ps, I can see this new container is listed
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
3ecc0412fd31 nginx "nginx -g 'daemon off" 19 seconds ago Up 17 seconds 0.0.0.0:80->80/tcp, 443/tcp webserver
Note:
I am using "Docker for Mac".
But I had "Docker Box" installed on the Mac before. I don't know if that is the invisible "webserver" container comes from.
As activatedgeek says in the comments, the container must have been stopped. docker ps -a shows stopped containers. Stopped containers still hold the name, along with the contents of their RW layer that shows any changes made to the RO image being used. You can reference containers by name or container id which can make typing and scripting easier. docker start webserver would have restarted the old container. docker rm webserver would remove a stopped container with that name.
You can also abbreviate the container id's to the shortest unique name to save typing or a long copy/paste. So in your example, docker rm 728d would also have removed the container.
The Docker Getting Started document asks the learners trying two statements first.
docker run hello-world
and
docker run -d -p 80:80 --name webserver nginx
I was wondering why I can run
docker run hello-world
many times but if I run
docker run -d -p 80:80 --name webserver nginx
the second time, I got the name conflicts error. Many beginners would be wondering too.
With your help and I did more search, now I understand
docker run hello-world,
we did not use --name, in this case, a random name was given so there will be no name conflicts error.
Thanks!
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!