I've got 3 containers that will run on a single server, which we'll call: A,B,C
Each server has a script on the host that has the commands to start docker:
A_start.sh
B_start.sh
C_start.sh
I'm trying to create a swarm script to start them all, but not sure how.
ABC_start.sh
UPDATE:
this seems to work, with the first being output to the terminal, cntrl+C exits out of them all.d
./A_start.sh & ./B_start.sh & ./C_start.sh
swarm will not help you start them at all..., it is used to distribute the work amongst docker machines that are part of the cluster.
there is no good reason not to use docker-compose for that use case, its main purpose is to link containers properly, and bring them up, so your collection of scripts could end up being a single docker-compose up command.
In bash,
you can do this:
nohup A_start.sh &
nohup B_start.sh &
nohup C_start.sh &
Related
I have two scripts that I would like to execute.
Script 1: A script that executes docker run (needs to stay active because if it is closed the docker container stops running)
Script 2: A script that runs docker exec and gets into the docker shell
Problem:
I need to run script 1 and script 2 in separate shells because script 1 needs to stay active and cannot be closed.
Separating the scripts into two separate files and then running both scripts from one file
sh script1.sh & sh script2.sh
Just run it as one big script.
When executing/running the docker container use the --detach or -d flag.
This ensures, that the container does not stay active in the terminal but moves into the background (it keeps running!).
The docker command would look something like
docker run -d ...
I'm using a Dockerfile that ends with a CMD ["/start.sh"]:
#!/bin/bash
service ssh start
/usr/bin/node /myApp/app.js
if for some reason i need to kill the node process, the ssh server is being closed as well (forces me to reboot the container to reconnect).
Any simple way to avoid this behavior?
Thank You.
The container exits as soon as main process of the container exits. In your case, the main process inside the container is start.sh shell script. The start.sh shell script is starting the ssh service and then running the nodejs process as child process. Once the nodejs process dies, the shell script exits as well and so the container exits. So what you can do is to put the nodejs process in background.
#!/bin/bash
service ssh start
/usr/bin/node /myApp/app.js &
# Need the following infinite loop as the shell script should not exit
while do:
sleep 2
done
I DO NOT recommend this approach though. You should have only a single process per container. Read the following answers to understand why -
Running multiple applications in one docker container
If you still want to run multiple processes inside container, there are better ways to do it like using supervisord - https://docs.docker.com/config/containers/multi-service_container/
I am having multi-node cluster of Hadoop, Kafka, Zookeeper, Spark.
I am running following commands to start respective service,
$ ./Hadoop/sbin/start-all.sh
$ ./zookeeper/bin/zkServer.sh start
$ ./Kafka/Kafka-server-start.sh ./config/server-properties.sh
$ ./spark/sbin/start-all.sh
and so on..
can anyone tell me how to write a script to automate this process of running each command individually?
Have you tried creating a simple shell script with all these commands and running that script instead? For example, following is a simple bash script
#!/bin/bash
./Hadoop/sbin/start-all.sh
./zookeeper/bin/zkServer.sh start
./kafka/kafka-server-start.sh ./config/server-properties.sh
./spark/sbin/start-all.sh
and so on ...
I need to develop a client and server program with using sockets. My program should get port number from the command line. I saw an example which says "myprogram 2454 &".
I wonder what that & (ampersand) means there.
It means to start the process in the background. http://tldp.org/LDP/abs/html/x9644.html so that you may continue to use your shell session to run other programs. You can then use fg to "foreground" your process again.
The ampersand (&) means that you want to run myprogram in background. This is normally used when you want to stay on your command-prompt and continue the work on the same session.
Example
somescript &
will run the somescript shell script in background. You will get the prompt back on the next line. If you run somescript without & then the prompt may not appear back because somescript may take more time.
The best way is to run it in background with no hangups, in which case even of you loose your connection to the host the process keeps running on the UNIX or Linux host.
For example
nohup somescript &
the jobs command will display the jobs running in background.
I'm running Docker commands from a management script and one of the commands I use is attach.
Attaching works fine but I can't seam to leave the output either by pressing CTRL+C or CTRL+P/CTRL+Q.
My theory is that the key signals are not fetched by Docker since bash is running front of it.
Is this correct? And how do I solve this?