All About Docker Compose Override Entrypoint Entrypoint helps use set the command and parameters that executes first when a container is run. In fact, the command line arguments in the following command become a part of the entrypoint command, thereby overriding all elements mentioned via CMD.
If it does have an entrypoint ( entrypoint: , docker run --entrypoint ... , ENTRYPOINT ), it's the entrypoint, which gets passed the command as arguments. In short: if you pass an entrypoint or command in docker-compose. yml , it gets run instead of the server the container would normally run.
Example of using CMD and ENTRYPOINT togetherIf both ENTRYPOINT and CMD are present, what is written in CMD is executed as an option of the command written in ENTRYPOINT. If an argument is added at the time of docker run , the contents of CMD will be overwritten and the ENTRYPOINT command will be executed.
The command
clause does work as @Karthik says above.
As a simple example, the following service will have a -inMemory
added to its ENTRYPOINT
when docker-compose up
is run.
version: '2'
services:
local-dynamo:
build: local-dynamo
image: spud/dynamo
command: -inMemory
Whatever is specified in the command
in docker-compose.yml should get appended to the entrypoint
defined in the Dockerfile, provided entrypoint
is defined in exec form in the Dockerfile.
If the EntryPoint is defined in shell form, then any CMD arguments will be ignored.
You can use docker-compose run
instead of docker-compose up
and tack the arguments on the end. For example:
docker-compose run dperson/samba arg1 arg2 arg3
If you need to connect to other docker containers, use can use --service-ports
option:
docker-compose run --service-ports dperson/samba arg1 arg2 arg3
To override the default entrypoint, use entrypoint
option. To pass the arguments use command
.
Here is the example of replacing bash
with sh
in ubuntu
image:
version: '3'
services:
sh:
entrypoint: /bin/sh
command: -c "ps $$(echo $$$$)"
image: ubuntu
tty: true
bash:
entrypoint: /bin/bash
command: -c "ps $$(echo $$$$)"
image: ubuntu
tty: true
Here is the output:
$ docker-compose up
Starting test_sh_1 ... done
Starting 020211508a29_test_bash_1 ... done
Attaching to test_sh_1, 020211508a29_test_bash_1
sh_1 | PID TTY STAT TIME COMMAND
sh_1 | 1 pts/0 Ss+ 0:00 /bin/sh -c ps $(echo $$)
020211508a29_test_bash_1 | PID TTY STAT TIME COMMAND
020211508a29_test_bash_1 | 1 pts/0 Rs+ 0:00 ps 1
I was facing the same issue with jenkins ssh slave 'jenkinsci/ssh-slave'. However, my case was a bit complicated because it was necessary to pass an argument which contained spaces. I've managed to do it like below (entrypoint in dockerfile is in exec form):
command: ["some argument with space which should be treated as one"]
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