Why docker restart recognizes modifications in docker-compose.yml file - docker

I am new in docker and docker-compose. I am working on a project which uses both docker and docker compose. After adding a line in the key "volumes" of docker-compose.yml. I did docker restart
docker restart service1
and the volume was automatically recognized. Below part of the docker-compose.yml
services:
service1:
build:
context: .
dockerfile: Dockerfile.service1
container_name: service1_name
hostname: service1_name
volumes:
- /etc/teste/service1/conf.d/:/usr/share/logstash/pipeline/ #I added this line
My question Why docker restart recognizes modifications in docker-compose.yml file, where can I find this "setting"?

Working with docker-compose the scenario should be the following:
Create your docker-compose.yml
docker-compose up # this will build everything and run your services
If you make any changes to your compose file, stating docker-compose build 'yourservicename' will rebuild that specific service.
The command "docker restart" as you can see in the help page is for restarting containers

Related

Docker container log does not appear anymore on Docker compose log

I'm running my Docker container through my Docker compose, but when my container stops and it restarts again, the log does not appear anymore related to this restarted container.
Would anyone know how to fix it?
I send below the docker compose command and the file for analysis.
Thank you in advance.
Command to start the compose
docker-compose -f docker-compose.dev.yml up
Docker compose
version: '3'
services:
ms3_executive_back:
image: ms3_executive_backend
ports:
- "5001:5001"
volumes:
- ./executive_backend:/app
restart: always
If you want to inspect the logs to determine cause of failure, you can try setting your restart: "no". This will ensure that docker-compose does not automatically restart your container and overwrite the existing logs.

Start particular service from docker-compose

I am new to Docker and have docker-compose.yml which is containing many services and iI need to start one particular service. I have docker-compose.yml file with information:
version: '2'
services:
postgres:
image: ${ARTIFACTORY_URL}/datahub/postgres:${BUILD_NUMBER}
restart: "no"
volumes:
- /etc/passwd:/etc/passwd
volumes_from:
- libs
depends_on:
- libs
setup:
image: ${ARTIFACTORY_URL}/setup:${B_N}
restart: "no"
volumes:
- ${HOME}:/usr/local/
I am able to call docker-compose.yml file using command:
docker-compose -f docker-compose.yml up -d --no-build
But I need to start "setup service" in docker-compose file:
How can I do this?
It's very easy:
docker compose up <service-name>
In your case:
docker compose -f docker-compose.yml up setup -d
To stop the service, then you don't need to specify the service name:
docker compose down
will do.
Little side note: if you are in the directory where the docker-compose.yml file is located, then docker-compose will use it implicitly, there's no need to add it as a parameter.
You need to provide it in the following situations:
the file is not in your current directory
the file name is different from the default one, eg. myconfig.yml
As far as I understand your question, you have multiple services in docker-compose but want to deploy only one.
docker-compose should be used for multi-container Docker applications. From official docs :
Compose is a tool for defining and running multi-container Docker
applications.
IMHO, you should run your service image separately with docker run command.
PS: If you are asking about recreating only the container whose image is changed among the multiple services in your docker-compose file, then docker-compose handles that for you.

What is the difference between `docker-compose build` and `docker build`?

What is the difference between docker-compose build and docker build?
Suppose in a dockerized project path there is a docker-compose.yml file:
docker-compose build
And
docker build
docker-compose can be considered a wrapper around the docker CLI (in fact it is another implementation in python as said in the comments) in order to gain time and avoid 500 characters-long lines (and also start multiple containers at the same time). It uses a file called docker-compose.yml in order to retrieve parameters.
You can find the reference for the docker-compose file format here.
So basically docker-compose build will read your docker-compose.yml, look for all services containing the build: statement and run a docker build for each one.
Each build: can specify a Dockerfile, a context and args to pass to docker.
To conclude with an example docker-compose.yml file :
version: '3.2'
services:
database:
image: mariadb
restart: always
volumes:
- ./.data/sql:/var/lib/mysql
web:
build:
dockerfile: Dockerfile-alpine
context: ./web
ports:
- 8099:80
depends_on:
- database
When calling docker-compose build, only the web target will need an image to be built. The docker build command would look like :
docker build -t web_myproject -f Dockerfile-alpine ./web
docker-compose build will build the services in the docker-compose.yml file.
https://docs.docker.com/compose/reference/build/
docker build will build the image defined by Dockerfile.
https://docs.docker.com/engine/reference/commandline/build/
Basically, docker-compose is a better way to use docker than just a docker command.
If the question here is if docker-compose build command, will build a zip kind of thing containing multiple images, which otherwise would have been built separately with usual Dockerfile, then the thinking is wrong.
Docker-compose build, will build individual images, by going into individual service entry in docker-compose.yml.
With docker images, command, we can see all the individual images being saved as well.
The real magic is docker-compose up.
This one will basically create a network of interconnected containers, that can talk to each other with name of container similar to a hostname.
Adding to the first answer...
You can give the image name and container name under the service definition.
e.g. for the service called 'web' in the below docker-compose example, you can give the image name and container name explicitly, so that docker does not have to use the defaults.
Otherwise the image name that docker will use will be the concatenation of the folder (Directory) and the service name. e.g. myprojectdir_web
So it is better to explicitly put the desired image name that will be generated when docker build command is executed.
e.g.
image: mywebserviceImage
container_name: my-webServiceImage-Container
example docker-compose.yml file :
version: '3.2'
services:
web:
build:
dockerfile: Dockerfile-alpine
context: ./web
ports:
- 8099:80
image: mywebserviceImage
container_name: my-webServiceImage-Container
depends_on:
- database
Few additional words about the difference between docker build and docker-compose build.
Both have an option for building images using an existing image as a cache of layers.
with docker build, the option is --cache-from <image>
with docker-composer, there is a tag cache_from in the build section.
Unfortunately, up until now, at this level, images made by one are not compatible with the other as a cache of layers (Ids are not compatible).
However, docker-compose v1.25.0 (2019-11-18), introduces an experimental feature COMPOSE_DOCKER_CLI_BUILD so that docker-compose uses native docker builder (therefore, images made by docker build can be used as a cache of layers for docker-compose build)

Docker Compose does not allow to use local images

The following command fails, trying to pull image from the Docker Hub:
$ docker-compose up -d
Pulling web-server (web-server:staging)...
ERROR: repository web-server not found: does not exist or no pull access
But I just want to use a local version of the image, which exists:
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
web-server staging b94573990687 7 hours ago 365MB
Why Docker doesn't search among locally stored images?
This is my Docker Compose file:
version: '3'
services:
chat-server:
image: chat-server:staging
ports:
- "8110:8110"
web-server:
image: web-server:staging
ports:
- "80:80"
- "443:443"
- "8009:8009"
- "8443:8443"
and my .env file:
DOCKER_HOST=tcp://***.***.**.**:2376
DOCKER_TLS_VERIFY=true
DOCKER_CERT_PATH=/Users/Victor/Documents/Development/projects/.../target/docker
In general, this should work as you describe it. Tried to reproduce it, but it simply worked...
Folder structure:
.
├── docker-compose.yml
└── Dockerfile
Content of Dockerfile:
FROM alpine
CMD ["echo", "i am groot"]
Build and tag image:
docker build -t groot .
docker tag groot:latest groot:staging
with docker-compose.yml:
version: '3.1'
services:
groot:
image: groot:staging
and start docker-compose:
$ docker-compose up
Creating groot_groot ...
Creating groot_groot_1 ... done
Attaching to groot_groot_1
groot_1 | i am groot
groot_groot_1 exited with code 0
Version >1.23 (2019 and newer)
Easiest way is to change image to build: and reference the Dockerfile in the relative directory, as shown below:
version: '3.0'
services:
custom_1:
build:
context: ./my_dir
dockerfile: Dockerfile
This allows docker-compose to manage the entire build and image orchestration in a single command.
# Rebuild all images
docker-compose build
# Run system
docker-compose up
In your docker-compose.yml, you can specify build: . instead of build: <username>/repo> for local builds (rather than pulling from docker-hub) - I can't verify this yet, but I believe you may be able to do relative paths for multiple services to the docker-compose file.
services:
app:
build: .
Reference: https://github.com/gvilarino/docker-workshop
March-09-2020 EDIT:
(docker version 18.09.9-ce build 039a7df,
dockercompose version 1.24.0, build 0aa59064)
I found that to just create a docker container, you can just docker-compose 'up -d' after tagging the container with a fake local registry server tag (localhost:5000/{image}).
$ docker tag {imagename}:{imagetag} localhost:5000/{imagename}:{imagetag}
You don't need to run the local registry server, but need to change the image url in dockercompose yaml file with the fake local registry server url:
version: '3'
services:
web-server:
image: localhost:5000/{your-image-name} #change from {imagename}:{imagetag} to localhost:5000/{imagename}:{imagetag}
ports:
- "80:80"
from {imagename}:{imagetag} to localhost:5000/{imagename}:{imagetag}
and just up -d
$ docker-compose -f {yamlfile}.yaml up -d
This creates the container if you already have the image (localhost:5000/{imagename}) in your local machine.
Adding to #Tom Saleeba's response,
I still got errors after tagging the container with "/"
(for ex: victor-dombrovsky/docker-image:latest)
It kept looking for the image from remote docker.io server.
registry_address/docker-image
It seems the url before "/" is the registry address and after "/" is the image name. and without "/" provided, docker-compose by default looks for the image from the remote docker.io.
It guess it's a known bug with docker-compose
I finally got it working by running the local registry, pushing the image to the local registry with the registry tag, and pulling the image from the local registry.
$ docker run -d -p 5000:5000 --restart=always --name registry registry:2
$ docker tag your-image-name:latest localhost:5000/your-image-name
$ docker push localhost:5000/your-image-name
and then change the image url in the dockerfile:
version: '3'
services:
chat-server:
image: chat-server:staging
ports:
- "8110:8110"
web-server:
image: localhost:5000/{your-image-name} #####change here
ports:
- "80:80"
- "443:443"
- "8009:8009"
- "8443:8443"
Similarly for the chat-server image.
You might need to change your image tag to have two parts separated by a slash /. So instead of
chat-server:staging
do something like:
victor-dombrovsky/chat-server:staging
I think there's some logic behind Docker tags and "one part" tags are interpreted as official images coming from DockerHub.
For me putting "build: ." did the trick. My working docker compose file looks like this,
version: '3.0'
services:
terraform:
build: .
image: tf:staging
env_file: .env
working_dir: /opt
volumes:
- ~/.aws:/.aws
You have a DOCKER_HOST entry in your .env 👀
From the looks of your .env file you seem to have configured docker-compose to use a remote docker host:
DOCKER_HOST=tcp://***.***.**.**:2376
Moreover, this .env is only loaded by docker-compose, but not docker. So in this situation your docker images output doesn't represent what images are available when running docker-compose.
When running docker-compose you're actually running Docker on the remote host tcp://***.***.**.**:2376, yet when running docker by itself you're running Docker locally.
When you run docker images, you're indeed seeing a list of the images that are stored locally on your machine. But docker-compose up -d is going to attempt to start the containers not on your local machine, but on ***.***.**.**:2376. docker images won't show you what images are available on the remote Docker host unless you set the DOCKER_HOST environment variable, like this for example:
DOCKER_HOST=tcp://***.***.**.**:2376 docker images
Evidently the remote Docker host doesn't have the web-server:staging image stored there, nor is the image available on Docker hub. That's why Docker complains it can't find the image.
Solutions
Run the container locally
If your intention was to run the container locally, then simply remove the DOCKER_HOST=... line from your .env and try again.
Push the image to a repository.
However if you plan on running the image remotely on the given DOCKER_HOST, then you should probably push it to a repository. You can create a free repository at Docker Hub, or you can host your own repository somewhere, and use docker push to push the image there, then make sure your docker-compose.yml referenced the correct repository.
Save the image, load it remotely.
If you don't want to push the image to Docker Hub or host your own repository you can also transfer the image using a combination of docker image save and docker image load:
docker image save web-server:staging | DOCKER_HOST=tcp://***.***.**.**:2376 docker image load
Note that this can take a while for big images, especially on a slow connection.
You can use pull_policy:
image: img:tag
pull_policy: if_not_present
My issue when getting this was that I had built using docker without sudo, and ran docker compose with sudo. Running docker images and sudo docker images gave me two different sets of images, where sudo docker compose up gave me access only to the latter.

docker container using the same volume even after running new container image

I have f.e. two containers in docker
compose.yml
version: '2'
services:
nginx:
image: local-nginx:0.3
ports:
- "81:81"
volumes_from:
- webapp
webapp:
image: local-webapp:0.65
webapp Dockerfile
FROM node:4.3.0
...
VOLUME /www
CMD npm run some_script
So, what's happening, webapp container shares folder /www to nginx, and static files are serving from nginx container.
I'm starting my app with command
docker-compose -f compose.yml up
everything working fine, good. But when I want for example run application with another version of webapp local-webapp:0.66
I change version to 0.66 in compose.yml, stop current containers and run again
docker-compose -f compose.yml up
But, I still see the same version of webapp. when i go inside nginx container I still see the same files from previous 0.65. To see correct files, I must remove all containers, and then again docker-compose -f compose.yml up.
So, the question. How is this possible to configure my compose.yml file to update volume without removing all containers?
This is because Compose preserves volumes.
If you want new data, you have two options:
don't use a volume
remove the containers first

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