I woud like to use Ansible to deploy one of my project (let's call it project-to-deploy).
project-to-deploy can be run locally using a docker-compose.yml file, which, among other things, mount the following volumes inside the docker-container.
version: "2"
services:
database:
image: mysql:5.6
volumes:
- ./docker/mysql.init.d:/docker-entrypoint-initdb.d
messages:
image: private.repo/project-to-deploy:latest
Nothing more useful here. To run the project: docker-compose up.
I have created a docker image of the project (in which I copy all the files from the project to the newly created docker image), and uploaded it to private.repo/project-to-deploy:latest.
Now comes the Ansible part.
For the project to run, I need:
The docker image
A MySQL instance (see part of my docker-compose.yml below)
In my docker-compose.yml (above), it is quite easy to do so. I just create the 2 services (database and project-to-deploy) and link them each-other.
How can I perform such action in Ansible?
First things I did is to fetch the image:
- name: Docker - pull project image
docker:
image: "private.repo/project-to-deploy:latest"
state: restarted
pull: always
Then, how can I link the MySQL docker image to this, knowing that the MySQL docker image need files from project-to-deploy ?
If you think of another way to do it, feel free to make suggestions !
slight correction, the docker module is for running containers, in your example you are not just fetching the image. You're actually pulling the image, creating a container, and running it.
I would typically accomplish this by using ansible to template each container's config files with the needed IP addresses, ports, credentials, etc. providing them all they need to know to communicate with each other.
Since your example only involves few connections you could set the links option in your ansible task. You should only need to set it on the "messages" container side.
- name: Docker - start MySQL container
docker:
name: database
image: "mysql:5.6"
state: restarted
volumes:
- /path/to/docker/mysql.init.d:/docker-entrypoint-initdb.d
pull: always
- name: Docker - start project container
docker:
name: messages
image: "private.repo/project-to-deploy:latest"
state: restarted
pull: always
links:
- database
Related
I have two docker images in Nexus repo
1. sql-db
2. main-svc
The main-svc need sql-db in order to run completely.
Can I defined such in gitlab-ci.yml?
Build:
image: test.com/main-svc:1.5
services: test.com/sql-db:1.0
script:
- docker pull test.com/main-svc:1.5
You can do this if you use docker-in-docker, but you don't need to. Simply define two service containers, as such:
build:
image: alpine
services:
- postgres:latest
- redis:latest
script:
- echo "hello world"
I didn't edit your example because I'm a bit confused about why you're using the same container for both the image and the docker pull inside it. My guess is you have a container you're trying to run integration tests with, then you're testing a container which needs to connect to a database as two different services. If not, it would be helpful for you to state what problem you're trying to solve and we can help more.
I'm trying to write a docker-compose file that will build and push a versioned (1.0, 1.1...) and latest build of my image to my local v2 docker registry. However when I run docker-compose build I get the following error:
ERROR: Couldn't connect to Docker daemon - you might need to run `docker-machine start default`.
I found a lot of people complaining about this error for many different reasons, in my case it has nothing to do with permissions or weather or not the docker service is running, I narrowed it down to my image naming having a URL on it (the URL of my local registry), I know that because if I name my image normally (like '/app:latest'), then the commands runs fine. So how can I have a URL as the image name?
Here is what I'm trying to do (docker-compose.yaml):
version: "3.8"
x-marvin-backend: &default-marvin-backend
container_name: marvin_backend
build: ./marvin-api
image: "http://my_registry_url:5000/marvin/backend:latest"
ports:
- "3000:3000"
networks:
- backend
x-marvin-frontend: &default-marvin-frontend
container_name: marvin_frontend
image: http://my_registry_url:5000/marvin/frontend:latest
build:
context: ./marvin-front
args:
- REACT_APP_SERVICES_HOST=http://marvin_backend:3000/
ports:
- "80:80"
networks:
- backend
depends_on:
- backend
services:
backend: *default-marvin-backend
backend_versioned:
<< : *default-marvin-backend
image: http://my_registry_url:5000/marvin/backend:1.0
frontend: *default-marvin-frontend
frontend_versioned:
<< : *default-marvin-frontend
image: http://my_registry_url:5000/marvin/frontend:1.0
networks:
backend:
I'm new to docker in general, my main goal here is to have a simple, preferably one command (e.g docker-compose build), that will build and tag both my front end and back end images so that I can just execute docker-compose push to push those newly created images to my registry running on AWS. With that I also want to be able to override the latest version of those images in the registry while also adding a versioned image for backup purposes, in case I want to revisit any of those version in the future.
Then in the AWS EC2 machine I have another docker-compose.yaml file that just fetches the latest versions of both images and run their containers.
So to summarize I would develop the application on my local machine, then add the new version manually to the versioned services in the local docker-compose.yaml file, then run docker-compose build followed by docker-compose push; then ssh into my AWS machine and run docker-compose up to fetch the latest and newly updated images and run them.
This could later evolve into a CI/CD pipeline, but right now I'm taking baby steps and trying to get my image name to have a URL in it.
Thank you.
Edit
I tried using a .env with REGISTRY=http://my_registry_url:5000/marvin and then using image: "${REGISTRY}/frontend:latest" or image: "$${REGISTRY}/frontend:latest" but that also didn't work
Just remove the http:// part from your images.
I have project with docker-compose file and want to migrate to V3, but when deploy with
docker stack deploy --compose-file=docker-compose.yml vertx
It does not understand build path, links, container names...
My file locate d here
https://github.com/armdev/vertx-spring/blob/master/docker-compose.yml
version: '3'
services:
eureka-node:
image: eureka-node
build: ./eureka-node
container_name: eureka-node
ports:
- '8761:8761'
networks:
- vertx-network
postgres-node:
image: postgres-node
build: ./postgres-node
container_name: postgres-node
ports:
- '5432:5432'
networks:
- vertx-network
environment:
POSTGRES_USER: postgres
POSTGRES_PASSWORD: socnet
POSTGRES_DB: socnet
vertx-node:
image: vertx-node
build: ./vertx-node
container_name: vertx-node
links:
- postgres-node
- eureka-node
ports:
- '8585:8585'
networks:
- vertx-network
networks:
vertx-network:
driver: overlay
when I run docker-compose up, it is working, but with
stack deploy not.
How to define path for docker file?
docker stack deploy works only on images, not on builds.
This means that you will have to push your images to an image registry (created with the build process), later docker stack deploy will download the images and execute them.
here you have an example of how was it done for a php application.
You have to pay attention to the parts 1, 3 and 4.
The articles are about php, but can easily be applied to any other language.
The swarm mode "docker service" interface has a few fundamental differences in how it manages containers. You are no longer directly running containers like with "docker run", and it is assumed that you will be doing this in a distributed environment more often than not.
I'll break down the answer by these specific things you listed.
It does not understand build path, links, container names...
Links
The link option has been deprecated for quite some time in favor of the network service discovery feature introduced alongside the "docker network" feature. You no longer need to specify specific links to/from containers. Instead, you simply need to ensure that all containers are on the same network and then they can discovery eachother by the container name or "network alias"
docker-compose will put all your containers into the same network by default, and it sets up the compose service name as an alias. That means if you have a service called 'postgres-node', you can reach it via dns by the name 'postgres-node'.
Container Names
The "docker service" interface allows you to declare a desired state. "I want x number of identical services". Since the interface must support x number of instances of a service, it doesn't allow you to choose the specific container name. Instead, you get to choose the service name. In the case of 'docker stack deploy', the service name defined under the services key in your docker-compose.yml file will be used, but it will also prepend the stack name to the service name.
In most cases, I would argue that overriding the container name in a docker-compose.yml file is unnecessary, even when using regular containers via docker-compose up.
If you need a different name for network service discovery purposes, add a different alias or use the service name alias that you get when using docker-compose or docker stack deploy.
build path
Because swarm mode was built to be a distributed system, building an image in place locally isn't something that "docker stack deploy" was meant to do. Instead, you should build and push your image to a registry that all nodes in your cluster can access.
In the case where you are using a single node swarm "cluster", you should be able to use the docker-compose build option to get the images built locally, and then use docker stack deploy.
I'm trying to deploy an app that's built with docker-compose, but it feels like I'm going in completely the wrong direction.
I have everything working locally—docker-compose up brings up my app with the appropriate networks and hosts in place.
I want to be able to run the same configuration of containers and networks on a production machine, just using a different .env file.
My current workflow looks something like this:
docker save [web image] [db image] > containers.tar
zip deploy.zip containers.tar docker-compose.yml
rsync deploy.zip user#server
ssh user#server
unzip deploy.zip ./
docker load -i containers.tar
docker-compose up
At this point, I was hoping to be able to run docker-compose up again when they get there, but that tries to rebuild the containers as per the docker-compose.yml file.
I'm getting the distinct feeling that I'm missing something. Should I be shipping over my full application then building the images at the server instead? How would you start composed containers if you were storing/loading the images from a registry?
The problem was that I was using the same docker-compose.yml file in development and production.
The app service didn't specify a repository name or tag, so when I ran docker-compose up on the server, it just tried to build the Dockerfile in my app's source code directory (which doesn't exist on the server).
I ended up solving the problem by adding an explicit image field to my local docker-compose.yml.
version: '2'
services:
web:
image: 'my-private-docker-registry:latest'
build: ./app
Then created an alternative compose file for production:
version: '2'
services:
web:
image: 'my-private-docker-registry:latest'
# no build field!
After running docker-compose build locally, the web service image is built with the repository name my-private-docker-registry and the tag latest.
Then it's just a case of pushing the image up to the repository.
docker push 'my-private-docker-registry:latest'
And running docker pull, it's safe to stop and recreate the running containers, with the new images.
I have a Node.js web-application that connects to a Neo4j database. I would like to encapsulate these in a single Docker image (using also a Neo4j Docker container), but I'm a docker novice and can't seem to figure this out. What's the recommended way to do it in the latest Docker versions?
My intuition would be to run the Neo4j container nested inside the app container. But from what I've read, I think the supported / recommended approach is to link the containers together. What I need is pretty well illustrated in this image. But the article where the image comes from isn't clear to me. Anyway, it's using the soon-to-be-deprecated legacy container linking, while networking is recommended these days. A tutorial or explanation would be much appreciated.
Also, how does docker-compose fit into all this?
Running a container within another container would imply to run a Docker engine within a Docker container. This is referenced as dind for Docker-in-Docker and I would strongly advise against it. You can search 'dind' online and discover why in most cases it is a bad idea, but as it is not the main object of your question I won't extend this subject any further.
Running both a node.js process and a neo4j process in the same container
While most people will tell you to refrain yourself from running more than one process within a Docker container, nothing prevents you from doing so. If you want to follow this path, take a look at the Using Supervisor with Docker from the Docker documentation website, or at the Phusion baseimage Docker image.
Just be aware that this way of doing things will make your Docker image more and more difficult to maintain over time.
Linking containers
As you found out, keeping Docker images as simple as you can (i.e: running one and only one app within a Docker container) will make your life easier on the long term.
Linking containers together is trivial when both containers run on the same Docker engine. It is just a matter of:
having your neo4j container expose the port its service listens on
running your node.js container with the --link <neo4j container name>:<alias> option
within the node.js application configuration, set the neo4j host to the <alias> hostname, docker will take care of forwarding that connection to the IP it assigned to the neo4j container
When you want to run those two containers on different hosts, things get more difficult.
With Docker Compose, you have to use the link: key to define your links
The new Docker network feature
You also discovered that linking containers won't be supported in the future and that the new way of making multiple Docker containers communicate is to create a virtual network and attach those 2 containers to that network.
Here's how to proceed:
docker network create mynet
docker run --detach --name myneo4j --net mynet neo4j
docker run --detach --name mynodejs --net mynet <your nodejs image>
Your node application configuration should then use myneo4j as the host to connect to.
To tell Docker Compose to use the new network feature, you would have to use the --x-networking option. Also you would not use the links: key.
Using the new networking feature also means that you won't be able to define any alias for the db. As a result you have to use the container name. Beware that unless you use the container_name: key in your docker-compose.yml file, Compose will create container names based on the directory which contains your docker-compose.yml file, the service name as found in the yml file and a number.
For instance, the following docker-compose.yml file, if within a directory named "foo" would create two containers named foo_web_1 and foo_db_1:
web:
build: .
ports:
- "8000:8000"
db:
image: postgres
when started with docker-compose --x-networking up, the web app configuration should then use foo_db_1 as the db hostname.
While if you use container_name:
web:
build: .
ports:
- "8000:8000"
db:
image: postgres
container_name: mydb
when started with docker-compose --x-networking up, the web app configuration should then use mydb as the db hostname.
Example of using Docker Compose to run a web app using nodeJS and neo4j
In this example, I will show how to dockerize the example app from github project aseemk/node-neo4j-template which uses nodejs and neo4j.
I assume you already have Docker 1.9.0+ and Docker Compose 1.5+ installed.
This project will use 2 docker containers, one to run the neo4j database and one to run the nodeJS web app.
Dockerizing the web app
We need to build a Docker image from which Docker compose will run a container. For that, we will write a Dockerfile.
Create a file named Dockerfile (mind the capital D) with the following content:
FROM node
RUN git clone https://github.com/aseemk/node-neo4j-template.git
WORKDIR /node-neo4j-template
RUN npm install
# ugly 20s sleep to wait for neo4j to initialize
CMD sleep 20s && node app.js
This Dockerfile describes the steps the Docker engine will have to follow to build a docker image for our web app. This docker image will:
be based on the official node docker image
clone the nodeJS example project from Github
change the working directory to the directory containing the git clone
run the npm install command to download and install the nodeJS app dependencies
instruct docker which command to use when running a container of that image
A quick review of the nodeJS code reveals that the author allows us to configure the URL to use to connect to the neo4j database using the NEO4J_URL environment variable.
Dockerizing the neo4j database
Well people took care of that for us already. We will use the official Docker image for neo4j which can be found on the Docker Hub.
A quick review of the readme tells us to use the NEO4J_AUTH environment variable to change the neo4j password. And setting this variable to none will disable the authentication all together.
Setting up Docker Compose
In the same directory as the one containing our Dockerfile, create a docker-compose.yml file with the following content:
db:
container_name: my-neo4j-db
image: neo4j
environment:
NEO4J_AUTH: none
web:
build: .
environment:
NEO4J_URL: http://my-neo4j-db:7474
ports:
- 80:3000
This Compose configuration file describes 2 services: db and web.
The db service will produce a container named my-neo4j-db from the official neo4j docker image and will start that container setting up the NEO4J_AUTH environment variable to none.
The web service will produce a container named at docker compose discretion using a docker image built from the Dockerfile found in the current directory (build: .). It will start that container setting up the environment variable NEO4J_URL to http://my-neo4j-db:7474 (note how we use here the name of the neo4j container my-neo4j-db). Furthermore, docker compose will instruct the Docker engine to expose the web container's port 3000 on the docker host port 80.
Firing it up
Make sure you are in the directory that contains the docker-compose.yml file and type: docker-compose --x-networking up.
Docker compose will read the docker-compose.yml file, figure out it has to first build a docker image for the web service, then create and start both containers and finally will provide you with the logs from both containers.
Once the log shows web_1 | Express server listening at: http://localhost:3000/, everything is cooked and you can direct your Internet navigator to http://<ip of the docker host>/.
To stop the application, hit Ctrl+C.
If you want to start the app in the background, use docker-compose --x-networking up -d instead. Then in order to display the logs, run docker-compose logs.
To stop the service: docker-compose stop
To delete the containers: docker-compose rm
Making neo4j storage persistent
The official neo4j docker image readme says the container persists its data on a volume at /data. We then need to instruct Docker Compose to mount that volume to a directory on the docker host.
Change the docker-compose.yml file with the following content:
db:
container_name: my-neo4j-db
image: neo4j
environment:
NEO4J_AUTH: none
volumes:
- ./neo4j-data:/data
web:
build: .
environment:
NEO4J_URL: http://my-neo4j-db:7474
ports:
- 80:3000
With that config file, when you will run docker-compose --x-networking up, docker compose will create a neo4j-data directory and mount it into the container at location /data.
Starting a 2nd instance of the application
Create a new directory and copy over the Dockerfile and docker-compose.yml files.
We then need to edit the docker-compose.yml file to avoid name conflict for the neo4j container and the port conflict on the docker host.
Change its content to:
db:
container_name: my-neo4j-db2
image: neo4j
environment:
NEO4J_AUTH: none
volumes:
- ./neo4j-data:/data
web:
build: .
environment:
NEO4J_URL: http://my-neo4j-db2:7474
ports:
- 81:3000
Now it is ready for the docker-compose --x-networking up command. Note that you must be in the directory with that new docker-compose.yml file to start the 2nd instance up.