Wondering what Docker Compose is?
Docker is the most popular containerization tool in the DevOps world. But, What is Docker Compose?
Docker Compose is used to run applications which have multiple containers using a YAML file.
There can be several cases where the docker application must run multiple containers for different technology stack. Now building, running, connecting separate dockerfiles for each container can be a difficult task; this is where docker-compose helps you out.
Using a single and straightforward docker-compose.yml file, you can build, connect, and launch all the containers by running a single command. This is very useful for enterprise applications in production, where several applications run inside containers. It saves a lot of time by running 100s of application inside docker containers with ease.
Installing Docker Compose
Docker should already be installed on your system before installing compose.
Run the command below to install docker-compose.
geekflare@geekflare:/home/geekflare$ sudo curl -L "https://github.com/docker/compose/releases/download/1.23.1/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
[sudo] password for geekflare:
% Total % Received % Xferd Average Speed Time Time Time Current
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100 617 0 617 0 0 1209 0 --:--:-- --:--:-- --:--:-- 1209
100 11.1M 100 11.1M 0 0 348k 0 0:00:32 0:00:32 --:--:-- 476kRun the command below to set file permissions.
geekflare@geekflare:/home/geekflare$ sudo chmod +x /usr/local/bin/docker-composeCheck if it got installed correctly, it should return the docker-compose version.
geekflare@geekflare:/home/geekflare$ docker-compose --version
docker-compose version 1.23.1, build b02f1306Below is the list of commands you can use with docker-compose.
geekflare@geekflare:/home/geekflare$ docker-compose
Define and run multi-container applications with Docker.
Usage:
docker-compose [-f <arg>…] [options] [COMMAND] [ARGS…]
docker-compose -h|--help
Options:
-f, --file FILE Specify an alternate compose file
(default: docker-compose.yml)
-p, --project-name NAME Specify an alternate project name
(default: directory name)
--verbose Show more output
--log-level LEVEL Set log level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
--no-ansi Do not print ANSI control characters
-v, --version Print version and exit
-H, --host HOST Daemon socket to connect to
--tls Use TLS; implied by –tlsverify
--tlscacert CA_PATH Trust certs signed only by this CA
--tlscert CLIENT_CERT_PATH Path to TLS certificate file
--tlskey TLS_KEY_PATH Path to TLS key file
--tlsverify Use TLS and verify the remote
--skip-hostname-check Don’t check the daemon’s hostname against the
name specified in the client certificate
--project-directory PATH Specify an alternate working directory
(default: the path of the Compose file)
--compatibility If set, Compose will attempt to convert deploy
keys in v3 files to their non-Swarm equivalent
Commands:
build Build or rebuild services
bundle Generate a Docker bundle from the Compose file
config Validate and view the Compose file
create Create services
down Stop and remove containers, networks, images, and volumes
events Receive real time events from containers
exec Execute a command in a running container
help Get help on a command
images List images
kill Kill containers
logs View output from containers
pause Pause services
port Print the public port for a port binding
ps List containers
pull Pull service images
push Push service images
restart Restart services
rm Remove stopped containers
run Run a one-off command
scale Set number of containers for a service
start Start services
stop Stop services
top Display the running processes
unpause Unpause services
up Create and start containers
version Show the Docker-Compose version informationDocker Compose File
Here is a sample docker-compose file which does all the magic.
version: '3'
services:
web:
build: .
ports:
- "5000:5000"
redis:
image: "redis:alpine"The first line in this file specifies the version being used. This number depends on the Docker engine installed on your system. I have Docker 18.09.6 installed which belongs to version 3 of docker-compose. Check out more details on versions here – https://docs.docker.com/compose/compose-file/compose-versioning/
This docker file is running two services/applications, web and Redis. The web service is built through a dockerfile and runs at default flask webserver port – 5000. The Redis service runs by pulling the Redis image from docker hub registry.
To execute the docker-compose.yml file, you need to run a very simple command: docker-compose up
Docker Compose Workflow
Below are the three steps to use docker-compose.
- Create dockerfile of each service
- Create a docker-compose.yml file to connect all the dockerfiles
- Run docker-compose up command to start the system
Let me take an example of the sample docker-compose file we saw earlier and show you how the project structure will be created.
my-app
|-----web
|---------Dockerfile
|-----redis
|docker-compose.ymlmy-app is my main project directory. This directory has web and Redis service directories and the docker-compose YAML file. Dockerfile of Web service is present in a web directory. Since Redis service is being pulled from docker hub directly, no dockerfile is required in Redis directory. This is how docker-compose workflow looks like.
Containerizing A MEAN Stack Application using Docker Compose
Now that you have understood fundamental concepts. Let me show a demo on how to containerize a MEAN stack application using docker-compose.
MEAN stands for MongoDB, Express, Angular and Node.js. Applications using these services together is also called a MEAN/Full-stack application.
For this demo, we will run three docker containers:
- Container 1 – Angular
- Container 2 – NodeJS and ExpressJS
- Container 3 – MongoDB
Download the complete application here: http://bit.ly/2St7r3A (not tested for production)
This is how my docker-compose.yml file will look like to run these three containers:
version: '3'
services:
angular:
build: angular-client
ports:
- "4200:4200"
volumes:
- ./angular-client/:/var/www/app
express:
build: express-server
ports:
- "3000:3000"
volumes:
- ./express-server/:/var/www/app
links:
- database
database:
image: mongo
ports:
- "27017:27017"- The first line specifies the docker-compose version being used
- We are running three services – angular, express and database
- Angular service will be built using a dockerfile. It will run on port 4200, and the application volume is /var/www/app
- Express service will be built using a dockerfile. The express server will run at port 3000, and the volume is /var/www/app
- Database service will pull MongoDB image from dockerhub and start it at post 27017
Extract the project in the home directory and go to the angular-client directory.
geekflare@geekflare:~$ cd mean
geekflare@geekflare:~/mean$ cd angular-client Run the command below if you don’t have node package manager (npm) installed on your system (ignore if it’s installed).
geekflare@geekflare:~/mean/angular-client$ sudo apt install npm
[sudo] password for geekflare:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
gyp javascript-common libc-ares2 libhttp-parser2.8 libjs-async libjs-inherits libjs-is-typedarray
libjs-jquery libjs-node-uuid libjs-underscore libssl1.0-dev libuv1 libuv1-dev node-abbrev node-ajv
node-ansi node-ansi-color-table node-ansi-regex node-ansi-styles node-ansistyles node-aproba node-archy
node-are-we-there-yet node-async node-aws-sign2 node-balanced-match node-block-stream node-bluebird
node-boom node-brace-expansion node-builtin-modules node-camelcase node-caseless node-chalk node-cliui
node-clone node-co node-color-convert node-color-name node-combined-stream node-concat-map
node-config-chain node-console-control-strings node-cookie-jar node-copy-concurrently node-core-util-is
node-yallist node-yargs node-yargs-parser nodejs nodejs-dev nodejs-doc
Suggested packages:
apache2 | lighttpd | httpd node-aws-sign node-oauth-sign node-http-signature debhelper
The following NEW packages will be installed:
gyp javascript-common libc-ares2 libhttp-parser2.8 libjs-async libjs-inherits libjs-is-typedarray
libjs-jquery libjs-node-uuid libjs-underscore libssl1.0-dev libuv1 libuv1-dev node-abbrev node-ajv
node-ansi node-ansi-color-table node-ansi-regex node-ansi-styles node-ansistyles node-aproba node-archy
node-are-we-there-yet node-async node-aws-sign2 node-balanced-match node-block-stream node-bluebird
0 upgraded, 212 newly installed, 0 to remove and 233 not upgraded.
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In angular-client directory and run npm install.
geekflare@geekflare:~/mean/angular-client$ npm install
> uws@0.14.5 install /home/geekflare/mean/angular-client/node_modules/uws
> node-gyp rebuild > build_log.txt 2>&1 || exit 0
> node-sass@4.7.2 install /home/geekflare/mean/angular-client/node_modules/node-sass
> node scripts/install.js
Downloading binary from https://github.com/sass/node-sass/releases/download/v4.7.2/linux-x64-57_binding.node
Download complete ] - :
Binary saved to /home/geekflare/mean/angular-client/node_modules/node-sass/vendor/linux-x64-57/binding.node
Caching binary to /home/geekflare/.npm/node-sass/4.7.2/linux-x64-57_binding.node
> uglifyjs-webpack-plugin@0.4.6 postinstall /home/geekflare/mean/angular-client/node_modules/webpack/node_modules/uglifyjs-webpack-plugin
> node lib/post_install.js
> node-sass@4.7.2 postinstall /home/geekflare/mean/angular-client/node_modules/node-sass
> node scripts/build.js
Binary found at /home/geekflare/mean/angular-client/node_modules/node-sass/vendor/linux-x64-57/binding.node
Testing binary
Binary is fine
added 1457 packages from 1250 contributors in 80.009sNow go to express directory and run npm install.
geekflare@geekflare:~/mean/angular-client$ cd ..
geekflare@geekflare:~/mean$ cd express-server/
geekflare@geekflare:~/mean/express-server$ npm installNow that everything is set, its time to run docker-compose.yml file which is going to launch all the docker containers and run the MEAN stack application.
geekflare@geekflare:~/mean/express-server$ cd ..
geekflare@geekflare:~/mean$ docker-compose up
Creating network "mean_default" with the default driver
Building angular
Step 1/8 : FROM node:8
8: Pulling from library/node
a4d8138d0f6b: Pull complete
dbdc36973392: Pull complete
f59d6d019dd5: Pull complete
aaef3e026258: Pull complete
6e454d3b6c28: Pull complete
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0314ab675d31: Pull complete
012886364728: Pull complete
Digest: sha256:310db2abcff097ef44af205d81833282a6d5471002a1b59d7b7459a74152c856
Status: Downloaded newer image for node:8
---> 8e45c884a32e
Step 2/8 : RUN mkdir -p /var/www/app
---> Running in c70a0cab7994
Removing intermediate container c70a0cab7994
---> 001c5e840b24
Step 3/8 : WORKDIR /var/www/app
---> Running in 622ebdc41b2f
Removing intermediate container 622ebdc41b2f
---> baa2e2347259
Step 4/8 : COPY package.json /var/www/app
---> 5b97543befab
Step 5/8 : RUN npm install
---> Running in 73e3d8b7a701
> uws@9.14.0 install /var/www/app/node_modules/uws
> node-gyp rebuild > build_log.txt 2>&1 || exit 0
> node-sass@4.12.0 install /var/www/app/node_modules/node-sass
> node scripts/install.js
Downloading binary from https://github.com/sass/node-sass/releases/download/v4.12.0/linux-x64-57_binding.node
Download complete
Binary saved to /var/www/app/node_modules/node-sass/vendor/linux-x64-57/binding.node
Caching binary to /root/.npm/node-sass/4.12.0/linux-x64-57_binding.node
> core-js@2.6.9 postinstall /var/www/app/node_modules/core-js
> node scripts/postinstall || echo "ignore"
The project needs your help! Please consider supporting of core-js on Open Collective or Patreon:
> https://opencollective.com/core-js
> https://www.patreon.com/zloirock
> uglifyjs-webpack-plugin@0.4.6 postinstall /var/www/app/node_modules/webpack/node_modules/uglifyjs-webpack-plugin
> node lib/post_install.js
> node-sass@4.12.0 postinstall /var/www/app/node_modules/node-sass
> node scripts/build.js
Binary found at /var/www/app/node_modules/node-sass/vendor/linux-x64-57/binding.node
Testing binary
Binary is fine
added 1606 packages from 1329 contributors and audited 15092 packages in 112.427s
Removing intermediate container 73e3d8b7a701
---> 55790d2fae93
Step 6/8 : COPY . /var/www/app
---> 61537aa487f4
Step 7/8 : EXPOSE 4200
---> Running in 632eedc35a45
Removing intermediate container 632eedc35a45
---> 51e75b0e2ebe
Step 8/8 : CMD ["npm", "start"]
---> Running in 36bbb12a0d38
Removing intermediate container 36bbb12a0d38
---> 9f8d61db600c
Successfully built 9f8d61db600c
Successfully tagged mean_angular:latest
Pulling database (mongo:)...
latest: Pulling from library/mongo
35b42117c431: Pull complete
ad9c569a8d98: Pull complete
293b44f45162: Pull complete
0c175077525d: Pull complete
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e03dcf51513f: Pull complete
c1956a9e136a: Pull complete
4c35cf22b1d5: Pull complete
Building express
Step 1/9 : FROM node:8
---> 8e45c884a32e
Step 2/9 : RUN mkdir -p /var/www/app
---> Using cache
---> 001c5e840b24
Step 3/9 : WORKDIR /var/www/app
---> Using cache
---> baa2e2347259
Step 4/9 : COPY package.json /var/www/app
---> 0232ad53c679
Step 5/9 : RUN npm install
---> Running in c309bf6f218e
added 128 packages from 151 contributors and audited 233 packages in 9.055s
Removing intermediate container c309bf6f218e
---> 49e652884562
Step 6/9 : RUN npm install -g nodemon
---> Running in 0ed5d7f3642b
/usr/local/bin/nodemon -> /usr/local/lib/node_modules/nodemon/bin/nodemon.js
> nodemon@1.19.1 postinstall /usr/local/lib/node_modules/nodemon
> node bin/postinstall || exit 0
Love nodemon? You can now support the project via the open collective:
> https://opencollective.com/nodemon/donate
+ nodemon@1.19.1
added 221 packages from 128 contributors in 18.856s
Removing intermediate container 0ed5d7f3642b
---> 32c55606f35e
Step 7/9 : COPY . /var/www/app
---> a618b38a2812
Step 8/9 : EXPOSE 3000
---> Running in bea389ab3ef1
Removing intermediate container bea389ab3ef1
---> 684bbfb31371
Step 9/9 : CMD ["npm", "start"]
---> Running in 9aa1b72e4a4e
Removing intermediate container 9aa1b72e4a4e
---> 35dcb3df9806
Successfully built 35dcb3df9806
Successfully tagged mean_express:latest
Creating mean_angular_1_de44b3f5b988 ... done
Creating mean_database_1_708f8f9c3c33 ... done
Creating mean_express_1_b57a483a72ee ... done
Attaching to mean_angular_1_f257e2233ef1, mean_database_1_ccc5c677e00b, mean_express_1_574f07b045fc
angular_1_f257e2233ef1 |
angular_1_f257e2233ef1 | > my-app@0.0.0 start /var/www/app
angular_1_f257e2233ef1 | > ng serve -H 0.0.0.0
angular_1_f257e2233ef1 |
database_1_ccc5c677e00b | 2019-07-20T22:33:25.933+0000 I CONTROL [main] Automatically disabling TLS 1.0, to force-enable TLS 1.0 specify --sslDisabledProtocols 'none'
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] MongoDB starting : pid=1 port=27017 dbpath=/data/db 64-bit host=f74b56905249
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] db version v4.0.10
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] git version: c389e7f69f637f7a1ac3cc9fae843b635f20b766
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] OpenSSL version: OpenSSL 1.0.2g 1 Mar 2016
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] allocator: tcmalloc
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] modules: none
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] build environment:
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] distmod: ubuntu1604
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] distarch: x86_64
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] target_arch: x86_64
database_1_ccc5c677e00b | 2019-07-20T22:33:25.937+0000 I CONTROL [initandlisten] options: { net: { bindIpAll: true } }
express_1_574f07b045fc |
express_1_574f07b045fc | > express-server@0.0.0 start /var/www/app
express_1_574f07b045fc | > nodemon ./bin/www
express_1_574f07b045fc |
express_1_574f07b045fc | [nodemon] 1.19.1
express_1_574f07b045fc | [nodemon] to restart at any time, enter `rs`
express_1_574f07b045fc | [nodemon] watching: *.*
express_1_574f07b045fc | [nodemon] starting `node ./bin/www`
database_1_ccc5c677e00b | 2019-07-20T22:33:33.543+0000 I NETWORK [listener] connection accepted from 172.19.0.4:38958 #1 (1 connection now open)
database_1_ccc5c677e00b | 2019-07-20T22:33:33.560+0000 I NETWORK [conn1] received client metadata from 172.19.0.4:38958 conn1: { driver: { name: "nodejs", version: "3.0.1" }, os: { type: "Linux", name: "linux", architecture: "x64", version: "4.18.0-25-generic" }, platform: "Node.js v8.16.0, LE, mongodb-core: 3.0.1" }
express_1_574f07b045fc | mongodb: connected
angular_1_f257e2233ef1 | ** NG Live Development Server is listening on 0.0.0.0:4200, open your browser on http://localhost:4200/ **
angular_1_f257e2233ef1 | Date: 2019-07-21T11:21:03.868Z - Hash: 639d9a968476ed482b5c - Time: 336ms
angular_1_f257e2233ef1 | 4 unchanged chunks
angular_1_f257e2233ef1 | chunk {main} main.bundle.js (main) 19.8 kB [initial] [rendered]
angular_1_f257e2233ef1 |
angular_1_f257e2233ef1 | webpack: Compiled successfully.
angular_1_f257e2233ef1 | webpack: Compiling...
angular_1_f257e2233ef1 | Date: 2019-07-21T11:25:15.661Z - Hash: e5a2b1c1afe0deb396c3 - Time: 251ms
angular_1_f257e2233ef1 | 4 unchanged chunks
angular_1_f257e2233ef1 | chunk {main} main.bundle.js (main) 19.8 kB [initial] [rendered]
angular_1_f257e2233ef1 |
angular_1_f257e2233ef1 | webpack: Compiled successfully.Go to your browser and check https://localhost:4200, your application will be up and running.
Go to https://localhost:3000 to check if an express server is running.
Also, you can run docker images command to see which all images are present in docker.
geekflare@geekflare:~/mean$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
mean_express latest 35dcb3df9806 14 hours ago 923MB
mean_angular latest 9f8d61db600c 14 hours ago 1.29GB
node 8 8e45c884a32e 9 days ago 895MB
mongo latest 785c65f61380 2 weeks ago 412MBRun the command below to see the containers running inside docker.
geekflare@geekflare:~/mean$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
681c9c34bee2 mean_express "docker-entrypoint.s…" 14 hours ago Up 14 hours 0.0.0.0:3000->3000/tcp mean_express_1_574f07b045fc
f74b56905249 mongo "docker-entrypoint.s…" 14 hours ago Up 14 hours 0.0.0.0:27017->27017/tcp mean_database_1_ccc5c677e00b
260ef1e52dab mean_angular "docker-entrypoint.s…" 14 hours ago Up 14 hours 0.0.0.0:4200->4200/tcp mean_angular_1_f257e2233ef1So now, all three docker containers are up and running.
Docker-compose took care of running all the containers with ease. This was a simple example for running three containers; you can imagine how useful it will be if the applications have to be launched on 100s of containers. Go ahead and try out to see how it works.
