I’ve been asked to configure a ubuntu 18.04 server with docker for multiple users.
Purpose:
We have multiple testers who write test cases. But our laptops aren’t fast enough to build the project and run tescases in docker environment.
We already have a jenkins server.But we need to build/test our code BEFORE push to git.
I’ve been given a high end ubuntu 18.04 server.
I have to configure the server where all our testers can run/debug our testcases on isolated environments.
When testers push there changes to remote servers project should build and run on isolated environments. Multiple users can work on same project but one testers builds must NOT affect another one.
I already installed Docker and tried with only changing docker-compose.yml and adding different networks (using multiple accounts of course). But it was very painful.
I need to have multiple selenoid servers(for different users),different allure reports with docker , Need the ability to build and run tests using our docker-compose files and need the ability to run the actual project on different ports so we can go through the system while writing test cases.
Is it possible to configure an environment without changing project docker-compose.yml ?
Whats the approach I should take ?
You can use Docker in Docker (docker:dind image) to run multiple instances of Docker daemon on the same host, and have each tester use a different DOCKER_HOST to run their Compose stack. Each app instance will be deployed on a separate Docker daemon and isolated without requiring any change in docker-compose.yml.
Docker in Docker can be used to run a Docker daemon from another Docker daemon. (Docker daemon is the process actually managing your container when using docker). See Docker architecture and DinD original blogpost for details.
Example: run 2 Docker daemons exposing the app port
Let's Consider 2 testers with this docker-compose.yml:
version: 3
services:
app:
image: my/app:latest
ports:
- 8080:80
Run 2 instances of Docker Daemon exposing Daemon port and any port that will be exposed by Docker Compose (see below why)
# Run docker dind and map port 23751 on localhost
# Expose Daemon 8080 on 8081 (port that will be used by Tester1)
# privileged is required to run dind (see dind-rootless exists but is experimental)
# DOCKER_TLS_CERTDIR="" is to deploy an unsecure Daemon
# it's easier to use but should only be used for testing/dev purposes
docker run -d \
-p 23751:2375 \
-p 8081:8080 \
--privileged \
--name dockerd-tester1 \
-e DOCKER_TLS_CERTDIR=""
docker:dind
# Second Daemon using port 23752
docker run -d \
-p 23752:2375 \
-p 8082:8080 \
--privileged \
--name dockerd-tester2 \
-e DOCKER_TLS_CERTDIR=""
docker:dind
Each tester can run their own stack on their Docker daemon by setting DOCKER_HOST env var:
# Tester 1 shell
# use dockerd-tester1 daemon on port 23751
export DOCKER_HOST=tcp://localhost:23751
# run our stack
docker-compose up -d
Same for Tester 2 on dockerd-tester2 port:
# Tester 2 shell
export DOCKER_HOST=tcp://localhost:23752
docker-compose up -d
Interacting with Tester 1 and 2's stacks
Need the ability to build and run tests using our docker-compose files and need the ability to run the actual project on different ports
The exposed ports for each testers will be exposed on the Docker daemon host and reachable via http://$DOCKER_HOST:$APP_PORT instead of localhost:$APP_PORT (that's why we also exposed app port on each Daemon).
Considering our docker-compose.yml, testers will be able to access application such as:
# Tester 1
# port 8081 is linked to port 8080 of Docker daemon running our app container
# itself redirect on port 8080
# in short: 8081 -> 8080 -> 80
curl localhost:8081
# Tester 2
# 8082 -> 8080 -> 80
curl localhost:8082
Our deployment will look like this
Alternative without exposing ports, using Docker daemon IP directly
Similar to the first example, you can also interact with the deployed app by using Docker daemon IP directly:
# Run daemon without exposing ports
docker run -d \
--privileged \
--name dockerd-tester1 \
-e DOCKER_TLS_CERTDIR=""
docker:dind
# Retrieve daemon IP
docker inspect --format '{{ .NetworkSettings.IPAddress }}' dockerd-tester1
# output like 172.17.0.2
# use it!
export DOCKER_HOST=172.17.0.2
docker-compose up -d
# our app port are exposed on Daemon
curl 172.17.0.2:8080
We contacted directly our Daemon via its IP instead of exposing its port on localhost.
You can even define your Docker daemons with static IPs in a docker-compose.yml such as:
version: "3"
services:
dockerd-tester1:
image: docker:dind
privileged: true
environment:
DOCKER_TLS_CERTDIR: ""
networks:
dind-net:
# static IP to set as DOCKER_HOST
ipv4_address: 10.5.0.6
# same for dockerd-tester2
# ...
networks:
dind-net:
driver: bridge
ipam:
config:
- subnet: 10.5.0.0/16
And then
export DOCKER_HOST=10.5.0.6
# ...
Notes:
This may have some performance impact depending on the machine on which Daemons are deployed
You can use dind-rootless instead of dind to avoid using --privileged flags
It's better to avoid DOCKER_TLS_CERTDIR: "" for security reasons, see TLS instruction on docker image for detailed usage of TLS
The OP has already an CI/CD-system running. The question is: How can testers wrote new testcases on a own enviroment which is not running on the local maschine.
I suggest that you setup a k8s (kubernetes) instance on your new "high-end"-server. The installation of minikube is very easy and enough when you has only one server (aka node).
With k8s you can control your docker-containers (or with the correct verb "orchestrate").
You can do one of these things next:
Wrote a script for the test-laptops, so they can start new environments. You can use the $USER-variable for the correct naming. Be aware that the testers may have access to k8s now.
My favorite: Don't create enviroments for users, create them for merge requets. They are not bound to users and can be created by your version-control-system (e.g. gitlab). The testers can open an MR, your server setup a new enviroment and the tester is ready to go. And your testers have no access to k8s.
Not recommended, but possible: Create enviroments manually for each tester.
I have two running docker containers. One docker container is calling the other docker container but when it is trying to call application is breaking. When I am giving my hostname of my machine inside the application.Application is working.
This is a really a dependency if i deploy these two containers i again have to find the hostname of that machine and then put inside my application is any other way so that which can remove this dependency.
This url is consumed by my docker container which is failing
http://localhost:8080/userData
Same when i update with my host name then it is working.
http://nl55443lldsfa:8080/userData
But this is really a dependency i cannot change inside my application everytime.Is any work around is there for the same.
You should use docker-compose to run both containers and link them using the link property on your yaml file.
This might be a good example:
web:
image: nginx:latest
ports:
- "8080:8080"
links:
- php
php:
image: php
Then the ip of each container will be associated to its service name on the /etc/hosts file of both containers and you will be able to access them from inside the containers just by using that hostname.
Also be sure to be mapping the ports correctly, using http://localhost:8080 shouldn't fail if you map the ports correctly and the service is running.
Put the two containers inside the same network when running them. Only then you can use hostnames for inter container communication.
Edit: And of course name you containers so you don’t get a random container name each time.
Edit 2: The commands are:
$ docker network create -d bridge my-bridge-network
$ docker run -d \
--name webserver \
--network=my-bridge-network \
nginx:latest
$ docker run -d \
--name dbserver \
--network=my-bridge-network \
mysql:5.7
Containers started both with a specified hostname and a common network can use hostnames internally to communicate with each other.
Kubernetes has a concept of pods where containers can share ports between them. For example within the same pod, a container can access another container (listening on port 80) via localhost:80.
However on docker-compose, localhost refers to the container itself.
Is there anyway to implement the kubernetes network config on docker?
Essentially I have a kubernetes config that I would like to reuse in a docker-compose config, without having to modify the images.
I seem to have gotten it to work by adding network_mode: host to each of the container configs within my docker-compose config.
Yes you can. You run a service and then you can use network_mode: service:<nameofservice>
version: '3'
services:
mainnetwork:
image: alpine
command: tail -f /dev/null
mysql:
image: mysql
network_mode: service:mainnetwork
environment:
- "MYSQL_ROOT_PASSWORD=root"
mysqltest:
image: mysql
command: bash -c "sleep 10 && mysql -uroot -proot -h 127.0.0.1 -e 'CREATE DATABASE tarun;'"
network_mode: service:mainnetwork
Edit-1
So the network_mode can have below possible values
host
service:(servicename in same compose file)
container:(name or id of a external container already running)
In this case i have used service:mainnetwork, so the mainnetwork needs to be up.
Also this has been tested on Docker 17.06 ce. So I assume you are using a newer version
Using Docker Links mechanism you can wire together containers and then declared ports will be available through localhost.
how can I ssh into a service created by docker swarm? I have created a service using docker stack and the yaml file looks like this:
version: '3'
services:
app:
image: "myimage1"
expose:
- "8080"
and I validated that the service is running but I'm not sure how to ssh into the service(container) that was created.
To ssh into container, you would need ssh service running inside container. This is generally not a good practice.
To get access to container shell without having ssh running, you can use:
docker exec -ti bash/sh
Ansible has docker modules for managing containers and images(http://docs.ansible.com/ansible/docker_container_module.html#docker-container, http://docs.ansible.com/ansible/docker_image_module.html#docker-image)
I created two docker containers based on two different images. One of db and another for webserver. Both containers are running on my mac osx.
I can access db container from host machine and same way can access webserver from host machine.
However, how do I access db connection from webserver?
The way I started db container is
docker run --name oracle-db -p 1521:1521 -p 5501:5500 oracle/database:12.1.0.2-ee
I started wls container as
docker run --name oracle-wls -p 7001:7001 wls-image:latest
I can access db on host by connecting to
sqlplus scott/welcome1#//localhost:1521/ORCLCDB
I can access wls on host as
http://localhost:7001/console
It's easy.
If you have two or more running container, complete next steps:
docker network create myNetwork
docker network connect myNetwork web1
docker network connect myNetwork web2
Now you connect from web1 to web2 container or the other way round.
Use the internal network IP addresses which you can find by running:
docker network inspect myNetwork
Note that only internal IP addresses and ports are accessible to the containers connected by the network bridge.
So for example assuming that web1 container was started with: docker run -p 80:8888 web1 (meaning that its server is running on port 8888 internally), and inspecting myNetwork shows that web1's IP is 172.0.0.2, you can connect from web2 to web1 using curl 172.0.0.2:8888).
Easiest way is to use --link, however the newer versions of docker are moving away from that and in fact that switch will be removed soon.
The link below offers a nice how too, on connecting two containers. You can skip the attach portion, since that is just a useful how to on adding items to images.
https://web.archive.org/web/20160310072132/https://deis.com/blog/2016/connecting-docker-containers-1/
The part you are interested in is the communication between two containers. The easiest way, is to refer to the DB container by name from the webserver container.
Example:
you named the db container db1 and the webserver container web0. The containers should both be on the bridge network, which means the web container should be able to connect to the DB container by referring to its name.
So if you have a web config file for your app, then for DB host you will use the name db1.
if you are using an older version of docker, then you should use --link.
Example:
Step 1: docker run --name db1 oracle/database:12.1.0.2-ee
then when you start the web app. use:
Step 2: docker run --name web0 --link db1 webapp/webapp:3.0
and the web app will be linked to the DB. However, as I said the --link switch will be removed soon.
I'd use docker compose instead, which will build a network for you. However; you will need to download docker compose for your system. https://docs.docker.com/compose/install/#prerequisites
an example setup is like this:
file name is base.yml
version: "2"
services:
webserver:
image: moodlehq/moodle-php-apache:7.1
depends_on:
- db
volumes:
- "/var/www/html:/var/www/html"
- "/home/some_user/web/apache2_faildumps.conf:/etc/apache2/conf-enabled/apache2_faildumps.conf"
environment:
MOODLE_DOCKER_DBTYPE: pgsql
MOODLE_DOCKER_DBNAME: moodle
MOODLE_DOCKER_DBUSER: moodle
MOODLE_DOCKER_DBPASS: "m#0dl3ing"
HTTP_PROXY: "${HTTP_PROXY}"
HTTPS_PROXY: "${HTTPS_PROXY}"
NO_PROXY: "${NO_PROXY}"
db:
image: postgres:9
environment:
POSTGRES_USER: moodle
POSTGRES_PASSWORD: "m#0dl3ing"
POSTGRES_DB: moodle
HTTP_PROXY: "${HTTP_PROXY}"
HTTPS_PROXY: "${HTTPS_PROXY}"
NO_PROXY: "${NO_PROXY}"
this will name the network a generic name, I can't remember off the top of my head what that name is, unless you use the --name switch.
IE docker-compose --name setup1 up base.yml
NOTE: if you use the --name switch, you will need to use it when ever calling docker compose, so docker-compose --name setup1 down this is so you can have more then one instance of webserver and db, and in this case, so docker compose knows what instance you want to run commands against; and also so you can have more then one running at once. Great for CI/CD, if you are running test in parallel on the same server.
Docker compose also has the same commands as docker so docker-compose --name setup1 exec webserver do_some_command
best part is, if you want to change db's or something like that for unit test you can include an additional .yml file to the up command and it will overwrite any items with similar names, I think of it as a key=>value replacement.
Example:
db.yml
version: "2"
services:
webserver:
environment:
MOODLE_DOCKER_DBTYPE: oci
MOODLE_DOCKER_DBNAME: XE
db:
image: moodlehq/moodle-db-oracle
Then call docker-compose --name setup1 up base.yml db.yml
This will overwrite the db. with a different setup. When needing to connect to these services from each container, you use the name set under service, in this case, webserver and db.
I think this might actually be a more useful setup in your case. Since you can set all the variables you need in the yml files and just run the command for docker compose when you need them started. So a more start it and forget it setup.
NOTE: I did not use the --port command, since exposing the ports is not needed for container->container communication. It is needed only if you want the host to connect to the container, or application from outside of the host. If you expose the port, then the port is open to all communication that the host allows. So exposing web on port 80 is the same as starting a webserver on the physical host and will allow outside connections, if the host allows it. Also, if you are wanting to run more then one web app at once, for whatever reason, then exposing port 80 will prevent you from running additional webapps if you try exposing on that port as well. So, for CI/CD it is best to not expose ports at all, and if using docker compose with the --name switch, all containers will be on their own network so they wont collide. So you will pretty much have a container of containers.
UPDATE: After using features further and seeing how others have done it for CICD programs like Jenkins. Network is also a viable solution.
Example:
docker network create test_network
The above command will create a "test_network" which you can attach other containers too. Which is made easy with the --network switch operator.
Example:
docker run \
--detach \
--name db1 \
--network test_network \
-e MYSQL_ROOT_PASSWORD="${DBPASS}" \
-e MYSQL_DATABASE="${DBNAME}" \
-e MYSQL_USER="${DBUSER}" \
-e MYSQL_PASSWORD="${DBPASS}" \
--tmpfs /var/lib/mysql:rw \
mysql:5
Of course, if you have proxy network settings you should still pass those into the containers using the "-e" or "--env-file" switch statements. So the container can communicate with the internet. Docker says the proxy settings should be absorbed by the container in the newer versions of docker; however, I still pass them in as an act of habit. This is the replacement for the "--link" switch which is going away. Once the containers are attached to the network you created you can still refer to those containers from other containers using the 'name' of the container. Per the example above that would be db1. You just have to make sure all containers are connected to the same network, and you are good to go.
For a detailed example of using network in a cicd pipeline, you can refer to this link:
https://git.in.moodle.com/integration/nightlyscripts/blob/master/runner/master/run.sh
Which is the script that is ran in Jenkins for a huge integration tests for Moodle, but the idea/example can be used anywhere. I hope this helps others.
You will have to access db through the ip of host machine, or if you want to access it via localhost:1521, then run webserver like -
docker run --net=host --name oracle-wls wls-image:latest
See here
Using docker-compose, services are exposed to each other by name by default. Docs.
You could also specify an alias like;
version: '2.1'
services:
mongo:
image: mongo:3.2.11
redis:
image: redis:3.2.10
api:
image: some-image
depends_on:
- mongo
- solr
links:
- "mongo:mongo.openconceptlab.org"
- "solr:solr.openconceptlab.org"
- "some-service:some-alias"
And then access the service using the specified alias as a host name, e.g mongo.openconceptlab.org for mongo in this case.
Environment: Windows 10, Docker Desktop version 4.5.1.
Use hostname host.docker.internal to access services running on your host machine from inside a container.
See: https://docs.docker.com/desktop/windows/networking/#use-cases-and-workarounds
I run PostgreSQL in one container and my app in a separate container.
I configure the app database connection to use host.docker.internal as the hostname and it just works.
Consider Example
We Create two containers here PostgreSQL server and pgadmin(for accessing servers like PHPMyAdmin, SQL studio, workbench).
Exposed port
PostgreSql --->5436
Pgadmin --->5050
After adding a server in pgadmin hostname as localhost.It will show a connection error. Because Docker container pgadmin getting localhost as their system instead we need PostgreSQL IP to solve the problem.
docker network create con
docker network connect con app1
docker network connect con app2
This command gets connected container IP address and other details.
docker network inspect con
Now you can see the IP address shown in the network inspect. Choose the Postgres container IP. You can access other exposed ports through this IP. Here postgre 5432 is only exposed.Now set hostname as the container ip and it will work.
You can use the default docker network. If you don't want to go through any docker networking, you can do this:
Copy the ip address in Docker subnet in Resources>Network in Docker Preferences in Mac:
Docker preferences screenshot
As you can see from the screenshot link the ip address is
192.168.65.0
You just need to replace “localhost” in your containers config file with “192.168.65.1" (i.e. IP address picked + 1 ).
You can start your containers and should be set for local development/testing.
For some more details, you can see my article:
Connect Docker containers the easy way
In my case, the host connection in the application to a container from an other container by the IP provide by the bridge didn't work.
But it works with the name of the container (see my screenshot).
So you can replace the IP by the name of the container.