I have 2 docker containers running on same virtual machine (Ubuntu server 18.04 on VMWare workstation 12 Player). The first one is MySql Container, which is running on port 3306 and the second one is asp.net core (v2.0) web api (port 5000 on vm and export outside through nginx with port 80 ). My VM api is 192.168.20.197
project architecture image
My connection string on web api project is: optionsBuilder.UseMySQL("server=localhost;port=3306;database=mydatabase;user=root;CharSet=utf8");
My docker file content is
FROM microsoft/dotnet:sdk AS build-env
WORKDIR /app
COPY *.csproj ./
RUN dotnet restore
COPY . ./
RUN dotnet publish -c Release -o out
FROM microsoft/dotnet:aspnetcore-runtime
WORKDIR /app
COPY --from=build-env /app/out .
ENTRYPOINT ["dotnet", "DemoMySql.dll"]
I have tried to make a HTTP request to the web api on VM but server response error(500) when i tried to interact with the database (the web api is still work normally when i make it return a sample string such as 192.168.20.197/api/values/samplestring). So How can i connect the web api to mysql on different container ?
p/s: Sorry for my bad grammar
Thanks for #Tao Zhou and #Nathan Werry advices, I solved the problem by replacing the localhost in connection string to the ip address of my virtual machine. Then I used docker --link tag (legacy feature of docker) to link the mysql container to the web api container.
docker run \
--name <webapi-container-name> \
-p 8082:8081 \
--link <mysql-container-name>:<mysql-image> \
-d <webapi-image>
For connecting from web api to mysql, you could add Compose which will create a shared network for web api and mysql, then you could access mysql with service container name.
version: "3"
services:
web:
build: .
ports:
- "8000:8000"
db:
image: postgres
ports:
- "8001:5432"
You could access db by postgres://db:5432, refer Networking in Compose.
For another option, you could create your own Bridge networks to share the network between two containers. refer Bridge networks.
Related
In company we migrating some applications to Docker Container but apps has been connected to MySQL databse.
task which I stuck is the application is running on Docker and also the MySQL database which used by app I dockerized from officle image. But problem is the database is empty. i need to connect to already existing DB which is seperate server or migrate Data to newly created conternized Image. So I don't know which is best way and how to connect already exisitng db to dockerized app
I wanna ask what is the best way?
a) Dockerize MySQL from official image and migrate all data from host.(but data is very big to migrate) b) Connect App to the already existing database which is outside Docker container. c) Or any other way?
I tried to connect database which is outside Docker but not successfully
docker run -d --network=host \
-e "DB_DBNAME=database-1" \
-e "DB_PORT=3306" \
-e "DB_USER=admin" \
-e "MYSQL_ROOT_PASSWORD=pass" \
-e "DB_PASS=4815162342" \
-e "DB_HOST=database-1.amazonaws.com" \
--name somemysql2 mysql:latest
Any idea how to connect Docker app to the database which on another server and not in Docker container?
Thanks in advance for your help and support.
You have MySQL running in a Docker Container on a Host.
Different scenario's to connect to that MySQL Database:
From an App in another Container started in the same docker-compose.yml
If you started an App in the same docker-compose.yml and want to connect to the MySQL Database:
Use the Service as the Hostname because docker-compose has its own network and will translate the servicename to to right container
version: '3.9'
services:
mydb:
image: mysql:latest
volumes:
- "./.mysql-data/db:/var/lib/mysql"
restart: always
environment:
MYSQL_DATABASE: mysqldb
MYSQL_USER: root
MYSQL_PASSWORD: root
myapp:
....
In myapp you connect to MySQL with mysql://mydb:3306/....
No Ports section!! This is because MySQL itself publishes port 3306, so no Ports section needed in docker-compose.
From an App in another Container started in another Docker command
Suppose your App is started on the same Host but in another Docker command (or in another docker-compose.yml file)
Then you need to access the database via the Host published port. But there's a problem since you cannot access the host from within a Docker Container. (At least not in a stable way, so I leave out the hacky solutions you see here on StackOverflow)
Just create a (sub)domain and point it to your Host.
And make small change in your docker-compose.yml file: Add a Ports section:
ports:
- 3333:3306
The database can be found on mysql://subdomain:3333/.....
From an App running somewhere else on another Host.
This is the same as the previous solution:
Create subdomain
Publish the port
Connect to that subdomain
From Docker Container on Host to MySQL on another Server (not in Docker)
Again, same as before
Create subdomain
Publish the port on the Host
Connect to that subdomain
Solution with the subdomain need a ProxyServer?
In case your host also answers other requests from outside, you might need a ProxyServer (Nginx?) to route the 3333 traffic to port 3306 in the container.
And if you do have that ProxyServer, you don't need the Ports section anymore.
Answer to the question in the Problem Description
You want to connect to a MySQL database running on some AWS host.
That database is already running. It has a host, username, password.
Why are you starting a new Docker Container with MySQL Image?
Only thing you should start is that 'sampleapp' container with software connecting to the external MySQL.
I don't understand why you start a MySQL Container again if you already have an external one running on AWS.
I know there have been many similar questions, but none of them are what I want. I'm following this because I specifically need 5.5, at least for now. My java project (which accesses mysql) is in a container I built with
docker build -t projectname-testing .
The Dockerfile is pretty standard, it just copies over a built tarball and extracts it to a specific folder. The CMD is a shell script run_dev_server.sh that just launches the server with dev configurations rather than production ones.
I created a percona docker container with the command given in the link with
docker run --name projectname-mysql-server -e MYSQL_ROOT_PASSWORD="" -d percona:5.5
So now the way I see it, just need the link the two as mentioned in the link:
docker run -p 3306:3306 --name projectname-local --link projectname-mysql-server projectname-testing
Which gives me
docker: Error response from daemon: Cannot link to a non running container: /projectname-mysql-server AS /projectname-local/projectname-mysql-server.
ERRO[0000] error getting events from daemon: net/http: request canceled
Which isn't very helpful and doesn't tell me what happened. Am I understanding this process wrong? What should I be doing?
First of all, I would recommend using the official Percona docker image from Docker Hub, instead of building your own image. The official image has a 5.5 version; https://hub.docker.com/_/percona/
You can either extend this image if you need specific changes (such as a custom configuration), for example;
FROM percona:5.5
COPY my-config.cnf /etc/mysql/conf.d/
Important: I notice you are publishing port 3306 (-p 3306:3306). Publishing a port makes it publicly accessible on the host's network-interface. You should only do this if you have external software that needs to connect to the database. If only your application needs access to the database, publishing the port is not needed, because containers can connect with eachother through the docker container-container network, which is "private" and not reachable from outside the host.
The --link option on the default network is a legacy option that is still around for backward compatibility, but should not be used for most situations. The --link option has a number of limitations;
legacy links are not dynamic; it's not possible to replace a linked container without re-creating all containers linked to that container
restarting a linked container can break the link, with no option to re-establish a link
legacy links are uni-directional
environment variables are shared between containers, which can easily lead to leaking (e.g.) credentials to other containers.
Docker 1.9 introduced custom docker networks, which allows
A simple example;
create a network for your application;
docker network create mynet
create a database container, and attach it to the network; there is no need to publish its ports for other containers to connect to it. (I'm using an nginx image here, just to illustrate the concept);
docker run -d --name db --network mynet nginx:alpine
create an "application" container and attach it to the same network; doing so
allows it to communicate with the db container over that network;
docker run -dit --name app --network mynet alpine sh
The application container can now connect to the db container, using its name
as hostname (db); to illustrate this, open a shell in the app container, install curl and connect to http://db:80;
docker exec -it app sh
/ # apk add --no-cache curl
fetch http://dl-cdn.alpinelinux.org/alpine/v3.5/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.5/community/x86_64/APKINDEX.tar.gz
(1/4) Installing ca-certificates (20161130-r1)
(2/4) Installing libssh2 (1.7.0-r2)
(3/4) Installing libcurl (7.52.1-r3)
(4/4) Installing curl (7.52.1-r3)
Executing busybox-1.25.1-r0.trigger
Executing ca-certificates-20161130-r1.trigger
OK: 5 MiB in 15 packages
/ # curl http://db:80
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
You can read more about networks (also how to dynamically attach and detach a container from a network) in the []"docker container networking" section of the documentation](https://docs.docker.com/engine/userguide/networking/)
Win 10
Composer version 1.4.1 2017-03-10 09:29:45
PHP 7
npm/Node
Docker CE
Apache 2.4
Powershell
git BASH shell
drush (installed via composer)
Noob Composer/Docker skills
I have a docker config yml specifying how mysql service can start:
version: "2"
services:
mysql:
image: mysql:5.6
ports:
- 3306:3306
volumes:
- /data/nbif_mysql:/var/lib/mysql
environment:
MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
And when I call
#!/bin/bash
docker-compose up -d mysql
I see that the container is running:
PS C:\dev\appname> docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f1a0ecab8af6 mysql:5.6 "docker-entrypoint..." 2 hours ago Up 5 seconds 0.0.0.0:3306->3306/tcp appname_mysql_1
But, notice that the reported IP is 0.0.0.0:3306->3306/tcp
So when I try to connect with the expected IP, it fails:
ERROR 2003 (HY000): Can't connect to MySQL server on '172.17.0.1' (10060)
How to I tell docker-compose to use that expected IP for docker?
Is this a setup issue, or some config tweak I need to do?
When you bind a port to your host, you have to use localhost instead of the container's IP address, because you're not assigning any local IP address.
Every container always runs in a isolated network (bridge), the container in your compose file will be able to find the others by their hostname, but inside of those containers, they are isolated from the local network so that's why you can't reach them.
In your compose file you only have a mysql container and you're binding that port in your host, so the only way to reach that container is by using localhost:3306
Remember, when you run a docker container it isn't like a server with an IP in your host network, it's more like a virtual machine with an isolated network configuration.
Take a look on the docker-compose docs in this specific topic:
https://docs.docker.com/compose/networking
UPDATE:
The link that finally answered the question was:
https://docs.docker.com/engine/userguide/networking/default_network/custom-docker0/
I have setup docker container with mysql that expose 3306.
I've specified database user, database password and create a test db and give the privileges to new user.
In another container i want to accesso to this db.
So i set up new container with a simply php script that create new table in this db.
I know that mysql container's ip is 172.17.0.2 so :
$mysqli = new mysqli("172.17.0.2", "mattia", "prova", "prova");
Than using mysqli i create new table and all works fine.
But i think that connect to container using his ip address is not good.
Is there another way to specify db host? I tryed with the hostname of the mysql container but it doens't work.
The --link flag is considered a legacy feature, you should use user-defined networks.
You can run both containers on the same network:
docker run -d --name php_container --network my_network my_php_image
docker run -d --name mysql_container --network my_network my_mysql_image
Every container on that network will be able to communicate with each other using the container name as hostname.
You need to link your docker containers together with --link flag in docker run command or using link feature in docker-compose. For instance:
docker run -d -name app-container-name --link mysql-container-name app-image-name
In this way docker will add the IP address of the mysql container into /etc/hosts file of your application container.
For a complete document refer to:
MySQL Docker Containers: Understanding the basics
In your docker-compose.yml file add a link property to your webserver service:
https://docs.docker.com/compose/networking/#links
Then in your query string, the host parameter's value is your database service name:
$mysqli = new mysqli("database", "mattia", "prova", "prova");
If you are using docker-compose, than the database will be accessible under the service name.
version: "3.9"
services:
web:
build: .
ports:
- "8000:8000"
db:
image: postgres
ports:
- "8001:5432"
Then the database is accessible using: postgres://db:5432.
Here the service name is at the same time the hostname in the internal network.
Quote from docker docs:
When you run docker-compose up, the following happens:
A network called myapp_default is created.
A container is created using web’s configuration. It joins the network myapp_default under the name web.
A container is created using db’s configuration. It joins the network myapp_default under the name db.
Source:
https://docs.docker.com/compose/networking/
My web application needs both mysql and redis server to function properly. I am able to link mysql container with app using link tag (mysql is name of mysql image set using -name tag)
sudo docker run -link mysql:amq -d -p 13310 hitesh/image node app
Now I am not sure how to attach redis to this container. Should it be done via same mysql image (if yes, how two ports i.e. 3306 & 6379 will be exposed?) or should I make another container for redis and link it to my node.js app (not sure about it is possible or not).
You should have 3 containers
your app
your mysql
your redis
then expose your mysql port and redis port on the relevant containers.
Then when you run your app container just link both mysql and redis containers to your app
so something like
sudo docker run -d -link mysql:mysql -link redis:redis ....
Now your app container will have environment variables for your other two databases
Also, if you want to expose two ports, then in your dockerfile just do EXPOSE port1 port2
e.g. EXPOSE 22 80
Then you'll get environment variables for both exposed ports. But i'd recommend you don't have a container that runs both mysql and redis. Separate your concerns :)