If I have a mysql database running on some host machine, and that host is also running a docker container: How would I access the mysql database from within the docker container that is running on the host?.
For instance, is there a way to publish a hosts port to the container (the inverse of what docker run -p does)?
From the 18.03 docs:
I want to connect from a container to a service on the host
The host has a changing IP address (or none if you have no network access). From 18.03 onwards our recommendation is to connect to the special DNS name
host.docker.internal, which resolves to the internal IP address used by the host.The gateway is also reachable as
gateway.docker.internal.
EXAMPLE: Here's what I use for my MySQL connection string inside my container to access the MySQL instance on my host:
mysql://host.docker.internal:3306/my_awesome_database
There are several long standing discussions about how to do this in a consistent, well understood and portable way. No complete resolution but I'll link you to the discussions below.
In any event you many want to try using the --add-host option to docker run to add the ip address of the host into the container's /etc/host file. From there it's trivial to connect to the host on any required port:
Adding entries to a container hosts file
You can add other hosts into a container's /etc/hosts file by using one or more --add-host flags. This example adds a static address for a host named docker:
$ docker run --add-host=docker:10.180.0.1 --rm -it debian $$ ping docker PING docker (10.180.0.1): 48 data bytes 56 bytes from 10.180.0.1: icmp_seq=0 ttl=254 time=7.600 ms 56 bytes from 10.180.0.1: icmp_seq=1 ttl=254 time=30.705 ms ^C--- docker ping statistics --- 2 packets transmitted, 2 packets received, 0% packet loss round-trip min/avg/max/stddev = 7.600/19.152/30.705/11.553 msNote: Sometimes you need to connect to the Docker host, which means getting the IP address of the host. You can use the following shell commands to simplify this process:
$ alias hostip="ip route show 0.0.0.0/0 | grep -Eo 'via \S+' | awk '{ print $2 }'" $ docker run --add-host=docker:$(hostip) --rm -it debian
Documentation:
https://docs.docker.com/engine/reference/commandline/run/
Discussions on accessing host from container:
Use host.docker.internal from Docker 18.03 onwards.
Docker version 18.03.0-ce, build 0520e24
18.03.1-ce-mac65
localhost with host.docker.internal From Docker 17.06 onwards, a special Mac-only DNS name is available in docker containers that resolves to the IP address of the host. It is:
docker.for.mac.localhost
The documentation is here: https://docs.docker.com/docker-for-mac/networking/#httphttps-proxy-support
docker.for.mac.host.internal from Docker 17.12.0 ce onwards. docs.docker.com/docker-for-mac/release-notes/…docker.for.mac.localhost works on 18.03.1-ce-mac65Other answers did not work well for me. My container could not resolve host ip using host.docker.internal. There are two ways
Sharing host network --net=host:
docker run -it --net=host myimage
Using docker's ip address, which is usually 172.17.0.1. You can check it by calling ifconfig command and grabbing inet addr of docker interface
user@ubuntu:~$ ifconfig
docker0 Link encap:Ethernet HWaddr 02:42:a4:a2:b2:f1
inet addr:172.17.0.1 Bcast:0.0.0.0 Mask:255.255.0.0
inet6 addr: fe80::42:a4ff:fea2:b2f1/64 Scope:Link
Once you have this ip address, you can pass it as an argument to docker run and then to application or as I do it, map the location of jdbc.properties via volume to the directory on host machine, so you can manage the file externally.
docker run -it -v /host_dir/docker_jdbc_config:${jetty_base}/var/config myimage
NOTE: Your database might not allow external connections. In case of postgresql, you need to edit 2 files, as described here and here:
Edit postgresql.conf to listen on all addresses. By default it will point to localhost.
listen_addresses = '*'
Edit pg_hba.conf to allow connections from all addresses. Add on the last line:
host all all 0.0.0.0/0 md5
IMPORTANT: Last step updating database access is not recommended for production use unless you are really sure what you are doing.
There is presumably a preferred way of doing this, working regardless of the host O/S.
When using docker run
docker run --add-host host.docker.internal:host-gateway
When using docker compose
services:
myservices:
extra_hosts:
- host.docker.internal:host-gateway
environments:
- DBHOST=host.docker.internal:5432
This will create an entry host.docker.internal in /etc/hosts
For Linux Only
Case 1:-Mysqldb running on localhost not on docker
You can fix the host Ip to connect and connect to that
ip instead of localhost.
For linux dockerhost is fixed which is 172.17.0.1.So connect to 172.17.0.1 instead of localhost.
Case2:- If the mysqldb is also running on docker then the best practice is to connect with the docker container name instead of IP address.
So docker-compose file should look like this
version: '3.8'
services:
mysqldb:
image: mysql:5.7
restart: unless-stopped
env_file: ./.env
environment:
- MYSQL_ROOT_PASSWORD=$MYSQLDB_ROOT_PASSWORD
- MYSQL_DATABASE=$MYSQLDB_DATABASE
ports:
- $MYSQLDB_LOCAL_PORT:$MYSQLDB_DOCKER_PORT
volumes:
- db:/var/lib/mysql
producer:
build: .
ports:
- '$LOCAL_PORT:$DOCKER_PORT'
depends_on:
- mysqlsb
volumes:
- ./:/usr/src/app
Now instead of an ip or localhost connect to mysqlsb
var mysql = require('mysql');
var con = mysql.createConnection({
host: mysqldb,
user: "yourusername",
password: "yourpassword"
});
con.connect(function(err) {
if (err) throw err;
console.log("Connected!");
});
I am using:
Ran the container either way by
docker run --detach --name some-mariadb --env MARIADB_ROOT_PASSWORD=123456 -p 3306:3306 mariadb:latest
OR used docker-compose.yml
version: "1.0"
name: "some_mariadb"
services:
db:
image: mariadb:10.5
command: '--default-authentication-plugin=mysql_native_password'
volumes:
- ./tmp:/var/lib/mysql
restart: always
environment:
- MYSQL_ROOT_PASSWORD=123456
ports:
- "3306:3306"
expose:
- 3306
And successfully connected to the container simply by
mysql -h 127.0.0.1 -u root -p123456
