I'm trying to create an MySQL cluster of 3 nodes using mysql-server docker containers.
I have 3 separate cloud instances and docker is setup on all 3 of them. Each server will have only 1 container running on it - to achieve High Availability when in cluster.
I start the containers on all 3 servers, individually, with the command
docker run --name=db -p 3301:3306 -v db:/var/lib/mysql -d mysql/mysql-server
I'm mapping the port 3306 of container to my server's 3301 port. I've also created a new user 'clusteradmin' for remote access.
Next, from mysql-shell, I ran following command - for all 3 servers
dba.configureInstance('clusteradmin#serverIp:3301')
I get similar message for all-
Note that it says 'This instance reports its own address as 39xxxxxxxxxx:3306'.
Next I create a cluster in one of the server successfully. But, when adding the other 2 servers to this cluster, I'm getting the following error
On checking the logs for that particular server, I see the following lines
It says 'peer address a9yyyyyyyyyy:33061 is not valid'. This is because, since the containers are running on different servers, the container-id is not recognised by other containers on other server.
I tried many options but to no avail. One method was to use report-host and report-port options when starting the container, like so
docker run --name=db2 -p 3301:3306 -v db2:/var/lib/mysql -d mysql/mysql-server --report-host=139.59.11.215 --report-port=3301
But, the issue with this approch is that, during dba.configureInstance(), it wants to update the port to default value and throws error like so
Anybody who has managed to create such a cluster of mysql-server containers running on different servers, I would really appreciate pointers in this regard.
I have gone over the documentation and source code but have not found an explanation why listening and advertising different ports is problematic.
I have solved the problem by using --port 3301 when invoking mysql-server:
docker run --name=db2 -p 3301:3301 -v db2:/var/lib/mysql -d mysql/mysql-server --report-host=139.59.11.215 --port 3301
Related
This might sound repeated question but it is not and this is a crazy bug I feel, however, let me quickly explain my setup:
A simple Spring bootstrap application that runs pretty well on my local and JDBC connection string in application.properites file is as follows.
spring.datasource.url=jdbc:mysql://minesql:3306/datamachine?serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=****
The docker running instances are:
I copied (with the help of docker cp command) the war file to alpine (unix container) and running it in interactive mode to test and it is throwing exception as it is unable to ping the mysql server. I am certain that the database configurations are fine and clueless why the springboot app is failing to connect to mysql container instance. Note, the mysql container does have "datamachine" database created manually.
This is the error reported:
Please help me understand what I am missing here or what is going wrong.
Just in-case if you wish to know how I started these containers.
For mysql:
docker run -d --name minesql -e MYSQL_ROOT_PASSWORD=**** -p 3306:3306 mysql
Running Java app from the alpine container and this is how I am starting the alpine,
docker run -it --name unix alpine
The interactive mode present me the bash prompt to run the spring-boot war file. (..and running the war file after installing the java 8 in alpine)
You have two docker containers which are running and connected via default bridge network. From docker bridge documentation
Containers on the default bridge network can only access each other by
IP addresses, unless you use the --link option, which is considered
legacy. On a user-defined bridge network, containers can resolve each
other by name or alias.
If you need the second container to be able to resolve the name minesql from inside, you need to create a user-defined network bridge and connect the docker container containers to that.
Create a new network using
docker network create my-net
And add your containers as specified here
Other alternative is to use docker-compose and avoid manual creation of bridge networks for name resolution. For production environment, that would be ideal.
I have a war file that uses the MySQL database in the backend.
I have deployed my war file in a docker container and I am able to ping this from my browser.
I want to connect my app with the MySQL database. This database exists on my host machine's localhost:3306
As I am unable to connect this from inside container's localhost, what I tried is,
I run a command docker inspect --format '{{ .NetworkSettings.IPAddress }}' 213be777a837
This command gave me an IP address 172.17.0.2. I went to MySQL server options and put this IP address in the bind field and restarted the server. After that, I have updated my projects database connection string with 172.17.0.2:3306
But it is not working. Could anyone please tell what I am missing?
I have also tried adding a new DB user with root#% and then run command allow all permission to 'root#%' but nothing worked.
Follow the steps:-
docker network create -d bridge --subnet 192.168.0.0/24 --gateway 192.168.0.1 dockernet
docker run -p 8082:8080 --network dockernet -d 6ab907c973d2
in your project set connection string : jdbc:mysql://host.docker.internal:3306/....
And then deploy.
tl;dr: Use 172.17.0.1:3306 if you're on Linux.
Longer description:
As I understand what you need to do is to connect from your Docker container to a host port. But what you have done is to try to bind the host process (MySQL) to the container networking interface. Not sure what the implications of a host process trying to bind to another host process network namespace, but IIUC your MySQL process should not be able to bind to that address.
When you start MySQL with default settings that bind it to 0.0.0.0 it's available for Docker containers through the Docker virtual bridge. Therefore, what you should do is to route your requests from the WAR process to the host process through that virtual bridge (if this is the networking mode you're using. If you have not changed any Docker networking settings, it should be). This is done by specifying the bridge gateway address as the MySQL address and the port it's started with.
You can get the bridge IP address by checking your network interfaces. When Docker is installed, it configures the virtual bridge by default, and that should show up as docker0 if you're on Linux. The IP address for this will most probably be 172.17.0.1. So your MySQL address from the container's point of view is jdbc:mysql://172.17.0.1:3306/....
1 - https://docs.docker.com/network/
2 - https://docs.docker.com/network/bridge/
From your question, I am assuming you both your war file and MySQL is deployed locally, and you want to connect them. One way to allow both containers that are locally deployed to talk to each other is by:
Create your own network docker network create <network-name>
Then when you run your war file and MySQL, deploy both of them using the --network. E.g.
War File: docker run --name war-file --network <network-name> <war file image>
MySQL: docker run --name mysql --network <network-name> <MySQL image>
After that, if you should be able to connect to your MySQL using mysql:3306 from inside your war file docker container, since they are both on the same custom network.
If you want to read up more about this, can take a look at docker documentation on network. (https://docs.docker.com/network/bridge/).
Your setup is fine. You just need to do this one change.
While running the application container (the one in which you are deploying your war file), you need to add following argument in its docker run command.
--net=host
Example:
docker run -itd -p 8082:8080 --net=host --name myapp myimage
With this change, you need not to change connection string as well. localhost:3306 would work fine. And you will be able to set up a connection with MySQL.
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/)
I'm trying to create a mini-demo with docker using mysql and phpmyadmin and i'm trying to make the two docker containers communicate with each other without using the --link flag since this has been flagged as "legacy" by docker (https://docs.docker.com/engine/userguide/networking/default_network/dockerlinks/#/connect-with-the-linking-system)
I managed to do this using docker-compose using the network section, but I want to implement the same scenario using normal dockerfiles and running the two containers in command prompt.
Here are the two dockerfiles I created:
Dockerfile for mysql
FROM mysql:5.7
ENV MYSQL_ROOT_PASSWORD=12345678
ENV MYSQL_DATABASE=mysql
ENV MYSQL_USER=user
ENV MYSQL_PASSWORD=12345678
Dockerfile for pma
FROM phpmyadmin/phpmyadmin:4.6
ENV PMA_HOST=mysql
ENV MYSQL_ROOT_PASSWORD=12345678
Docker images are created correctly using docker build and these are the commands that i use to run the two containers:
mysql:
docker run -d --name mysql sebastian/db-mysql
pma:
docker run -d -p 7777:80 --name pma sebastian/db-pma
When i try to connecto to Pma using username root and password 12345678 i get the following error:
mysqli_real_connect(): (HY000/2005): Unknown MySQL server host 'mysql' (-2)
I'm sure I'm missing something when spinning the two containers and I cannot fully understand how the two containers are suppose to communicate and/or how pma will find host mysql (the name i defined when running the mysql container)
Is docker suppose to allow communication between the two containers?
How do containers should find each other by using names and not ip addresses?
P.S. i'm using dockertoolbox on windows 10 (maybe that is the real problem :D )
The problem:
You are not specifying any networks in your docker run so you will use default bridge, Default bridge will not give you internal DNS but containers on that network can communicate via IP Addresses.
Follow these steps:
First create a user-defined network:
docker network create <yournetworkname>
Now run containers using the network we just created:
docker run -d --name mysql --network <yournetworkname> sebastian/db-mysql
docker run -d -p 7777:80 --name --network <yournetworkname> pma sebastian/db-pma
User defined networks provide connectivity by default and internal dns to the containers on the same network. For example you can ping mysql from pma by:
ping mysql
HI I have my web app running on my local machine and connected to Mysql workbench, I am now trying to dockerize the webapp. I can't seem to get it to connect to the DB on my local dev machine (I am running Docker Desktop for Windows), can anyone tell me how I would go about this? Here is what I have so far.
`docker run -it -e "CATALINA_OPTS=-Dspring.profiles.active=dev -DPARAM1=DEV" -p 8080:8080 -p 8005:8005 -p 8009:8009 -p 3306:3306 --add-host=docker:192.168.1.7 -v C:\myapp\trunk\target\myapp.war:/usr/local/tomcat/webapps/myapp.war --name waitapp tomcat:8.0.38-jre8`
after a few second, I run docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2a1764dd9640 tomcat:8.0.38-jre8 "catalina.sh run" 2 minutes ago Up 2 minutes 0.0.0.0:3306->3306/tcp, 0.0.0.0:8005->8005/tcp, 0.0.0.0:8009->8009/tcp, 0.0.0.0:8080->8080/tcp waitapp
The container seems to be running, but I get a 404 Not found when I try the rest request, this is the same as I do when running from inside spring tool suite using built in tomcat server.
NOTE
I don't want to run a separate mysql container and link the two over a network, I just want to try get my newly created docker app to connect to my local DB MySQL.
As mentioned on this post, you can try 2 things:
Add gateway and use it from containers, like
docker network create -d bridge --subnet 192.168.0.0/24 --gateway 192.168.0.1 dockernet
In addition to your app container, run proxy (ngnix?) container, which will rout the calls to DB when required
This answer also show how can you obtain the host IP inside the docker container.