I have a Postgres Database which was deployed as a Docker container in Linux server. How can i add this as a data source in grafana? I tried finding the docker host IP address using sudo ip addr show docker0 and got the result as 172.17.255.255. I added this URL in Host name field. And added the port number as 5432. But still, grafana is unable to fetch the data from DB. How can i do this?
If your database has its port closed you should use a docker networks but if the port is exposed you should try to use your host ip address instead of the docker gateway address
With docker ps, check if your Postgres container expose the port, eg.
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e25459aa0ed6 postgres:10.17 "docker-entrypoint.s…" 12 seconds ago Up 11 seconds 0.0.0.0:5432->5432/tcp, :::5432->5432/tcp jovial_merkle
If not, stop the service, then restart it exposing the port with docker run -d -p 5432:5432 ....
Check if there is any firewall rule that allow to access the port from outside the server.
Now you can reach you DB using the server IP
Related
I am newbie on docker.
I want to migrate my nodejs app to docker, and existing database already installed on server (172.17.2.1). I set mariadb host 172.17.2.1 on my nodejs config.
After that, I created an images and run with :
docker run -p 3009:3009 -d my-node
actually its already running, but when I tested to open by browser, I got an error that my app cannot connect to 172.17.2.1 (connecting to database).
I try to create bridge IP (172.17.2.135) and make a same subnet, but still got a same error.
My images on docker inside doesn't know 172.17.2.1 on my LAN.
Please help me,
I use windows 10 environment
You have two options to allow your container to reach an external server:
Run your docker container on your host network:
docker run -p 3009:3009 --network host -d my-node
This way your container will be able to reach anything reachable from your machine
create a network bridge: in this case docker will route the traffic from the container to the external server. the bridge IP can't be your docker machine IP as you tried to do.
I'm running a webpack-dev-server application inside a Docker container (node:4.2.1). If I try to connect to the server port from within the container - it works fine. However, trying to connect it from the host computer results in reset connection (the port is published, of course). How can I fix it?
This issue is not a docker problem.
Add --host=0.0.0.0 to your webpack command.
You need to connect to your page like this:
http://host:port/webpack-dev-server/index.html
Look to the iframe mode
You need to make sure:
you docker container has mapped the EXPOSE'd port to a host port
docker run -p x:y
your VM (if you are using docker machine with a VM) has forwarded that mapped port to the actual host (the host of the VM).
See "How to access tomcat running in docker container from browser?"
I pull a docker image (will use python 3 as an example)
docker pull python:3.6
Then I launch a docker container
docker run -it -p 127.0.0.1:8000:8000 python:3.6 bash
(note that here 127.0.0.1 in 127.0.0.1:8000:8000 allows to specify the destination, host IP but not the source)
So if I launch a server inside the container at 0.0.0.0:
python -m http.server 8000 --bind 0.0.0.0
then I can access the container's server from the host machine without any problem by going to http://127.0.0.1:8000 at the host machine
However if my docker server binds to 127.0.0.1 instead of 0.0.0.0:
python -m http.server 8000 --bind 127.0.0.1
then accessing http://127.0.0.1:8000 from the host does not work.
What's the proper way of binding the container's loopback 127.0.0.1 to the host loopback?
What's the proper way of binding the container's loopback 127.0.0.1 to the host loopback?
On Linux, this can be done by configuring your Docker container to use the hosts network namespace, ie:
docker run --network=host
This only works on Linux because on Linux, your machine is the host, and the containers run as containers in your machines OS. On Windows/OSX, the Docker host runs as a virtual machine, with the containers running in the virtual machine, and so they can't share your machines network namespace.
What's the proper way of binding the container's loopback 127.0.0.1 to the host loopback?
You can't do that. The loopback interface inside a container means "only this container", just like on the host means "only this host". If a service is binding to 127.0.0.1 then there is no way -- from your host or from another container -- to reach that service.
The only way to do what you want is either:
Modify the application configuration to listen on all interfaces (or eth0 specifically), or
Run a proxy inside your container that binds to all interfaces and forwards connections to the localhost address.
Say, if I use this command inside a docker container.
/opt/lampp/bin/mysql -h localhost -u root -pThePassword
What would the localhost here refer to? The host machine's IP or the docker container's own IP?
From inside a container, localhost always refers to the current container. It never refers to another container, and it never refers to anything else running on your physical system that's not in the same container. It's not usually useful to make outbound connections to localhost or configure localhost as your database host.
From a shell on your host system, localhost could refer to daemons running on your system outside Docker, or to ports you've published with docker run -p options.
From a different system, localhost refers to the system it's called from.
In terms of IP addresses, localhost is always 127.0.0.1, and that IP address is special and is always localhost and behaves the same way as above.
If you want to make a connection to a container...
...from another container, the best way is to make sure they're on the same Docker network (you started them from the same Docker Compose YAML file; you did a docker network create and then did docker run --net ... on the same network) and use Docker's internal DNS service to refer to them by the container's --name or its name in the Docker Compose YAML file and the port number inside the container. Even if the target has a published port with a docker run -p option or Docker Compose ports: setting, use the second (container-internal) port number.
...from outside Docker space, make sure you started the container with a docker run -p or Docker Compose ports: option, and connect to the host's IP address or DNS name using the first port number from that option.
...from a terminal window or browser on the same physical host, not in a container, in this case and in this case only, localhost will work consistently.
Except:
If you started a container with --net host, localhost refers to the physical host, and you're in the "terminal window on the same physical host" scenario.
If you've gone out of your way to have multiple servers in the same container, you can use localhost to communicate between them.
If you're running in Kubernetes, and you have multiple containers in the same pod, you can use localhost to communicate between them. Between pods, you should set up a service in front of each pod/deployment, and use DNS names of the form service-name.namespace-name.svc.cluster.local.
Definitely, It will be your container, if you are running command in container.
/opt/lampp/bin/mysql -h localhost -u root -pThePassword
If you run this command inside container then it will try to connect mysql running inside container.
I have a MariaDB up and running in a Docker container. I want to know how to connect to it from an app running locally (not) in the docker container. How can I open up access?
your MariaDB container must publish ports, and you will connect using those ports. See for example http://amattn.com/p/installing_maria_db_mysql_with_docker.html
the port 3306 in the container will be mapped to a port on the host, and you will connect to that port.
when you call docker run to start your container you can bind a specific port like this
docker run -p your_port:3306
this will make your container accessible on docker_host_ip:your_port and the docker service will take care of forwarding the connection to the right container at the port 3306