How to change the IP address of a docker after creating it? - docker

I have a docker linked to a bridge with IP address 192.168.150.1/24.
Once I create the docker instance from a docker image it gets an IP address, 192.168.150.2, but according to my requirement, this IP address, 192.168.150.2, must be reserved since I want to use it for some other thing.
Now, I want to change the IP address of this docker instance as 192.168.150.3. Is it possible to do? if so how? Please, help.

You will have to first detach the container from the custom network and the connect it back by providing the ip.
You can follow the following steps :
docker network disconnect [OPTIONS] NETWORK CONTAINER
docker network connect --ip 192.168.150.3 NETWORK CONTAINER

You can specify a particular IP address when you define the port mapping, for example
-p 192.168.150.3:6379:6379

here is another option, try to use -b bridge option to use a certain ip range, like for instance -b br0=192.168.150.3/24
here is more complete example configure docker bridge network

Related

How docker process communication between different containers on default bridge on the same host?

Here is my situation:
First,I run a MySQL container(IP:172.17.0.2) on centOS;
Then I run a Nacos contanier with specified datasource(MySQL above) on the same host, but i didn't use the ip of the MySQL container, instead I used the ip of the bridge Gateway(172.17.0.1)(two containers both link to the default bridge).
What surprised me was that Nacos works well, it can query config data from MySQL container normally.
How did this happen? I have read some documention but didn't get the answer.It really confused me.
On modern Docker installations, try to avoid using the default bridge network. docker network create a network (it doesn't need any special options, but it does need to be created) and then launch your containers on --net that network. If you're using Compose, it creates a ("user bridge") network named default for you.
On your CentOS host, if you run ifconfig, you should see a docker0 interface with the 172.17.0.1 address. When you launch a container with the docker run -p option, that container is accessible via the first port number on all host interfaces, including the docker0 interface.
Meanwhile, inside a container (on the default bridge network), it sees that same IP address as the normal IPv4 gateway address (try docker run --rm busybox route -n). So, when you connect to 172.17.0.1:3306, you're connecting out to the host, and then connecting to the published port of the database container.
This isn't a totally standard way to connect between containers, though it will work. You should prefer using Docker named networks, which will let you connect to another container using the container's name without manually doing any IP-address lookups. If you really can't move off of the default bridge network, then the standard approach is to --link to the other container, but this entire path is considered outdated.

Use static IP for Docker container to run web app on another network

I deployed a demo web API project on port 8086.I am able to run it on my local browser using localhost:8086/api/controllername and also using local machine IP address for example: 192.0.0.0:8086/api/controllername. I tried accessing the URL from another machine on same LAN and I am able to access it.
But now I want to access it from machines on other networks (publicly).
How can I assign a static IP so that I can use the API from any machine irrespective of network? I created a network using below commands
docker network create --driver bridge --subnet 172.18.0.0/16 -- gateway=172.18.0.1 IPStatic
and
docker network connect --ip 172.18.0.2 IPStatic Containerid.
But unable to access the api using 172.18.0.2:8086/api. Am I missing something? I am using asp.net core web api and I am fairly new to Docker.
You always use the host IP address for this, the same way as if you were running the service outside of Docker. The container-private IP addresses are unreachable from other hosts (and on some platforms aren't even reachable from outside Docker on the same host); it's usually wrong to manually set them or to try to look them up.
If it's specifically important that this service have its own IP address, you need to ask your network administrator to assign an additional address to the host. The docker run -p option can bind a service to only specific network interfaces or addresses. On a Linux host I might run
# Assign the alias address
ifconfig eth0:0 192.0.0.2
# Run the service bound to only this interface
docker run -p 192.0.0.2:80:8080 ...
You might need to reconfigure other services to not listen on this new interface. For Docker services you'd use the same docker run -p option to bind to only the host's primary interface and to localhost (127.0.0.1); configuration for non-Docker services is specific to the service.

Is it possible to assign a static IP address to a docker container after it's creation?

Is it possible to assign a static IP address and hostname to a docker container after it's creation ?
All my container are in the same network (bridge). The docker IP 172.17.0.x assigned by bridge network to my containers change some time after a restart of docker service and I need a static IP to save the communication between container.
Another idea is to associate hostname to container. IP address is not static.
Here a simple way to use docker network to add hostname to existing container.
[link] https://stackoverflow.com/a/41298050/6288254

How to link docker host to container by name

I know how to link two containers, but can I link the host to a container in a similar way?
I have an nginx server on the host, I want it to connect to a container named my-varnish, which is linked to my-apachephp linked to my-mysql.
Currently I either map a port -p 8080:80 or find the bridge IP address (which is different each time I destroy and build a new set of containers). I would like to use the bridge IP by hostname without adding a dyn-dns registration process to each container.
Thoughts?!
Use the Docker run's add host functionality.It adds the host mapping in the container's host file.
From Usage :
--add-host value Add a custom host-to-IP mapping (host:ip) (default [])

docker containers static IP to communicate two different hosts

is it possible to change the ip of docker0 or provide a static IP to docker containers, because by default docker containers have the ip range of 172.17.0.2/16 but my network is 192.168.X.X/24 in this situation on the server container is running there all the containers is able to communicate within servers but from other server this failed to connect.
How do you set up your cluster? Do you use Swarm? If so, you need to use a k/v storage backend to enable communication between two containers hosted on different hosts. Is this what you aim to do, or do you want the host to communicate with the container on the other host?
Anyway, the solution is similar.
I re-writing a tuto for Docker Swarm to pull request it into their Swarm doc, you may want to take a look: https://www.auzias.net/en/docker-network-multihost/
Have a nice day!
problem can be fix by using --network=host
this will allow your container to use the host machine network. for direct accessing your container you can change the ssh port of the container and access your container with the specific port number.
I answered a similar question here
https://stackoverflow.com/a/35359185/4094678
The difference in your case would be to create a netowrk with subnet 192.168.X.X/24 and then assign desired ip addr to container with --ip
Here we can't able to change docker0 Ip address, but we have option to create multiple networks.
Solution 1:
can be by using start container with host network --network=host
Solution2:
we can also start the container by exposing the cluster required port and from another node we can communicate it.
-p hostport:serviceport
Or, Solution3:
We can deploy cluster over docker swarm.

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