I'm a little bit newbie with Docker. The problem is my server provider changed the public IP recently. When I ran my wordpress container I used the following:
docker run -e WORDPRESS_DB_PASSWORD=xxx --name wordpress-xx --link wordpressdb-xx -p 185.166.xx.xx:8081:80 -v "$PWD/docker/data/wordpress/xx":/var/www/html -d wordpress
How can I change the old IP in order to assign the new one in a container that is already running?
Is it possible to run this containers with localhost IP? For example:
docker run -e WORDPRESS_DB_PASSWORD=xxx --name wordpress-xx --link wordpressdb-xx -p 127.0.0.1:8081:80 -v "$PWD/docker/data/wordpress/xx":/var/www/html -d wordpress
You can also try to save the current container as an image using docker commit and then run the image as a new container with the new IP.
If you have only a single network interface just pass the port only. You can also use the 127.0.0.1 address
See https://docs.docker.com/engine/reference/commandline/run/#publish-or-expose-port--p-expose
Related
I want nginx in a Docker container to host a simple static hello world html website. I want to simply start it with "docker run imagename". In order to do that I added the run parameters to the Dockerfile. The reason I want to do that is that I would like to host the application on Cloud Foundry in a next step. Unfortunately I get the following error when doing it like this.
Dockerfile
FROM nginx:alpine
COPY . /usr/share/nginx/html
EXPOSE 5000
CMD ["nginx -d -p 5000:5000"]
Error
Error starting userland proxy: Bind for 0.0.0.0:5000: unexpected error Permission denied.
From ::
https://docs.docker.com/engine/reference/builder/#expose
EXPOSE does not make the ports of the container accessible to the host. To do that, you must use either the -p flag to publish a range of ports or the -P flag to publish all of the exposed ports. You can expose one port number and publish it externally under another number
CMD ["nginx -d -p 5000:5000"]
You add your dockerfile
FROM nginx:alpine
its already starts nginx.
after you build from your dockerfile
you should use this on
docker run -d -p 5000:5000 <your_image>
Edit:
If you want to use docker port 80 -> machine port 5000
docker run -d -p 5000:80 <your_image>
In my local setup, I can run ...
docker run --name myapp -e HOST=$(docker-machine ip default) --user root myapp
... and then use $HOST to connect to any other container (e.g. one running mongodb).
However, in Travis, docker-machine does not exist. Thus, I cannot simply put that line in my .travis.yml.
How do I get the network IP?
The flag --link adds an entry to /etc/hosts with the ip address of the specified running container
docker run --name myapp --link mongodb:mongodb myapp
However please note that:
The default docker0 bridge network supports the use of port mapping
and docker run --link to allow communications between containers in
the docker0 network. These techniques are cumbersome to set up and
prone to error. While they are still available to you as techniques,
it is better to avoid them and define your own bridge networks
instead.
Another option is using the flag --add-host if you want to add a known ip address
docker run --name myapp --add-host mongodb:10.10.10.1 myapp
Option 2
Create a network
docker network create --subnet=172.18.0.0/16 mynet123
Run mongodb container assigning an static ip
docker run --network mynet123 --ip 172.18.0.22 -d mongodb
Add that ip to the other container
docker run --network mynet123 --add-host mongodb:172.18.0.22 -d myapp
I'm following Digital Ocean's tutorial on how to start a nginx docker container (Currently on Step 4). Currently this is their output:
$ docker run --name docker-nginx -p 80:80 -d nginx
d3ccb73a91985651ec61231bca9f9c716f0dec807e354a29eeef2144f883a01c
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
b91f3ce26553 nginx "nginx -g 'daemon off" About a minute ago Up About a minute 0.0.0.0:80->80/tcp, 443/tcp docker-nginx
But when I run it, this is my output (noticed the different IP of the container):
C:\>docker run --name docker-nginx -p 80:80 -d nginx
d3ccb73a91985651ec61231bca9f9c716f0dec807e354a29eeef2144f883a01c
C:\>docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d3ccb73a9198 nginx "nginx -g 'daemon off" 14 hours ago Up 2 seconds 10.0.75.2:80->80/tcp, 443/tcp docker-nginx
Why does this happen? And how can I get the same results as Digital Ocean's? (Getting the server to start on localhost)
Edit: I'm using Docker for windows (recently released) which apparently runs native using Hyper-V. My output for docker-machine ls is this:
C:\>docker-machine ls
NAME ACTIVE DRIVER STATE URL SWARM DOCKER ERRORS
C:\>
But when I run it, this is my output (noticed the different IP of the
container)
Since this a Windows machine, I assume that you're using Docker Toolbox Docker for Windows. 10.0.75.2 is the IP of the boot2docker virtual machine.
If you are using Windows or Mac OS, you will need some form of virtualization in
order to run Docker. The IP you just saw is the IP of that lightweight virtual machine.
And how can I get the same results as Digital Ocean's? (Getting the
server to start on localhost)
Use a Linux distribution! Also you can enable Expose container ports on localhost in Docker For Windows Settings:
Despite you created the containers in your local machine. These are actually running on a different machine (a virtual machine)
First, check what is the IP of your docker machine (the virtual machine)
$docker-machine ls
NAME ACTIVE DRIVER STATE URL SWARM
default * virtualbox Running tcp://192.168.99.100
Then run curl command (or open a browser) to view the default web site on your nginx web server inside the container
curl http://192.168.99.100:80
if you are using a virtual machine on windows:
docker-machine ip default
https://docs.docker.com/machine/concepts/
When I ran this command for the first time: docker run -d -p 80:80 --name docker-tutorial docker101tutorial
I got this error:
docker: Error response from daemon: Conflict. The container name
"/docker-tutorial" is already in use by container "LONG_CONTAINER_ID".
You have to remove (or rename) that container to be able to reuse that
name.
so, I tried to remove this container using: docker rm -f LONG_CONTAINER_ID
then I did: docker run -d -p 3080:80 --name docker-tutorial docker101tutorial
note 3080:80 instead of 80:80... Had I run this from the docker desktop, I would see this default option below:
I am following the docker official doc"Linking Containers Together". At the bottom of this doc, on the container's /etc/hosts file, it defines ip address for both ends of a link.
$ sudo docker run -t -i --rm --link db:db training/webapp /bin/bash
root#aed84ee21bde:/opt/webapp# cat /etc/hosts
172.17.0.7 aed84ee21bde
. . .
172.17.0.5 db
And then, it says:
If you restart the source container, the linked containers /etc/hosts files will be automatically updated with the source container's new IP address, allowing linked communication to continue.
$ sudo docker restart db
db
$ sudo docker run -t -i --rm --link db:db training/webapp /bin/bash
root#aed84ee21bde:/opt/webapp# cat /etc/hosts
172.17.0.7 aed84ee21bde
. . .
172.17.0.9 db
I am wandering, what about the link created before container 'db' restart, the old recipient's /etc/hosts file still keep 'db' old ip, but after 'db' container's ip changed after it restarted, the /etc/hosts file lost its effect.
There is a known bug in docker that affects some versions of it #6350. Also some versions of docker has this problem when you are using link aliases. So if you upgrade your docker to latest version (currently 1.8.1) the problem can be solved.
I'm trying to set up a docker dnsmasq container so that I can have all my docker containers look up the domain names rather than having hard-coded IPs (if they are on the same host). This fixes an issue with the fact that one cannot alter the /etc/hosts file in docker containers, and this allows me to easily update all my containers in one go, by altering a single file that the dnsmasq container references.
It looks like someone has already done the hard work for me and created a dnsmasq container. Unfortunately, it is not "working" for me. I wrote a bash script to start the container as shown below:
name="dnsmasq_"
timenow=$(date +%s)
name="$name$timenow"
sudo docker run \
-v="$(pwd)/dnsmasq.hosts:/dnsmasq.hosts" \
--name=$name \
-p='127.0.0.1:53:5353/udp' \
-d sroegner/dnsmasq
Before running that, I created the dnsmasq.hosts directory and inserted a single file within it called hosts.txt with the following contents:
192.168.1.3 database.mydomain.com
Unfortunately whenever I try to ping that domain from within:
the host
The dnsmasq container
another container on the same host
I always receive the ping: unknown host error message.
I tried starting the dnsmasq container without daemon mode so I could debug its output, which is below:
dnsmasq: started, version 2.59 cachesize 150
dnsmasq: compile time options: IPv6 GNU-getopt DBus i18n DHCP TFTP conntrack IDN
dnsmasq: reading /etc/resolv.dnsmasq.conf
dnsmasq: using nameserver 8.8.8.8#53
dnsmasq: read /etc/hosts - 7 addresses
dnsmasq: read /dnsmasq.hosts//hosts.txt - 1 addresses
I am guessing that I have not specified the -p parameter correctly when starting the container. Can somebody tell me what it should be for other docker containers to lookup the DNS, or whether what I am trying to do is actually impossible?
The build script for the docker dnsmasq service needs to be changed in order to bind to your server's public IP, which in this case is 192.168.1.12 on my eth0 interface
#!/bin/bash
NIC="eth0"
name="dnsmasq_"
timenow=$(date +%s)
name="$name$timenow"
MY_IP=$(ifconfig $NIC | grep 'inet addr:'| grep -v '127.0.0.1' | cut -d: -f2 | awk '{ print $1}')
sudo docker run \
-v="$(pwd)/dnsmasq.hosts:/dnsmasq.hosts" \
--name=$name \
-p=$MY_IP:53:5353/udp \
-d sroegner/dnsmasq
On the host (in this case ubuntu 12), you need to update the resolv.conf or /etc/network/interfaces file so that you have registered your public IP (eth0 or eth1 device) as the nameserver.
You may want to set a secondary nameserver to be google for whenever the container is not running, by changing the line to be dns-nameservers xxx.xxx.xxx.xxx 8.8.8.8 E.g. there is no comma or another line.
You then need to restart your networking service sudo /etc/init.d/networking restart if you updated the /etc/network/interfaces file so that this auto updates the /etc/resolve.conf file that docker will copy to the container during the build.
Now restart all of your containers
sudo docker stop $CONTAINER_ID
sudo docker start $CONTAINER_ID
This causes their /etc/resolv.conf files update so they point to the new nameserver settings.
DNS lookups in all your docker containers (that you built since making the changes) should now work using your dnsmasq container!
As a side note, this means that docker containers on other hosts can also take advantage of your dnsmasq service on this host as long as their host's nameserver settings is set to using this server's public IP.