completely new to the shell script. I want to run the sql image (image is just there to take a db dump) and take a dump of the db and copy file to the host using shell script.
how i do manually is
1) docker run -it <image_name> bash (this takes in image bash)
2) mysqldump -h <ip> -u <user> -p db > filename.sql
3) docker cp <containerId>:/file/path/within/container /host/path/target (running this in host machine)
doing this i get the dump from container to host manually.
but while making shell script, i am having problem with the point 1) docker run -it <image_name> bash (this takes in image bash) since this takes me to the bash and i have to manually type the command.
how can i do it in the shell script.
any help will be greatly appreciated!
If I understand this correctly, you don't want to type those command manually and instead shell script should execute your command as and when you container is up and running. Now if you can modify sql related Dockerfile and can re-create image then use ENTRYPOINT [and if needed CMD] to execute shell script at startup. Check this link for details on ENTRYPOINT shell script.
Else, if you cannot recreate image then check this post i.e. how to run bash script from run command.
NOTE in both these cases you will have to mount your directory/volume and your sqldump command should copy dump this map volume/directory
You can pass the command to Bash as a parameter:
docker run -it <image_name> --name sqldump bash -c "mysqldump -h <ip> -u <user> -p db > /tmp/filename.sql"
docker cp sqldump:/tmp/filename.sql /path/on/host/filename.sql
Ignore the Docker steps, and just run mysqldump on your host. The -h option is the IP address or DNS name of the host running the database (can be 127.0.0.1 if the container is running on the same host, but not localhost because MySQL misinterprets that); if you mapped the database external port to a non-default port, you also need a -P (capital P) option to specify that port.
For example, if you started the container with
docker run -p 5433:5432 ... mysql:8
then you can take the dump from the host with
mysqldump -h 127.0.0.1 -P 5433 -p db > dump.sql
and not worry about the Docker details at all.
How can I connect to a docker container using its name instead of its IP address using the ping command?
ping <container_name> instead of ping <IP_address>
Check Network-scoped alias. It allows you to ping a container by its name.
ping $(docker inspect -f {{.NetworkSettings.IPAddress}} <container_name>)
I am running Docker (1.10.2) on Windows. I created a script to echo 'Hello World' on my machine and stored it in C:/Users/username/MountTest. I created a new container and mounted this directory (MountTest) as a data volume. The command I ran to do so is shown below:
docker run -t -i --name mounttest -v /c/Users/sarin/MountTest:/home ubuntu /bin/bash
Next, I run the command to execute the script within the container mounttest.
docker exec -it mounttest sh /home/helloworld.sh
The result is as follows:
: not foundworld.sh: 2: /home/helloworld.sh:
Hello World
I get the desired output (echo Hello World) but I want to understand the reason behind the not found errors.
Note: This question might look similar to Run shell script on docker from shared volume, but it addresses permission related issues.
References:
The helloworld.sh file:
#!/bin/sh
echo 'Hello World'
The mounted volumes information is captured below.
Considering the default ENTRYPOINT for the 'ubuntu' image is sh -c, the final command executed on docker exec is:
sh -c 'sh /home/helloworld.sh'
It looks a bit strange and might be the cause of the error message.
Try simply:
docker exec -it mounttest /home/helloworld.sh
# or
docker exec -it mounttest sh -c '/home/helloworld.sh'
Of course, the docker exec should be done in a boot2docker ssh session, simalar to the shell session in which you did a docker run.
Since the docker run opens a bash, you should make a new boot2docker session (docker-machine ssh), and in that new boot2docker shell session, try the docker exec.
Trying docker exec from within the bash made by docker run means trying to do DiD (Docker in Docker). It is not relevant for your test.
I have two docker containers A & B, I want to do is in both containers can ping the other container. How should I do? And in one container, what's ip address should I use to ping the other container?
My OS is ubuntu:14.04, docker version is 1.6.2
You can get the ip-address of containers from bridge by using
"docker network inspect bridge"
then from one container ping the other with the ip address using
"ping -w3 ip-address"
You can get the container's IP address using:
docker inspect -f '{{ .NetworkSettings.IPAddress }}' container1
Then just pass this in to the second container somehow, for example:
docker exec -it container2 bash -c "echo 1.2.3.4 > pingip"
And vice-versa for container2.
You can test using:
docker exec -it container2 bash -c "ping \$(cat pingip)"
I'm perfectly happy with the IP range that docker is giving me by default 176.17.x.x, so I don't need to create a new bridge, I just want to give my containers a static address within that range so I can point client browsers to it directly.
I tried using
RUN echo "auto eth0" >> /etc/network/interfaces
RUN echo "iface eth0 inet static" >> /etc/network/interfaces
RUN echo "address 176.17.0.250" >> /etc/network/interfaces
RUN echo "netmask 255.255.0.0" >> /etc/network/interfaces
RUN ifdown eth0
RUN ifup eth0
from a Dockerfile, and it properly populated the interfaces file, but the interface itself didn't change. In fact, running ifup eth0 within the container gets this error:
RTNETLINK answers: Operation not permitted Failed to bring up eth0
I have already answered this here
https://stackoverflow.com/a/35359185/4094678
but I see now that this question is actually older then the aforementioned one, so I'll copy the answer as well:
Easy with Docker version 1.10.1, build 9e83765.
First you need to create you own docker network (mynet123)
docker network create --subnet=172.18.0.0/16 mynet123
than simply run the image (I'll take ubuntu as example)
docker run --net mynet123 --ip 172.18.0.22 -it ubuntu bash
then in ubuntu shell
ip addr
Additionally you could use
--hostname to specify a hostname
--add-host to add more entries to /etc/hosts
Docs (and why you need to create a network) at https://docs.docker.com/engine/reference/commandline/network_create/
I'm using the method written here from the official Docker documentation and I have confirmed it works:
# At one shell, start a container and
# leave its shell idle and running
$ sudo docker run -i -t --rm --net=none base /bin/bash
root#63f36fc01b5f:/#
# At another shell, learn the container process ID
# and create its namespace entry in /var/run/netns/
# for the "ip netns" command we will be using below
$ sudo docker inspect -f '{{.State.Pid}}' 63f36fc01b5f
2778
$ pid=2778
$ sudo mkdir -p /var/run/netns
$ sudo ln -s /proc/$pid/ns/net /var/run/netns/$pid
# Check the bridge's IP address and netmask
$ ip addr show docker0
21: docker0: ...
inet 172.17.42.1/16 scope global docker0
...
# Create a pair of "peer" interfaces A and B,
# bind the A end to the bridge, and bring it up
$ sudo ip link add A type veth peer name B
$ sudo brctl addif docker0 A
$ sudo ip link set A up
# Place B inside the container's network namespace,
# rename to eth0, and activate it with a free IP
$ sudo ip link set B netns $pid
$ sudo ip netns exec $pid ip link set dev B name eth0
$ sudo ip netns exec $pid ip link set eth0 up
$ sudo ip netns exec $pid ip addr add 172.17.42.99/16 dev eth0
$ sudo ip netns exec $pid ip route add default via 172.17.42.1
Using this approach I run my containers always with net=none and set IP addresses with an external script.
Actually, despite my initial failure, #MarkO'Connor's answer was correct. I created a new interface (docker0) in my host /etc/network/interfaces file, ran sudo ifup docker0 on the host, and then ran
docker run --net=host -i -t ...
which picked up the static IP and assigned it to docker0 in the container.
Thanks!
This worked for me:
docker run --cap-add=NET_ADMIN -d -it myimages/image1 /bin/sh -c "/sbin/ip addr add 172.17.0.8 dev eth0; bash"
Explained:
--cap-add=NET_ADMIN have rights for administering the net (i.e. for the /sbin/ip command)
myimages/image1 image for the container
/bin/sh -c "/sbin/ip addr add 172.17.0.8 dev eth0 ; bash"
Inside the container run ip addr add 172.17.0.8 dev eth0 to add a new ip address 172.17.0.8 to this container (caution: do use a free ip address now and in the future). Then run bash, just to not have the container automatically stopped.
Bonus:
My target scene: setup a distributed app with containers playing different roles in the dist-app. A "conductor container" is able to run docker commands by itself (inside) so to start and stop containers as needed.
Each container is configured to know where to connect to access a particular role/container in the dist-app (so the set of ip's for each role must be known by each partner).
To do this:
"conductor container"
image created with this Dockerfile
FROM pin3da/docker-zeromq-node
MAINTAINER Foobar
# install docker software
RUN apt-get -yqq update && apt-get -yqq install docker.io
# export /var/run/docker.sock so we can connect it in the host
VOLUME /var/run/docker.sock
image build command:
docker build --tag=myimages/conductor --file=Dockerfile .
container run command:
docker run -v /var/run/docker.sock:/var/run/docker.sock --name=conductor1 -d -it myimages/conductor bash
Run containers with different roles.
First (not absolutely necessary) add entries to /etc/hosts to locate partners by ip or name (option --add-host)
Second (obviously required) assign a ip to the running container (use
/sbin/ip in it)
docker run --cap-add=NET_ADMIN --add-host worker1:172.17.0.8 --add-host worker2:172.17.0.9 --name=worker1 -h worker1.example.com -d -it myimages/image1 /bin/sh -c "/sbin/ip addr add 172.17.0.8 dev eth0; bash"
Docker containers by default do not have sufficient privileges to manipulate the network stack. You can try adding --cap-add=NET_ADMIN to the run command to allow this specific capability. Or you can try --privileged=true (grants all rights) for testing.
Another option is to use pipework from the host.
Setup your own bridge (e.g br0)
Start docker with: -b=br0
& with pipework (192.168.1.1 below being the default gateway ip address):
pipework br0 container-name 192.168.1.10/24#192.168.1.1
Edit: do not start with --net=none : this closes container ports.
See further notes
I understood that you are not looking at multi-host networking of containers at this stage, but I believe you are likely to need it soon. Weave would allow you to first define multiple container networks on one host, and then potentially move some containers to another host without loosing the static IP you have assigned to it.
pipework also great, but If you can use hostname other than ip then you can try this script
#!/bin/bash
# This function will list all ip of running containers
function listip {
for vm in `docker ps|tail -n +2|awk '{print $NF}'`;
do
ip=`docker inspect --format '{{ .NetworkSettings.IPAddress }}' $vm`;
echo "$ip $vm";
done
}
# This function will copy hosts file to all running container /etc/hosts
function updateip {
for vm in `docker ps|tail -n +2|awk '{print $NF}'`;
do
echo "copy hosts file to $vm";
docker exec -i $vm sh -c 'cat > /etc/hosts' < /tmp/hosts
done
}
listip > /tmp/hosts
updateip
You just need to run this command everytime you boot up your docker labs
You can find my scripts with additional function here dockerip
For completeness: there's another method suggested on the Docker forums. (Edit: and mentioned in passing by the answer from Андрей Сердюк).
Add the static IP address on the host system, then publish ports to that ip, e.g. docker run -p 192.0.2.1:80:80 -d mywebserver.
Of course that syntax won't work for IPv6 and the documentation doesn't mention that...
It sounds wrong to me: the usual wildcard binds (*:80) on the host theoretically conflict with the container. In practice the Docker port takes precedence and doesn't conflict, because of how it's implemented using iptables. But your public container IP will still respond on all the non-conflicting ports, e.g. ssh.
I discovered that --net=host might not always be the best option, as it might allow users to shut down the host from the container! In any case, it turns out that the reason I couldn't properly do it from inside was because network configuration was designed to be restricted to sessions that begun with the --privileged=true argument.
You can set up SkyDns with service discovery tool - https://github.com/crosbymichael/skydock
Or: Simply create network interface and publish docker container ports in it like here https://gist.github.com/andreyserdjuk/bd92b5beba2719054dfe