I have a server VLAN of 10.101.10.0/24 and my Docker host is 10.101.10.31. How do I configure a bridge network on my Docker host (VM) so that all the containers can connect directly to my LAN network without having to redirect ports around on the default 172.17.0.0/16? I tried searching but all the howtos I've found so far have resulted in losing SSH session which I had to go into the VM from a console to revert the steps I did.
There's multiple ways this can be done. The two I've had most success with are routing a subnet to a docker bridge and using a custom bridge on the host LAN.
Docker Bridge, Routed Network
This has the benefit of only needing native docker tools to configure docker. It has the down side of needing to add a route to your network, which is outside of dockers remit and usually manual (or relies on the "networking team").
Enable IP forwarding
/etc/sysctl.conf: net.ipv4.ip_forward = 1
sysctl -p /etc/sysctl.conf
Create a docker bridge with new subnet on your VM network, say 10.101.11.0/24
docker network create routed0 --subnet 10.101.11.0/24
Tell the rest of the network that 10.101.11.0/24 should be routed via 10.101.10.X where X is IP of your docker host. This is the external router/gateway/"network guy" config. On a linux gateway you could add a route with:
ip route add 10.101.11.0/24 via 10.101.10.31
Create containers on the bridge with 10.101.11.0/24 addresses.
docker run --net routed0 busybox ping 10.101.10.31
docker run --net routed0 busybox ping 8.8.8.8
Then your done. Containers have routable IP addresses.
If you're ok with the network side, or run something like RIP/OSPF on the network or Calico that takes care of routing then this is the cleanest solution.
Custom Bridge, Existing Network (and interface)
This has the benefit of not requiring any external network setup. The downside is the setup on the docker host is more complex. The main interface requires this bridge at boot time so it's not a native docker network setup. Pipework or manual container setup is required.
Using a VM can make this a little more complicated as you are running extra interfaces with extra MAC addresses over the main VM's interface which will need additional "Promiscuous" config first to allow this to work.
The permanent network config for bridged interfaces varies by distro. The following commands outline how to set the interface up and will disappear after reboot. You are going to need console access or a seperate route into your VM as you are changing the main network interface config.
Create a bridge on the host.
ip link add name shared0 type bridge
ip link set shared0 up
In /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE=shared0
TYPE=Bridge
BOOTPROTO=static
DNS1=8.8.8.8
GATEWAY=10.101.10.1
IPADDR=10.101.10.31
NETMASK=255.255.255.0
ONBOOT=yes
Attach the primary interface to the bridge, usually eth0
ip link set eth0 up
ip link set eth0 master shared0
In /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
TYPE=Ethernet
IPV6INIT=no
USERCTL=no
BRIDGE=shared0
Reconfigure your bridge to have eth0's ip config.
ip addr add dev shared0 10.101.10.31/24
ip route add default via 10.101.10.1
Attach containers to bridge with 10.101.10.0/24 addresses.
CONTAINERID=$(docker run -d --net=none busybox sleep 600)
pipework shared1 $CONTAINERID 10.101.10.43/24#10.101.10.Y
Or use a DHCP client inside the container
pipework shared1 $CONTAINERID dhclient
Docker macvlan network
Docker has since added a network driver called macvlan that can make a container appear to be directly connected to the physical network the host is on. The container is attached to a parent interface on the host.
docker network create -d macvlan \
--subnet=10.101.10.0/24 \
--gateway=10.101.10.1 \
-o parent=eth0 pub_net
This will suffer from the same VM/softswitch problems where the network and interface will need be promiscuous with regard mac addresses.
Related
my app live inside the docker log all in-coming traffic from 172.17.0.1
I believe it's named dock0 bridge hub??
is it possible to avoid it? to let the app inside see ourside client real ip?
I also saw a way name network type as host but the docker container will share the same ip with host?
is that possible to do it like host is 192.168.1.101 docker container is 192.168.1.102?
OK.. I found there is a solution, docker have something named macvlan driver.
basicly it's like the br0 for normal homerouter.
it can plug container into the REAL L2 bridge instead of the fake docker0 NAT ("bridge.")
but I can't use it, macvlan only support on linux host, but im using a mac.
I have an environment where I need to run some external software into Docker containers. This software is trying to connect to our product by specific IP address - let's say 192.168.255.2 - and this address is fixed and cannot be changed. Moreover, host IP address must be also set to specific IP - let's say 192.168.255.3.
Product supports 2 ethernet interfaces:
first of them has strict restrictions regarding IP addressing - let's call it "first"
second does not have such restrictions and provides similar functionalities - for this example let's assume that the IP address of this interface is set to 10.1.1.2/24 - let's call it "second"
I need to run simultaneously multiple docker containers, each container shall be connected to one product (1 to 1 relationship).
Things that are run inside containers must think that they're reaching connectivity to product by using "first" network interface (one which have static IP assignment and which cannot be changed).
All I want to do is to create containers with the same IP addresses to pretend that application inside container is using "first" ethernet interface of product and then at host level I want to redirect all traffic using IPTables to "second" interface.
Therefore I have one major problem: how to create multiple docker containers with the same IP address?
From the exact phrasing of your question, docker has the option to share the network stack of another container. Simply run:
docker run -d --name containera yourimage
docker run -d --net container:containera anotherimage
And you'll see that the second container has the same IP interfaces and can even see ports being used by the first container.
I'd recommend instead that you install both interfaces on your docker host and bind to the IP on the host that you need, then don't worry about the actual IP of the container. The result will be much simpler to manage. Here's how you bind to a single IP on the host with ports 8080 and 8888 that's mapped to two different container's port 80:
docker run -d -p 192.168.255.2:8080:80 --name nginx8080 nginx
docker run -d -p 192.168.255.2:8888:80 --name nginx8888 nginx
I'm new to Docker (have been working with KVM earlier). The first problem I ran in to was how to configure a bridged network in Docker. I would to have a similiar configuration as a KVM bridged network. Does anyone know if this is possible?
docker run --network=host
But if what you want is to access your container from outside use the port mapping option.
docker run -p 80:80
You will access your container using the host ip and the port you specified.
Docker internally in linux use iptables to redirect the traffic from your host to the container.
Regards
I'm trying to set up a container with docker.
The container can access the internet while I'm under my home network which doesn't have any filter, but fails to connect while under the university network (I can't even docker run ubuntu ping 8.8.8.8. I just get nothing). From my experience the university network drops everything that's not on port :80 and is not an http/https/ftp(and similar protocols) request.
I can ask for a specific MAC address to not be filtered.
With which MAC address does docker interface with internet?
Does it use my wireless board? I think it creates a new interface, but I have no idea if all the containers traffic goes through it.
Which MAC address should I ask to unlock in order for my containers not to be filtered?
Thanks!
I can ask for a specific MAC address to not be filtered. With which MAC address does docker interface with internet?
When communicating with the outside world, Docker is using the MAC address and source IP address of your host. If you are connected to the University network using your wireless NIC, then this is the NIC that Docker containers use for external connectivity.
Docker creates a bridge device on your system named docker0. All containers connect to this bridge, and use a private range of ip addresses. Communication external to your host happens via NAT rules configured using iptables (you can view them by running iptables -t nat -S). These rules make traffic originating in Docker containers appear to originate from your host instead.
Can I run docker container that will have access to eth1.
DSL provider is connected to eth1.
I have default internet on eth0.
I wish to docker container to dial pppoe on eth1 and apps in docker to use that internet with full access to internet without port mapping.
I don't see any reason why you cannot do what you are attempting. Add the flag
--cap-add=NET_ADMIN
to the docker run command. This will give the container sufficient privileges to create and configure interfaces.
The easiest option is to run with the host's network stack. You won't have any network isolation between containers, but eth1 will be there as if you were running a regular process.
To do this, use docker run --net=host [rest of run command]
It may also be possible to build your own bridge and link a veth from the container to the bridge to eth1. I haven't tried that, nor have I ever tried to control pppoe.